WorldWideScience

Sample records for bolted joints

  1. A Modelling Method of Bolt Joints Based on Basic Characteristic Parameters of Joint Surfaces

    Science.gov (United States)

    Yuansheng, Li; Guangpeng, Zhang; Zhen, Zhang; Ping, Wang

    2018-02-01

    Bolt joints are common in machine tools and have a direct impact on the overall performance of the tools. Therefore, the understanding of bolt joint characteristics is essential for improving machine design and assembly. Firstly, According to the experimental data obtained from the experiment, the stiffness curve formula was fitted. Secondly, a finite element model of unit bolt joints such as bolt flange joints, bolt head joints, and thread joints was constructed, and lastly the stiffness parameters of joint surfaces were implemented in the model by the secondary development of ABAQUS. The finite element model of the bolt joint established by this method can simulate the contact state very well.

  2. Optimal tightening process of bolted joints

    Directory of Open Access Journals (Sweden)

    Monville Jean-Michel

    2016-01-01

    Full Text Available Threaded fasteners were developed long time (let’s remember that Archimedes – 287-212 BC – invented the water screw. Nowadays, bolted joints are used in almost all sectors of the industry. But in spite of having been an important machine part for centuries, problems may be encountered with them. They are so common that they are taken for granted and too often, not analyzed as deeply as it should be. The wrong tightening is one of the most frequent causes of ductile rupture and by far the most frequent cause of fatigue failure. The tightening operation is never easy. It is necessary to pay particular attention to the choice of the tightening tool, the process and the control method. The tightening operation may itself cause damage on parts. The tightening load must not be too low, or excessive or not equally distributed among the bolts. These three defects can even be made on the same bolted joint! This impacts badly the performance of the assembly and leads to a shorter lifespan. If insufficient precautions are taken, the real tightening preload on all the bolts will not fit well with the requirements and would be badly distributed. Consequently, the practical conditions are quite different from the hypothesizes which are taken for the initial calculations (analytics or FEM at the design stage. Thus, the results of the calculations of bolted joints cannot be considered as accurate and reliable. Practically, there are several means to tighten a bolt. The two ways most frequently used are torque wrench and hydraulic bolt tensioner. Torque wrench involves exerting a torque to the bolt head or the nut. Hydraulic bolt tensioner applies a traction load directly on the bolt. It is well known that bolt tensioners give better accuracy and homogeneity in the final tightening load than the torque method, but the tension load applied with the tensioner must be higher than the final remaining tightening load. So, the paper focusses on the hydraulic

  3. Study on Fatigue Performance of Composite Bolted Joints with Bolt-Hole Delamination

    Science.gov (United States)

    Liu, M. J.; Yu, S.; Zhao, Q. Y.

    2018-03-01

    Fatigue performance of composite structure with imperfections is a challenging subject at present. Based on cohesive zone method and multi-continuum theory, delamination evolution response and fatigue life prediction of a 3D composite single-lap joint with a bolt-hole have been investigated through computer codes Abaqus and Fe-safe. Results from the comparison of a perfect composite bolted joint with another defect one indicates that a relatively small delamination damage around the bolt hole brings about significant degradation of local material performance. More notably, fatigue life of stress concentration region of composite bolted joints is highly sensitive to external loads, as an increase of 67% cyclic load amplitude leads to an decrease of 99.5% local fatigue life in this study. However, the numerical strategy for solving composite fatigue problems is meaningful to engineering works.

  4. Decision Fusion System for Bolted Joint Monitoring

    Directory of Open Access Journals (Sweden)

    Dong Liang

    2015-01-01

    Full Text Available Bolted joint is widely used in mechanical and architectural structures, such as machine tools, industrial robots, transport machines, power plants, aviation stiffened plate, bridges, and steel towers. The bolt loosening induced by flight load and environment factor can cause joint failure leading to a disastrous accident. Hence, structural health monitoring is critical for the bolted joint detection. In order to realize a real-time and convenient monitoring and satisfy the requirement of advanced maintenance of the structure, this paper proposes an intelligent bolted joint failure monitoring approach using a developed decision fusion system integrated with Lamb wave propagation based actuator-sensor monitoring method. Firstly, the basic knowledge of decision fusion and classifier selection techniques is briefly introduced. Then, a developed decision fusion system is presented. Finally, three fusion algorithms, which consist of majority voting, Bayesian belief, and multiagent method, are adopted for comparison in a real-world monitoring experiment for the large aviation aluminum plate. Based on the results shown in the experiment, a big potential in real-time application is presented that the method can accurately and rapidly identify the bolt loosening by analyzing the acquired strain signal using proposed decision fusion system.

  5. Response surface reconciliation method of bolted joints structure

    Directory of Open Access Journals (Sweden)

    Yunus Mohd Azmi

    2017-01-01

    Full Text Available Structural joining methods such as bolted joints are commonly used for the assembly of structural components due to their simplicity and easy maintenance. Understandably, the dynamic characteristic of bolted joined structure is mainly influenced by the properties of their joints such as preload on the bolts and joints stiffness which alter the measured dynamics response of the structure. Therefore, the need to include the local effect of the bolted joints into the numerical model of the bolted joined structure is vitally important in order to represent the model accurately. In this paper, a few types of connector elements that can be used to represent the bolted joints such as CBAR, CBEAM and CELAS have been investigated numerically and experimentally. The initial numerical results of these element connectors are compared with the experimental results in term of natural frequencies and mode shapes. The comparative evaluation of numerical and the experimental data are performed in order to provide some insights of inaccuracies in the numerical model due to invalid assumption in the numerical modelling such as geometry, material properties, and boundary conditions. The discrepancies between both results (numerical and experimental data are then corrected using the response surface reconciliation method (RSRM through which the finite element model is altered in order to provide closer agreement with the measured data so that it can be used for subsequence analysis.

  6. Image Registration-Based Bolt Loosening Detection of Steel Joints

    Science.gov (United States)

    2018-01-01

    Self-loosening of bolts caused by repetitive loads and vibrations is one of the common defects that can weaken the structural integrity of bolted steel joints in civil structures. Many existing approaches for detecting loosening bolts are based on physical sensors and, hence, require extensive sensor deployment, which limit their abilities to cost-effectively detect loosened bolts in a large number of steel joints. Recently, computer vision-based structural health monitoring (SHM) technologies have demonstrated great potential for damage detection due to the benefits of being low cost, easy to deploy, and contactless. In this study, we propose a vision-based non-contact bolt loosening detection method that uses a consumer-grade digital camera. Two images of the monitored steel joint are first collected during different inspection periods and then aligned through two image registration processes. If the bolt experiences rotation between inspections, it will introduce differential features in the registration errors, serving as a good indicator for bolt loosening detection. The performance and robustness of this approach have been validated through a series of experimental investigations using three laboratory setups including a gusset plate on a cross frame, a column flange, and a girder web. The bolt loosening detection results are presented for easy interpretation such that informed decisions can be made about the detected loosened bolts. PMID:29597264

  7. Image Registration-Based Bolt Loosening Detection of Steel Joints.

    Science.gov (United States)

    Kong, Xiangxiong; Li, Jian

    2018-03-28

    Self-loosening of bolts caused by repetitive loads and vibrations is one of the common defects that can weaken the structural integrity of bolted steel joints in civil structures. Many existing approaches for detecting loosening bolts are based on physical sensors and, hence, require extensive sensor deployment, which limit their abilities to cost-effectively detect loosened bolts in a large number of steel joints. Recently, computer vision-based structural health monitoring (SHM) technologies have demonstrated great potential for damage detection due to the benefits of being low cost, easy to deploy, and contactless. In this study, we propose a vision-based non-contact bolt loosening detection method that uses a consumer-grade digital camera. Two images of the monitored steel joint are first collected during different inspection periods and then aligned through two image registration processes. If the bolt experiences rotation between inspections, it will introduce differential features in the registration errors, serving as a good indicator for bolt loosening detection. The performance and robustness of this approach have been validated through a series of experimental investigations using three laboratory setups including a gusset plate on a cross frame, a column flange, and a girder web. The bolt loosening detection results are presented for easy interpretation such that informed decisions can be made about the detected loosened bolts.

  8. Testing program for burning plasma experiment vacuum vessel bolted joint

    International Nuclear Information System (INIS)

    Hsueh, P.K.; Khan, M.Z.; Swanson, J.; Feng, T.; Dinkevich, S.; Warren, J.

    1992-01-01

    As presently designed, the Burning Plasma Experiment vacuum vessel will be segmentally fabricated and assembled by bolted joints in the field. Due to geometry constraints, most of the bolted joints have significant eccentricity which causes the joint behavior to be sensitive to joint clamping forces. Experience indicates that as a result of this eccentricity, the joint will tend to open at the side closest to the applied load with the extent of the opening being dependent on the initial preload. In this paper analytical models coupled with a confirmatory testing program are developed to investigate and predict the non-linear behavior of the vacuum vessel bolted joint

  9. Comparative study of bolt spacing formulas used in bolted joint designs

    International Nuclear Information System (INIS)

    Bouzid, Abdel-Hakim

    2014-01-01

    Bolted flange joints are the most popular type of connection between pressure vessels and piping equipment. They are very attractive type of connection because they are simple to mount and offer the possibility of disassembly. However, they are very complex structures to design and analyze and often result in leakage failure. One of the raisons is the loss of tightness that results from the uneven distribution of the gasket contact stresses in the radial and circumferential direction. Many factors contribute to such a failure; bolt load non-uniformity, inadequate flange to gasket stiffness, inappropriate bolt spacing requirements or a combinations of some of these. The variation of the contact stress in the circumferential direction between any two bolts is dictated by bolt spacing. This paper is an extension of the work in which the more accurate analytical solution based on the theory of circular beams resting on a linear elastic foundation is used to validate some existing flange bolt spacing formulas and in particular the TEMA formula, Robert's formula and the one recently developed by Koves. The relationship between bolt spacing and the gasket compression modulus, flange thickness and size is deduced from an analysis that considers a maximum tolerated gasket contact stress difference obtained at the bolt and between two bolts. Comparison between these different methods is also provided. - Highlights: • Gasket stress is estimated using theory of circular beams on linear elastic foundation. • TEMA, Robert's and Koves' formulas are compared against the developed model. • A recommendation is made to use Koves' formula for design. • Use a correction factor of 1/(1-ν 2 ) to accommodate small diameter flanges

  10. Analysis on Sealing Reliability of Bolted Joint Ball Head Component of Satellite Propulsion System

    Science.gov (United States)

    Guo, Tao; Fan, Yougao; Gao, Feng; Gu, Shixin; Wang, Wei

    2018-01-01

    Propulsion system is one of the important subsystems of satellite, and its performance directly affects the service life, attitude control and reliability of the satellite. The Paper analyzes the sealing principle of bolted joint ball head component of satellite propulsion system and discuss from the compatibility of hydrazine anhydrous and bolted joint ball head component, influence of ground environment on the sealing performance of bolted joint ball heads, and material failure caused by environment, showing that the sealing reliability of bolted joint ball head component is good and the influence of above three aspects on sealing of bolted joint ball head component can be ignored.

  11. Failure analysis of bolted joints in foam-core sandwich composites

    DEFF Research Database (Denmark)

    Zabihpoor, M.; Moslemian, Ramin; Afshin, M.

    2008-01-01

    This study represents an effort to predict the bearing strength, failure modes, and failure load of bolted joints in foam-core sandwich composites. The studied joints have been used in a light full composite airplane. By using solid laminates, a new design for the joint zone is developed. These s......This study represents an effort to predict the bearing strength, failure modes, and failure load of bolted joints in foam-core sandwich composites. The studied joints have been used in a light full composite airplane. By using solid laminates, a new design for the joint zone is developed...

  12. Optimized bolt tightening strategies for gasketed flanged pipe joints of different sizes

    International Nuclear Information System (INIS)

    Abid, Muhammad; Khan, Ayesha; Nash, David Hugh; Hussain, Masroor; Wajid, Hafiz Abdul

    2016-01-01

    Achieving a proper preload in the bolts of a gasketed bolted flanged pipe joint during joint assembly is considered important for its optimized performance. This paper presents results of detailed non-linear finite element analysis of an optimized bolt tightening strategy of different joint sizes for achieving proper preload close to the target stress values. Industrial guidelines are considered for applying recommended target stress values with TCM (torque control method) and SCM (stretch control method) using a customized optimization algorithm. Different joint components performance is observed and discussed in detail.

  13. Dynamic modeling method of the bolted joint with uneven distribution of joint surface pressure

    Science.gov (United States)

    Li, Shichao; Gao, Hongli; Liu, Qi; Liu, Bokai

    2018-03-01

    The dynamic characteristics of the bolted joints have a significant influence on the dynamic characteristics of the machine tool. Therefore, establishing a reasonable bolted joint dynamics model is helpful to improve the accuracy of machine tool dynamics model. Because the pressure distribution on the joint surface is uneven under the concentrated force of bolts, a dynamic modeling method based on the uneven pressure distribution of the joint surface is presented in this paper to improve the dynamic modeling accuracy of the machine tool. The analytic formulas between the normal, tangential stiffness per unit area and the surface pressure on the joint surface can be deduced based on the Hertz contact theory, and the pressure distribution on the joint surface can be obtained by the finite element software. Futhermore, the normal and tangential stiffness distribution on the joint surface can be obtained by the analytic formula and the pressure distribution on the joint surface, and assigning it into the finite element model of the joint. Qualitatively compared the theoretical mode shapes and the experimental mode shapes, as well as quantitatively compared the theoretical modal frequencies and the experimental modal frequencies. The comparison results show that the relative error between the first four-order theoretical modal frequencies and the first four-order experimental modal frequencies is 0.2% to 4.2%. Besides, the first four-order theoretical mode shapes and the first four-order experimental mode shapes are similar and one-to-one correspondence. Therefore, the validity of the theoretical model is verified. The dynamic modeling method proposed in this paper can provide a theoretical basis for the accurate dynamic modeling of the bolted joint in machine tools.

  14. Efficient finite element modelling for the investigation of the dynamic behaviour of a structure with bolted joints

    Science.gov (United States)

    Omar, R.; Rani, M. N. Abdul; Yunus, M. A.; Mirza, W. I. I. Wan Iskandar; Zin, M. S. Mohd

    2018-04-01

    A simple structure with bolted joints consists of the structural components, bolts and nuts. There are several methods to model the structures with bolted joints, however there is no reliable, efficient and economic modelling methods that can accurately predict its dynamics behaviour. Explained in this paper is an investigation that was conducted to obtain an appropriate modelling method for bolted joints. This was carried out by evaluating four different finite element (FE) models of the assembled plates and bolts namely the solid plates-bolts model, plates without bolt model, hybrid plates-bolts model and simplified plates-bolts model. FE modal analysis was conducted for all four initial FE models of the bolted joints. Results of the FE modal analysis were compared with the experimental modal analysis (EMA) results. EMA was performed to extract the natural frequencies and mode shapes of the test physical structure with bolted joints. Evaluation was made by comparing the number of nodes, number of elements, elapsed computer processing unit (CPU) time, and the total percentage of errors of each initial FE model when compared with EMA result. The evaluation showed that the simplified plates-bolts model could most accurately predict the dynamic behaviour of the structure with bolted joints. This study proved that the reliable, efficient and economic modelling of bolted joints, mainly the representation of the bolting, has played a crucial element in ensuring the accuracy of the dynamic behaviour prediction.

  15. Experimental study of friction in aluminium bolted joints

    Science.gov (United States)

    Croccolo, D.; de Agostinis, M.; Vincenzi, N.

    2010-06-01

    This study aims at developing an experimental tool useful to define accurately the friction coefficients in bolted joints and, therefore, at relating precisely the tightening torque to the bolt preloading force in some special components used in front motorbike suspensions. The components under investigation are some clamped joints made of aluminium alloy. The preloading force is achieved by applying a torque wrench to the bolt head. Some specific specimens have been appropriately designed and realized in order to study the tribological aspects of the tightening phase. Experimental tests have been performed by applying the Design of Experiment (DOE) method in order to obtain a mathematical model for the friction coefficients. Three replicas of a full factorial DOE at two levels for each variable have been carried out. The levels include cast versus forged aluminium alloy, anodized versus spray-painted surface, lubricated versus unlubricated screw, and first tightening (fresh unspoiled surfaces) versus sixth tightening (spoiled surfaces). The study considers M8x1.25 8.8 galvanized screws.

  16. Health monitoring of 90° bolted joints using fuzzy pattern recognition of ultrasonic signals

    International Nuclear Information System (INIS)

    Jalalpour, M; El-Osery, A I; Austin, E M; Reda Taha, M M

    2014-01-01

    Bolted joints are important parts for aerospace structures. However, there is a significant risk associated with assembling bolted joints due to potential human error during the assembly process. Such errors are expensive to find and correct if exposed during environmental testing, yet checking the integrity of individual fasteners after assembly would be a time consuming task. Recent advances in structural health monitoring (SHM) can provide techniques to not only automate this process but also make it reliable. This integrity monitoring requires damage features to be related to physical conditions representing the structural integrity of bolted joints. In this paper an SHM technique using ultrasonic signals and fuzzy pattern recognition to monitor the integrity of 90° bolted joints in aerospace structures is described. The proposed technique is based on normalized fast Fourier transform (NFFT) of transmitted signals and fuzzy pattern recognition. Moreover, experimental observations of a case study on an aluminum 90° bolted joint are presented. We demonstrate the ability of the proposed method to efficiently monitor and indicate bolted joint integrity. (paper)

  17. Experimental study on tunnel lining joints temporarily strengthened by SMA bolts

    International Nuclear Information System (INIS)

    Wu, Bo; Ou, Yunlong

    2014-01-01

    Shield tunnels have been widely used in city metros all over the world. During the long-term period of the metro operation, the joints of shield tunnel’s neighboring segments may degrade due to some environmental factors, leading to the increasing of the joint opening and some resulting adverse consequences. In this paper, a temporary strengthening method by using shape memory alloy (SMA) bolts is proposed and experimentally studied for the joints of neighboring segments, and a revised electric heating method which suits with the strengthening method is presented and experimentally validated for the SMA bolts. The purpose of the proposed temporary strengthening method is to create favorable conditions for the following permanent strengthening. Test results show that: (a) for the joints of shield tunnel’s neighboring segments, the strengthening method can effectively reduce the joint opening, joint deflection, concrete strain in joint’s compression zone, and strain of joint’s steel bolts; (b) the revised electric heating method can be used to heat the SMA rod to a temperature higher than the SMA’s austenite finish temperature quickly, and the average heating rate related to Type 2 inner resistance element is larger than that related to Type 1 inner resistance element; and (c) the reduction percentages of the joint opening increment, joint deflection, concrete strain in joint’s compression zone, and strain of joint’s steel bolts for Specimen I are all larger than those for Specimen II, implying that the less the joint opening is, the more significant the strengthening effect is. (paper)

  18. Behavior of single lap composite bolted joint under traction loading: Experimental investigation

    Science.gov (United States)

    Awadhani, L. V.; Bewoor, Anand

    2018-04-01

    Composite bolted joints are preferred connection in the composite structures to facilitate the dismantling for the replacements/ maintenance work. The joint behavior under tractive forces has been studied in order to understand the safety of the structure designed. The main objective of this paper is to investigate the behavior of single-lap joints in carbon fiber reinforced epoxy composites under traction loading conditions. The experiments were designed to identify the effect of bolt diameter, stacking sequence and loading rate on the properties of the joint. The experimental results show that the parameters influence the joint performance significantly.

  19. Seismic Properties of Moment-resisting Timber Joints with a Combination of Bolts and Nails

    Directory of Open Access Journals (Sweden)

    Awaludin A.

    2011-01-01

    Full Text Available Improvement of cyclic or dynamic performance of timber connections has been intensively conducted since the overall response of wooden structures is merely a function of joint performance. For a bolted joint, filling the lead-hole clearance with epoxy resin or gluing high embedding-strength materials at the interface of the individual timber member are probably the most common methods. This study presents cyclic test results of moment-resisting joints with a combination of bolts and nails. The nails were placed closer to the joint centroid than the bolts, acting as additional fasteners and were expected to improve the seismic performance of the joints. Static-cyclic test results confirmed the increase of joint stiffness and moment resistance due to the additional nails. The nails contribute to the increase of hysteretic damping significantly though pinching behavior or narrowing the hysteresis loops close to zero rotation points was still observed. The results indicated that contribution of nails or bolts on moment resistance and hysteretic damping can be superimposed.

  20. Health Monitoring of Bolted Spherical Joint Connection Based on Active Sensing Technique Using Piezoceramic Transducers

    Directory of Open Access Journals (Sweden)

    Jing Xu

    2018-05-01

    Full Text Available Bolted spherical joints are widely used to form space steel structures. The stiffness and load capacity of the structures are affected by the looseness of bolted spherical joint connections in the structures. The looseness of the connections, which can be caused by fabrication error, low modeling accuracy, and “false twist” in the installation process, may negatively impact the load capacity of the structure and even lead to severe accidents. Furthermore, it is difficult to detect bolted spherical joint connection looseness from the outside since the bolts connect spheres with rods together from the inside. Active sensing methods are proposed in this paper to monitor the tightness status of the bolted spherical connection using piezoceramic transducers. A triangle-on-triangle offset grid composed of bolted spherical joints and steel tube bars was fabricated as the specimen and was used to validate the active sensing methods. Lead Zirconate Titanate (PZT patches were used as sensors and actuators to monitor the bolted spherical joint tightness status. One PZT patch mounted on the central bolted sphere at the upper chord was used as an actuator to generate a stress wave. Another PZT patch mounted on the bar was used as a sensor to detect the propagated waves through the bolted spherical connection. The looseness of the connection can impact the energy of the stress wave propagated through the connection. The wavelet packet analysis and time reversal (TR method were used to quantify the energy of the transmitted signal between the PZT patches by which the tightness status of the connection can be detected. In order to verify the effectiveness, repeatability, and consistency of the proposed methods, the experiments were repeated six times in different bolted spherical connection positions. The experimental results showed that the wavelet packet analysis and TR method are effective in detecting the tightness status of the connections. The

  1. A Mathematical Model for Temperature Induced Loosening due to Radial Expansion of Rectangle Thread Bolted Joints

    Directory of Open Access Journals (Sweden)

    Shiyuan Hou

    2015-01-01

    Full Text Available This paper proposed a mathematical model to investigate the radial expansion induced loosening of rectangle thread bolted joints that were subjected to cyclic temperature variation, which could cause slippage between contact pairs of engaged threads and bolt bearing. Firstly, integral equations were derived for the shear stress components caused by expansion difference, as well as the bearing and thread friction torque components, which depended on the temperature variation. Secondly, the relationship of displacement components was developed based on quasi-static hypotheses. Then, treating the rotation of bolt as plastic elongation, the bolt tension's evolution was obtained by using a one-dimensional bolted joint model. Numerical results showed that the temperature variation decreased the bearing and thread friction torque components, which could lead bolted joint to loosen. Finally, the effects of some associated factors on the progress were discussed.

  2. Experimental verification of lifetime of bolting joints for WWER reactor pressure vessels

    International Nuclear Information System (INIS)

    Brumovsky, M.; Polachova, H.

    1992-01-01

    This paper presents results from experimental verification of cyclic lifetime of bolting joints of M 140x6 mm type used for WWER-440 MW reactor pressure vessels. Bolting joints or real dimensions were tested in a special testing equipment ZS 1000 in Skoda Concern. Stud bolts are made from 25Kh1MF or 38KhN3MFA type of steels. Tests were carried out at operating as well as at room temperatures with coefficient of asymmetry equal to 0.1; one tests was realized with given bending moment. Experimental results have been compared with calculated lifetimes according to ASME, Soviet and CMEA Codes. In all cases calculations give conservative assessments. (orig.)

  3. STAMINA OF A GASKETED BOLTED FLANGED PIPE JOINT UNDER DYNAMIC LOADING

    Directory of Open Access Journals (Sweden)

    Muhammad Abid

    2016-11-01

    Full Text Available Gasketed bolted flange joints are the most critical components in pipelines for their sealing and strength under operating conditions. Most of the work available in literature is under static loading, whereas in industry, cyclic loads are applied due to the vibrating machinery such as motors, pumps, sloshing in offshore applications and in the ships etc. In this study a three dimensional finite element analysis of a gasketed joint is carried out using a spiral wound gasket under bolt up and dynamic operating conditions (internal pressure, axial and bending singly and in combination. The cyclic axial loads are concluded relatively more challenging for both the sealing and strength of the joint. Higher magnitudes of loads and frequencies are also observed more challenging to the joints performance.

  4. A clamping force measurement system for monitoring the condition of bolted joints on railway track joints and points

    International Nuclear Information System (INIS)

    Tesfa, B; Horler, G; Thobiani, F Al; Gu, F; Ball, A D

    2012-01-01

    Many industrial structures associated with railway infrastructures rely on a large number of bolted joint connections to ensure safe and reliable operation of the track and trackside furniture. Significant sums of money are spent annually to repair the damage caused by bolt failures and to maintain the integrity of bolted structures. In the UK, Network Rail (the organization responsible for rail network maintenance and safety) conducts corrective and preventive maintenance manually on 26,000 sets of points (each having approximately 30 bolted joints per set), in order to ensure operational success and safety for the travelling public. Such manual maintenance is costly, disruptive, unreliable and prone to human error. The aim of this work is to provide a means of automatically measuring the clamping force of each individual bolted joint, by means of an instrumented washer. This paper describes the development of a sensor means to be used in the washer, which satisfies the following criteria. 1. Sense changes in the clamping force of the joint and report this fact. 2. Provide compatibility with the large dynamic range of clamping force. 3. Satisfy the limitations in terms of physical size. 4. Provide the means to electronically interface with the washer. 5. Provide a means of powering the washer in situ. 6. Provide a solution at an acceptable cost. Specifically the paper focuses on requirements 1, 2 and 3 and presents the results that support further development of the proposed design and the realization of a pre-prototype system. In the paper, various options for the force sensing element (strain gage, capacitor, piezo-resistive) have been compared, using design optimization techniques. As a result of the evaluation, piezo-resistive sensors in concert with a proprietary force attenuation method, have been found to offer the best performance and cost trade-off The performance of the novel clamping force sensor has been evaluated experimentally and the results show

  5. Flanged joints with contact outside the bolt circle: ASME Part B design rules

    International Nuclear Information System (INIS)

    Rodabaugh, E.C.; Moore, S.E.

    1976-05-01

    The ASME Boiler and Pressure Vessel Code, Section VIII, Division 1, gives rules which are subdivided into ''Part A'' and ''Part B''. Part A covers flanged joints where contact between flanges occurs through a gasket located inside the bolt holes. Part B covers flanged joints with contact outside the bolt holes. This report (a) summarizes the theory for Part B flanged joints, (b) presents examples which show the significant differences between Part A flanged joints and Part B flanged joints, (c) presents the available test data relevant to the characteristics of Part B flanged joints, (d) gives listings of two computer programs which can be used to evaluate the characteristics of Part B flanged joints, and (e) gives recommendations for Code revisions and other aspects of Part B flanged-joint design

  6. Reinforcement of Bolted Timber Joints Using GFRP Sheets in Poplar and Pine Woods

    Directory of Open Access Journals (Sweden)

    Mehrab Madhoushi

    2013-01-01

    Full Text Available Failure in timber structures occurs mainly in crucial points such as joints areas. Therefore, the idea of using composite sheets in timber joints has been intro-duced as a method in order to increase the strength and ductility behaviour of timber joints. This research aims to study the behaviour of bolted joints in poplar and pine woods, which are reinforced by two types of GFRP sheets. A single shear bolted joint consisted of 3 timber members whose length and width were 30 cm in length and 5 cm in width. The thickness of each member was 4 cm for internal part and 2 cm for external part. The employed steel bolt was 10 cm in length and 1 cm in diameter. In this respect, one layer of GFRP sheet was used to be bonded to timber members by using epoxy resin and left between the clamps for 24 hours. They were then kept at room temperature for three weeks. Also the effect of adding a wood veneer on the reinforced joints was investigated. The tensile strength of the reinforced and control samples (un-reinforced joints was measured according to ASTM D5652-92 standard. The results show that the reinforced samples have higher tensile strength compared to that of reinforced joints, although it is not statistically signifcant. Also, two types of sheets infuence the joint behaviour as the reinforced joints display more ductility behaviour.

  7. Best practices for the design and installation of bolted joints

    Energy Technology Data Exchange (ETDEWEB)

    Tetteh-Wayoe, D. [Enbridge Pipelines Inc., Edmonton, AB (Canada)

    2004-07-01

    Bolted joints are often used in liquid pipeline facilities instead of welded joints because they must be frequently disassembled and reassembled as part of regular maintenance. Some bolted joints must retain their seal for the lifetime of the pipeline. As such, the design and installation practices used for bolted connections must have the same integrity as welded pipe. However, repeated flange leaks during hydrotesting has prompted an investigation into flange assembly practices. This paper addressed several aspects of proper flange assembly, including gaskets, lubricants, misalignment, hardened washers, studs and nuts, tools, torque values, tightening procedures, and quality control. A flange assembly procedure was then developed based on best practice recommendations. The objective was to eliminate flange leaks to reduce the effort needed during hydrotesting, and to create a seal that has the highest probability to last for the service life of the flange connection, regardless of service demands. It was concluded that obtaining the specified results depends highly on whether or not the personnel responsible for carrying out the work are well trained. Thirteen measures that can be implemented to improve the integrity of flange connections were listed. It was recommended that a regular review of flange assembly procedures should be performed with vendors, construction and operations personnel. Procedures should be updated when required. 12 refs., 5 tabs., 3 figs.

  8. STUDY, EVALUATION AND TEST OF SUBMODULE TO GIRDER BOLTED JOINT

    CERN Document Server

    Blocki, J; Miralles, Ll; Topilin, N D

    2000-01-01

    The object of the present work is to study the bolted joint submodule to girder. This joint is critical from the point of view of the mechanical integrity of the Tilecal Barrel and Extended Barrel modules and LAr Endcaps. Theoretical analysis, FEM calculations and tests have been carried out in order to find a solution that fulfils the safety factors design criteria.

  9. Research on compliance coefficient calculation for heterogeneity material bolted joints of reactor internal

    International Nuclear Information System (INIS)

    Li Qing; Ren Xin; Zhang Kangda

    2009-01-01

    Using the finite element method, calculation and test are conducted on the bolted joints of four different diameters, and the existing calculation method for bolt compliance coefficient is analyzed. The results indicate that the calculated and test results by finite element method are agreed well, and value D/t f and β have a linear relation. (authors)

  10. Bolt-loosening identification of bolt connections by vision image-based technique

    Science.gov (United States)

    Nguyen, Tuan-Cuong; Huynh, Thanh-Canh; Ryu, Joo-Young; Park, Jae-Hyung; Kim, Jeong-Tae

    2016-04-01

    In this study, an algorithm using image processing techniques is proposed to identify bolt-loosening in bolted connections of steel structures. Its basic concept is to identify rotation angles of nuts from a pictured image, and is mainly consisted of the following 3 steps: (1) taking a picture for a bolt joint, (2) segmenting the images for each nut by image processing techniques, and (3) identifying rotation angle of each nut and detecting bolt-loosening. By using the concept, an algorithm is designed for continuous monitoring and inspection of the bolt connections. As a key imageprocessing technique, Hough transform is used to identify rotation angles of nuts, and then bolt-loosening is detected by comparing the angles before and after bolt-loosening. Then the applicability of the proposed algorithm is evaluated by experimental tests for two lab-scaled models. A bolted joint model which consists of a splice plate and 8 sets of bolts and nuts with 2×4 array is used to simulate inspection of bridge connections, and a model which is consisted of a ring flange and 32 sets of bolt and nut is used to simulate continuous monitoring of bolted connections in wind turbine towers.

  11. The ITER EC H and CD upper launcher: Design, analysis and testing of a bolted joint for the Blanket Shield Module

    Energy Technology Data Exchange (ETDEWEB)

    Gessner, Robby, E-mail: robby.gessner@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, D-76021 Karlsruhe (Germany); Aiello, Gaetano; Grossetti, Giovanni; Meier, Andreas [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, D-76021 Karlsruhe (Germany); Ronden, Dennis [DIFFER – Dutch Institute for Fundamental Energy Physics, P.O. Box 1207, NL-3430 BE Nieuwegein (Netherlands); Spaeh, Peter; Scherer, Theo; Schreck, Sabine; Strauss, Dirk; Vaccaro, Alessandro [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, D-76021 Karlsruhe (Germany)

    2013-10-15

    Highlights: ► The BSM of the ECH Launcher is attached to the Launcher Main Frame by a bolted joint. ► The bolts were designed as “captive” in order to avoid their accidental removal from the joint. ► The bolted flange connection using two sets of 15 captive bolts (M22 × 2) placed along the sides. ► The captive bolt design is based on a concept that uses a dedicated spring ring, a standard spiral spring and a tensioning screw with two threads to secure the bolts in a form-locking stop. -- Abstract: The final design of the structural system for the ITER EC H and CD upper launcher is in progress. Many design features of the preliminary design are under revision with the aim to achieve the built-to-print-status. This paper deals with design and analysis of a bolted joint for the Blanket Shield Module with special perspective on Remote Handling capability. The BSM of the ECH Launcher is attached to the Launcher Main Frame by a bolted joint conceived so that in the Hot Cell Facility, RH maintenance can be performed on internal components. The joint must be capable to resist very high Electro-Magnetic loads from disruptions, while it has to sustain substantial thermal cycling during operation. Thus the need for a rigid and reliable design is essential. Beside the set of pre-stressed bolts the flanges were therefore equipped with additional shear keys to divert radial moments away from the bolts. Main focus of the work performed was the mechanical design of the joint and the assessment of the structural integrity with respect to the loads applied and its capability for maintenance by RH procedures. To fulfill a major aspect of the RH requirements, the bolts were designed as “captive” in order to avoid their accidental removal from the joint. The captive bolt design is based on a concept that uses a dedicated spring ring, a standard spiral spring and a tensioning screw with two threads to secure the bolts in a form-locking stop. The final approval phase of

  12. The ITER EC H and CD upper launcher: Design, analysis and testing of a bolted joint for the Blanket Shield Module

    International Nuclear Information System (INIS)

    Gessner, Robby; Aiello, Gaetano; Grossetti, Giovanni; Meier, Andreas; Ronden, Dennis; Spaeh, Peter; Scherer, Theo; Schreck, Sabine; Strauss, Dirk; Vaccaro, Alessandro

    2013-01-01

    Highlights: ► The BSM of the ECH Launcher is attached to the Launcher Main Frame by a bolted joint. ► The bolts were designed as “captive” in order to avoid their accidental removal from the joint. ► The bolted flange connection using two sets of 15 captive bolts (M22 × 2) placed along the sides. ► The captive bolt design is based on a concept that uses a dedicated spring ring, a standard spiral spring and a tensioning screw with two threads to secure the bolts in a form-locking stop. -- Abstract: The final design of the structural system for the ITER EC H and CD upper launcher is in progress. Many design features of the preliminary design are under revision with the aim to achieve the built-to-print-status. This paper deals with design and analysis of a bolted joint for the Blanket Shield Module with special perspective on Remote Handling capability. The BSM of the ECH Launcher is attached to the Launcher Main Frame by a bolted joint conceived so that in the Hot Cell Facility, RH maintenance can be performed on internal components. The joint must be capable to resist very high Electro-Magnetic loads from disruptions, while it has to sustain substantial thermal cycling during operation. Thus the need for a rigid and reliable design is essential. Beside the set of pre-stressed bolts the flanges were therefore equipped with additional shear keys to divert radial moments away from the bolts. Main focus of the work performed was the mechanical design of the joint and the assessment of the structural integrity with respect to the loads applied and its capability for maintenance by RH procedures. To fulfill a major aspect of the RH requirements, the bolts were designed as “captive” in order to avoid their accidental removal from the joint. The captive bolt design is based on a concept that uses a dedicated spring ring, a standard spiral spring and a tensioning screw with two threads to secure the bolts in a form-locking stop. The final approval phase of

  13. Device for measuring hole elongation in a bolted joint

    Science.gov (United States)

    Wichorek, Gregory R. (Inventor)

    1987-01-01

    A device to determine the operable failure mode of mechanically fastened lightweight composite joints by measuring the hole elongation of a bolted joint is disclosed. The double-lap joint test apparatus comprises a stud, a test specimen having a hole, two load transfer plates, and linear displacement measuring instruments. The test specimen is sandwiched between the two load transfer plates and clamped together with the stud. Spacer washers are placed between the test specimen and each load transfer plate to provide a known, controllable area for the determination of clamping forces around the hole of the specimen attributable to bolt torque. The spacer washers also provide a gap for the mounting of reference angles on each side of the test specimen. Under tensile loading, elongation of the hole of the test specimen causes the stud to move away from the reference angles. This displacement is measured by the voltage output of two linear displacement measuring instruments that are attached to the stud and remain in contact with the reference angles throughout the tensile loading. The present invention obviates previous problems in obtaining specimen deformation measurements by monitoring the reference angles to the test specimen and the linear displacement measuring instruments to the stud.

  14. Application of FE-analysis in Design and Verification of Bolted Joints according to VDI 2230 at CERN

    CERN Document Server

    AUTHOR|(CDS)2225945; Dassa, Luca; Welo, Torgeir

    This thesis investigates how finite element analysis (FEA) can be used to simplify and improve analysis of bolted joints according to the guideline VDI 2230. Some aspects of how FEA can be applied to aid design and verification of bolted joints are given in the guideline, but not in a streamlined way that makes it simple and efficient to apply. The scope of this thesis is to clarify how FEA and VDI 2230 can be combined in analysis of bolted joints, and to present a streamlined workflow. The goal is to lower the threshold for carrying out such combined analysis. The resulting benefits are improved analysis validity and quality, and improved analysis efficiency. A case from the engineering department at CERN, where FEA has been used in analysis of bolted joints is used as basis to identify challenges in combining FEA and VDI 2230. This illustrates the need for a streamlined analysis strategy and well described workflow. The case in question is the Helium vessel (pressure vessel) for the DQW Crab Cavities, whi...

  15. Mathematical representation of bolted-joint stiffness: A new suggested model

    Energy Technology Data Exchange (ETDEWEB)

    Haidar, Nawras; Obeed, Salwan; Jawad, Mohamed [College of Engineering, University of Babylon, Babel (Iraq)

    2011-11-15

    Joint member stiffness in a bolted connection directly influences the safety of a design in regard to both static and fatigue loading, as well as in the prevention of separation in the connection. This work provides a new simple model for computing the member stiffness in bolted connections for both fully and partially developed stress envelope fields. The new model is built using a stress distribution polynomial of third order. Finite element analysis (FEA) is performed for some joints geometries, and the results are used to estimate the best analytical envelope angle in the proposed analytical model that gives suitable convergence between the compared results. An experimental effort is exerted to validate the accuracy of a suggested model. When analytical results are compared with FEA results and experimental data, the maximum absolute percentage errors are found to be 2.69 and 14.69, respectively. Also, a good agreement is obtained when the analytical results are compared with other researchers' results.

  16. Study of failure mechanism of double-lap joints of steel to FRP by bolt and resin

    Directory of Open Access Journals (Sweden)

    Amir Hossein Zakeri

    2017-05-01

    Full Text Available In this study, the behavior of joints in two sides of steel coat which are screwed to the composite plate, and joints of two sides of compound steel coat (bolted and bonded to the composite plate has been studied. In the standards, distance of mechanical bolts from the edges and the distance of mechanical bolts from each other have been discussed. Different distances in the range of the standards determined for the distance of screws from edges and screws from each other. In this paper, the screw joints and the combined joints with different terminal distances for screws from the edges are modeled and studied. The results showed the basic effects of the terminal distance of the screw from the connection edges on the resistance and mechanism of break of screw joints. In combined joints, the terminal distance of the screw had trivial effects in the resistance and mechanism of joint break. In addition, overlap length of the connection elements on increase of joint resistance analyzed and studied. To do so, a combined joint with configuration of two steel plates and one CFRP/GFRP composite plates which were joined by two screws and adhesive layers with different overlap were modeled. The results showed the direct relationship between increase of overlap length and increase in resistance of the joint. Finally, a design guide to be used in practice was proposed.

  17. Stress analysis of closure bolts for shipping casks

    International Nuclear Information System (INIS)

    Mok, G.C.; Fischer, L.E.; Hsu, S.T.

    1993-01-01

    This report specifies the requirements and criteria for stress analysis of closure bolts for shipping casks containing nuclear spent fuels or high level radioactive materials. The specification is based on existing information conceming the structural behavior, analysis, and design of bolted joints. The approach taken was to extend the ASME Boiler and Pressure Vessel Code requirements and criteria for bolting analysis of nuclear piping and pressure vessels to include the appropriate design and load characteristics of the shipping cask. The characteristics considered are large, flat, closure lids with metal-to-metal contact within the bolted joint; significant temperature and impact loads; and possible prying and bending effects. Specific formulas and procedures developed apply to the bolt stress analysis of a circular, flat, bolted closure. The report also includes critical load cases and desirable design practices for the bolted closure, an in-depth review of the structural behavior of bolted joints, and a comprehensive bibliography of current information on bolted joints

  18. Self-healing bolted joint employing a shape memory actuator

    Science.gov (United States)

    Muntges, Daniel E.; Park, Gyuhae; Inman, Daniel J.

    2001-08-01

    This paper is a report of an initial investigation into the active control of preload in the joint using a shape memory actuator around the axis of the bolt shaft. Specifically, the actuator is a cylindrical Nitinol washer that expands axially when heated, according to the shape memory effect. The washer is actuated in response to an artificial decrease in torque. Upon actuation, the stress generated by its axial strain compresses the bolted members and creates a frictional force that has the effect of generating a preload and restoring lost torque. In addition to torque wrenches, the system in question was monitored in all stages of testing using piezoelectric impedance analysis. Impedance analysis drew upon research techniques developed at Center for Intelligent Material Systems and Structures, in which phase changes in the impedance of a self-sensing piezoceramic actuator correspond to changes in joint stiffness. Through experimentation, we have documented a successful actuation of the shape memory element. Due to complexity of constitutive modeling, qualitative analysis by the impedance method is used to illustrate the success. Additional considerations encountered in this initial investigation are made to guide further thorough research required for the successful commercial application of this promising technique.

  19. Lightweight structural design of a bolted case joint for the space shuttle solid rocket motor

    Science.gov (United States)

    Dorsey, John T.; Stein, Peter A.; Bush, Harold G.

    1988-01-01

    The structural design of a bolted joint with a static face seal which can be used to join Space Shuttle Solid Rocket Motor (SRM) case segments is given. Results from numerous finite element parametric studies indicate that the bolted joint meets the design requirement of preventing joint opening at the O-ring locations during SRM pressurization. A final design recommended for further development has the following parameters: 180 one-in.-diam. studs, stud centerline offset of 0.5 in radially inward from the shell wall center line, flange thickness of 0.75 in, bearing plate thickness of 0.25 in, studs prestressed to 70 percent of ultimate load, and the intermediate alcove. The design has a mass penalty of 1096 lbm, which is 164 lbm greater than the currently proposed capture tang redesign.

  20. Structural design of an in-line bolted joint for the space shuttle solid rocket motor case segments

    Science.gov (United States)

    Dorsey, John T.; Stein, Peter A.; Bush, Harold G.

    1987-01-01

    Results of a structural design study of an in-line bolted joint concept which can be used to assemble Space Shuttle Solid Rocket Motor (SRM) case segments are presented. Numerous parametric studies are performed to characterize the in-line bolted joint behavior as major design variables are altered, with the primary objective always being to keep the inside of the joint (where the O-rings are located) closed during the SRM firing. The resulting design has 180 1-inch studs, an eccentricity of -0.5 inch, a flange thickness of 3/4 inch, a bearing plate thickness of 1/4 inch, and the studs are subjected to a preload which is 70% of ultimate. The mass penalty per case segment joint for the in-line design is 346 lbm more than the weight penalty for the proposed capture tang fix.

  1. Reliability aspects of a composite bolted scarf joint. [in wing skin splice

    Science.gov (United States)

    Reed, D. L.; Eisenmann, J. R.

    1975-01-01

    The design, fabrication, static test, and fatigue test of both tension and compression graphite-epoxy candidates for a wing splice representative of a next-generation transport aircraft was the objective of the reported research program. A single-scarf bolted joint was selected as the design concept. Test specimens were designed and fabricated to represent an upper-surface and a lower-surface panel containing the splice. The load spectrum was a flight-by-flight random-load history including ground-air-ground loads. The results of the fatigue testing indicate that, for this type of joint, the inherent fatigue resistance of the laminate is reflected in the joint behavior and, consequently, the rate of damage accumulation is very slow under realistic fatigue loadings.

  2. Evaluation of long-term relaxation for high-strength bolted connections

    International Nuclear Information System (INIS)

    Nah, H. S.; Lee, H. J.; Kim, K. S.

    2010-01-01

    It is general that the clamping forces of high-strength bolts diminish within a certain time period after the initial clamping force. In case that special treatments are applied on a faying surface, the clamping force is relaxed severely. Tests were conducted for slip critical joints subjected to various faying surface parameters. The candidates for bolt were two kinds: Korean Standard and American Standard. Relaxation occurred for slip resistant joints with an uncoated surface that had been shot-blasted, cleaned, milled or rusted. In case of ASTM hexagon bolts, the initial clamping force dropped from 7.9% to 13.6% after 1, 000 hours while relaxation ratio was the range from 8.7% to 15.4% for KS bolts. For ASTM hexagon bolt joints with a 5 mil thick zinc coating, the clamping force of the bolts decreased 15.0%, while relaxation ratio was 12.85% for KS bolts. For 4.9 mil thick red lead painted treatment, the relaxation ratio was 18.7% for ASTM hexagon bolt, 34.9% for KS bolts. Regardless of faying surface treatments, the first week charged at least 86% of total relaxation from this test. (authors)

  3. Multi-field coupled sensing network for health monitoring of composite bolted joint

    Science.gov (United States)

    Wang, Yishou; Qing, Xinlin; Dong, Liang; Banerjee, Sourav

    2016-04-01

    Advanced fiber reinforced composite materials are becoming the main structural materials of next generation of aircraft because of their high strength and stiffness to weight ratios, and excellent designability. As key components of large composite structures, joints play important roles to ensure the integrity of the composite structures. However, it is very difficult to analyze the strength and failure modes of composite joints due to their complex nonlinear coupling factors. Therefore, there is a need to monitor, diagnose, evaluate and predict the structure state of composite joints. This paper proposes a multi-field coupled sensing network for health monitoring of composite bolted joints. Major work of this paper includes: 1) The concept of multifunctional sensor layer integrated with eddy current sensors, Rogowski coil and arrayed piezoelectric sensors; 2) Development of the process for integrating the eddy current sensor foil, Rogowski coil and piezoelectric sensor array in multifunctional sensor layer; 3) A new concept of smart composite joint with multifunctional sensing capability. The challenges for building such a structural state sensing system and some solutions to address the challenges are also discussed in the study.

  4. Experimental and Numerical Investigations of Fretting Fatigue Behavior for Steel Q235 Single-Lap Bolted Joints

    Directory of Open Access Journals (Sweden)

    Yazhou Xu

    2016-01-01

    Full Text Available This work aims to investigate the fretting fatigue life and failure mode of steel Q235B plates in single-lap bolted joints. Ten specimens were prepared and tested to fit the S-N curve. SEM (scanning electron microscope was then employed to observe fatigue crack surfaces and identify crack initiation, crack propagation, and transient fracture zones. Moreover, a FEM model was established to simulate the stress and displacement fields. The normal contact stress, tangential contact stress, and relative slipping displacement at the critical fretting zone were used to calculate FFD values and assess fretting fatigue crack initiation sites, which were in good agreement with SEM observations. Experimental results confirmed the fretting fatigue failure mode for these specimens. It was found that the crack initiation resulted from wear regions at the contact surfaces between plates, and fretting fatigue cracks occurred at a certain distance away from hole edges. The proposed FFD-N relationship is an alternative approach to evaluate fretting fatigue life of steel plates in bolted joints.

  5. Tapping and listening: a new approach to bolt looseness monitoring

    Science.gov (United States)

    Kong, Qingzhao; Zhu, Junxiao; Ho, Siu Chun Michael; Song, Gangbing

    2018-07-01

    Bolted joints are among the most common building blocks used across different types of structures, and are often the key components that sew all other structural parts together. Monitoring and assessment of looseness in bolted structures is one of the most attractive topics in mechanical, aerospace, and civil engineering. This paper presents a new percussion-based non-destructive approach to determine the health condition of bolted joints with the help of machine learning. The proposed method is very similar to the percussive diagnostic techniques used in clinical examinations to diagnose the health of patients. Due to the different interfacial properties among the bolts, nuts and the host structure, bolted joints can generate unique sounds when it is excited by impacts, such as from tapping. Power spectrum density, as a signal feature, was used to recognize and classify recorded tapping data. A machine learning model using the decision tree method was employed to identify the bolt looseness level. Experiments demonstrated that the newly proposed method for bolt looseness detection is very easy to implement by ‘listening to tapping’ and the monitoring accuracy is very high. With the rapid in robotics, the proposed approach has great potential to be implemented with intimately weaving robotics and machine learning to produce a cyber-physical system that can automatically inspect and determine the health of a structure.

  6. Experimental study of bolted connections using light gauge channel sections and packing plates at the joints

    Science.gov (United States)

    Kulkarni, Ravindra B.; Vaghe, Vishal M.

    2014-12-01

    Cold-formed structural members are being used more widely in routine structural design as the world steel industry moves from the production of hot-rolled section and plate to coil and strip, often with galvanized and/or painted coatings. Steel in this form is more easily delivered from the steel mill to the manufacturing plant where it is usually cold-rolled into open and closed section members. In the present experimental study, the use of packing plate at the joints in cold-formed channel sections may increase the load carrying capacity and also reduce the buckling of unconnected cold form channel steel plate at joints. The present study focuses on examining the experimental investigation to use mild steel as a packing plate with cold-formed channel sections by bolted connection at the joints and the connection subjected to axial tension. Series of tests are carried out with increase in the thickness of packing plate and results are observed and analyzed. Total Twelve experimental tests have been carried out on cold-formed channel tension members fastened with single as well as three numbers of bolts at the connection and from the observations the strength of the joint is increased by increasing the various thicknesses of packing plates and also the buckling of unconnected leg of channel specimen is reduced. It is analyzed by plotting the entire load versus elongation path, so that the behavior of the connection is examined.

  7. Mechanics of Re-Torquing in Bolted Flange Connections

    Science.gov (United States)

    Gordon, Ali P.; Drilling Brian; Weichman, Kyle; Kammerer, Catherine; Baldwin, Frank

    2010-01-01

    It has been widely accepted that the phenomenon of time-dependent loosening of flange connections is a strong consequence of the viscous nature of the compression seal material. Characterizing the coupled interaction between gasket creep and elastic bolt stiffness has been useful in predicting conditions that facilitate leakage. Prior advances on this sub-class of bolted joints has lead to the development of (1) constitutive models for elastomerics, (2) initial tightening strategies, (3) etc. The effect of re-torque, which is a major consideration for typical bolted flange seals used on the Space Shuttle fleet, has not been fully characterized, however. The current study presents a systematic approach to characterizing bolted joint behavior as the consequence of sequentially applied torques. Based on exprimenta1 and numerical results, the optimal re-torquing parameters have been identified that allow for the negligible load loss after pre-load application

  8. A Synthetic Phased Array Surface Acoustic Wave Sensor for Quantifying Bolt Tension

    Directory of Open Access Journals (Sweden)

    Rasim Guldiken

    2012-09-01

    Full Text Available In this paper, we report our findings on implementing a synthetic phased array surface acoustic wave sensor to quantify bolt tension. Maintaining proper bolt tension is important in many fields such as for ensuring safe operation of civil infrastructures. Significant advantages of this relatively simple methodology is its capability to assess bolt tension without any contact with the bolt, thus enabling measurement at inaccessible locations, multiple bolt measurement capability at a time, not requiring data collection during the installation and no calibration requirements. We performed detailed experiments on a custom-built flexible bench-top experimental setup consisting of 1018 steel plate of 12.7 mm (½ in thickness, a 6.4 mm (¼ in grade 8 bolt and a stainless steel washer with 19 mm (¾ in of external diameter. Our results indicate that this method is not only capable of clearly distinguishing properly bolted joints from loosened joints but also capable of quantifying how loose the bolt actually is. We also conducted detailed signal-to-noise (SNR analysis and showed that the SNR value for the entire bolt tension range was sufficient for image reconstruction.

  9. Calculation of parameters of combined frame and roof bolting

    Science.gov (United States)

    Ivanov, S. I.; Titov, N. V.; Privalov, A. A.; Trunov, I. T.; Sarychev, V. I.

    2017-10-01

    The paper presents the method of calculation of the combined frame and roof bolting. Recommendations on providing joint operation of roof bolting with steel support frames are given. Graphs for determining standard rock movement, as well as for defining proof load on the yielding support, were developed.

  10. Bolted Flanged Connection for Critical Plant/Piping Systems

    International Nuclear Information System (INIS)

    Efremov, Anatoly

    2006-01-01

    A novel type of Bolted Flanged Connection with bolts and gasket manufactured on a basis of advanced Shape Memory Alloys is examined. Presented approach combined with inverse flexion flange design of plant/piping joint reveals a significant increase of internal pressure under conditions of a variety of operating temperatures relating to critical plant/piping systems. (author)

  11. Improved bolt models for use in global analyses of storage and transportation casks subject to extra-regulatory loading

    International Nuclear Information System (INIS)

    Kalan, R.J.; Ammerman, D.J.; Gwinn, K.W.

    2004-01-01

    Transportation and storage casks subjected to extra-regulatory loadings may experience large stresses and strains in key structural components. One of the areas susceptible to these large stresses and strains is the bolted joint retaining any closure lid on an overpack or a canister. Modeling this joint accurately is necessary in evaluating the performance of the cask under extreme loading conditions. However, developing detailed models of a bolt in a large cask finite element model can dramatically increase the computational time, making the analysis prohibitive. Sandia National Laboratories used a series of calibrated, detailed, bolt finite element sub-models to develop a modified-beam bolt-model in order to examine the response of a storage cask and closure to severe accident loadings. The initial sub-models were calibrated for tension and shear loading using test data for large diameter bolts. Next, using the calibrated test model, sub-models of the actual joints were developed to obtain force-displacement curves and failure points for the bolted joint. These functions were used to develop a modified beam element representation of the bolted joint, which could be incorporated into the larger cask finite element model. This paper will address the modeling and assumptions used for the development of the initial calibration models, the joint sub-models and the modified beam model

  12. The Fatigue Characteristics of Bolted Lap Joints of 24S-T Alclad Sheet Materials

    Science.gov (United States)

    1946-10-01

    extremely close bolt fits are needed to o%tain maximum life of bolt ~oint~ under repeated etreseeci. -. Szvzral ty~+?+s of bolt patterns hava been tegted...Memorial Institute on spec~meris of 0.102-i.nch sheet. In particular, figure 4 shows, on a load- life diagram, . results of tests Qn single-bolt...results of tests at the Univer- sity of’ il~~nols on single—bolt specimens, Tables 10 and 11 give reeults of tests, made at the U“ uiversity of Illino~8 , on

  13. Nonlinear Modeling and Identification of an Aluminum Honeycomb Panel with Multiple Bolts

    Directory of Open Access Journals (Sweden)

    Yongpeng Chu

    2016-01-01

    Full Text Available This paper focuses on the nonlinear dynamics modeling and parameter identification of an Aluminum Honeycomb Panel (AHP with multiple bolted joints. Finite element method using eight-node solid elements is exploited to model the panel and the bolted connection interface as a homogeneous, isotropic plate and as a thin layer of nonlinear elastic-plastic material, respectively. The material properties of a thin layer are defined by a bilinear elastic plastic model, which can describe the energy dissipation and softening phenomena in the bolted joints under nonlinear states. Experimental tests at low and high excitation levels are performed to reveal the dynamic characteristics of the bolted structure. In particular, the linear material parameters of the panel are identified via experimental tests at low excitation levels, whereas the nonlinear material parameters of the thin layer are updated by using the genetic algorithm to minimize the residual error between the measured and the simulation data at a high excitation level. It is demonstrated by comparing the frequency responses of the updated FEM and the experimental system that the thin layer of bilinear elastic-plastic material is very effective for modeling the nonlinear joint interface of the assembled structure with multiple bolts.

  14. The ITER EC H&CD upper launcher: Design, analysis and testing of a bolted joint for the Blanket Shield Module

    NARCIS (Netherlands)

    Gessner, R.; Aiello, G.; Grossetti, G.; Meier, A.; Ronden, D.; Spaeh, P.; Scherer, T.; Schreck, S.; Strauss, D.; Vaccaro, A.

    2013-01-01

    The final design of the structural system for the ITER EC H&CD upper launcher is in progress. Many design features of the preliminary design are under revision with the aim to achieve the built-to-print-status. This paper deals with design and analysis of a bolted joint for the Blanket Shield

  15. Bolting applications

    International Nuclear Information System (INIS)

    Czajkowski, C.J.

    1984-05-01

    An investigation of bolting practices specific to the nuclear industry was performed. The report covered a large spectrum of topics e.g., bolts embedded in concrete, specifications, inspection of bolting, both at receipt and inservice. Plots of preload versus yield strength for different bolting materials in different environments are presented as well as information relative to the stress corrosion cracking resistance of the more recent reactor internals bolting materials A286 and Inconel X-750. Part of the report contains input by Standard Pressed Steel Inc. (a bolting consultant) relative to bolting standards, cottering methods and potential areas for bolting improvement

  16. Piezoelectric Bolt Breakers and Bolt Fatigue Testers

    Science.gov (United States)

    Sherrit, Stewart; Badescu, Mircea; Bar-Cohen, Yoseph; Barengoltz, Jack; Heckman, Vanessa

    2008-01-01

    A proposed family of devices for inducing fatigue in bolts in order to break the bolts would incorporate piezoelectric actuators into resonant fixtures as in ultrasonic/ sonic drills/corers and similar devices described in numerous prior NASA Tech Briefs articles. These devices were originally intended primarily for use as safer, more-reliable, more-versatile alternatives to explosive bolts heretofore used to fasten spacecraft structures that must subsequently be separated from each other quickly on command during flight. On Earth, these devices could be used for accelerated fatigue testing of bolts. Fatigue theory suggests that a bolt subjected to both a constant-amplitude dynamic (that is, oscillatory) stress and a static tensile stress below the ultimate strength of the bolt material will fail faster than will a bolt subjected to only the dynamic stress. This suggestion would be applied in a device of the proposed type. The device would be designed so that the device and the bolt to be fatigue-tested or broken would be integral parts of an assembly (see figure). The static tension in the tightened bolt would apply not only the clamping force to hold the joined structures (if any) together but also the compression necessary for proper operation of the piezoelectric actuators as parts of a resonant structural assembly. The constant-amplitude dynamic stress would be applied to the bolt by driving the piezoelectric actuators with a sinusoidal voltage at the resonance frequency of longitudinal vibration of the assembly. The amplitude of the excitation would be made large enough so that the vibration would induce fatigue in the bolt within an acceptably short time. In the spacecraft applications or in similar terrestrial structural-separation applications, devices of the proposed type would offer several advantages over explosive bolts: Unlike explosive bolts, the proposed devices would be reusable, could be tested before final use, and would not be subject to

  17. Review of Bolt Preload and Torque for Assembling Threaded Fasteners in Nuclear Power Plant

    International Nuclear Information System (INIS)

    Lee, Yong-Sung; Lee, Jae-Gon; Kang, Yong-Chul; Shin, Ki-Jong

    2007-01-01

    There are numerous threaded fasteners such as bolts, studs, nuts, cap screws and anchor bolts used in nuclear power plants(NPPs). The major applications of threaded fasteners are reactor coolant pressure boundary components, their internals and supports. With the increase of commercial operation period of NPPs, the incidents caused by degradation of threaded fasteners have been occurred. A large number of reported incidents are involved in the pressure boundary and major component supports. The degradation and failure of threaded fasteners is affected by material, preload and torque value at assembly, bolting practice, etc. It is very important to select appropriate bolt preload and decide assembly torque value because torque control using a torque wrench is the most common method in a power plant to assemble a bolted flange connection. Many researches have been studied to define the proper bolt preload and desired torque value with regard to the integrity of bolted connections including pressure boundary joints by EPRI and other plant industry. But in domestic NPPs, considerably few works are done on the bolted joint assembly in spite of increasing events related with threaded faster. Therefore we investigated degradation or failure of the threaded fasteners used in NPPs, also examined the codes, standards and technical trends concerning bolt preload and assembly torque in NPPs. It is the purpose of this study to provide proper technical information for assuring integrity of the threaded fasteners

  18. Preloading of bolted connections in nuclear reactor component supports

    International Nuclear Information System (INIS)

    Yahr, G.T.

    1984-10-01

    A number of failures of threaded fasteners in nuclear reactor component supports have been reported. Many of those failures were attributed to stress corrosion cracking. This report discusses how stress corrosion cracking can be avoided in bolting by controlling the maximum bolt preloads so that the sustained stresses in the bolts are below the level required to cause stress corrosion cracking. This is a basic departure from ordinary bolted joint design where the only limits on preload are on the minimum preload. Emphasis is placed on the importance of detailed analysis to determine the acceptable range of preload and the selection of a method for measuring the preload that is sufficiently accurate to ensure that the preload is actually within the acceptable range. Procedures for determining acceptable preload range are given, and the accuracy of various methods of measuring preload is discussed

  19. Preloading of bolted connections in nuclear reactor component supports

    Energy Technology Data Exchange (ETDEWEB)

    Yahr, G T

    1984-10-01

    A number of failures of threaded fasteners in nuclear reactor component supports have been reported. Many of those failures were attributed to stress corrosion cracking. This report discusses how stress corrosion cracking can be avoided in bolting by controlling the maximum bolt preloads so that the sustained stresses in the bolts are below the level required to cause stress corrosion cracking. This is a basic departure from ordinary bolted joint design where the only limits on preload are on the minimum preload. Emphasis is placed on the importance of detailed analysis to determine the acceptable range of preload and the selection of a method for measuring the preload that is sufficiently accurate to ensure that the preload is actually within the acceptable range. Procedures for determining acceptable preload range are given, and the accuracy of various methods of measuring preload is discussed.

  20. 30 CFR 18.31 - Enclosures-joints and fastenings.

    Science.gov (United States)

    2010-07-01

    ... used, it refers to a machine bolt or a cap screw, and for either of these studs may be substituted...″ 0.006″ 0.006″ Maximum bolt 7,8 spacing; joints all in one plane (16) (16) (16) Maximum bolt spacing; joints, portions of which are in different planes (9) (9) (9) Minimum diameter of bolt (without regard to...

  1. Wireless Impedance-Based SHM for Bolted Connections via Multiple PZT-Interfaces

    International Nuclear Information System (INIS)

    Nguyen, Khac Duy; Kim, Jeong Tae

    2011-01-01

    This study presents a structural health monitoring(SHM) method for bolted connections by using multi-channel wireless impedance sensor nodes and multiple PZT-interfaces. To achieve the objective, the following approaches are implemented. Firstly, a PZT-interface is designed to monitor bolt loosening in bolted connection based on variation of electro-mechanical(EM) impedance signatures. Secondly, a wireless impedance sensor node is designed for autonomous, cost-efficient and multi-channel monitoring. For the sensor platform, Imote2 is selected on the basis of its high operating speed, low power requirement and large storage memory. Finally, the performance of the wireless sensor node and the PZT-interfaces is experimentally evaluated for a bolt-connection model. Damage monitoring method using root mean square deviation(RMSD) index of EM impedance signatures is utilized to estimate the strength of the bolted joint

  2. Turbine casing bolts; a life assessment and bolt replacement strategy

    Energy Technology Data Exchange (ETDEWEB)

    Bulloch, J H [ESB, Power Generation, Dublin (Ireland)

    1999-12-31

    The present presentation describes a detailed study concerning the life assessment and replacement strategy of large turbine casing bolts in a 120 MW steam raising unit. After 122000 hours service, circa 1991/92, the Cr-Mo-V steel casing bolts, involving a total of 184 bolts, from two identical 120 MW units, termed Units 1 and 2, were examined to establish the extent of Reverse Temper Embrittlement, RTE, and creep damage suffered during service. The bolt replacement plans for the two units were as follows; Unit 1 bolts were completely replaced with new bolts while Unit 2 embrittled bolts were withdrawn from service and replaced with Non- Embrittled bolts from Unit 1; basically Unit 2 bolts were made up from a mixture of Unit 1 and 2 Non- Embrittled bolts which had been in service for 122000 hours. Remnant life assessments, concerning both embrittlement and creep damage aspects, were earned out on this series of easing bolts at service times 122000, 150000 and 200000 hours. These assessments involved the use of general embrittlement and creep damage laws which were empirically derived and concerned such parameters as microstructural grain size, bulk phosphorus content and accumulated service strain. (orig.) 7 refs.

  3. Turbine casing bolts; a life assessment and bolt replacement strategy

    Energy Technology Data Exchange (ETDEWEB)

    Bulloch, J.H. [ESB, Power Generation, Dublin (Ireland)

    1998-12-31

    The present presentation describes a detailed study concerning the life assessment and replacement strategy of large turbine casing bolts in a 120 MW steam raising unit. After 122000 hours service, circa 1991/92, the Cr-Mo-V steel casing bolts, involving a total of 184 bolts, from two identical 120 MW units, termed Units 1 and 2, were examined to establish the extent of Reverse Temper Embrittlement, RTE, and creep damage suffered during service. The bolt replacement plans for the two units were as follows; Unit 1 bolts were completely replaced with new bolts while Unit 2 embrittled bolts were withdrawn from service and replaced with Non- Embrittled bolts from Unit 1; basically Unit 2 bolts were made up from a mixture of Unit 1 and 2 Non- Embrittled bolts which had been in service for 122000 hours. Remnant life assessments, concerning both embrittlement and creep damage aspects, were earned out on this series of easing bolts at service times 122000, 150000 and 200000 hours. These assessments involved the use of general embrittlement and creep damage laws which were empirically derived and concerned such parameters as microstructural grain size, bulk phosphorus content and accumulated service strain. (orig.) 7 refs.

  4. A Reduced Order Model of Force Displacement Curves for the Failure of Mechanical Bolts in Tension.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Keegan J. [Univ. of Illinois, Urbana-Champaign, IL (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brake, Matthew Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    Assembled mechanical systems often contain a large number of bolted connections. These bolted connections (joints) are integral aspects of the load path for structural dynamics, and, consequently, are paramount for calculating a structure's stiffness and energy dissipation prop- erties. However, analysts have not found the optimal method to model appropriately these bolted joints. The complexity of the screw geometry causes issues when generating a mesh of the model. This report will explore different approaches to model a screw-substrate connec- tion. Model parameters such as mesh continuity, node alignment, wedge angles, and thread to body element size ratios are examined. The results of this study will give analysts a better understanding of the influences of these parameters and will aide in finding the optimal method to model bolted connections.

  5. A new design concept of fully grouted rock bolts in underground construction

    Science.gov (United States)

    Phich Nguyen, Quang; Nguyen, Van Manh; Tuong Nguyen, Ke

    2018-04-01

    The main problem after excavating an underground excavation is to maintain the stability of the excavation for a certain period of time. Failure in meeting this demand is a threat to safety of men and equipment. Support and reinforcement are different instruments with different mechanisms. Among the common support systems in tunnelling and mining, rock bolts have been widely used to reinforce rock mass and also to reduce geological hazards. Furthermore rock bolts can be applied under varying different geological conditions with cost-effectiveness. Although different methods are developed for grouted rock bolts design until now, the interaction mechanism of the rock bolts and rock mass is still very complicated issue. The paper addresses an analytical model for the analysis and design of fully grouted rock bolts based on the reinforcement principle. According to this concept the jointed rock mass reinforced by grouted rock bolts is considered as composite material which includes rock mass, the grout material and the bolt shank. The mechanical properties of this composite material depend on the ratio of the components. The closed-form solution was developed based on the assumption that the rock mass arround a circular tunnel remained elastic after installing fully grouted rock bolts. The main parameters of the rock-bolt system (the diameter and length of bolt shank, the space between the bolts) are then easily estimated from the obtained solution.

  6. Single-impact calibrated electromagnetic tightening of long-life bolted joints in aviation structures

    Science.gov (United States)

    Firsov, V. A.; Bekhmet'ev, V. I.

    The general design and operation of a newly developed electromagnetic impact driver for the assembly of aviation structures is described. The electromagnetic impact driver makes it possible to considerably improve the precision of bolt torquing during the assembly. To test the performance of the new tool, M6 bolts of 16KhSN steel (tensile strength 120 +/- 10 kg/sq mm) were tightened by a manual torque wrench and by the electromagnetic impact driver. It is shown that the scatter of bolt elongation during the tightening by the impact driver is a factor of 3-5 less than in the case of manual torquing, which corresponds to a torque precision of 1.5-2 percent.

  7. Bolt Shear Force Sensor

    Science.gov (United States)

    2015-03-12

    0030] FIG. 7 is an isometric view of a deformable ring of the bolt shear force sensor of the present invention with an optical Attorney Docket No...102587 9 of 19 fiber having Bragg gratings wound around the ring; [0031] FIG. 8 is an isometric view of the deformable ring with wire strain... strength . [0047] Once the joint is subjected to an external load (see force arrows “F” and “F/2”); any frictional resistance to slip is overcome and

  8. Effect of hot dip galvanization on the fatigue strength of steel bolted connections

    Directory of Open Access Journals (Sweden)

    S.M.J. Razavi

    2017-07-01

    Full Text Available Hot dip galvanized steel bolted joints has been tested under fatigue loading to evaluate the effect of galvanizing coating on the fatigue strength of S355 structural steel. The experimental results showed that the decrease of the fatigue life of coated specimens in comparison with that of uncoated joints is very limited and the results are in good agreement with Eurocode detail category, without substantial reductions. The procedure for coating and preparation of the bolted joints is described in detail in this paper providing a useful tool for engineers involved in similar practical applications. The experimental results are compared with the previously published data on central hole notched galvanized and not treated specimens characterized by the same geometry.

  9. Limit load analysis of bolted flange connections

    International Nuclear Information System (INIS)

    Kauer, R.; Deininger, J.

    2005-01-01

    In Europe as well as in other countries a lot of efforts are invested into developing new codes and standards for bolted joints under various loading conditions. The standardization of gasket factors and the improvement of calculation methods with respect to these factors characterize the last couple of years in this area. In Germany, the nuclear code (KTA-Regeln) is also influenced by this development. So, the leak rate dependency of gasket factors and the results of a research program on metal-to-metal contact type flanges were introduced into the new approach of the code for Class 2 and 3 components. Herein; flange calculations can be performed for various flange types, floating type and metal-to-metal contact type. Generally, the calculations to be performed can be separated into a design step and the proof of sufficient tightness and strength of flange, bolts and gasket for the various operating conditions according to the chosen bolting method. In Europe, the most recent development in the field of flange calculations is the new standard EN 1591-1 for flange connections. The structure of the EN 1591-1 is also a two-step approach, but due to the more sophisticated and iterative calculation method, the design step is neglected and instead the focus in the first step is the determination of a suitable bolting force. In cases, where the allowable stress values are not satisfied by performing code calculations or in cases, where the applicability of the code is not given, e. g. due to geometric facts, Finite-Element analyses often replace code calculations but have to demonstrate code compliance. Therefore, numerical Finite-Element analyses, performed according to a special code, e. g. KTA, must also fulfill the requirements of the code with respect to considered load cases, bolting condition, allowable stresses etc., to get an adequate testimony for a certain flange joint. Usually this can be done by checking relevant cross sections according to the stress

  10. Hydraulic nuts (hydranuts) for critical bolted joints

    International Nuclear Information System (INIS)

    Greenwell, S.

    2008-01-01

    HydraNuts replace the original nut and torquing equipment, combining the two functions into one system. Designed for simple installation and operation, HydraNuts are fitted to the stud bolts. Once all HydraNuts are fitted to the application, flexible hydraulic hoses are connected, forming a closed loop hydraulic harness, allowing simultaneous pressurization of all HydraNuts. Hydraulic pressure is obtained by the use of a pumping unit and the resultant load generated is transferred to the studs and flange closure is obtained. Locking rings are rotated into place, supporting the tensioned load mechanically after hydraulic pressure is released. The hose harness is removed. (author)

  11. Bolt Stress Monitor

    Science.gov (United States)

    1978-01-01

    In photo, an engineer is using a new Ultrasonic Bolt Stress Monitor developed by NASA's Langley Research Center to determine whether a bolt is properly tightened. A highly accurate device, the monitor is an important tool in construction of such structures as pressure vessels, bridges and power plants, wherein precise measurement of the stress on a tightened bolt is critical. Overtightened or undertightened bolts can fail and cause serious industrial accidents or costly equipment break-downs. There are a number of methods for measuring bolt stress. Most widely used and least costly is the torque wrench, which is inherently inaccurate; it does not take into account the friction between nut and bolt, which has an influence on stress. At the other end of the spectrum, there are accurate stress-measuring systems, but they are expensive and not portable. The battery-powered Langley monitor fills a need; it is inexpensive, lightweight, portable and extremely accurate because it is not subject to friction error. Sound waves are transmitted to the bolt and a return signal is received. As the bolt is tightened, it undergoes changes in resonance due to stress, in the manner that a violin string changes tone when it is tightened. The monitor measures the changes in resonance and provides a reading of real stress on the bolt. The device, patented by NASA, has aroused wide interest and a number of firms have applied for licenses to produce it for the commercial market.

  12. Evaluation of Interlaminar Stresses in Composite Laminates with a Bolt-Filled Hole Using a Linear Elastic Traction-Separation Description

    Directory of Open Access Journals (Sweden)

    Yong Cao

    2017-01-01

    Full Text Available Determination of the local interlaminar stress distribution in a laminate with a bolt-filled hole is helpful for optimal bolted joint design, due to the three-dimensional (3D nature of the stress field near the bolt hole. A new interlaminar stress distribution phenomenon induced by the bolt-head and clamp-up load, which occurs in a filled-hole composite laminate, is investigated. In order to efficiently evaluate interlaminar stresses under the complex boundary condition, a calculation strategy that using zero-thickness cohesive interface element is presented and validated. The interface element is based on a linear elastic traction-separation description. It is found that the interlaminar stress concentrations occur at the hole edge, as well as the interior of the laminate near the periphery of the bolt head. In addition, the interlaminar stresses near the periphery of the bolt head increased with an increase in the clamp-up load, and the interlaminar normal and shear stresses are not at the same circular position. Therefore, the clamp-up load cannot improve the interlaminar stress distribution in the laminate near the periphery of the bolt head, although it can reduce the magnitude of the interlaminar shear stress at the hole edge. Thus, the interlaminar stress distribution phenomena may lead to delamination initiation in the laminate near the periphery of the bolt head, and should be considered in composite bolted joint design.

  13. PERL - European research project on characterization of gaskets for bolted flange connections

    International Nuclear Information System (INIS)

    Kockelmann, H.; Hahn, R.

    2004-01-01

    Great progress was observed in the European standardization in the last years in the field of the design of floating type bolted flange connections. New design rules were developed (EN 1591) which include new definitions of gasket characteristics for the calculation of floating type flanged joints. In addition a new gasket testing standard was drafted (prEN 13555) which assures a comprehensive characterization of gaskets for bolted flanged joints. This draft standard contains some new features which were examined and validated within the European research project PERL (Pressure Equipment - Reduction of Leak Rate). The gasket testing strategy laid down in prEN 13555 is presented in this paper. Some testing results highlighten the measuring procedures and the evaluation of the gasket characteristics. (orig.)

  14. Application of Composite Indices for Improving Joint Detection Capabilities of Instrumented Roof Bolt Drills in Underground Mining and Construction

    Science.gov (United States)

    Liu, Wenpeng; Rostami, Jamal; Elsworth, Derek; Ray, Asok

    2018-03-01

    Roof bolts are the dominant method of ground support in mining and tunneling applications, and the concept of using drilling parameters from the bolter for ground characterization has been studied for a few decades. This refers to the use of drilling data to identify geological features in the ground including joints and voids, as well as rock classification. Rock mass properties, including distribution of joints/voids and strengths of rock layers, are critical factors for proper design of ground support to avoid instability. The goal of this research was to improve the capability and sensitivity of joint detection programs based on the updated pattern recognition algorithms in sensing joints with smaller than 3.175 mm (0.125 in.) aperture while reducing the number of false alarms, and discriminating rock layers with different strengths. A set of concrete blocks with different strengths were used to simulate various rock layers, where the gap between the blocks would represent the joints in laboratory tests. Data obtained from drilling through these blocks were analyzed to improve the reliability and precision of joint detection systems. While drilling parameters can be used to detect the gaps, due to low accuracy of the results, new composite indices have been introduced and used in the analysis to improve the detection rates. This paper briefly discusses ongoing research on joint detection by using drilling parameters collected from a roof bolter in a controlled environment. The performances of the new algorithms for joint detection are also examined by comparing their ability to identify existing joints and reducing false alarms.

  15. Fatigue-Arrestor Bolts

    Science.gov (United States)

    Onstott, Joseph W.; Gilster, Mark; Rodriguez, Sergio; Larson, John E.; Wickham, Mark D.; Schoonover, Kevin E.

    1995-01-01

    Bolts that arrest (or, more precisely, retard) onset of fatigue cracking caused by inelastic strains developed. Specifically developed to be installed in flange holes of unrestrained rocket engine nozzle. Fanges sometimes used to bolt nozzle to test stand; however, when rocket engine operated without this restraint, region around bolt holes experience severe inelastic strains causing fatigue cracking. Interference fits introduce compressive preloads that retard fatigue by reducing ranges of strains. Principle of these fatigue-arrestor bolts also applicable to holes in plates made of other materials and/or used for different purposes.

  16. Anchor Bolt Position in Base Plate In Terms Of T and J Anchor Bolt

    Directory of Open Access Journals (Sweden)

    b Osman Mohamad Hairi

    2017-01-01

    Full Text Available Generally, L anchor bolt system has been used for a long period of time in construction industry as one of the distributing load structures. However, there are some weaknesses in L anchor bolt which may straighten and pullup when charged with tensile load. Current practices prefer to use other types of anchor bolt systems, such as headed studs anchor bolt system to replace the L anchor bolt design. There has been lack of studies to prove that it is more effective in terms of performance. A new T anchor bolt which was basically modified from headed studs anchor bolt was proposed in this study to compare its performance of tensile loading in concrete failure to typical L design. This study aims to determine whether the T anchor bolt system gives better performance as compared to an L anchor bolt system. The performance was rated based on tensile loading on concrete failure pattern. A pullout test was conducted on two different anchor bolt systems, namely L and T. The anchor bolt embedded depth, h in concrete were varied according to their hook or bend radius. Each sample was repeated twice. There were totally eight samples. The hook or bend radius used were 50 mm and 57.5 mm for sample L1 and L2, respectively. 90-degree bend were used on sample T1 and T2. Based on test results, it can be seen that the performance of concrete failure pattern under tensile load on both L and T anchor bolt design samples with 200 mm embedment depth was better than deeper embedment depth of 230 mm. But the L anchor bolt design gives the best results as compared to T design. Although T anchor bolt design shows higher resistance before first bond failure to the concrete sample. T anchor bolt was analysed and needed deeper embedment depth to allow formation of cone pull-out shape to acquire better performance.

  17. Numerical design and test on an assembled structure of a bolted joint with viscoelastic damping

    Science.gov (United States)

    Hammami, Chaima; Balmes, Etienne; Guskov, Mikhail

    2016-03-01

    Mechanical assemblies are subjected to many dynamic loads and modifications are often needed to achieve acceptable vibration levels. While modifications on mass and stiffness are well mastered, damping modifications are still considered difficult to design. The paper presents a case study on the design of a bolted connection containing a viscoelastic damping layer. The notion of junction coupling level is introduced to ensure that sufficient energy is present in the joints to allow damping. Static performance is then addressed and it is shown that localization of metallic contact can be used to meet objectives, while allowing the presence of viscoelastic materials. Numerical prediction of damping then illustrates difficulties in optimizing for robustness. Modal test results of three configurations of an assembled structure, inspired by aeronautic fuselages, are then compared to analyze the performance of the design. While validity of the approach is confirmed, the effect of geometric imperfections is shown and stresses the need for robust design.

  18. 30 CFR 75.204 - Roof bolting.

    Science.gov (United States)

    2010-07-01

    ... accessories addressed in ASTM F432-95, “Standard Specification for Roof and Rock Bolts and Accessories,” the.... (4) In each roof bolting cycle, the actual torque or tension of the first tensioned roof bolt... during each roof bolting cycle shall be tested during or immediately after the first row of bolts has...

  19. 46 CFR 56.25-20 - Bolting.

    Science.gov (United States)

    2010-10-01

    ..., Blanks, Flange Facings, Gaskets, and Bolting § 56.25-20 Bolting. (a) General. (1) Bolts, studs, nuts, and....01-2). (2) Bolts and studs must extend completely through the nuts. (3) See § 58.30-15(c) of this... steel stud bolts must be threaded full length or, if desired, may have reduced shanks of a diameter not...

  20. INJECTION MOLDING AND STRUCTURAL ANALYSIS IN METAL TO PLASTIC CONVERSION OF BOLTED FLANGE JOINT BY CAE

    Directory of Open Access Journals (Sweden)

    Marian Blaško

    2014-12-01

    Full Text Available Many metal parts in various applications are being replaced by plastic parts. There are several reasons for that depending on actual application - minimize part cost, enhance corrosion resistance, integrating more components into one part etc. Most important steps of metal to plastic conversion are material selection and design of plastic part. Plastic part has to withstand the same load as metal part. To fulfill this requirement fiber reinforced engineering plastics are often used. Also it is convenient to substitute heavy wall sections with ribbed structure to increase load-carrying ability of part and decrease cycle time, eliminate voids, sink marks etc. Mechanical properties of such part could be highly affected by fiber orientation. Results of fiber orientation from injection molding filling analysis can be used in stress analysis for better prediction of part response to mechanical load. Such coupled analysis is performed here in this case study on bolted flange joint.

  1. Quick-Connect, Slow-Disconnect Bolt

    Science.gov (United States)

    Weddendorf, Bruce

    1995-01-01

    Proposed bolt functions similarly to device described in article "Quick-Connect, Slow-Disconnect Nut" (MFS-28833). Bolt installed in standard threaded hole simply by pushing it into hole. Once inserted, bolt withdrawn only by turning it in conventional way.

  2. Relaxation behaviour of gasketed joints during assembly using finite ...

    Indian Academy of Sciences (India)

    Faculty of Mechanical Engineering, Ghulam Ishaq Khan (GIK) Institute of ... Bolt scatter, bolt bending, joint relaxation and gasket stress variation are concluded the main .... In the present work, following two ..... American Society of Mech.

  3. Plug and play type joints in steel and steel-concrete composite constructions

    NARCIS (Netherlands)

    Bijlaard, F.S.K.; Brekelmans, J.W.P.M.

    2007-01-01

    Traditionally for Western Europe countries, joints in steel frame structures are realised using bolts and welds. In the workshop the components are made using welding and drilling of the bolt holes. On site these structural components are connected together using bolts and nuts. The actions on site

  4. Perspectives of roof bolt use in the Kuzbass

    Energy Technology Data Exchange (ETDEWEB)

    Shirokov, A P

    1983-10-01

    Use of roof bolting for strata control in mine roadways and underground chambers in Kuzbass mines is discussed. Use of roof bolting in the Kuzbass is increasing. In 1982 roof bolting was used in 50% of workings driven in the basin; in 15 coal mines roof bolting was the predominant method for strata control. Use of roof bolting rather than timber props permitted advance rate of mine drivage in the Kuzbass to be increased by 1.5-2.0 times. Interaction between roof bolts and rock strata is analyzed. The following bolt types are considered: timber roof bolts, steel expansion shell bolts and thread bar bolts. Bolt design is shown, along with methods for roof bolt installation in roadways and chambers. Roof bolting during level, inclined or steep seam mining, for strata control at junctions of working faces with gate roads, at junctions of 2 roadways, in coal chutes, in hydraulic mines, during thick seam slicing with hardening stowing and longwall mining with hydraulic stowing is analyzed. Effects of roof bolting on strata control efficiency in steep coal mines employing AShchM systems are evaluated.

  5. Effects of bolt pre-loading variations on performance of GDL in a bolted PEMFC by 3-D FEM analysis

    International Nuclear Information System (INIS)

    Chien, Chi-Hui; Hu, Yao-Lun; Su, Ting-Hsuan; Liu, Hsuan-Ting; Wang, Chung-Ting; Yang, Ping-Feng; Lu, Ying-Xu

    2016-01-01

    This study numerically investigated the effects of different bolt pre-loadings on the performance of the gas diffusion layer (GDL) in a bolted proton exchange membrane fuel cell (PEMFC). Firstly, a complete three-dimensional finite element model of a PEMFC bolted by 12 bolts with a reactive area of 5 cm by 5 cm was established using the commercial software SolidWorks. Then, a pre-loading of 1 MPa to 7 MPa on each bolt was applied, increasing in increments 1 MPa, and the corresponding deformation and stress fields of each component of the fuel cell were obtained using the commercial software ANSYS 15.0/Workbench. Finally, the effects of the bolt pre-loading variations on the performance of the GDL were discussed. The results showed that the compression ratio of the GDL increased linearly with the magnitude of bolt pre-loading, and improving the performance of the GDL. However, when the pre-loading on each bolt reached 7 MPa, the compression ratio exceeded 15%, degrading the efficiency of the PEMFC. Also, by comparing the relationships between bolt pre-loading and conductivity and porosity of GDL, in order to obtain the maximum performance of GDL, an optimum value of 4 MPa for bolt preloading was recommended. - Highlights: • Effect of bolt pre-loading on deformations is more serious than that of thermal loading. • Bolt pre-loading improves compression ratio of GDL. • For obtaining a maximum performance of GDL, 4 MPa of bolt pre-loading was recommended. • Flow channel volume reduced by bolt pre-loading degrades the efficiency of PEMFC.

  6. Bolting multicenter solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bena, Iosif [Institut de Physique Théorique, Université Paris Saclay, CEA, CNRS, 91191 Gif-sur-Yvette Cedex (France); Bossard, Guillaume [Centre de Physique Théorique, Ecole Polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau Cedex (France); Katmadas, Stefanos; Turton, David [Institut de Physique Théorique, Université Paris Saclay, CEA, CNRS, 91191 Gif-sur-Yvette Cedex (France)

    2017-01-30

    We introduce a solvable system of equations that describes non-extremal multicenter solutions to six-dimensional ungauged supergravity coupled to tensor multiplets. The system involves a set of functions on a three-dimensional base metric. We obtain a family of non-extremal axisymmetric solutions that generalize the known multicenter extremal solutions, using a particular base metric that introduces a bolt. We analyze the conditions for regularity, and in doing so we show that this family does not include solutions that contain an extremal black hole and a smooth bolt. We determine the constraints that are necessary to obtain smooth horizonless solutions involving a bolt and an arbitrary number of Gibbons-Hawking centers.

  7. Design of mechanical joints

    CERN Document Server

    Blake, Alexander

    2018-01-01

    A cornerstone publication that covers the basic principles and practical considerations of design methodology for joints held by rivets, bolts, weld seams, and adhesive materials, Design of Mechanical Joints gives engineers the practical results and formulas they need for the preliminary design of mechanical joints, combining the essential topics of joint mechanics...strength of materials...and fracture control to provide a complete treatment of problems pertinent to the field of mechanical connections.

  8. Inexpensive Bolt-Load Gage

    Science.gov (United States)

    Long, M. J.

    1983-01-01

    "Built-in" gage determines whether large bolt or stud has been torqued to desired load and provides for continuous inspection to ensure proper load is being maintained. Gage detects longitudinal stress/strain bolt; requires no electronic or sonic test equipment.

  9. TEM investigation of plant-irradiated NPP bolt material

    International Nuclear Information System (INIS)

    Pakarinen, J.; Ehrnsten, U.; Keinaenen, H.; Karlsen, W.; Karlsen, T.

    2015-01-01

    Analytical transmission electron microscopy (ATEM) was used to examine irradiation-induced damage in material removed from two different bolts from two different nuclear power plants. One section came from a French PWR, was made of CW AISI 316, and included a section of the bolt that had accumulated a dose of approximately 15 dpa during 19 operation cycles at 350 - 390 C. degrees. Another section came from a VVER bolt that was removed from the plant due to indications found in non-destructive examinations (NDE). The VVER bolt was made of solution annealed titanium stabilized 0X18H10T (corresponding to Type AISI 321) and had accumulated a fluence of 2.9 dpa. During the removal of that bolt, it was found that the bolt washer had been inappropriately spot welded to the shielding plate during assembly. Destructive investigations showed that the bolt had two large intergranular cracks, and the TEM samples were prepared from the material adjacent to those cracks. The PWR bolt had not failed, although cracks in the bolts with a similar history had been found previously. The fluence for the cold-worked AISI 316 PWR bolt was estimated to be about 15 dpa. Both the examined bolts showed a clear radiation induced segregation of alloying elements at the grain boundaries (GB-RIS), the presence of dislocation loops, the formation of precipitates, and linear deformation microstructures. Additionally, voids were found from the PWR bolt and the VVER bolt had a high density of dislocations. (authors)

  10. Professional users handbook for rock bolting

    Energy Technology Data Exchange (ETDEWEB)

    Stillborg, B.

    1986-01-01

    The paper is a practical handbook which reviews the basic principles of rock bolting and sets out the design considerations used for most types of rockbolts in current use. It discusses the characteristics of these bolts and gives information on installation procedures and the observations and measurement of rockbolt performance. Rockbolting is considered under the following chapter headings: review of typical rockbolt systems; rockbolt installation; testing of rockbolts; design considerations; design of rock reinforcement; monitoring; cost of rock bolting; and Atlas Lopco auxillary equipment for rock bolting. 45 refs.

  11. Stud bolt handling equipment for reactor vessel

    International Nuclear Information System (INIS)

    Bunyan, T.W.

    1989-01-01

    Reactor vessel stud bolt handling equipment includes means for transferring a stud bolt to a carrier from a parking station, or vice versa. Preferably a number of stud bolts are handled simultaneously. The transfer means may include cross arms rotatable about extendable columns, and the equipment is mounted on a mobile base for movement into and out of position. Each carrier comprises a tubular socket and an expandable sleeve to grip a stud bolt. (author)

  12. A Review of Rock Bolt Monitoring Using Smart Sensors

    Directory of Open Access Journals (Sweden)

    Gangbing Song

    2017-04-01

    Full Text Available Rock bolts have been widely used as rock reinforcing members in underground coal mine roadways and tunnels. Failures of rock bolts occur as a result of overloading, corrosion, seismic burst and bad grouting, leading to catastrophic economic and personnel losses. Monitoring the health condition of the rock bolts plays an important role in ensuring the safe operation of underground mines. This work presents a brief introduction on the types of rock bolts followed by a comprehensive review of rock bolt monitoring using smart sensors. Smart sensors that are used to assess rock bolt integrity are reviewed to provide a firm perception of the application of smart sensors for enhanced performance and reliability of rock bolts. The most widely used smart sensors for rock bolt monitoring are the piezoelectric sensors and the fiber optic sensors. The methodologies and principles of these smart sensors are reviewed from the point of view of rock bolt integrity monitoring. The applications of smart sensors in monitoring the critical status of rock bolts, such as the axial force, corrosion occurrence, grout quality and resin delamination, are highlighted. In addition, several prototypes or commercially available smart rock bolt devices are also introduced.

  13. A Review of Rock Bolt Monitoring Using Smart Sensors.

    Science.gov (United States)

    Song, Gangbing; Li, Weijie; Wang, Bo; Ho, Siu Chun Michael

    2017-04-05

    Rock bolts have been widely used as rock reinforcing members in underground coal mine roadways and tunnels. Failures of rock bolts occur as a result of overloading, corrosion, seismic burst and bad grouting, leading to catastrophic economic and personnel losses. Monitoring the health condition of the rock bolts plays an important role in ensuring the safe operation of underground mines. This work presents a brief introduction on the types of rock bolts followed by a comprehensive review of rock bolt monitoring using smart sensors. Smart sensors that are used to assess rock bolt integrity are reviewed to provide a firm perception of the application of smart sensors for enhanced performance and reliability of rock bolts. The most widely used smart sensors for rock bolt monitoring are the piezoelectric sensors and the fiber optic sensors. The methodologies and principles of these smart sensors are reviewed from the point of view of rock bolt integrity monitoring. The applications of smart sensors in monitoring the critical status of rock bolts, such as the axial force, corrosion occurrence, grout quality and resin delamination, are highlighted. In addition, several prototypes or commercially available smart rock bolt devices are also introduced.

  14. 21 CFR 137.280 - Bolted yellow corn meal.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Bolted yellow corn meal. 137.280 Section 137.280... Flours and Related Products § 137.280 Bolted yellow corn meal. Bolted yellow corn meal conforms to the definition and standard of identity prescribed by § 137.255 for bolted white corn meal except that cleaned...

  15. 3D finite element analysis of tightening process of bolt and nut connections with pitch difference

    Science.gov (United States)

    Liu, X.; Noda, N.-A.; Sano, Y.; Huang, Y. T.; Takase, Y.

    2018-06-01

    In a wide industrial field, the bolt-nut joint is unitized as an important machine element and anti-loosening performance is always required. In this paper, the effect of a slight pitch difference between a bolt and nut is studied. Firstly, by varying the pitch difference, the prevailing torque required for the nut rotation, before the nut touches the clamped body, is measured experimentally. Secondly, the tightening torque is determined as a function of the axial force of the bolt after the nut touches the clamped body. The results show that a large value of pitch difference may provide large prevailing torque that causes an anti-loosening effect although a very large pitch difference may deteriorate the bolt axial force under a certain tightening torque. Thirdly, a suitable pitch difference is determined taking into account the anti-loosening and clamping abilities. Furthermore, the chamfered corners at nut ends are considered, and it is found that the 3D finite element analysis with considering the chamfered nut threads has a good agreement with the experimental observation. Finally, the most desirable pitch difference required for improving anti-loosening is proposed.

  16. Automation of strata bolting in iron mines

    Energy Technology Data Exchange (ETDEWEB)

    Belin, M; Lethuaire, M

    1978-01-01

    The Moyeure iron mine (Lorraine), with an output of 16,000 t/day, works 2 seams separated by a dirt band 6.50 m thick. The tyre-mounted Diesel Secoma jumbo for bolting operations can insert resin-embedded bolts 1.70 m in length. The jumbo is fitted with a standard universal boom with two settings - one for drilling and one for bolting. As the operator has to work in the unbolted zone in order to offer up the bolt on the boom and insert the resin cartridge, the mine in conjunction with the manufacturers, Secoma, have improved the safety and performance of the machine by adding three special attachments to the standard boom: a reamer, a resin-injection system and a bolt supply-magazine. Gives details of the results achieved. (In French)

  17. Optimization of Bolt Stress

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The state of stress in bolts and nuts with ISO metric thread design is examined and optimized. The assumed failure mode is fatigue so the applied preload and the load amplitude together with the stress concentrations define the connection strength. Maximum stress in the bolt is found at, the fillet...... under the head, at the thread start or at the thread root. To minimize the stress concentration shape optimization is applied....

  18. Investigation of Fastening Performance of Subminiature Serrated Bolt

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Myung Guen; Jeong, Jin Hwan; Jang, Yeon Hui; Kim, Hee Cheol; Kim, Jong-Bong [Seoul Nat’l Univ. of Science & Tech, Seoul (Korea, Republic of)

    2017-04-15

    As the size of electric products such as mobile phones and smart watches decrease, the bolts used to assemble these products should also be miniaturized. A miniature-sized bolt has to provide sufficient joining torque and anti-releasing torque to keep the components together. We studied a serrated bolt as a candidate for a miniature-sized fastener to increase the anti-releasing torque. In a serrated bolt, a serrated shape is formed on the bottom surface of the bolt head to create an obstacle to releasing. In this study, finite element analyses for the joining and releasing of bolts were carried out, and the anti-releasing performance was predicted. Based on the results of analyses using various numbers of serrations and fastening depths, the effects of the number of serrations and fastening depth on the anti-releasing performance were investigated.

  19. Investigation of Fastening Performance of Subminiature Serrated Bolt

    International Nuclear Information System (INIS)

    Jang, Myung Guen; Jeong, Jin Hwan; Jang, Yeon Hui; Kim, Hee Cheol; Kim, Jong-Bong

    2017-01-01

    As the size of electric products such as mobile phones and smart watches decrease, the bolts used to assemble these products should also be miniaturized. A miniature-sized bolt has to provide sufficient joining torque and anti-releasing torque to keep the components together. We studied a serrated bolt as a candidate for a miniature-sized fastener to increase the anti-releasing torque. In a serrated bolt, a serrated shape is formed on the bottom surface of the bolt head to create an obstacle to releasing. In this study, finite element analyses for the joining and releasing of bolts were carried out, and the anti-releasing performance was predicted. Based on the results of analyses using various numbers of serrations and fastening depths, the effects of the number of serrations and fastening depth on the anti-releasing performance were investigated.

  20. Investigation of the Chooz-A nuclear power plant bolts

    International Nuclear Information System (INIS)

    Monnet, I.; Decroix, G.M.; Dubuisson, P.; Reuchet, J.; Morlent, O.

    2002-01-01

    In Pressurised Water Reactor, some baffle-former bolts in austenitic stainless steel, are submitted to an important Intergranular cracking. This cracking may be attributed to the irradiation hardening during in pile service. As part of its concern of safety related to the ageing of the plant and, in particular, to the behaviour of the internals, IRSN wished to take part in the expertise Program on CHOOZ A power nuclear plant, within the framework of a convention with EDF, which provided the baffle-bolts. Examinations of these bolts, after 140 000 of in pile service, were carried out by the laboratories of the CEA. Hardness profiles were carried out on four bolts, which were irradiated at different doses, ranging from 0 to 22 dpa. The bolt of the core barrel, considered as unirradiated, shows a constant value of hardness, equal to the value of unirradiated material, all along the bolt and a slight increase in the head of the screw. The axial profile of hardness carried out on an irradiated bolt shows that there is a gradient of hardness between the most irradiated part (400 Hv) and the least irradiated part (270 Hv). The hardness of this bolt starts to evolve at 2.5 dpa and the maximum of hardening is reached for the most irradiated part (3.6 dpa). The hardness profile on the most irradiated bolt (between 10 and 22 dpa) indicate that hardness is homogeneous all along the bolt, 400 Hv. It confirms the existence of a threshold dose beyond which hardness does not vary any more, this threshold is estimated to be between 3.6 dpa and 10 dl Microstructural examinations of these bolts led us to conclude that hardening is correlated to dislocation microstructure. Indeed, the examination of the bolt of the core barrel confirms that this bolt is hardly unirradiated since the initial network of dislocations was not modified and that only some rare dislocation loops were observed. This is in agreement with hardness results showing no hardening of this bolt. On the two more

  1. Bolt study - behaviour of bolts in drop accident scenarios of the Nirex 3m3 Box ILW package

    International Nuclear Information System (INIS)

    Turner, G.; Tso, C.F.

    2004-01-01

    The mission of Nirex is to provide the UK with safe, environmentally sound and publicly acceptable options for the long-term management of radioactive materials. One of the key tasks is to ensure that waste is packaged by waste producers in a form which is suitable for safe storage, transport, handling and potential disposal. In pursuit of this key requirement, Nirex has developed specifications to set the standard for the design and performance of waste packages, and has developed standard containers for the packaging of intermediate level (ILW) and some low level waste (LLW) - one of these is the 3m 3 Box for immobilised operational and decommissioning ILW. The dimension envelope of this package is 1716 mm x 1716 mm in plan with 430 mm corner radii, 1226 mm tall. The maximum loaded weight is 12 tonnes. A generic design of this container has been developed, which is a welded structure manufactured from austenitic stainless steel (EN 10088-2 steel number 1.4404). The lid is connected to the body by 28 stainless steel bolts. An extensive study was carried out to develop a robust FE model of the bolts. The specific focus of this work was to use improved bolt modelling to optimize the design of the 3m 3 Box, although this work could be applied to other bolted containers. This paper presents a summary of the findings from the study as follows: 1. Development of a FE bolt model for application in a 3m 3 Box model. 2. Development and execution of a bolt testing programme which included tensile and shear tests on a total of 88 bolts, representing four grades of stainless steel materials, three thread sizes, and two geometries at three strain rates. 3. Benchmarking of the FE bolt model that can be used with confidence in simulating waste package behaviour in drop scenarios

  2. Evaluation of bolted connections in wood-plastic composites

    Science.gov (United States)

    Arnandha, Yudhi; Satyarno, Iman; Awaludin, Ali; Irawati, Inggar Septia; Ihsan, Muhamad; Wijanarko, Felyx Biondy; William, Mahdinur, Fardhani, Arfiati

    2017-03-01

    Wood-plastic composite (WPC) is a relatively new material that consists of sawdust and plastic polymer using the extrusion process. Due to its attributes such as low water content, low maintenance, UV durability and being fungi and termite resistant. Nowadays, WPC has already been produced in Indonesia using sawdust from local wood such as Albizia (Paraserianthes falcataria) and Teak (Tectona grandis). Moreover preliminary studies about the physical and mechanical WPC board from Albizia sawdust and HDPE plastic have been carried out. Based on these studies, WPC has a high shear strength around 25-30 MPa higher than its original wood shear strength. This paper was a part of the research in evaluating WPC as potential sheathing in a shear wall system. Since still little is known about connection behavior in WPC using Indonesian local wood, this study evaluated the connection for both of these two types of wood-plastic composite. WPC board from Albizia sawdust will be projected as shear wall sheathing and WPC stud from Teak sawdust projected to be shear wall frame. For this study, the embedding strength for both WPC was determined according to ASTM D 5764 standard, using two types of bolts (stainless bolt and standard bolt) with several diameters as variation (6 mm, 8 mm, 10 and 12 mm). Hence, dowel-bearing test under fastened condition conducted accordance to ASTM D5652, hereby the yield strength then compared with the prediction yield strength from European Yield Model (EYM). According to both single and double shear connection, it can be concluded that yield strength from the EYM method tended to under-predict the 5% diameter offset yield than the actual yield strength from the test. The yield strength itself increase with the increase of bolt diameter. For single shear connection, the highest yield strength was 12 mm standard bolt around 9732 N, slightly higher than stainless bolt around 9393 N. Whereby for double shear connection, the highest yield strength was

  3. Improvement in or relating to bolts or studs

    International Nuclear Information System (INIS)

    Seward, W.H.

    1977-01-01

    Reference is made to anti-seize bolts or studs for use in extreme conditions, such as in nuclear power plants. A number of methods have been proposed for avoiding seizure, but have met with limited success. One approach to this problem is to coat the surfaces of the steel bolt in such a way that the contacting surfaces of the bolt and its associated nut are sufficiently dissimilar for molecular seizure to be avoided. It has been discovered that greatly improved resistance to seizing can be obtained by hard plating the entire thread of an alloy steel bolt with Cr. After Cr plating the bolt is de-embrittled by suitable heat treatment. (U.K.)

  4. Remote Impedance-based Loose Bolt Inspection Using a Radio-Frequency Active Sensing Node

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seung Hee; Yun, Chung Bang [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Inman, Daniel J. [Virginia Polytechnic Institute and State University, Virginia (United States)

    2007-06-15

    This paper introduces an active sensing node using radio-frequency (RF) telemetry. This device has brought the traditional impedance-based structural health monitoring (SHM) technique to a new paradigm. The RF active sensing node consists of a miniaturized impedance measuring device (AD5933), a microcontroller (ATmega128L), and a radio frequency (RF) transmitter (XBee). A macro-fiber composite (MFC) patch interrogates a host structure by using a self-sensing technique of the miniaturized impedance measuring device. All the process including structural interrogation, data acquisition, signal processing, and damage diagnostic is being performed at the sensor location by the microcontroller. The RF transmitter is used to communicate the current status of the host structure. The feasibility of the proposed SHM strategy is verified through an experimental study inspecting loose bolts in a bolt-jointed aluminum structure

  5. Remote Impedance-based Loose Bolt Inspection Using a Radio-Frequency Active Sensing Node

    International Nuclear Information System (INIS)

    Park, Seung Hee; Yun, Chung Bang; Inman, Daniel J.

    2007-01-01

    This paper introduces an active sensing node using radio-frequency (RF) telemetry. This device has brought the traditional impedance-based structural health monitoring (SHM) technique to a new paradigm. The RF active sensing node consists of a miniaturized impedance measuring device (AD5933), a microcontroller (ATmega128L), and a radio frequency (RF) transmitter (XBee). A macro-fiber composite (MFC) patch interrogates a host structure by using a self-sensing technique of the miniaturized impedance measuring device. All the process including structural interrogation, data acquisition, signal processing, and damage diagnostic is being performed at the sensor location by the microcontroller. The RF transmitter is used to communicate the current status of the host structure. The feasibility of the proposed SHM strategy is verified through an experimental study inspecting loose bolts in a bolt-jointed aluminum structure

  6. Overall bolt stress optimization

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The state of stress in bolts and nuts with International Organization for Standardization metric thread design is examined and optimized. The assumed failure mode is fatigue, so the applied preload and the load amplitude together with the stress concentrations define the connection strength....... Maximum stress in the bolt is found at the fillet under the head, at the thread start, or at the thread root. To minimize the stress concentration, shape optimization is applied. Nut shape optimization also has a positive effect on the maximum stress. The optimization results show that designing a nut......, which results in a more evenly distribution of load along the engaged thread, has a limited influence on the maximum stress due to the stress concentration at the first thread root. To further reduce the maximum stress, the transition from bolt shank to the thread must be optimized. Stress reduction...

  7. 5/8'' baffle bolt replacement

    International Nuclear Information System (INIS)

    Pinaud, T.; Grypczynski, D.

    1999-01-01

    Both Framatome Nuclear Services in France and its U.S. arm, FT1, are now equipped with baffle bolt inspection and replacement packages. These packages allow them to tackle baffle bold degradation on both two- and three-loop nuclear power plants. Framatome and FT1 together are world leaders in addressing reactor vessel internal bolting concerns

  8. Bolt beam propagation analysis

    Science.gov (United States)

    Shokair, I. R.

    BOLT (Beam on Laser Technology) is a rocket experiment to demonstrate electron beam propagation on a laser ionized plasma channel across the geomagnetic field in the ion focused regime (IFR). The beam parameters for BOLT are: beam current I(sub b) = 100 Amps, beam energy of 1--1.5 MeV (gamma =3-4), and a Gaussian beam and channel of radii r(sub b) = r(sub c) = 1.5 cm. The N+1 ionization scheme is used to ionize atomic oxygen in the upper atmosphere. This scheme utilizes 130 nm light plus three IR lasers to excite and then ionize atomic oxygen. The limiting factor for the channel strength is the energy of the 130 nm laser, which is assumed to be 1.6 mJ for BOLT. At a fixed laser energy and altitude (fixing the density of atomic oxygen), the range can be varied by adjusting the laser tuning, resulting in a neutralization fraction axial profile of the form: f(z) = f(sub 0) e(exp minus z)/R, where R is the range. In this paper we consider the propagation of the BOLT beam and calculate the range of the electron beam taking into account the fact that the erosion rates (magnetic and inductive) vary with beam length as the beam and channel dynamically respond to sausage and hose instabilities.

  9. Investigation of Reliabilities of Bolt Distances for Bolted Structural Steel Connections by Monte Carlo Simulation Method

    Directory of Open Access Journals (Sweden)

    Ertekin Öztekin Öztekin

    2015-12-01

    Full Text Available Design of the distance of bolts to each other and design of the distance of bolts to the edge of connection plates are made based on minimum and maximum boundary values proposed by structural codes. In this study, reliabilities of those distances were investigated. For this purpose, loading types, bolt types and plate thicknesses were taken as variable parameters. Monte Carlo Simulation (MCS method was used in the reliability computations performed for all combination of those parameters. At the end of study, all reliability index values for all those distances were presented in graphics and tables. Results obtained from this study compared with the values proposed by some structural codes and finally some evaluations were made about those comparisons. Finally, It was emphasized in the end of study that, it would be incorrect of the usage of the same bolt distances in the both traditional designs and the higher reliability level designs.

  10. Critical joints in large composite aircraft structure

    Science.gov (United States)

    Nelson, W. D.; Bunin, B. L.; Hart-Smith, L. J.

    1983-01-01

    A program was conducted at Douglas Aircraft Company to develop the technology for critical structural joints of composite wing structure that meets design requirements for a 1990 commercial transport aircraft. The prime objective of the program was to demonstrate the ability to reliably predict the strength of large bolted composite joints. Ancillary testing of 180 specimens generated data on strength and load-deflection characteristics which provided input to the joint analysis. Load-sharing between fasteners in multirow bolted joints was computed by the nonlinear analysis program A4EJ. This program was used to predict strengths of 20 additional large subcomponents representing strips from a wing root chordwise splice. In most cases, the predictions were accurate to within a few percent of the test results. In some cases, the observed mode of failure was different than anticipated. The highlight of the subcomponent testing was the consistent ability to achieve gross-section failure strains close to 0.005. That represents a considerable improvement over the state of the art.

  11. Experimental Study on Shear Performance of Bolt in Roadway Supporting

    Directory of Open Access Journals (Sweden)

    D.J. Li

    2014-09-01

    Full Text Available The corner bolt is proved to be effective in the control of floor deformation of roadway, and the relevant studies on bolting mechanisms are of great significance in improving roadway stability. In this paper, two types of shear tests on six forms of bolts are performed by using self-designed shear test device, the electro-hydraulic servo triaxial testing system. The shear characteristics of different types of bolts are obtained. The results show that different bolt rods or different internal filling conditions result in large differences in shear resistance and different deformation adaptability. We find that the filling materials added can improve the shear performance of bolt significantly, and the bolt with steel not only can improve the strength of bolt body, but also has the bimodal characteristic that makes the bolt have the secondary bearing capacity and withstand larger deformation range during the process of shear, and shows a better support performance. Hoping to provide the experiment basis for support design and field application in the future.

  12. A structural health monitoring fastener for tracking fatigue crack growth in bolted metallic joints

    Science.gov (United States)

    Rakow, Alexi Schroder

    sensor, data acquisition hardware, algorithm, and diagnostic display. The AIME sensor design, SHM Fastener, and complete SHM system are presented along with experimental results from a series of single-layer and bolted double lap joint aluminum laboratory specimens to validate the capability of these sensors to monitor metallic joints for fastener hole cracks. Fatigue cracks were successfully tracked to over 0.7 inches from the fastener hole in these tests. Sensor output obtained from single-layer fatigue specimens was compared with analytical predictions for fatigue crack growth versus cycle number showing a good correlation in trend between sensor output and predicted crack size.

  13. Device for ultrasonic and eddy current testing of bolts

    International Nuclear Information System (INIS)

    Hromek, J.; Kaspar, P.

    1989-01-01

    The device provides pivoting fitting of the bolt of a WWER reactor steam generator while ultrasonic and eddy current probes are brought near. The bolt under study is clamped between a drive funnel and a securing cone. The eddy current probes are adjusted using guide arms to the point requested and are fitted over the bolt such as for their thread segments to engage the bolt thread. The ultrasonic transducers are then adjusted to the required point. The device can be used for testing bolts of a thread size from M54x5 and a maximum length of 600 mm. (J.B.). 1 fig

  14. Bolt and nut evaluator

    Science.gov (United States)

    Kerley, James J.; Burkhardt, Raymond; White, Steven

    1994-02-01

    A device for testing fasteners such as nuts and bolts is described which consists of a fixed base plate having a number of threaded and unthreaded holes of varying size for receiving the fasteners to be tested, a torque marking paper taped on top the fixed base plate for marking torque-angle indicia, a torque wrench for applying torque to the fasteners being tested, and an indicator for showing the torque applied to the fastener. These elements provide a low cost, nondestructive device for verifying the strength of bolts and nuts.

  15. Behaviour of steel-concrete composite beams using bolts as shear connectors

    Science.gov (United States)

    Tran, Minh-Tung; Nguyen Van Do, Vuong; Nguyen, Tuan-Anh

    2018-04-01

    The paper presents an experimental program on the application of bolts as shear connectors for steel-composite beams. Four steel- concrete composite beams and a reference steel beam were made and tested. The aim of the testing program is to examine which forms of the steel bolts can be used effectively for steel-composite beams. The four types of the bolts include: Type 1 the bolt with the nut at the end; Type 2 the bolt bending at 900 hook; Type 3 the bolt without the nut at the end and Type 4 the bolt with the nut at the end but connected with the steel beam by hand welding in other to be connected with the steel beam by bolt connection as in the first three types. The test results showed that beside the traditional shear connectors like shear studs, angle type, channel type, bolts can be used effectively as the shear connectors in steel-composite beams and the application of bolts in Types 1 and 2 in the composite beams gave the better performance for the tested beam.

  16. Alloy-steel bolting materials for special applications

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This specification covers regular and special-quality alloy steel bolting materials which may be used for nuclear and other special applications. Bolting materials as used in the specification cover rolled or forged bars, rotary pierced or extruded seamless tubes, bored bars, or forged hollows from forged or rolled bar segments to be machined into bolts, studs, washers, and nuts. Several grades of steel are covered and supplementary requirements of an optional nature are provided for use when special quality is desired

  17. 21 CFR 137.255 - Bolted white corn meal.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Bolted white corn meal. 137.255 Section 137.255... Flours and Related Products § 137.255 Bolted white corn meal. (a) Bolted white corn meal is the food prepared by so grinding and sifting cleaned white corn that: (1) Its crude fiber content is less than 1.2...

  18. Development of a Unified Rock Bolt Model in Discontinuous Deformation Analysis

    Science.gov (United States)

    He, L.; An, X. M.; Zhao, X. B.; Zhao, Z. Y.; Zhao, J.

    2018-03-01

    In this paper, a unified rock bolt model is proposed and incorporated into the two-dimensional discontinuous deformation analysis. In the model, the bolt shank is discretized into a finite number of (modified) Euler-Bernoulli beam elements with the degrees of freedom represented at the end nodes, while the face plate is treated as solid blocks. The rock mass and the bolt shank deform independently, but interact with each other through a few anchored points. The interactions between the rock mass and the face plate are handled via general contact algorithm. Different types of rock bolts (e.g., Expansion Shell, fully grouted rebar, Split Set, cone bolt, Roofex, Garford and D-bolt) can be realized by specifying the corresponding constitutive model for the tangential behavior of the anchored points. Four failure modes, namely tensile failure and shear failure of the bolt shank, debonding along the bolt/rock interface and loss of the face plate, are available in the analysis procedure. The performance of a typical conventional rock bolt (fully grouted rebar) and a typical energy-absorbing rock bolt (D-bolt) under the scenarios of suspending loosened blocks and rock dilation is investigated using the proposed model. The reliability of the proposed model is verified by comparing the simulation results with theoretical predictions and experimental observations. The proposed model could be used to reveal the mechanism of each type of rock bolt in realistic scenarios and to provide a numerical way for presenting the detailed profile about the behavior of bolts, in particular at intermediate loading stages.

  19. FLANGE-ORNL, Flanged Pipe Joint Stress Analysis, Internal Pressure, Moment Loads, Temperature

    International Nuclear Information System (INIS)

    Rodabaugh, E.C.; Moore, S.E.

    1979-01-01

    1 - Description of problem or function: FLANGE-ORNL calculates appropriate loads, stresses, and displacements for the flanges, bolts, and gaskets that comprise a flanged piping joint for internal pressure or moment loading on the pipe, temperature difference between the flange hub and ring, and variations in bolt load that result from pressure, hub-ring temperature gradient and/or bolt-ring temperature differences. Flanges considered may be tapered-hub, straight or blind. 2 - Method of solution: The solution is based on discontinuity analysis and the theory of plates and shells

  20. A Probabilistic Approach to Baffle Bolt IASCC Predictions

    International Nuclear Information System (INIS)

    Griesbach, Timothy J.; Licina, George J.; Riccardella, Peter C.; Rashid, Joe R.; Nickell, Robert E.

    2012-01-01

    A methodology for evaluating the probability of baffle-former bolt cracking was developed for applicability to PWRs. The methodology is based upon IASCC test results for the stainless steels most commonly used for baffle-former bolts (e.g., Type 304 SA, Type 347 SA, and Type 316 CW) and predictions of the representative stress patterns in those bolts that were developed as inputs to the model. The predictive methodology for IASCC is based on a single parameter that was developed to incorporate the combined effects of dose and stress ratio (applied stress divided by yield strength, where the yield strength includes irradiation hardening) plus a Weibull statistical distribution that is defined in terms of that parameter. Baffle-former bolt cracking has been observed in a number of PWRs, and these incidents have raised concerns about the likelihood of future cracking or failures. In this damage model, IASCC 'failure' is defined when the component becomes fully susceptible to stress corrosion cracking; that is, after a certain level of irradiation and sustained stress. The length of time required for the material to become fully susceptible was determined from IASCC test data. IASCC crack initiation, which is defined to be equivalent to failure as noted above, is defined by an IASCC susceptibility curve from the test data that relates applied stress and cumulative neutron dose. The dose duration under constant stress is interpreted as the incubation time needed to make the material susceptible to stress corrosion cracking, after which crack initiation and propagation to full rupture under constant stress will occur within a relatively short time (hundreds of hours). The IASCC failure model uses the calculated stress in a material such as the baffle-former bolt and calculates a damage index as the ratio of the current applied stress to the allowable stress as a function of irradiation dose. IASCC initiation data for various irradiated bolting materials was obtained from

  1. Ageing management of baffle former bolts in Belgian nuclear power plants

    International Nuclear Information System (INIS)

    Somville, F.; Gerard, R.; Bosch, R.W.; Bertolis, D.; Vissers, S.

    2015-01-01

    The Pressurized Water Reactors internals support the reactor core, distribute the coolant flow through the core, and guide and protect the rod control cluster assemblies and in-core instrumentation. The baffle-to-former bolts are used in Pressurized Water Reactors to attach the baffle plates to the former plates in the reactor vessel lower internals. The resulting structure forms a boundary for the flow of coolant and provides lateral support to the fuel assemblies. Some edge bolts are also present, assembling together the baffle plates. After an operating time of the order of 120.000 hours, some bolts exhibit cracking at the junction of the head and the shank of the bolt. Examinations of failed bolts have made it possible to identify the cause of cracking as irradiation assisted stress corrosion cracking (IASCC). Up to now, baffle bolt cracking has been detected in units older than 15 years, where the baffle bolts are not cooled (no holes in the former to allow a water flow on the bolt shank). In Belgium, the concerned units are Tihange 1 and Doel 1-2. The paper summarizes the experience with baffle bolts cracking in Belgian units and the strategy implemented to mitigate this problem, consisting of structural integrity analyses, baffle bolts inspections and replacement, and research programs in the field of IASCC, including examinations of highly irradiated replaced bolts. (authors)

  2. A study of high-strength bolts after dephosphoring

    Directory of Open Access Journals (Sweden)

    Shao-Yi Hsia

    2016-03-01

    Full Text Available A wide variety of fasteners are produced, including those for the automobile industry, household electrical appliances industry, architectural engineering, and even the aviation industry. The effects of the high-tensile bolt dephosphoring process on the entire fastener manufacturing process and its organizational characteristics and mechanical properties are analyzed and discussed in this study. Our experimental results reveal that the bolt dephosphoring process must be completed before heat treatment, which can be confirmed with a dephosphoring reagent or metallographic observation. Once bolt heat treatment is completed, bolts without dephosphoring appear to be coated with δ ferrite (delta ferrite composed of a phosphate coating and a phosphatizing coating, which are not easily removed. Heat treatment with phosphorus results in grain boundary segregation, causing embrittlement and a reduction in lattice bonding forces and resulting in a high risk of fracturing when bolts are used in high-temperature environments or undergo multiaxial stresses.

  3. Result from systematic compilation of barrel bolt findings in S/KWU type PWRs in the context of computational analysis

    International Nuclear Information System (INIS)

    Kilian, R.; Devrient, B.; Koenig, G.; Stanislowski, M.; Widera, M.; Beusekom, R. van; Wermelinger, T.

    2015-01-01

    In 2005 intergranular stress corrosion cracking (IGSCC) of barrel bolts was observed in several S/KWU type PWRs. The bolts, known as star bolts, are made of SS type 316 Ti (German Material No. 1.4571 K) bars which are cold worked to adjust the required mechanical properties. This damage mechanism was so far less understood for PWR primary conditions. Therefore an extended joint research program was launched by AREVA GmbH and VGB e.V. to clarify the specific conditions which contributed to the observed findings on barrel bolts. A systematic analysis of the IGSCC affecting parameters as material, heats, environment and mechanical load was performed based on a plant data compilation from all six S/KWU PWRs with comparable core barrel design using barrel and baffle bolts made from type 316Ti. Using the outcome of this systematic data compilation additional computational fluid dynamics calculations in combination with radiolysis calculations were performed. The results showed that by a combination of reduced volume exchange by local flow conditions and radiolysis reactions forming oxidizing species as dissolved oxygen and/or hydrogen peroxide may locally affect the corrosion behavior of cold worked austenitic stainless steels. Therefore, small local volumes with oxidizing water chemistry conditions are assumed to lead to the IGSCC of cold worked type 316Ti. The comparison of the initial cold worked microstructure by TEM with the cold worked and in service irradiated microstructure (void formation, dislocation loop density, etc.) clearly reveals that neutron irradiation hardening in terms of IASCC (Irradiation-Assisted Stress Corrosion Cracking) is not the leading mechanism for these cases of barrel bolt cracking in the analyzed PWRs. (authors)

  4. On analysis and redesign of bolted L-flanged connections

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2017-01-01

    and the tensile force in the bolt. In the literature and also in standards,different models are presented for this important non-linear response. In the present paper, a simplified expression for the non-linear force response is presented based on finite element calculations using contact analysis. The L......-flange connection is in essence a bad design because it leads to a non-optimal ratio between external force and bolt force. Furthermore,bolt bending results in an even higher bolt stress resulting in a reduction of strength. The present paper presents simple modifications of the L-flange design that considerably...

  5. In situ ultrasonic examination of high-strength steam generator support bolts

    International Nuclear Information System (INIS)

    Jusino, A.

    1985-01-01

    Currently employed high-strength steam generator support bolting material (designed prior to ASME Section III Part NF or Component Supports), 38.1 mm in diameter, in combination with high preloads are susceptible to stress corrosion cracking because of the relatively low stress corrosion resistance (K/sub ISCC/) properties. These bolts are part of the pressurized water reactor steam generator supports at the integral support pads (three per steam generator, with each pad housing six, eight, or ten bolts depending on the design). The US Nuclear Regulatory Commission concerns for high-strength bolting were identified in NUREG-0577, ''Potential for Low Fracture Toughness and Laminar Tearing in PWR Steam Generator and Reactor Coolant Pump Supports,'' which was issued for comment on unresolved safety issue A-12. Subsequently, the bolting issues were addressed in generic issue B29. One of the issues deals specifically with high-strength bolting materials, which are vulnerable to stress corrosion cracking. A Westinghouse Owners Group funded program was established to develop in situ ultrasonic examination techniques to determine steam generator support bolting integrity at the head-to-shank and first-thread locations. This program was established in order to determine bolting integrity in place. Ultrasonic techniques were developed for both socket-head and flat-head bolt configurations. As a result of this program, in situ ultrasonic examination techniques were developed for examination of PWR steam generator support bolts. By employing these techniques utilities will be able to ensure the integrity of this in-place bolting without incurring the costs previously experienced during removal for surface examinations

  6. Evaluation of Roof Bolting Requirements Based on In-Mine Roof Bolter Drilling

    Energy Technology Data Exchange (ETDEWEB)

    Syd S. Peng

    2005-10-01

    Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on this information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. For the prediction of roof geology and stability condition in real time, a micro processor was used and a program developed to monitor and record the drilling parameters of roof bolter. These parameters include feed pressure, feed flow (penetration rate), rotation pressure, rotation rate, vacuum pressure, oil temperature of hydraulic circuit, and signals for controlling machine. From the results of a series of laboratory and underground tests so far, feed pressure is found to be a good indicator for identifying the voids/fractures and estimating the roof rock strength. The method for determining quantitatively the location and the size of void/fracture and estimating the roof rock strength from the drilling parameters of roof bolter was developed. Also, a set of computational rules has been developed for in-mine roof using measured roof drilling parameters and implemented in MRGIS (Mine Roof Geology Information System), a software package developed to allow mine engineers to make use of the large amount of roof drilling parameters for predicting roof geology properties automatically. For the development of roof bolting criteria, finite element models were developed for tensioned and fully grouted bolting

  7. A new energy-absorbing bolt for rock support in high stress rock masses

    Energy Technology Data Exchange (ETDEWEB)

    Charlie Chunlin Li [Norwegian University of Science and Technology (NTNU) (Norway)

    2010-04-15

    An energy-absorbing rock support device, called a D bolt, has been recently developed to counteract both burst-prone and squeezing rock conditions that occur during underground excavation. The bolt is a smooth steel bar with a number of anchors along its length. The anchors are firmly fixed within a borehole using either cement grout or resin, while the smooth sections of the bolt between the anchors may freely deform in response to rock dilation. Failure of one section does not affect the reinforcement performance of the other sections. The bolt is designed to fully use both the strength and the deformation capacity of the bolt material along the entire length. The bolt has large load-bearing and deformation capacities. Static pull tests and dynamic drop tests show that the bolt length elongates by 14-20% at a load level equal to the strength of the bolt material, thereby absorbing a large amount of energy. The impact average load of a 20 mm D bolt is 200-230 kN, with only a small portion of the load transferred to the bolt plate. The cumulative dynamic energy absorption of the bolt is measured to be 47 kJ/m. D bolts were tested in three deep mines. Filed measurements show that D bolts are loaded less than rebar bolts. This paper presents the layout and principle of the D bolt, and corresponding results from static, dynamic, and field tests.

  8. Small-Bolt Torque-Tension Tester

    Science.gov (United States)

    Posey, Alan J.

    2009-01-01

    The device described here measures the torque-tension relationship for fasteners as small as #0. The small-bolt tester consists of a plate of high-strength steel into which three miniature load cells are recessed. The depth of the recess is sized so that the three load cells can be shimmed, the optimum height depending upon the test hardware. The three miniature load cells are arranged in an equilateral triangular configuration with the test bolt aligned with the centroid of the three. This is a kinematic arrangement.

  9. Failure Analysis on Tail Rotor Teeter Pivot Bolt on a Helicopter

    Science.gov (United States)

    Qiang, WANG; Zi-long, DONG

    2018-03-01

    Tail rotor teeter pivot bolt of a helicopter fractured when in one flight. Failure analysis on the bolt was finished in laboratory. Macroscopic observation of the tailor rotor teeter pivot bolt, macro and microscopic inspection on the fracture surface of the bolt was carried out. Chemical components and metallurgical structure was also carried out. Experiment results showed that fracture mode of the tail rotor teeter pivot bolt is fatigue fracture. Fatigue area is over 80% of the total fracture surface, obvious fatigue band characteristics can be found at the fracture face. According to the results were analyzed from the macroscopic and microcosmic aspects, fracture reasons of the tail rotor teeter pivot bolt were analyzed in detail

  10. Effect of fiberglass reinforcement on the behavior of bolted wood connections

    Science.gov (United States)

    Lawrence A. Soltis; Robert J. Ross; Daniel E. Windorski

    1997-01-01

    Bolted connections often fail by a shear plug or by splitting beneath the bolt caused by tension perpendicular-to-grain stress as the bolt wedges its way through the wood. Preventing this type of failure enhances both the capacity and reliability of bolted connections. This research investigated the use of fiberglass reinforcement to enhance the load-carrying capacity...

  11. Development of design and analysis methodology for composite bolted joints

    Science.gov (United States)

    Grant, Peter; Sawicki, Adam

    1991-05-01

    This paper summarizes work performed to develop composite joint design methodology for use on rotorcraft primary structure, determine joint characteristics which affect joint bearing and bypass strength, and develop analytical methods for predicting the effects of such characteristics in structural joints. Experimental results have shown that bearing-bypass interaction allowables cannot be defined using a single continuous function due to variance of failure modes for different bearing-bypass ratios. Hole wear effects can be significant at moderate stress levels and should be considered in the development of bearing allowables. A computer program has been developed and has successfully predicted bearing-bypass interaction effects for the (0/+/-45/90) family of laminates using filled hole and unnotched test data.

  12. Visual recognition of the load of roof-bolts by an indicator

    Energy Technology Data Exchange (ETDEWEB)

    Leonhardt, J. [Leon Industries (Germany)

    2001-07-01

    Hundreds of bolt-indicators were already used successfully in the German deep hard coal-mines to increase the safety and economy. The bolt-indicator offers the simple possibility to guard roof-bolt loads, to state weak points as well as to optimize the anchor density and the dimension. The bolt-indicator are mushroom shaped and are of coated metal. It is brought in between the anchor plate and the anchor mother. The loads appearing at the anchor will transfer to the bolt-indicators and can be recognized visually at the cylindrical part by the amount of the surface coating. A select example clarifies itself application aims, operation and a usage of the bolt-indicator and the yielding advantages in practice. (orig.)

  13. An interactive roof bolting selection and performance system

    Energy Technology Data Exchange (ETDEWEB)

    Agioutantis, Z.; Stiakakis, C.; Stiakakis, N. [Technical Univ. of Crete, Chania (Greece); Karmis, M. [Virginia Polytechnic Inst. and State Univ. (United States)

    2001-07-01

    In the last decades, bolting has become one of the most dominant support methods in underground construction, including both mining as well as civil engineering applications. A variety of bolt types has been developed in order to meet the support needs of different geological and geotechnical settings. The selection of the appropriate bolt type, as well as the troubleshooting procedures in case of failure or suspected failure, are often complex and require extensive experience. To facilitate bolt type selection as well as troubleshooting, various tools have been presented in the form of nomograms, computer programs or trouble shooting guides. The approach described in this paper incorporates information and data developed by laboratory and field investigations and has led to the development of a dynamic knowledge base system that can aid in the selection of appropriate bolting systems and, also, help troubleshoot existing installations. Additionally, the user can enhance the functionality of the existing database with site-specific information and geological behavior as experienced by field personnel. The package is developed as a Windows trademark based application, where data is stored in Microsoft Access trademark database. (orig.)

  14. Experimental study on birefringence effect in high-tension bolts

    International Nuclear Information System (INIS)

    Kim, No You; Lee, Sang Soon; Jang, Kyung Young

    2005-01-01

    Bolts widely used in machine parts and assemblies are pre-loaded to prevent the parts from separating and to maintain the strength of the assemblies. Conventional technique for measurement of this axial stress applied to bolts is torque meter, but it has two disadvantages. The first one is its inherent inaccuracy. The second is that the stress cannot be determined after assembly without twisting bolts. The most promising technique for measurement of the axial stress is the acousto-elasticity. In this study, a new acousto-elasticity technique based on birefringence principle is proposed and tested to measure the axial stress in bolts which uses two longitudinal and shear waves instead of two horizontally polarized shear waves. From experimental results, the difference between the longitudinal and shear wave velocity is shown to be linearly related to the applied stress and be able to be used effectively to monitor the axial stress in bolts.

  15. ["Bolt projectiles" discharged from modified humane killers (author's transl)].

    Science.gov (United States)

    Pollak, S; Reiter, C

    1981-01-01

    Some common types of "humane killers" are supplied with rubber bushings and recoil springs holding back the bolt, which afterwards is rebound into the barrel. Removal of the rubber bush and withdrawal spring before firing can cause the bolt to break and become a free projectile. A suicide case is reported, in which a livestock stunner discharged a steel bolt penetrating the forehead and getting stuck in the skull.

  16. Conveyor system bolt failure analysis

    International Nuclear Information System (INIS)

    McCutcheon, S.H.; Waaser, R.E.

    1981-07-01

    The Savannah River Plant (SRP) is operated for the U.S. Department of Energy (DOE) by E.I. du Pont de Nemours and Co. Reactors at SRP are used to produce nuclear isotopes for national defense. As part of the routine operation of each of the reactors, irradiated fuel assemblies are remotely discharged from the reactor, transferred in air, and placed underwater in a Deposit and Exit (D and E) canal. The D and E conveyor transports the assemblies under the reactor room wall into the disassembly basin, where they are stored for several months before shipment to the separations areas. On August 13, 1980, a broken bolt was discovered on the D and E conveyor during a routine pre-operational inspection. The failed bolt was one of four which anchor a bearing on one of the conveyor drive shafts. All four of the bolts on the affected bearing were replaced as an immediate corrective measure and the discharge of irradiated fuel assemblies was subsequently completed without difficulty

  17. A novel method for detecting second harmonic ultrasonic components generated from fastened bolts

    Science.gov (United States)

    Fukuda, Makoto; Imano, Kazuhiko

    2012-09-01

    This study examines the use of ultrasonic second harmonic components in the quality control of bolt-fastened structures. An improved method for detecting the second harmonic components, from a bolt fastened with a nut, using the transmission method is constructed. A hexagon head iron bolt (12-mm diameter and 25-mm long) was used in the experiments. The bolt was fastened using a digital torque wrench. The second harmonic component increased by approximately 20 dB before and after the bolt was fastened. The sources of second harmonic components were contact acoustic nonlinearity in the screw thread interfaces of the bolt-nut and were the plastic deformation in the bolt with fastening bolt. This result was improved by approximately 10 dB compared with previous our method. Consequently, usefulness of the novel method for detecting second harmonic ultrasonic components generated from fastened bolt was confirmed.

  18. Thermo-mechanical finite element analyses of bolted cask lid structures

    International Nuclear Information System (INIS)

    Wieser, G.; Qiao Linan; Eberle, A.; Voelzke, H.

    2004-01-01

    The analysis of complex bolted cask lid structures under mechanical or thermal accident conditions is important for the evaluation of cask integrity and leak-tightness in package design assessment according to the Transport Regulations or in aircraft crash scenarios. In this context BAM is developing methods based on Finite Elements to calculate the effects of mechanical impacts onto the bolted lid structures as well as effects caused by severe fire scenarios. I n case of fire it might be not enough to perform only a thermal heat transfer analysis. The complex cask design in connection with a severe hypothetical time-temperature-curve representing an accident fire scenario will create a strong transient heating up of the cask body and its lid system. This causes relative displacements between the seals and its counterparts that can be analyzed by a so-called thermo-mechanical calculation. Although it is currently not possible to correlate leakage rates with results from deformation analyses directly an appropriate Finite Element model of the considered type of metallic lid seal has been developed. For the present it is possible to estimate the behaviour of the seal based on the calculated relative displacements at its seating and the behaviour of the lid bolts under the impact load or the temperature field respectively. Except of the lid bolts the geometry of the cask and the mechanical loading is axial-symmetric which simplifies the analysis considerably and a two-dimensional Finite Element model with substitute lid bolts may be used. The substitute bolts are modelled as one-dimensional truss or beam elements. An advanced two-dimensional bolt submodel represents the bolts with plane stress continuum elements. This paper discusses the influence of different bolt modelling on the relative displacements at the seating of the seals. Besides this, the influence of bolt modelling, thermal properties and detail in geometry of the two-dimensional Finite Element models on

  19. Bolt Thread Stress Optimization

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2012-01-01

    of threads and therefore indirectly the bolt fatigue life. The root shape is circular, and from shape optimization for minimum stress concentration it is well known that the circular shape is seldom optimal. An axisymmetric Finite Element (FE) formulation is used to analyze the bolted connection, and a study...... is performed to establish the need for contact modeling with regard to finding the correct stress concentration factor. Optimization is performed with a simple parameterization with two design variables. Stress reduction of up to 9% is found in the optimization process, and some similarities are found...... in the optimized designs leading to the proposal of a new standard. The reductions in the stress are achieved by rather simple changes made to the cutting tool....

  20. Computerized UT system for stud bolt

    International Nuclear Information System (INIS)

    Kisanuki, T.; Uchida, K.; Fushimi, T.; Onda, K.

    1988-01-01

    Cracking of stud bolts used in steam turbine casing, valve and pressure vessel has caused concern regarding the safety and reliability of power plants. In order to detect harmful cracks in early state, the improvement of UT technique is required. As regarding the ultrasonic inspection technique, a longitudinal beam technique and/or an angle beam technique are generally used. The authors report their development of a computerized UT system for bolt inspection and improvement of the angle beam technique

  1. More Nuts and Bolts of Michaelis-Menten Enzyme Kinetics

    Science.gov (United States)

    Lechner, Joseph H.

    2011-01-01

    Several additions to a classroom activity are proposed in which an "enzyme" (the student) converts "substrates" (nut-bolt assemblies) into "products" (separated nuts and bolts) by unscrewing them. (Contains 1 table.)

  2. Evaluation of Rock Bolt Support for Polish Hard Rock Mines

    Science.gov (United States)

    Skrzypkowski, Krzysztof

    2018-03-01

    The article presents different types of rock bolt support used in Polish ore mining. Individual point resin and expansion rock bolt support were characterized. The roof classes for zinc and lead and copper ore mines were presented. Furthermore, in the article laboratory tests of point resin rock bolt support in a geometric scale of 1:1 with minimal fixing length of 0.6 m were made. Static testing of point resin rock bolt support were carried out on a laboratory test facility of Department of Underground Mining which simulate mine conditions for Polish ore and hard coal mining. Laboratory tests of point resin bolts were carried out, especially for the ZGH Bolesław, zinc and lead "Olkusz - Pomorzany" mine. The primary aim of the research was to check whether at the anchoring point length of 0.6 m by means of one and a half resin cartridge, the type bolt "Olkusz - 20A" is able to overcome the load.The second purpose of the study was to obtain load - displacement characteristic with determination of the elastic and plastic range of the bolt. For the best simulation of mine conditions the station steel cylinders with an external diameter of 0.1 m and a length of 0.6 m with a core of rock from the roof of the underground excavations were used.

  3. Operational monitoring of temperature and state of stress of primary collectors, their stud bolts and cover and temperatures of steam generator's pressure vessel at the nuclear power unit WWER 440

    International Nuclear Information System (INIS)

    Matal, O.; Simo, T.; Holy, F.; Vejvoda, S.

    1992-01-01

    Both primary collectors of the WWER 440 steam generator (STGE) are vertically positioned inside the STGE pressure vessel and connected in their lower part to the primary piping and closed at their upper part by primary covers. The primary cover is pushed against the primary collector flange by 20 stud bolts. Two nickel packing rings are fitted between the primary cover and collector. A leakage in the collector-cover junction could cause flow of the radioactive water into the clean secondary water. If the junction is made in accordance with the Soviet standard design the computed stresses exceed the allowable value in the stud bolts by a factor of 1.5. Therefore an improved design of the primary collector - primary cover flange joint was designed and tested on one STGE at a WWER 440 nuclear power unit in Czechoslovakia. The paper describes the system of joint properties measurement, gives some substantial characteristics of the new stud bolts and primary cover design and comments on significant measured results of state of stress and temperatures in comparison with the operational regime of the STGE. (orig.)

  4. Effect of Different Connection Modes on Bolt Structural Properties of TC4 Alloy in Selective Laser Melting

    Science.gov (United States)

    Li, Xiaodan; Huang, Shuangjun; Xu, Liang; Hui, Li; Zhou, Song

    2017-12-01

    The bolt structural properties of selective laser melted (SLM) samples produced from TC4 powder metal has been investigated. Two different connection molds relative to single lap joint and bilateral lap joint as well as two different state of surface quality were considered. Samples and test procedures were designed in accordance with HB 5143 and HB 5287 standard. The results show that there is a strong influence of connection molds on the dynamic behavior of SLM produced TC4. The mechanical properties of bilateral lap joint are better than those of the single lap joint. Meanwhile the fatigue performance of the bilateral lap joint is much stronger than that of the single lap joint which it is a symmetrical structure of the two-shear test on both sides of the force evenly, while the single lap joint is a single shear sample of the uneven force. There are two kinds of fracture form most of which are broken in the first row of screw and a small part in the middle of the connecting plate.

  5. Design Procedure on Stud Bolt for Reactor Vessel Assembly

    International Nuclear Information System (INIS)

    Kim, Jong-Wook; Lee, Gyu-Mahn; Jeoung, Kyeong-Hoon; Kim, Tae-Wan; Park, Keun-Bae; Kim, Keung-Koo

    2008-10-01

    The reactor pressure vessel flange is welded to the upper part of reactor pressure vessel, and there are stud holes to mount the closure head with stud bolts. The surface mating the closure head is compressed with O-ring, which acts as a sealing gasket to prevent coolant leakage. Bolted flange connections perform a very important structural role in the design of a reactor pressure vessel. Their importance stems from two important functions: (a) maintenance of the structural integrity of the connection itself, and (b) prevention of leakage through the O-ring preloaded by stud bolts. In the present study, an evaluation procedure for the design of stud bolt is developed to meet ASME code requirements. The developed design procedure could provide typical references in the development of advanced reactor design in the future

  6. EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING

    Energy Technology Data Exchange (ETDEWEB)

    Syd S. Peng

    2003-07-15

    Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal, potash, salt etc. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on such information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. In this quarter, the field, theoretical and programming works have been performed toward achieving the research goals set in the proposal. The selected site and the field testing plan enabled us to test all three aspects of roof geological features. The development of the data interpretation methodologies and the geology mapping computer program have also been preceding well.

  7. Effects of Head Size on the Performance of Twist-Off Bolts

    OpenAIRE

    Schnupp, Keith Otto

    2003-01-01

    This study examines a specific application of button-head type twist-off bolts. Currently, the Research Council on Structural Connections Specification (2000) removes the requirement for ASTM F436 washers (ASTM 2000a) under the bolt head of twist-off bolts where the head diameter equals or exceeds that of an ASTM F436 washer when oversized and slotted holes are used. The need for washers is also removed for A490 strength bolts used on steels with specified yield strengths less than 40 ksi p...

  8. Ultimate load capacities of expansion anchor bolts

    International Nuclear Information System (INIS)

    Czarnecki, R.M.; Manrique, M.A.; Samaddar, S.K.

    1993-01-01

    A summary of available experimental expansion anchor bolt test data is presented. These data were collected as part of programs by the nuclear industry to address generic issues related to verification of seismic adequacy of equipment in nuclear power plants. Some of the data presented are suitable for use in seismic probabilistic risk assessments. For example, mean values of ultimate strength, along with their standard deviation and coefficients of variation, for a range of most typical expansion anchor bolt sizes are presented. Effects of interaction between shear and tension, edge distance, spacing, and cracking of the concrete are presented in a manner that is more suitable for use in deterministic evaluations. Related industry programs to derive anchor bolt capacities are briefly discussed. Recommendations for areas of further investigation are also presented

  9. Reinforcement of Underground Excavation with Expansion Shell Rock Bolt Equipped with Deformable Component

    Directory of Open Access Journals (Sweden)

    Korzeniowski Waldemar

    2017-03-01

    Full Text Available The basic type of rock mass reinforcement method for both preparatory and operational workings in underground metal ore mines, both in Poland and in different countries across the world, is the expansion shell or adhesive-bonded rock bolt. The article discusses results of static loading test of the expansion shell rock bolts equipped with originally developed deformable component. This component consists of two profiled rock bolt washers, two disk springs, and three guide bars. The disk spring and disk washer material differs in stiffness. The construction materials ensure that at first the springs under loading are partially compressed, and then the rock bolt washer is plastically deformed. The rock bolts tested were installed in blocks simulating a rock mass with rock compressive strength of 80 MPa. The rock bolt was loaded statically until its ultimate loading capacity was exceeded. The study presents the results obtained under laboratory conditions in the test rig allowing testing of the rock bolts at their natural size, as used in underground metal ore mines. The stress-strain/displacement characteristics of the expansion shell rock bolt with the deformable component were determined experimentally. The relationships between the geometric parameters and specific strains or displacements of the bolt rod were described, and the percentage contribution of those values in total displacements, resulting from the deformation of rock bolt support components (washer, thread and the expansion shell head displacements, were estimated. The stiffness of the yielded and stiff bolts was empirically determined, including stiffness parameters of every individual part (deformable component, steel rod. There were two phases of displacement observed during the static tension of the rock bolt which differed in their intensity.

  10. Post-Service Examination of PWR Baffle Bolts, Part I. Examination and Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, Keith J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sokolov, Mikhail A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-04-30

    In support of extended service and current operations of the US nuclear reactor plants, the Oak Ridge National Laboratory (ORNL), through the Department of Energy (DOE), Light Water Reactor Sustainability (LWRS) Program, is coordinating with Ginna Nuclear Power Plant, The Westinghouse Electric Company, LLC, and ATI Consulting, the selective procurement of baffle bolts that were withdrawn from service in 2011 and currently stored on site at Ginna. The goal of this program is to perform detailed microstructural and mechanical property characterization of baffle former bolts following in-service exposures. This report outlines the selection criteria of the bolts and the techniques to be used in this study. The bolts available are the original alloy 347 steel fasteners used in holding the baffle plates to the baffle former structures within the lower portion of the pressurized water reactor vessel. Of the eleven possible bolts made available for this work, none were identified to have specific damage. The bolts, however, did show varying levels of breakaway torque required in their removal. The bolts available for this study varied in peak fluence (highest dose within the head of the bolt) between 9.9 and 27.8x1021 n/cm2 (E>1MeV). As no evidence for crack initiation was determined for the available bolts from preliminary visual examination, two bolts with the higher fluence values were selected for further post-irradiation examination. The two bolts showed different breakaway torque levels necessary in their removal. The information from these bolts will be integral to the LWRS program initiatives in evaluating end of life microstructure and properties. Furthermore, valuable data will be obtained that can be incorporated into model predictions of long-term irradiation behavior and compared to results obtained in high flux experimental reactor conditions. The two bolts selected for the ORNL study will be shipped to Westinghouse with bolts of

  11. Parametric study on the behaviour of bolted composite connections

    Directory of Open Access Journals (Sweden)

    M. N. Kataoka

    Full Text Available The studied connections are composed of concrete filled steel tubes (CFT connected to composite beams by passing through bolts, endplates and steel deck, which also contributes to support the applied loads. The parametric analysis presented in this work is based on numerical simulations performed with software TNO Diana, using experimental results to calibrate the reference numerical model. The influence of three main parameters, being them the bolts diameter, the slab height and the beams cross section, was evaluated. According to the obtained bending moment versus rotation curves, it was concluded that, among the three parameters analyzed, the most important one was the bolts diameter. About the beams cross section, inconclusive results were achieved, probably due to the incompatibility between the 16 mm bolts and the robust beam cross sections considered in the parametric analysis.

  12. Metallurgical examinations update of baffle bolts removed from operating French PWR. Microstructural investigations of a baffle to former bolt located on a high level of the internal structures

    International Nuclear Information System (INIS)

    Panait, C.; Fargeas, E.; Miloudi, S.; Moulart, P.; Tommy-Martin, M.; Monteil, N.; Pokor, C.

    2015-01-01

    This paper presents the microstructural investigations conducted on a cracked baffle to former bolt extracted from an upper former level of the internal structures of a French Pressurized Water Reactor (PWR). Extensive microstructural investigations using Light Microscopy, Scanning Electron Microscopy and Transmission Electron Microscopy (TEM) have been conducted to understand the degradation mechanisms of this bolt. TEM investigations have revealed neutron irradiation damage in the microstructure of the bolt such as Frank loops and cavities and/or bubbles. The number of features per unit volume as a function of diameter was determined in the head and in the shank of the bolt. The obtained results are relatively similar to those obtained for other damaged bolts extracted from PWR-type reactors and irradiated in similar conditions (dose and temperature). The irradiation damage has induced an evolution of the mechanical properties (hardening of the material), as revealed by the hardness measurements along the bolt, with a higher average value in the head (400 HV), compared to the shank (15 mm under the head), about 340 HV. The metallurgical investigations have confirmed that this bolt was damaged by Irradiation Assisted Stress Corrosion Cracking (IASCC)

  13. Nuclear reactor incorporating locking device for threaded bolt connections

    International Nuclear Information System (INIS)

    Blaushild, R.M.

    1987-01-01

    A nuclear reactor having a pressure vessel and a first element is described comprising a core barrel situated within the pressure vessel. The core barrel has a baffle former secured in and to the core barrel by bolted connections, and a second element comprising baffle plates secured to the inner surface of the baffle former by bolted connections, with a locking device to prevent loosening of bolted connections between the baffle former and at least one of the elements. The baffle former and at least one element are held together by a headed, threaded bolt engaged in a bore coaxially extending in the baffle former and at least one element and threadedly engaged in a threaded section in at least the baffle former. The threaded section has first threaded of a first direction, with the head of the bolt engaged with a shoulder about the bore in at least one element to hold the baffle formed and at least one element together, the head of the bolt having a first diameter and a cavity, having an unsymmetrical wall thereabout, in the end surface thereof. It comprises a recess in at least one element coaxial with the bore forming a wall thereabout and extending inwardly from the outer surface of at least one element, the recess having a second diameter greater than the first diameter, with at least one element having second threads in the wall of a direction opposite the direction of the first threads of the threaded bore; a locking nut having a base with a downwardly depending cylindrical wall thereabout

  14. Enhancement of crack detection in stud bolts of nuclear reactor by ultrasonic technique

    International Nuclear Information System (INIS)

    Lee, Joon-Hyun; Choi, Sang-Woo; Oh, Won-Deok

    2004-01-01

    The stud bolt is one of crucial parts for safety of reactor vessels in nuclear power plants. Crack initiation and propagation were reported in stud bolts using closure of reactor vessel and head. Stud bolts are inspected by ultrasonic technique during overhaul periodically for the prevention of stud bolt failure and radioactive leakage from nuclear reactor. In conventional ultrasonic testing for inspection of stud bolts, crack was detected by using shadow effect. It takes too much time to inspect stud bolt by using conventional ultrasonic technique. In addition, there were numerous spurious signals reflected from every oblique surfaces of thread. In this study, the signal processing technique for enhancing conventional ultrasonic technique and the advanced ultrasonic phased array technique were introduced for inspect stud bolts. The signal processing technique provides removing spurious signal reflected from every oblique surfaces of thread and enhances detectability of defects. The phased array technique provides fast inspection and can be applied for structure of complex shape. There are sector scanning and linear scanning methods in phased array technique, and these scanning methods were applied to inspect stud bolt and detectability was investigated. (author)

  15. Structural analysis of closure bolts for shipping casks

    International Nuclear Information System (INIS)

    Mok, G.C.; Fischer, L.E.

    1993-04-01

    This paper identifies the active forces and moments in a closure bolt of a shipping cask. It examines the interactions of these forces/moments and suggest simplified methods for their analysis. The paper also evaluates the role that the forces and moments play in the structure integrity of the closure bolt and recommends stress limits and desirable practices to ensure its integrity

  16. Laboratory testing of a long expansion rock bolt support for energy-absorbing applications

    Directory of Open Access Journals (Sweden)

    Skrzypkowski Krzysztof

    2018-01-01

    Full Text Available The main purpose of rock support and reinforcement in underground mining is to maintain excavations safe and open for their intended lifespan. The basic type of rock mass reinforcement method both in ore and hard coal mining is rock bolt support. Very often, existing bolt support systems are not always capable of providing a reliable controlled performance. Therefore, in recent years energy-absorbing bolts which are exposed to dynamic loading, for example from rock burst caused by high rock stresses, earthquakes, or blasting have appeared. In this article particular attention was paid to short and long expansion bolts. Quasi-static tests of expansion bolts were carried out at the laboratory test facility in simulated mining conditions, especially for the KGHM Polska Miedź S.A. mines. In the underground mines of the Legnica-Głogów Copper District (LGOM the main way to protect the room excavation is rock bolt support with a length from 1.2 m to 2.6 m. Rock bolt support longer than 2.6 m is considered as additional support of excavations and is increasingly being used to reinforce the roofs. The comparisons of energy-absorbing short and long expansion bolts with a length of 1.8m, 3.6m and 5.2m were presented. In addition, for elastic and plastic range of each bolts were determined.

  17. Laboratory testing of a long expansion rock bolt support for energy-absorbing applications

    Science.gov (United States)

    Skrzypkowski, Krzysztof

    2018-01-01

    The main purpose of rock support and reinforcement in underground mining is to maintain excavations safe and open for their intended lifespan. The basic type of rock mass reinforcement method both in ore and hard coal mining is rock bolt support. Very often, existing bolt support systems are not always capable of providing a reliable controlled performance. Therefore, in recent years energy-absorbing bolts which are exposed to dynamic loading, for example from rock burst caused by high rock stresses, earthquakes, or blasting have appeared. In this article particular attention was paid to short and long expansion bolts. Quasi-static tests of expansion bolts were carried out at the laboratory test facility in simulated mining conditions, especially for the KGHM Polska Miedź S.A. mines. In the underground mines of the Legnica-Głogów Copper District (LGOM) the main way to protect the room excavation is rock bolt support with a length from 1.2 m to 2.6 m. Rock bolt support longer than 2.6 m is considered as additional support of excavations and is increasingly being used to reinforce the roofs. The comparisons of energy-absorbing short and long expansion bolts with a length of 1.8m, 3.6m and 5.2m were presented. In addition, for elastic and plastic range of each bolts were determined.

  18. An investigation into the anti-releasing performance of a serrated bolt

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jin Hwan; Lee, Hyun Kyu; Park, Ke Un; Kim, Jong Bong [Seoul Natinal University, Seoul (Korea, Republic of)

    2015-11-15

    As the sizes of electric products, such as mobile phones and watch phones, decrease, the joining bolt for the electric product should also be miniaturized. However, the miniature-sized bolt has to support sufficient joining torque and joining force. The bolt also has to support sufficient anti-releasing torque to keep the product fastened. We investigated a serrated bolt as a candidate for a miniature-sized fastener to increase the anti-release torque. In the serrated bolt, serration shapes are formed on the bottom surface of a bolt head to create an obstacle to releasing. In this study, finite element analyses were carried out on joining and releasing, and the anti-release torque was predicted. Through the joining and releasing analyses for various values of the elastic modulus and yield strength of the joined part, the effect of the mechanical properties of the joined part on the anti-releasing performance were investigated. The analysis results showed that a high strength insert nut is needed to increase the anti-releasing torque when the yield strength of the joined part is low, such as a plastic board in a mobile phone.

  19. Joint seal in tank

    International Nuclear Information System (INIS)

    Colquhoun, J.; White, G.V.

    1981-01-01

    A seal for a joint or gap between edges of adjacent wall sections (e.g. of concrete) of a liquid-containing vessel, such as a nuclear reactor cooling pond, comprises a sheet metal strip having longitudinally-extending edge parts, secured to the respective vessel-section edges, and a central part which is longitudinally corrugated to provide sufficient flexibility to accommodate slight relative movements between the vessel-section edges (e.g. due to thermal expansions). The edges of the sheet metal of the strip are turned in so that the edge parts of the strip are formed as generally U-section channels. These accommodate longitudinally extending securing bars which are bolted to the vessel wall sections by bolts which pass through the bars, through the free-edged wall of the channel section and through a longitudinally extending resilient seal pad compressed between that wall of the channel section and the vessel wall section to which it is secured. The other wall of the channel section (integral with the corrugated central part of the strip) has access windows through which the bolts are inserted and tightened, the windows being then closed off in liquid-tight manner by welding closure caps over them. (author)

  20. Galvanic corrosion study of aluminium alloy plates mounted to stainless and mild steel bolts by accelerated exposure test

    OpenAIRE

    MREMA, Emmanuel; ITOH, Yoshito; KANEKO, Akira; HIROHATA, Mikihito

    2016-01-01

    Despite the fact that aluminium alloy members have a proven durability over stainless steel members, their joint fasteners like bolts, nuts and washers are drawn from steel material due to aluminium alloy inferior mechanical properties. Bare contact between aluminium alloy members and stainless steel fasteners results to galvanic corrosion of aluminium alloy members. A corrosion behaviour study was carried out on different aluminium alloy types with different surface treatments mounted to sta...

  1. Pneumatic wrench retains or discharges nuts or bolts as desired

    Science.gov (United States)

    Bouille, J. R.

    1966-01-01

    Pneumatic wrench grips, screws or unscrews, and discharges a nut or bolt as desired. The device consists of a standard pneumatic wrench modified with a special hex bolt head socket assembly and a diaphragm air cylinder.

  2. Ultrasonic extensometer measures bolt preload

    Science.gov (United States)

    Daniels, C. M., Jr.

    1978-01-01

    Extensometer using ultrasonic pulse reflections to measure elongations in tightened belts and studs is much more accurate than conventional torque wrenches in application of specified preload to bolts and other threaded fasteners.

  3. Mechanical testing and development of the helical field coil joint for the Advanced Toroidal Facility

    International Nuclear Information System (INIS)

    Nelson, B.E.; Bryan, W.E.; Goranson, P.L.; Warwick, J.E.

    1985-01-01

    The helical field (HF) coil set for the Advanced Toroidal Facility (ATF) is an M = 12, l = 2, constant-ratio torsatron winding consisting of 2 coils, each with 14 turns of heavy copper conductor. The coils are divided into 24 identical segments to facilitate fabrication and minimize the assembly schedule. The segments are connected across through-bolted lap joints that must carry up to 124,000 A per turn for 5 s or 62,500 A steady-state. In addition, the joints must carry the high magnetic and thermal loads induced in the conductor and still fit within the basic 140- by 30-mm copper envelope. Extensive testing and development were undertaken to verify and refine the basic joint design. Tests included assembly force and clamping force for various types of misalignment; joint resistance as a function of clamping force; clamp bolt relaxation due to thermal cycling; fatigue testing of full-size, multiturn joint prototypes; and low-cycle fatigue and tensile tests of annealed CDA102 copper. The required performance parameters and actual test results, as well as the final joint configuration, are presented. 2 refs., 9 figs., 4 tabs

  4. Anticorrosion protection of strength bolts

    Directory of Open Access Journals (Sweden)

    Jiří Votava

    2012-01-01

    Full Text Available Corrosion damage may, from the technical point of view, cause changes in mechanical and physical characteristics in particular, at the same time it may also cause changes in surface geometry. These aspects are likely to manifest themselves in all steel parts. The presented study looks at corrosion protection in bolts and bolt connections protected by metal coating based on zinc.Four different types of passivation, easily accessible on the Czech market, have been selected for this experiment. They are as follows: first, galvanic plating using white zinc; second, galvanic plating using yellow zinc; third, hot dip galvanizing; fourth, specific type of plating using the technology Dacromet 500 LC. In order to compare the given parameters there have been selected a unified M bolt size of 8 × 30 mm. The experimental part of this study can be further divided into two phases. The initial phase puts stress on the exact specification of the protection layer, namely, the analysis and establishment of the elemental compositon contained in the given coating, its microhardness, weight and thickness. The second phase of the experiment analyses the results of tests according to the norm ČSN ISO 9227 (Salt Fog Test and ČSN ISO 6988 (Sulphur Dioxide Test. With the tests we have concentrated on the initial stages of corrosion degradation and its overall process.

  5. Fewer complications with bolt-connected than tunneled external ventricular drainage

    DEFF Research Database (Denmark)

    Jensen, Torben Slott; Carlsen, Jakob Gram; Poulsen, Frantz Rom

    2016-01-01

    BACKGROUND: Ventriculostomy/external ventricular drain (EVD) is a common neurosurgical procedure. Various techniques are used to fixate the drain and the objective of this study was, in a retrospective setting, to compare the incidence of complications when using bolt-connected EVD (BC-EVD) versus...... tunneled EVD (T-EVD). METHODS: All patients subjected to an EVD performed through a new burr hole from 2009 through 2010 at two Depts. of Neurosurgery in Denmark (Odense and Aarhus) were retrospectively identified. Patient files were evaluated for EVD fixation technique (tunneled or bolt-connected EVD...... %), compared to the bolt-connected EVD group (6.5 %). There was no significant difference in infection rates. CONCLUSIONS: Tunneled EVD has a relatively high frequency of complications leading to reinsertion. The use of Bolt-connected EVD technique can lower this frequency significantly. The number needed...

  6. Development of a smart rock bolt for underground monitoring operations

    CSIR Research Space (South Africa)

    Moema, JS

    2003-07-01

    Full Text Available of magnetic methods in measuring the stress or microstructural transformation in an individual bolt in both laboratory and underground environment. The corrosion performance of the smart bolt alloy was evaluated in synthetic mine water and compared...

  7. Experimental tests on slip factor in friction joints: comparison between European and American Standards

    Directory of Open Access Journals (Sweden)

    Emanuele Maiorana

    2018-01-01

    Full Text Available Friction joints are used in steel structures submitted to cyclic loading such as, for example, in steel and composite bridges, in overhead cranes, and in equipment subjected to fatigue. Slip-critical steel joints with preloaded bolts are characterized by high rigidity and good performance against fatigue and vibrational phenomena. The most important parameter for the calculation of the bolt number in a friction connection is the slip factor, depending on the treatment of the plane surfaces inside the joint package. The paper focuses on the slip factor values reported in European and North American Specifications, and in literature references. The differences in experimental methods of slip test and evaluation of them for the mentioned standards are discussed. The results from laboratory tests regarding the assessment of the slip factor related to only sandblasted and sandblasted and coated surfaces are reported. Experimental data are compared with other results from the literature review to find the most influent parameters that control the slip factor in friction joint and differences between the slip tests procedures

  8. Application of ultrasonic phased array technique for inspection of stud bolts in nuclear reactor vessel

    International Nuclear Information System (INIS)

    Choi, Sang Woo; Lee, Joon Ho; Park, Min Su; Cho, Youn Ho; Park, Moon Ho

    2004-01-01

    The stud bolt is one of crucial parts for safety of reactor vessels in nuclear power plants. Cracks initiation and propagation were reported in stud bolts using closure of reactor vessel and head. Stud bolts are inspected by ultrasonic technique during overhaul periodically for the prevention of stud bolt failure and radioactive leakage from nuclear reactor. In conventional ultrasonic testing for inspection of stud bolts, crack was detected by using shadow effect. It take too much time to inspect stud bolt by using conventional ultrasonic technique. In addition, there were numerous spurious signal reflected from every thread. In this study, the advanced ultrasonic phased array technique was introduced for inspect stud bolts. The phased array technique provide fast inspection and high detectability of defects. There are sector scanning and linear scanning method in phased array technique, and these scanning methods were applied to inspect stud bolt and detectability was investigated.

  9. Monitoring of Pre-Load on Rock Bolt Using Piezoceramic-Transducer Enabled Time Reversal Method.

    Science.gov (United States)

    Huo, Linsheng; Wang, Bo; Chen, Dongdong; Song, Gangbing

    2017-10-27

    Rock bolts ensure structural stability for tunnels and many other underground structures. The pre-load on a rock bolt plays an important role in the structural reinforcement and it is vital to monitor the pre-load status of rock bolts. In this paper, a rock bolt pre-load monitoring method based on the piezoceramic enabled time reversal method is proposed. A lead zirconate titanate (PZT) patch transducer, which works as an actuator to generate stress waves, is bonded onto the anchor plate of the rock bolt. A smart washer, which is fabricated by sandwiching a PZT patch between two metal rings, is installed between the hex nut and the anchor plate along the rock bolt. The smart washer functions as a sensor to detect the stress wave. With the increase of the pre-load values on the rock bolt, the effective contact surface area between the smart washer and the anchor plate, benefiting the stress wave propagation crossing the contact surface. With the help of time reversal technique, experimental results reveal that the magnitude of focused signal clearly increases with the increase of the pre-load on a rock bolt before the saturation which happens beyond a relatively high value of the pre-load. The proposed method provides an innovative and real time means to monitor the pre-load level of a rock bolt. By employing this method, the pre-load degradation process on a rock bolt can be clearly monitored. Please note that, currently, the proposed method applies to only new rock bolts, on which it is possible to install the PZT smart washer.

  10. Laboratory evaluation of alloy X-750 clevis bolts removed from D.C. cook unit 1

    International Nuclear Information System (INIS)

    Hyres, J.; Xu, H.; Kalchik, K.; Thompson, G.

    2015-01-01

    This paper summarizes the results of the laboratory evaluation performed by Babcock and Wilcox on Alloy X-750 clevis bolts removed from the Lower Radial Support System (LRSS) at D.C. Cook Unit 1. A total of 29 clevis bolts - 16 broken and 13 intact - were provided for laboratory analysis and testing to document the extent of degradation, evaluate the integrity of the intact bolts, and identify the bolt degradation/failure mechanism(s). The laboratory work scope included visual and stereo-visual examinations of all bolts. Based on the results of these examinations, four bolts - two broken and two intact - were selected for more detailed analysis/testing, including Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), optical metallography, microhardness, chemical analysis by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS), Rockwell hardness testing, and tensile testing. The laboratory data indicated the bolts failed by intergranular stress corrosion cracking (IGSCC). There was no evidence that the bolts failed due to fatigue cracking or mechanical overload. (authors)

  11. PIXE Analysis of Metal Hull Bolts From HMB DeBraak

    International Nuclear Information System (INIS)

    Correll, Francis D.; Cole, Lord K.; Slater, Charles J.; Vanhoy, Jeffrey R.; Fithian, Charles H.

    2009-01-01

    HMB DeBraak was a 16-gun British brig-sloop that sank in a squall on May 25, 1798 off Cape Henlopen, Delaware. Silt covered the wooden hull shortly after it sank, preserving it until DeBraak was raised in 1986. The items recovered from the ship include metal bolts that held the hull together. We used PIXE to measure the compositions of 45 of the bolts and found that they are nearly pure copper (98.3% on average), with most also containing small amounts of iron (0.87%), nickel (0.039%), arsenic (0.43%), silver (0.089%), lead (0.18%), and bismuth (0.12%). A few contain a little indium, tin, or antimony, but none contain zinc above the quantization level. The compositions are similar to those reported for 18th-century English copper, but different from several copper alloys also used to make hull bolts. We conclude that, when DeBraak was last fitted out in 1795-1797, the Royal Navy was still using bolts similar to William Forbes's mechanically hardened pure copper bolts. Forbes's process represents the successful innovation and application of new technology in Royal Navy ships during the wars of the late 18th century.

  12. PIXE Analysis of Metal Hull Bolts From HMB DeBraak

    Science.gov (United States)

    Correll, Francis D.; Cole, Lord K.; Slater, Charles J.; Vanhoy, Jeffrey R.; Fithian, Charles H.

    2009-03-01

    HMB DeBraak was a 16-gun British brig-sloop that sank in a squall on May 25, 1798 off Cape Henlopen, Delaware. Silt covered the wooden hull shortly after it sank, preserving it until DeBraak was raised in 1986. The items recovered from the ship include metal bolts that held the hull together. We used PIXE to measure the compositions of 45 of the bolts and found that they are nearly pure copper (98.3% on average), with most also containing small amounts of iron (0.87%), nickel (0.039%), arsenic (0.43%), silver (0.089%), lead (0.18%), and bismuth (0.12%). A few contain a little indium, tin, or antimony, but none contain zinc above the quantization level. The compositions are similar to those reported for 18th-century English copper, but different from several copper alloys also used to make hull bolts. We conclude that, when DeBraak was last fitted out in 1795-1797, the Royal Navy was still using bolts similar to William Forbes's mechanically hardened pure copper bolts. Forbes's process represents the successful innovation and application of new technology in Royal Navy ships during the wars of the late 18th century.

  13. The evaluation on clamping force of high strength bolts by length parameter

    International Nuclear Information System (INIS)

    Kim, Kang-Seok; Nah, Hwan-Seon; Lee, Hyeon-Ju; Lee, Kang-Min

    2009-01-01

    It has been reported that the length parameter of high strength bolts results in the variance in tension loads. The required turn for each length is specified in AISC RCSC specification. This study was focused on evaluating any influence on the clamping torque subjected to length parameter of high strength bolts. The two kinds of high strength bolts of specimen are as follows; High Strength Hexagon bolt defined on ASTM A490 and Torque Shear Bolt on KS B 2819. The length parameter ranged from 60mm(3d) to 140mm(7d). The torque, turn of nut and the clamping force were analyzed to review whether length parameter can be affected on the required tension load. To test whether the length parameter has an impact on the torque and turn of nut for the required strength and clamping force, statistical analysis is carried out. (author)

  14. The Influence on Modal Parameters of Thin Cylindrical Shell under Bolt Looseness Boundary

    Directory of Open Access Journals (Sweden)

    Hui Li

    2016-01-01

    Full Text Available The influence on modal parameters of thin cylindrical shell (TCS under bolt looseness boundary is investigated. Firstly, bolt looseness boundary of the shell is divided into two types, that is, different bolt looseness numbers and different bolt looseness levels, and natural frequencies and mode shapes are calculated by finite element method to roughly master vibration characteristics of TCS under these conditions. Then, the following measurements and identification techniques are used to get precise frequency, damping, and shape results; for example, noncontact laser Doppler vibrometer and vibration shaker with excitation level being precisely controlled are used in the test system; “preexperiment” is adopted to determine the required tightening torque and verify fixed constraint boundary; the small-segment FFT processing technique is employed to accurately measure nature frequency and laser rotating scanning technique is used to get shape results with high efficiency. Finally, based on the measured results obtained by the above techniques, the influence on modal parameters of TCS under two types of bolt looseness boundaries is analyzed and discussed. It can be found that bolt looseness boundary can significantly affect frequency and damping results which might be caused by changes of nonlinear stiffness and damping and in bolt looseness positions.

  15. Non-destructive testing of full-length bonded rock bolts based on HHT signal analysis

    Science.gov (United States)

    Shi, Z. M.; Liu, L.; Peng, M.; Liu, C. C.; Tao, F. J.; Liu, C. S.

    2018-04-01

    Full-length bonded rock bolts are commonly used in mining, tunneling and slope engineering because of their simple design and resistance to corrosion. However, the length of a rock bolt and grouting quality do not often meet the required design standards in practice because of the concealment and complexity of bolt construction. Non-destructive testing is preferred when testing a rock bolt's quality because of the convenience, low cost and wide detection range. In this paper, a signal analysis method for the non-destructive sound wave testing of full-length bonded rock bolts is presented, which is based on the Hilbert-Huang transform (HHT). First, we introduce the HHT analysis method to calculate the bolt length and identify defect locations based on sound wave reflection test signals, which includes decomposing the test signal via empirical mode decomposition (EMD), selecting the intrinsic mode functions (IMF) using the Pearson Correlation Index (PCI) and calculating the instantaneous phase and frequency via the Hilbert transform (HT). Second, six model tests are conducted using different grouting defects and bolt protruding lengths to verify the effectiveness of the HHT analysis method. Lastly, the influence of the bolt protruding length on the test signal, identification of multiple reflections from defects, bolt end and protruding end, and mode mixing from EMD are discussed. The HHT analysis method can identify the bolt length and grouting defect locations from signals that contain noise at multiple reflected interfaces. The reflection from the long protruding end creates an irregular test signal with many frequency peaks on the spectrum. The reflections from defects barely change the original signal because they are low energy, which cannot be adequately resolved using existing methods. The HHT analysis method can identify reflections from the long protruding end of the bolt and multiple reflections from grouting defects based on mutations in the instantaneous

  16. Construction method of pre assembled unit of bolt sphere grid

    Science.gov (United States)

    Hu, L. W.; Guo, F. L.; Wang, J. L.; Bu, F. M.

    2018-03-01

    The traditional construction of bolt sphere grid has many disadvantages, such as high cost, large amount of work at high altitude and long construction period, in order to make up for these shortcomings, in this paper, a new and applicable construction method is explored: setting up local scaffolding, installing the bolt sphere grid starting frame on the local scaffolding, then the pre assembled unit of bolt sphere grid is assembled on the ground, using small hoisting equipment to lift pre assembled unit to high altitude and install. Compared with the traditional installation method, the construction method has strong practicability and high economic efficiency, and has achieved good social and economic benefits.

  17. Thermo-mechanical analysis of PWR bolts susceptible to IASCC

    International Nuclear Information System (INIS)

    Matteoli, C.; Hannink, M.H.C.; Blom, F.J.; Marck, S.C. van der; Charpin-Jacobs, F.

    2015-01-01

    Irradiation Assisted Stress Corrosion Cracking (IASCC) is considered a primary ageing issue for the Reactor Pressure Vessel (RPV) internals of Pressurized Water Reactors (PWR). In particular, this complex phenomenon which develops in an environment featuring thermal and mechanical stresses, interaction with corrosive compounds and irradiation, is affecting the bolts connecting the baffles and the formers in the Nuclear Power Plants' RPVs. The baffle-former assembly is the structure that borders the fuel assemblies region, contributing to keep them in position and separating in the radial direction, the core region from the downcomer region. An evaluation of the stresses and temperatures reached in the baffle-former bolts during normal operation was performed by means of a coupled thermo-mechanical study which uses reactor physics calculations to obtain the fluence in the reactor core and as a consequence the heat deposition in the RPV internals. The heat deposition data are coupled with a finite element model of the bolts and the RPV internals in order to perform a complete analysis taking in account thermal, mechanical and radiation loadings. The study is first carried out focusing on a section of the RPV internals, showing a single row of baffle-former bolts. Then the work is extended to the full core height. The model set up in this work, includes an in-depth study of the behavior of the core internals, in particular baffle-former bolts. The model has the capability of understanding the mechanical and thermal behavior of essential internal components in a PWR. (authors)

  18. Numerical Study on Ultimate Behaviour of Bolted End-Plate Steel Connections

    Directory of Open Access Journals (Sweden)

    R.E.S. Ismail

    Full Text Available Abstract Bolted end-plate steel connections have become more popular due to ease of fabrication. This paper presents a three dimension Finite Element Model (FEM, using the multi-purpose software ABAQUS, to study the effect of different geometrical parameters on the ultimate behavior of the connection. The proposed model takes into account material and geometrical non-linearities, initial imperfection, contact between adjacent surfaces and the pretension force in the bolts. The Finite Element results are calibrated with published experimental results ''briefly reviewed in this paper'' and verified that the numerical model can simulate and analyze the overall and detailed behavior of different types of bolted end-plate steel connections. Using verified FEM, parametric study is then carried out to study the ultimate behavior with variations in: bolt diameter, end-plate thickness, length of column stiffener, angle of rib stiffener. The results are examined with respect to the failure modes, the evolution of the resistance, the initial stiffness, and the rotation capacity. Finally, the ultimate behavior of the bolted end-plate steel connection is discussed in detail, and recommendations for the design purpose are made.

  19. Development of plastic media blasting device for stud bolt

    International Nuclear Information System (INIS)

    Yoshihisa, Y.; Miyashita, T.

    1999-01-01

    Plastic media blasting is a mechanical cleaning method for removing paint, rust and/or anti-galling material etc on the surface of metal without damaging the metal surface. The method is suitable for cleaning the surface of reusable elements and parts such as bolts and nuts. Anti-galling material such as molybdenum disulfide is applied to fastening stud bolts used for the steam turbine rotor casing. It is necessary to remove this material when new anti-galling material is to be applied. Genden Engineering Services and Construction Co., and Morikawa Industries Corp., have developed a plastic media blasting device to clean the surface of stud bolt screw threads installed in the facility such as lower casing of the turbine. This paper reports the outline of the results. (author)

  20. A Study on the Fracture Control of Rock Bolts in High Ground Pressure Roadways of Deep Mines

    Directory of Open Access Journals (Sweden)

    Wen Jinglin

    2015-01-01

    Full Text Available According to the frequent fractures of rock bolts in high ground pressure roadways of deep mines, this paper analyzes the mechanism of fractures and concludes that high ground pressure and material de-fects are main reasons for the fracture of rock bolts. The basic idea of fracture control of rock bolts in high ground pressure roadways of deep mines is to increase the yield load and the limit load of rock bolt materials and reduce the actual load of rock bolts. There are four ways of controlling rock bolt fracture: increasing the rock bolt diameter, strengthening bolt materials, weakening support rigidity and the implementation of double supporting. With the roadway support of the 2302 working face of a coal mine as the project background, this paper carries out a study on the effect of two schemes, increasing the rock bolt diameter and the double supporting technique through methods of theoretical analysis, numerical simulation and so on. It determines the most reasonable diam-eter of rock bolts and the best delay distance of secondary support. Practices indicate that rock bolt fracture can be effectively controlled through the double supporting technique, which strengthens the roof and two sides through the first supporting technique and strengthens side angles through the secondary supporting technique.

  1. Design and analysis of lid closure bolts for packages used to transport radioactive materials

    International Nuclear Information System (INIS)

    Raske, D.T.; Stojimirovic, A.

    1995-01-01

    The design criterion recommended by the U.S. Department of Energy for Category I radioactive packaging is found in Section III, Division 1, of the ASME Boiler and Pressure Vessel Code. This criterion provides material specifications and allowable stress limits for bolts used to secure lids of containment vessels. This paper describes the design requirements for Category I containment vessel lid closure bolts, and provides an example of a bolting stress analysis. The lid-closure bolting stress analysis compares calculations based on handbook formulas with an analysis performed with a finite-element computer code. The results show that the simple handbook calculations can be sufficiently accurate to evaluate the bolt stresses that occur in rotationally rigid lid flanges designed for metal-to-metal contact

  2. Manufacture and tests of shape memory actuators for bolted joints of the oil and gas industry; Fabricacao e testes de atuadores de ligas com memoria de forma para unioes aparafusadas do setor de petroleo e gas

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Niedson J. da; Silva, Marcos M. da [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Curso de Pos-graduacao em Ciencia e Engenharia de Materiais; Araujo, Carlos J. de; Santos, Marco A. dos [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia Mecanica

    2008-07-01

    Shape memory alloys (SMA) actuators have a great potential for applications in the engineering field due to the ability of mechanical force generation through the Shape Memory Effect (SME). The SME behavior is the capacity of SMA remember a form established previously when submitted to a temperature variation. In the oil and gas industry there is a variety of possible applications for these active materials, from thermostatic valves to safety devices for piping. Thus, the aim of this work was to study the technical viability of developing SMA washers for potential application in bolted joints of pipelines to improve the reliability of these joints. NiTi SMA washer actuators were produced through casting by plasma skull melting and molding by Push Pull method using the Discovery all machine from EDG equipment and controls. The NiTi SMA washers were obtained and analyzed using electrical resistance and force generation as a function of temperature. The results of force generation as a function of the temperature have demonstrated that important mechanical efforts can be obtained, justifying the application of these SMA for pipeline joints employed in the oil and gas industry. (author)

  3. Corrosion failure of a bolt made of the 25Kh1MF material

    International Nuclear Information System (INIS)

    Liska, V.; Cechova, D.; Velkoborsky, J.

    1989-01-01

    M36x4 bolts, of which there are 222 at each nuclear power plant unit, are made of the 25Kh1MF or 38KhN3MFA steel. They are located in an environment with elevated temperature, with damp air and with boric acid. Corrosion of these bolts is due to the rather poor metallurgical quality of the steel. No inadmissible inhomogeneities of the type of lines of inclusions occur in the bolt material produced by cold rolling but defects of the type of laps were found on the threads. It is suggested that if the cold rolling technology were obviated, corrosion failure of the bolts might not occur. (M.D.). 7 figs., 3 refs

  4. Development of Automatic Ultrasonic Testing Equipment for Pressure-Retaining Studs and Bolts in Nuclear Power Plant

    International Nuclear Information System (INIS)

    Suh, D. M.; Park, M. H.; Hong, S. S.

    1989-01-01

    Bolting degradation problems in primary coolant pressure boundary applications have become a major concern in the nuclear industry. In the bolts concerned, the failure mechanism was either corrosion wastage(loss of bolt diameter) or stress-corrosion cracking. Here the manual ultrasonic testing of RPV(Reactor Pressure Vessel) and RCP(Reactor Coolant Pump) stud has been performed. But it is difficult to detect indications because examiner can not exactly control the rotation angle and can not distinguish the indication from signals of bolt. In many cases, the critical sizes of damage depth are very small(1-2 mm order). At critical size, the crack tends to propagatecompletly through the bolt under stress, Resulting in total fracture. Automatic stud scanner for studs(bolts) was developed because the precise measurement of bolt diameter is required in this circumstance. By use of this scanner, the rotation angle of probe was exactly controlled and the exposure time of radiations was reduced

  5. The baffle-barrel-bolting analysis program: evolution and technical accomplishments

    International Nuclear Information System (INIS)

    Schwirian, R.E.; Forsyth, D.R.; Snyder, M.D.; Bhandari, D.R.; Barsic, J.A.; Rabenstein, W.D.

    2001-01-01

    In Westinghouse pressurized water reactors (PWR) the reactor core is surrounded by baffle plates, which provide lateral restraint for the fuel assemblies at the core boundary. Baffle plates are attached to horizontal supports called former plates by baffle-former bolts. The formers are attached to the core barrel which also provides vertical support for the core. The B3 analysis program addresses the possibility of reduced baffle-former bolting in Westinghouse U.S. domestic plant designs with respect to the relevant design criteria. Since safety is the overriding motivation for the program, faulted events have received the most in-depth attention. This focus has been reinforced by the fact that the loads produced by the loss-of-coolant-accident (LOCA) have usually been the most limiting of all those considered. Consequently, much of the presentation below deals with the development of analysis techniques and acceptance criteria to demonstrate that LOCA-induced loads on the bolts and the fuel assemblies will be acceptable with significantly reduced baffle-former bolting. A discussion of the other faulted, normal, and upset analyses performed as part of the program will also be presented. (author)

  6. Prevention of bolting degradation or failure in pressure boundary and support applications

    International Nuclear Information System (INIS)

    Merrick, E.A.; Rivers, A.; Bickford, J.; Marston, T.U.

    1986-01-01

    A discussion is presented of bolting degradation or failure experience in pressure boundary and component support applications in US commercial nuclear plants and the industry program to prevent failures in the future. The focus turns to steps which plant owners can take today to guard against pressure boundary bolt failure or degradation for existing plants or units being constructed. 'Tools' or products which the plant owner can expect from current industry programs which will be available in the near future to aid in understanding and improving bolting practices are described. (author)

  7. Ultrasonic Phased Array Techniques for Detection of Flaws of Stud Bolts in Nuclear Power Plants

    International Nuclear Information System (INIS)

    Lee, Joon Hyun; Choi, Sang Woo

    2006-01-01

    The reactor vessel body and closure head are fastened with the stud bolt that is one of crucial parts for safety of the reactor vessels in nuclear power plants. It is reported that the stud bolt is often experienced by fatigue cracks initiated at threads. Stud bolts are inspected by the ultrasonic technique during the overhaul periodically for the prevention of failure which leads to radioactive leakage from the nuclear reactor. The conventional ultrasonic inspection for stud bolts was mainly conducted by reflected echo method based on shadow effect. However, in this technique, there were numerous spurious signals reflected from every oblique surfaces of the thread. In this study, ultrasonic phased array technique was applied to investigate detectability of flaws in stud bolts and characteristics of ultrasonic images corresponding to different scanning methods, that is, sector and linear scan. For this purpose, simplified stud bolt specimens with artificial defects of various depths were prepared

  8. Study on Mechanical Characteristics of Fully Grouted Rock Bolts for Underground Caverns under Seismic Loads

    Directory of Open Access Journals (Sweden)

    Guoqing Liu

    2017-01-01

    Full Text Available This study establishes an analytical model for the interaction between the bolt and surrounding rock based on the bearing mechanism of fully grouted rock bolts. The corresponding controlled differential equation for load transfer is deduced. The stress distributions of the anchorage body are obtained by solving the equations. A dynamic algorithm for the bolt considering shear damage on the anchoring interface is proposed based on the dynamic finite element method. The rationality of the algorithm is verified by a pull-out test and excavation simulation of a rounded tunnel. Then, a case study on the mechanical characteristics of the bolts in underground caverns under seismic loads is conducted. The results indicate that the seismic load may lead to stress originating from the bolts and damage on the anchoring interface. The key positions of the antiseismic support can be determined using the numerical simulation. The calculated results can serve as a reference for the antiseismic optimal design of bolts in underground caverns.

  9. Behaviour of Frictional Joints in Steel Arch Yielding Supports

    Czech Academy of Sciences Publication Activity Database

    Horyl, P.; Šňupárek, Richard; Maršálek, P.

    2014-01-01

    Roč. 59, č. 3 (2014), s. 723-734 ISSN 0860-7001 R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk ED1.1.00/02.0070 Institutional support: RVO:68145535 Keywords : steel arch yielding support * friction al joints * bolt connection * slip support * fem Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 0.608, year: 2013

  10. Neutron generation in lightning bolts

    International Nuclear Information System (INIS)

    Shah, G.N.; Razdan, H.; Bhat, C.L.; Ali, Q.M.

    1985-01-01

    To ascertain neutron generation in lightning bolts, the authors have searched for neutrons from individual lightning strokes, for a time-interval comparable with the duration of the lightning stroke. 10 7 -10 10 neutrons per stroke were found, thus providing the first experimental evidence that neutrons are generated in lightning discharges. (U.K.)

  11. An approach for the design of closure bolts of spent fuel elements transportation packages

    International Nuclear Information System (INIS)

    Mattar Neto, Miguel; Miranda, Carlos A.J.; Fainer, Gerson

    2009-01-01

    The spent fuel elements transportation packages must be designed for severe conditions including significant fire and impact loads corresponding to hypothetical accident conditions. In general, these packages have large flat lids connected to cylindrical bodies by closure bolts that can be the weak link in the containment system. The bolted closure design depends on the geometrical characteristics of the flat lid and the cylindrical body, including their flanges, on the type of the gaskets and their dimensions, and on the number, strength, and tightness of the bolts. There are well established procedures for the closure bolts design used in pressure vessels and piping. They can not be used directly in the bolts design applied to transportation packages. Prior to the use of these procedures, it is necessary consider the differences in the main loads (pressure for the pressure vessels and piping and impact loads for the transportation packages) and in the geometry (large flat lids are not used in pressure vessels and piping). So, this paper presents an approach for the design of the closure bolts of spent fuel elements transportation packages considering the impact loads and the typical geometrical configuration of the transportation packages. (author)

  12. Causes of Failure of High-Tensile Stud Bolts Used for Joining Metal Parts of Tower Crane

    Science.gov (United States)

    Tingaev, A. K.; Gubaydulin, R. G.; Shaburova, N. A.

    2017-11-01

    The causes of the failure of a high-tensile stud 2M48-6gx500 10.9 made from steel grade 30HGSA which led to a temporary inoperability of a tower crane were investigated. The bolts were used to assemble the tower sections and collapsed after 45 days from the moment the crane was commissioned. The cracks in the fracture are identified as fatigue with the characteristic sites of nucleation, sustainable development and static dolomite. To determine the possible causes of stud bolts destruction, metallographic, durometric and mechanical tests were carried out from which it follows that the stud bolt material in its original state corresponded to the delivery conditions. The destruction of the stud bolt appears to have resulted from a combination of several unfavorable factors: uncertainty about the actual tension of the stud bolt due to the lack of information about the magnitude of the twist factor; partial displacement of the centers of the brackets holes and rotation of the stud bolt axis during the sections’ assembly; no tight contact on the support surfaces of the section brackets. All this led to a discrepancy between the actual design of the stud bolt, the appearance of additional forces and the destruction of the stud bolt.

  13. Impedance-Based Pre-Stress Monitoring of Rock Bolts Using a Piezoceramic-Based Smart Washer—A Feasibility Study

    Science.gov (United States)

    Wang, Bo; Huo, Linsheng; Chen, Dongdong; Li, Weijie; Song, Gangbing

    2017-01-01

    Pre-stress degradation or looseness of rock bolts in mining or tunnel engineering threatens the stability and reliability of the structures. In this paper, an innovative piezoelectric device named a “smart washer” with the impedance method is proposed with the aim of developing a real-time device to monitor the pre-stress level of rock bolts. The proposed method was verified through tests on a rock bolt specimen. By applying high-frequency sweep excitations (typically >30 kHz) to the smart washer that was installed on the rock bolt specimen, we observed that the variation in impedance signatures indicated the rock bolt pre-stress status. With the degradation of rock bolt pre-stress, the frequency in the dominating peak of the real part of the electrical impedance signature increased. To quantify the effectiveness of the proposed technique, a normalized root mean square deviation (RMSD) index was developed to evaluate the degradation level of the rock bolt pre-stress. The experimental results demonstrated that the normalized RMSD-based looseness index, which was computed from the impedance value detected by the “smart washer”, increased with loss of the pre-stress of the rock bolt. Therefore, the proposed method can effectively detect the degradation of rock bolt pre-stress, as demonstrated by experiments. PMID:28134811

  14. Usage of Cable Bolts for Gateroad Maintenance in Soft Rocks

    Directory of Open Access Journals (Sweden)

    Iurii Khalymendyk

    2014-01-01

    Originality/value: 1. There are no regulations and state standards in regard to cable bolt installation parameters in the mines of Ukraine, consequently the usage of cable bolts for gateroad maintenance required preliminary testing under geological conditions at the Western Donbass mines with soft enclosing rocks. 2. Combining levelling with observations using extensometers allowed for the detection of the rock layers' uniform sagging zone in the roof of the gateroad.

  15. Bolt-Grout Interactions in Elastoplastic Rock Mass Using Coupled FEM-FDM Techniques

    Directory of Open Access Journals (Sweden)

    Debasis Deb

    2010-01-01

    Full Text Available Numerical procedure based on finite element method (FEM and finite difference method (FDM for the analysis of bolt-grout interactions are introduced in this paper. The finite element procedure incorporates elasto-plastic concepts with Hoek and Brown yield criterion and has been applied for rock mass. Bolt-grout interactions are evaluated based on finite difference method and are embedded in the elasto-plastic procedures of FEM. The experimental validation of the proposed FEM-FDM procedures and numerical examples of a bolted tunnel are provided to demonstrate the efficacy of the proposed method for practical applications.

  16. Theoretical Calculation and Analysis on the Composite Rock-Bolt Bearing Structure in Burst-Prone Ground

    Directory of Open Access Journals (Sweden)

    Liang Cheng

    2015-01-01

    Full Text Available Given the increase in mining depth and intensity, tunnel failure as a result of rock burst has become an important issue in the field of mining engineering in China. Based on the Composite Rock-Bolt Bearing Structure, which is formed due to the interaction of the bolts driven into the surrounding rock, this paper analyzes a rock burst prevention mechanism, establishes a mechanical model in burst-prone ground, deduces the strength calculation formula of the Composite Rock-Bolt Bearing Structure in burst-prone ground, and confirms the rock burst prevention criterion of the Composite Rock-Bolt Bearing Structure. According to the rock burst prevention criterion, the amount of the influence on rock burst prevention ability from the surrounding rock parameters and bolt support parameters is discussed.

  17. The influence of joint technologies on ELV recyclability.

    Science.gov (United States)

    Soo, Vi Kie; Compston, Paul; Doolan, Matthew

    2017-10-01

    Stricter vehicle emission legislation has led to the increasing use of lightweight materials and multi-material concepts to reduce the vehicle mass. To account for the complexity of multi-material vehicle designs, the choice of joining techniques used is becoming more diverse. Moreover, the different material combinations, and their respective joining methods play an important role in determining the potential of full material separation in a closed-loop system. This paper evaluates the types of joining technologies used in the automotive industry, and identifies those that hinder the sorting of ELV materials. The study is based on an industrial shredding trial of car doors. Observations from the case study showed that steel screws and bolts are increasingly used to combine different material types and are less likely to be perfectly liberated during the shredding process. The characteristics of joints that lead to impurities and valuable material losses, such as joint strength, material type, size, diameter, location, and protrusion level, can influence the material liberation in the current sorting practices and thus, lead to ELV waste minimisation. Additionally, the liberation of joints is also affected by the density and thickness of materials being joined. Correlation analyses are carried out to further support the influence of mechanical screws and bolts on material separation efficiencies. The observations are representative of the initial phases of current global ELV sorting practices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Core Baffle Former Bolts Inspection and Repair at Farley NPP

    International Nuclear Information System (INIS)

    Marsat, E.

    1998-01-01

    As operating light water reactors are getting older and some of them are approaching their designed lifetime, the question of plant ageing, and the determination of their potential lifetime becomes mores and more important. This calls for a better understanding of ageing phenomena by an optimization of operating strategies and a development of innovative inspection and repair or replacement strategies. Definitely, this task is complex because it covers technical issues, cost, a given licensing situation and possibly, public acceptance. From a technical point it seems to be a common understanding that nuclear power plants can be operated for 40, 50 or even more years today. The inspection and repair technologies are of a very practical importance in achieving this goal. Bolts are subjected to flaws due to material, stress, and fluence issues. These issues are present in varying degrees depending on location in the core barrel. The issue depending on the number of failed bolts is a safety concern. It is not presently a concern if plants are operated with sufficient margin (sufficient acceptable bolts to allow continued operation). Historically there have been no greater than 10% of the bolts with detected flaws but as plants age, the flaw density may increase. (Author)

  19. Reactor shroud joint

    International Nuclear Information System (INIS)

    Ballas, G.J.; Fife, A.B.; Ganz, I.

    1998-01-01

    A shroud for a nuclear reactor is described. In one embodiment, the shroud includes first and second shroud sections, and each shroud section includes a substantially cylindrical main body having a first end and a second end. With respect to each shroud section, a flange is located at the main body first end, and the flange has a plurality of bolt openings therein and a plurality of scalloped regions. The first shroud section is welded to the second shroud section, and at least some of the bolt openings in the first shroud section flange align with respective bolt openings in the second shroud section flange. In the event that the onset of inter-granular stress corrosion cracking is ever detected in the weld between the shroud section, bolts are inserted through bolt openings in the first shroud section flange and through aligned bolt openings the second shroud section flange. Each bolt, in one embodiment, has a shank section and first and second threaded end sections. Nuts are threadedly engaged to the threaded end sections and tightened against the respective flanges. 4 figs

  20. Simulation and experiment for depth sizing of cracks in anchor bolts by ultrasonic phased array technology

    Science.gov (United States)

    Lin, Shan

    2018-04-01

    There have been lots of reports about the occurrence of cracks in bolts in aging nuclear and thermal power plants. Sizing of such cracks is crucial for assessing the integrity of bolts. Currently, hammering and visual tests are used to detect cracks in bolts. However, they are not applicable for sizing cracks. Although the tip diffraction method is well known as a crack sizing technique, reflection echoes from threads make it difficult to apply this technique to bolts. This paper addresses a method for depth sizing of cracks in bolts by means of ultrasonic phased array technology. Numerical results of wave propagation in bolts by the finite element method (FEM) shows that a peak associated within the vicinity of a crack tip can be observed in the curve of echo intensity versus refraction angle for deep cracks. The refraction angle with respect to this peak decreases as crack depth increases. Such numerical results are verified by experiments on bolt specimens that have electrical discharge machining notches or fatigue cracks with different depths. In the experiment, a 10-MHz linear array probe is used. Depth of cracks in bolts using the refraction angle associated with the peak is determined and compared to actual depths. The comparison shows that accurately determining a crack depth from the inspection results is possible.

  1. The structural behavior of a bolted flanged connection subjected to a cyclic load

    International Nuclear Information System (INIS)

    Cesari, F.

    1981-01-01

    In the vessel of BWR nuclear plants, the bolted flanged connection is subjected to a cyclic load, consisting of four steps: the bolt load, the pressure load with decreasing of bolt load, depressurization with increasing bold load, and at the end, unbolting. In the case of rigid, bolted flange, the elastic behavior is essentially correct, but if the height of the flange is decreased, then the stress gradients are so high that the strains move into the plastic range. In addition, the design of pressure vessels is not complete without an appraisal of failure by progressive distortion or stress ratchteing. There is therefore a need for numerical results for the structures subjected to well-known loading. The aim of this paper is to follow the stress and strain of a bolted flange subjected to the cyclic load, progressively varying the height of the flange, so that the maximum stress intensity becomes 3 Ssub(m). The number of cycles was sufficient to verify the conditions of shakedown or ratcheting. The numerical analysis, using finite element technique and the Adina code, is well established and frequently used. (orig.)

  2. A Component-Based Study of the Effect of Diameter on Bond and Anchorage Characteristics of Blind-Bolted Connections.

    Directory of Open Access Journals (Sweden)

    Muhammad Nasir Amin

    Full Text Available Structural hollow sections are gaining worldwide importance due to their structural and architectural advantages over open steel sections. The only obstacle to their use is their connection with other structural members. To overcome the obstacle of tightening the bolt from one side has given birth to the concept of blind bolts. Blind bolts, being the practical solution to the connection hindrance for the use of hollow and concrete filled hollow sections play a vital role. Flowdrill, the Huck High Strength Blind Bolt and the Lindapter Hollobolt are the well-known commercially available blind bolts. Although the development of blind bolts has largely resolved this issue, the use of structural hollow sections remains limited to shear resistance. Therefore, a new modified version of the blind bolt, known as the "Extended Hollo-Bolt" (EHB due to its enhanced capacity for bonding with concrete, can overcome the issue of low moment resistance capacity associated with blind-bolted connections. The load transfer mechanism of this recently developed blind bolt remains unclear, however. This study uses a parametric approach to characterising the EHB, using diameter as the variable parameter. Stiffness and load-carrying capacity were evaluated at two different bolt sizes. To investigate the load transfer mechanism, a component-based study of the bond and anchorage characteristics was performed by breaking down the EHB into its components. The results of the study provide insight into the load transfer mechanism of the blind bolt in question. The proposed component-based model was validated by a spring model, through which the stiffness of the EHB was compared to that of its components combined. The combined stiffness of the components was found to be roughly equivalent to that of the EHB as a whole, validating the use of this component-based approach.

  3. A Component-Based Study of the Effect of Diameter on Bond and Anchorage Characteristics of Blind-Bolted Connections.

    Science.gov (United States)

    Amin, Muhammad Nasir; Zaheer, Salman; Alazba, Abdulrahman Ali; Saleem, Muhammad Umair; Niazi, Muhammad Umar Khan; Khurram, Nauman; Amin, Muhammad Tahir

    2016-01-01

    Structural hollow sections are gaining worldwide importance due to their structural and architectural advantages over open steel sections. The only obstacle to their use is their connection with other structural members. To overcome the obstacle of tightening the bolt from one side has given birth to the concept of blind bolts. Blind bolts, being the practical solution to the connection hindrance for the use of hollow and concrete filled hollow sections play a vital role. Flowdrill, the Huck High Strength Blind Bolt and the Lindapter Hollobolt are the well-known commercially available blind bolts. Although the development of blind bolts has largely resolved this issue, the use of structural hollow sections remains limited to shear resistance. Therefore, a new modified version of the blind bolt, known as the "Extended Hollo-Bolt" (EHB) due to its enhanced capacity for bonding with concrete, can overcome the issue of low moment resistance capacity associated with blind-bolted connections. The load transfer mechanism of this recently developed blind bolt remains unclear, however. This study uses a parametric approach to characterising the EHB, using diameter as the variable parameter. Stiffness and load-carrying capacity were evaluated at two different bolt sizes. To investigate the load transfer mechanism, a component-based study of the bond and anchorage characteristics was performed by breaking down the EHB into its components. The results of the study provide insight into the load transfer mechanism of the blind bolt in question. The proposed component-based model was validated by a spring model, through which the stiffness of the EHB was compared to that of its components combined. The combined stiffness of the components was found to be roughly equivalent to that of the EHB as a whole, validating the use of this component-based approach.

  4. Analytical Investigation of the Cyclic Behavior of Smart Recentering T-Stub Components with Superelastic SMA Bolts

    Directory of Open Access Journals (Sweden)

    Junwon Seo

    2017-09-01

    Full Text Available Partially restrained (PR bolted T-stub connections have been widely used in replacement of established fully restrained (FR welded connections, which are susceptible to sudden brittle failure. These bolted T-stub connections can permit deformation, easily exceeding the allowable limit without any fracture because they are constructed with a design philosophy whereby the plastic deformation concentrates on bolt fasteners made of ductile steel materials. Thus, the PR bolted connections take advantage of excellent energy dissipation capacity in their moment and rotation behavior. However, a considerable amount of residual deformation may occur at the bolted connection subjected to excessive plastic deformation, thereby requiring additional costs to recover the original configuration. In this study, superelastic shape memory alloy (SMA bolts, which have a recentering capability upon unloading, are fabricated so as to solve these drawbacks, and utilized by replacing conventional steel bolts in the PR bolted T-stub connection. Instead of the full-scale T-stub connection, simplified T-stub components subjected to axial force are designed on the basis of a basic equilibrium theory that transfers the bending moment from the beam to the column and can be converted into equivalent couple forces acting on the beam flange. The feasible failure modes followed by corresponding response mechanisms are taken into consideration for component design with superelastic SMA bolts. The inelastic behaviors of such T-stub components under cyclic loading are simulated by advanced three-dimensional (3D finite element (FE analysis. Finally, this study suggests an optimal design for smart recentering T-stub components with respect to recentering and energy dissipation after observing the FE analysis results.

  5. Genetic analyses of bolting in bulb onion (Allium cepa L.).

    Science.gov (United States)

    Baldwin, Samantha; Revanna, Roopashree; Pither-Joyce, Meeghan; Shaw, Martin; Wright, Kathryn; Thomson, Susan; Moya, Leire; Lee, Robyn; Macknight, Richard; McCallum, John

    2014-03-01

    We present the first evidence for a QTL conditioning an adaptive trait in bulb onion, and the first linkage and population genetics analyses of candidate genes involved in photoperiod and vernalization physiology. Economic production of bulb onion (Allium cepa L.) requires adaptation to photoperiod and temperature such that a bulb is formed in the first year and a flowering umbel in the second. 'Bolting', or premature flowering before bulb maturation, is an undesirable trait strongly selected against by breeders during adaptation of germplasm. To identify genome regions associated with adaptive traits we conducted linkage mapping and population genetic analyses of candidate genes, and QTL analysis of bolting using a low-density linkage map. We performed tagged amplicon sequencing of ten candidate genes, including the FT-like gene family, in eight diverse populations to identify polymorphisms and seek evidence of differentiation. Low nucleotide diversity and negative estimates of Tajima's D were observed for most genes, consistent with purifying selection. Significant population differentiation was observed only in AcFT2 and AcSOC1. Selective genotyping in a large 'Nasik Red × CUDH2150' F2 family revealed genome regions on chromosomes 1, 3 and 6 associated (LOD > 3) with bolting. Validation genotyping of two F2 families grown in two environments confirmed that a QTL on chromosome 1, which we designate AcBlt1, consistently conditions bolting susceptibility in this cross. The chromosome 3 region, which coincides with a functionally characterised acid invertase, was not associated with bolting in other environments, but showed significant association with bulb sucrose content in this and other mapping pedigrees. These putative QTL and candidate genes were placed on the onion map, enabling future comparative studies of adaptive traits.

  6. Stress corrosion cracking susceptibility of selected materials for steam plant bolting applications

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, P.; Noga, J.O.; Ogundele, G.

    1996-12-01

    The incidence of alloy steel bolting failure in nuclear and fossil fired generating plants was discussed. The problem manifests itself in the form of intergranular stress corrosion cracking. A study was conducted to rank the susceptibility of three materials (Alloy AISI, type 4140, Alloy ASTM A564-92AXM 13 and Inconel 718) to stress corrosion cracking and to determine threshold stress intensity factors of currently used and alternate alloys in service environments typically encountered in steam generating utility plants. Although most alloy steel bolting failures have involved Cr-Mo, failures have also been reported for all the above mentioned materials. Attempts to minimize the occurrence of stress corrosion cracking have involved a ban on molybdenum disulphide, limiting bolt tightening torque and placing an upper limit on bolt hardness, and by correlation on tensile strength. Slow strain rate and wedge opening-loading specimen tests were used to evaluate commonly used and superior alternative bolting materials. Electrochemical polarization tests were also conducted. Threshold stresses in a H{sub 2}S environment were determined according to NACE standard TM-01-77. Results showed that, to a certain degree, all tested materials were susceptible to stress corrosion cracking. They ranked as follows from best to worst performance: (1) the Inconel 718, (2) alloy SM 13, and (3) alloy 4140. 9 refs., 20 tabs., 34 figs.

  7. Development of a Sealing-Bolt for the safeguarding of large containers such as multielement bottles

    International Nuclear Information System (INIS)

    D'Agraives, B.C.; Toornvliet

    1985-01-01

    A preliminary study on the development of a ''Sealing-Bolt'' is currently being carried out at JRC-Ispra. It is required for the safeguarding of large containers. A ''Sealing-Bolt'' would replace one - or more - of the conventional bolts, normally used for tightening a container's cover. It could not be removed - or unscrewed - without the knowledge of Inspectors. Thus, it has to meet the requirements of an Underwater Verifiable Seal and of a Threaded Stud-Bolt. It is proposed to derive the sealing feature from the VAK III seal, a LWR Fuel Assembly Ultrasonic Seal which has been developed by JRC-Ispra and is field tested at the Kahl Reactor Facility (FRG) since October 1983, while under evaluation for use by IAEA. The mechanical part asks for a specific study of a reliable system able to evidence that the bolt has been unscrewed during an opening of the lid

  8. Stud-bolts strength for cell-liner design under shearing deformation

    International Nuclear Information System (INIS)

    Watashi, Katsumi; Nakanishi, Seiji

    1991-01-01

    This paper presents experimental and analytical stud-bolt strength subjected to large shearing deformation at high temperature. Tensile test result of the material, SM41B, was shown in the range of room temperature to 550degC at 10 -3 and 10 -4 m/m/s in strain rate. Shearing fracture test result of the stud-bolt is shown at room temperature and 530degC. Shearing fracture criterion was discussed based on both test results and FEM analysis result. (author)

  9. Enhancement of crack detection in stud bolts of nuclear reactor by ultrasonic signal processing technique

    International Nuclear Information System (INIS)

    Lee, J.H.; Oh, W.D.; Choi, S.W.; Park, M.H.

    2004-01-01

    'Full-text:' The stud bolts is one of the most critical parts for safety of reactor vessels in the nuclear power plants. However, in the application of ultrasonic technique for crack detection in stud bolt, some difficulties encountered are classification of crack signal from the signals reflected from threads part in stud bolt. In this study, shadow effect technique combined with new signal processing method is Investigated to enhance the detectability of small crack initiated from root of thread in stud bolt. The key idea of signal processing is based on the fact that the shape of waveforms from the threads is uniform since the shape of the threads in a bolt is same. If some cracks exist in the thread, the flaw signals are different to the reference signals. It is demonstrated that the small flaws are efficiently detected by novel ultrasonic technique combined with this new signal processing concept. (author)

  10. Expression of NO scavenging hemoglobin is involved in the timing of bolting in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Hebelstrup, Kim Henrik; Jensen, Erik Østergaard

    2008-01-01

    -symbiotic hemoglobin gene, GLB2, in Arabidopsis thaliana. Lines with GLB1 silencing had a significant delay of bolting and after bolting, shoots reverted to the rosette vegetative phase by formation of aerial rosettes at lateral meristems. Lines with overexpression of GLB1 or GLB2 bolted earlier than wild type plants....... By germinating the lines in a medium containing the nitric oxide (NO) donor, sodium nitroprusside (SNP), it was demonstrated that both GLB1 and GLB2 promote bolting by antagonizing the effect of NO, suggesting that non-symbiotic plant hemoglobin controls bolting by scavenging the floral transition signal...... molecule, NO. So far, NO scavenging has only been demonstrated for class 1 non-symbiotic hemoglobins. A direct assay in Arabidopsis leaf cells shows that GLB1 as well as the class 2 non-symbiotic hemoglobin, GLB2, scavenge NO in vivo. NO has also been demonstrated to be a growth stimulating signal...

  11. Analysis of anchor bolt belongs to fan in nuclear power plant

    International Nuclear Information System (INIS)

    Miao Xueliang; Luan Xingfeng; Zhang Wei; Bian Chunhua; Yu Xiaoyan; Xu Ke; Liu Hongqun

    2014-01-01

    Through on the fan anchor bolt material components, metallurgical structure and fracture analysis indicates that: material composition and microscopic are abnormal, it led to material brittle increased, the fracture is rock-candy structure, the last part is toughness structure. The reason is the the fan vibrate oversize. At last, we put forward some measures. Just like, control the vibration of the fan, set a nominal tightening torque when installing bolt. (authors)

  12. Preliminary aseismic analysis on bolts of driving mechanism in absorption sphere shutdown system

    International Nuclear Information System (INIS)

    Chen Feng; Li Tianjin; Zhang Zhengming; Huang Zhiyong; Bo Hanliang

    2012-01-01

    The absorption sphere shutdown system performs an important role in reactivity regulating and control. Driving mechanism is a set of key mechanical moving parts which is used to control falling of absorption spheres in absorption sphere shutdown system. It is about 5 m for driving mechanism with the slim structure, which is connected with the upper supported plate of metal reactor internals through storage vessel with bolts. Both the storage vessel and driving mechanism are equipment of seismic classification I. It is significant to calculate and check the bolts strength of driving mechanism. In this paper, complicate structure of driving mechanism was simplified to three variable cross sections and statically indeterminate problem was solved. The bolts at the bottom and on the top of the storage vessel were calculated and checked. The preliminary results indicate that the bolts strength is reliable and safe, and the supporting force at the most weak point of driving mechanism is as well obtained. (authors)

  13. Experimental studies on the effects of bolt parameters on the bearing characteristics of reinforced rock.

    Science.gov (United States)

    Cheng, Liang; Zhang, Yidong; Ji, Ming; Zhang, Kai; Zhang, Minglei

    2016-01-01

    Roadways supported by bolts contain support structures that are built into the rock surrounding the roadway, referred to as reinforced rocks in this paper. Using physical model simulation, the paper investigates the bearing characteristics of the reinforced rock under different bolt parameters with incrementally increased load. The experimental results show that the stress at the measurement point inside the structure varies with the kinetic pressure. The stress increases slowly as the load is initially applied, displays accelerated growth in the middle of the loading application, and decreases or remains constant in the later stage of the loading application. The change in displacement of the surrounding rock exhibits the following characteristics: a slow increase when the load is first applied, accelerated growth in the middle stage, and violent growth in the later stage. There is a good correlation between the change in the measured stress and the change in the surrounding rock displacement. Increasing the density of the bolt support and the length and diameter of the bolt improves the load-bearing performance of the reinforced rock, including its strength, internal peak stress, and residual stress. Bolting improves the internal structure of the surrounding rocks, and the deterioration of the surrounding rock decreases with the distance between the bolt supports.

  14. Inedible Nuts and Non-Lightning Bolts

    Science.gov (United States)

    Rynone, William

    2010-01-01

    In this article, the author provides detailed information on a wide variety of commonly used screws, bolts, and other fasteners. The information has been gathered in his engineering career and outside interests (maintenance on his car and airplane, and woodworking). The topic should be of interest to students and educators in many technical…

  15. Piezoelectric Washer for Accurate Application of Bolt Preload

    Data.gov (United States)

    National Aeronautics and Space Administration — A concept is proposed for monitoring bolt preload that offers accuracy and low-cost features not available in existing preload monitoring systems. Existing washer...

  16. Handbook on dynamics of jointed structures.

    Energy Technology Data Exchange (ETDEWEB)

    Ames, Nicoli M.; Lauffer, James P.; Jew, Michael D.; Segalman, Daniel Joseph; Gregory, Danny Lynn; Starr, Michael James; Resor, Brian Ray

    2009-07-01

    The problem of understanding and modeling the complicated physics underlying the action and response of the interfaces in typical structures under dynamic loading conditions has occupied researchers for many decades. This handbook presents an integrated approach to the goal of dynamic modeling of typical jointed structures, beginning with a mathematical assessment of experimental or simulation data, development of constitutive models to account for load histories to deformation, establishment of kinematic models coupling to the continuum models, and application of finite element analysis leading to dynamic structural simulation. In addition, formulations are discussed to mitigate the very short simulation time steps that appear to be required in numerical simulation for problems such as this. This handbook satisfies the commitment to DOE that Sandia will develop the technical content and write a Joints Handbook. The content will include: (1) Methods for characterizing the nonlinear stiffness and energy dissipation for typical joints used in mechanical systems and components. (2) The methodology will include practical guidance on experiments, and reduced order models that can be used to characterize joint behavior. (3) Examples for typical bolted and screw joints will be provided.

  17. Mechanical Behaviour of Bolted Joints Under Impact Rates of Loading

    Science.gov (United States)

    2012-01-01

    M. (1995). Bearing Strength of Autoclave and oven cured kevlar / epoxy laminates under static and dynamic loading. Compostes, 451-456. Kretsis, G...Joints in Glass Fibre/ Epoxy Laminates. Composites, Volume 16. No 2. Kolsky, H. (1949). An Investigation of the Mechanical Properties of Materials at...elongating the pulse width. The responses are read by the strain gages bonded on the incident and transmission bar with Vishay AE-10 epoxy . The gages

  18. Evaluation of the clamping force in high tension bolt by using the ultrasonic nonlinearity

    International Nuclear Information System (INIS)

    Jang, Kyung Young; Cheon, Hae Wha; Ha, Hob; Park, Man Sick; Kim, No You

    2005-01-01

    High tension bolts have been used widely for the clamping of many kinds of large structure. Therefore, its estimation has been regarded as main issue in the maintenance of high tension bolts. This paper proposes a novel method using the ultrasonic nonlinearity, which is based on the dependency of sound speed on the stress. For this we introduce nonlinear elastic constants in the stress-strain relationship, and derive the sound speed as a linear function of stress. In order to verify the usefulness of the proposed method, two kinds of experiments are carried out: The first one is to measure the sound speed when the bolt is stressed by the tension tester. The result showed good agreement with the expected linear relationship between the sound speed and the axial stress. The second one is to measure the sound speed when the bolt is stressed by the torque wrench. The results showed that the sound speed was decreased when the torque was increased. From these results we can say that the proposed method is enough useful to evaluate the clamping force in the high tension bolt.

  19. Ultrasonic Inspection of Cracks in Stud Bolts of Reactor Vessels in Nuclear Power Plants by Signal Processing of Differential Operation

    International Nuclear Information System (INIS)

    Choi, Sang Woo; Lee, Joon Hyun; Oh, Won Deok

    2005-01-01

    The stud bolt is one of crucial parts for safe operation of reactor vessels in nuclear power plants, Crack initiation and propagation were reported in stud bolts that arc used for closure of reactor vessel and head, Stud bolts are inspected by ultrasonic technique during overhaul periodically for the prevention of stud bolt failure which could induce radioactive leakage from nuclear reactor, In conventional ultrasonic testing for inspection of stud bolts, cracks are detected by using shadow effect It takes too much time to inspect stud bolts by using conventional ultrasonic technique. In addition, there were numerous spurious signals reflected from every oblique surfaces of thread, In this study, the signal processing technique for enhancing conventional ultrasonic technique was introduced for inspecting stud bolts. The signal processing technique provides removing spurious signal reflected from every oblique surfaces of thread and enhances detectability of defects. Detectability for small crack was enhanced by using this signal processing in ultrasonic inspection of stud bolts in Nuclear Power Plants

  20. Visual Inspection of the Flow Distribution Plate Bolts of a Nuclear Steam Generator

    International Nuclear Information System (INIS)

    Jeong, Woo Tae; Kim, Suk Tae; Sohn, Wook; Kang, Duk Won; Kang, Seok Chul

    2007-01-01

    To develop a system for visually inspecting the flow distribution plate (FDP) bolts of a nuclear steam generator, we reviewed several types of similar inspection equipment. The equipment which are currently available are mostly for inspecting lower part of a steam generator such as tube sheets and annulus except ELVS (Eggcrate Visual Inspection System). However, the design concept of ELVS could not be used for developing a device which enables the visual inspection of flow distribution plate bolts. Therefore, based on the current state of the art technology on the similar equipment, we conceptually designed a new inspection system for checking the FDP bolts

  1. Experimental Investigation on Strengthening of Bolted Connections in Transmission/Communication Towers

    Science.gov (United States)

    Balagopal, R.; Prasad Rao, N.; Rokade, R. P.; Umesha, P. K.

    2018-02-01

    Due to increase in demand for power supply and increase in bandwidth for communication industry, the existing transmission line (TL) and communication towers needs to be strengthened. The strengthening of existing tower is economical rather than installation of new towers due to constraints in acquisition of land. The size of conductors have to be increased or additional number of antenna needs to be installed in existing TL/communication tower respectively. The compression and tension capacity of members in the existing towers have to be increased to sustain the additional loads due to wind and self-weight of these components. The tension capacity enhancement of existing angle sections in live line condition without power shut-down is a challenging task. In the present study, the use of Glass Fiber Reinforced Plastic (GFRP) plate/angle sections is explored to strengthen existing bolted connections in TL/communication towers. Experimental investigation conducted at component level on strengthening of existing two types of single cover steel butt joint, one made of steel plate and another joint made of steel angle sections respectively. First series of experiment conducted on strengthening the connection using GFRP plate/cleat angle sections. The second series of strengthening experiment is conducted using steel plate/angle sections to replace GFRP sections. The load sharing behaviour of strengthened GFRP and steel section is compared and suitable recommendations are given.

  2. Experimental Investigation on Strengthening of Bolted Connections in Transmission/Communication Towers

    Science.gov (United States)

    Balagopal, R.; Prasad Rao, N.; Rokade, R. P.; Umesha, P. K.

    2018-06-01

    Due to increase in demand for power supply and increase in bandwidth for communication industry, the existing transmission line (TL) and communication towers needs to be strengthened. The strengthening of existing tower is economical rather than installation of new towers due to constraints in acquisition of land. The size of conductors have to be increased or additional number of antenna needs to be installed in existing TL/communication tower respectively. The compression and tension capacity of members in the existing towers have to be increased to sustain the additional loads due to wind and self-weight of these components. The tension capacity enhancement of existing angle sections in live line condition without power shut-down is a challenging task. In the present study, the use of Glass Fiber Reinforced Plastic (GFRP) plate/angle sections is explored to strengthen existing bolted connections in TL/communication towers. Experimental investigation conducted at component level on strengthening of existing two types of single cover steel butt joint, one made of steel plate and another joint made of steel angle sections respectively. First series of experiment conducted on strengthening the connection using GFRP plate/cleat angle sections. The second series of strengthening experiment is conducted using steel plate/angle sections to replace GFRP sections. The load sharing behaviour of strengthened GFRP and steel section is compared and suitable recommendations are given.

  3. The effect of cultivar, sowing date and transplant location in field on bolting of Welsh onion (Allium fistulosum L.).

    Science.gov (United States)

    Dong, Yinxin; Cheng, Zhihui; Meng, Huanwen; Liu, Hanqiang; Wu, Cuinan; Khan, Abdul Rehman

    2013-10-07

    Bolting reduces the quality and commercial yield of Welsh onion (Allium fistulosum L.) in production. However, seed production is directly dependent on flower induction and bolting. The Welsh onion belongs to the green plant vernalisation type, specific seedling characteristics and sufficient accumulated time at low temperature are indispensible for the completion of its vernalisation process. Only if these conditions for vernalisation are fulfilled, the plants will bolt in the following year. The present investigation evaluated the effects of cultivar, sowing date and transplant location in field on the bolting of Welsh onion at the Horticultural Farm of the College of Horticulture, Northwest A&F University, Yangling, Shannxi Province, China in two succeeding production years: 2010-2011 and 2011-2012. A strip split plot layout within a randomised complete block design with three replications was used. The results revealed that all three factors (cultivar, sowing date and transplant location) and their interaction had significant effects on the initiation and final rate of bolting observed by 30 April. The earliest bolting date (14 February, 2011 and 15 February, 2012) and the highest bolting rate (100% in 2011 and 62% in 2012) occurred when the JinGuan cultivar was sown on 20 August and transplanted in a plastic tunnel, whereas the latest date and lowest rate (no bolting observed until 30 April) of bolting occurred when the XiaHei cultivar was sown on 29 September and transplanted in an open field. These results suggest that we can control bolting in Welsh onion production by choosing an appropriate cultivar, sowing date and transplant location. Choosing a late bolting cultivar, such as cultivar XiaHei, sowing around October, and transplanting in the open field can significantly delay bolting, while a sowing date in late August should be selected for seed production, and the seedlings should be transplanted in a plastic tunnel to accelerate development of the

  4. Interaction between an Eco-Spiral Bolt and Crushed Rock in a Borehole Evaluated by Pull-Out Testing

    Directory of Open Access Journals (Sweden)

    Seong-Seung Kang

    2017-01-01

    Full Text Available The interactions between an eco-spiral bolt and crushed rocks in a borehole were evaluated by pull-out testing in a laboratory and numerical analysis. The porosity of the crushed rock surrounding the bolt depended on the size of the eco-spiral bolt and affected the eco-spiral bolt’s axial resistance force. The axial resistance force and the porosity of the crushed rocks in the borehole showed an inverse relationship. The porosity was also related to the size of the eco-spiral bolt. The maximum principal stress between the bolt and the rock was related to the porosity of the crushed rock and the size difference between the eco-spiral bolt and the borehole. At low porosity the experimental and numerical analyses show similar relationships between the axial resistance force and the displacement. However, at high porosity, the numerical results deviated greatly from the experimental observation. The initial agreement is attributed to the state of residual resistance after the maximum axial resistance force, and the latter divergence was due to the decreasing axial resistance force owing to slippage.

  5. Theoretical Calculation and Analysis on the Composite Rock-Bolt Bearing Structure in Burst-Prone Ground

    OpenAIRE

    Cheng, Liang; Zhang, Yidong; Ji, Ming; Cui, Mantang; Zhang, Kai; Zhang, Minglei

    2015-01-01

    Given the increase in mining depth and intensity, tunnel failure as a result of rock burst has become an important issue in the field of mining engineering in China. Based on the Composite Rock-Bolt Bearing Structure, which is formed due to the interaction of the bolts driven into the surrounding rock, this paper analyzes a rock burst prevention mechanism, establishes a mechanical model in burst-prone ground, deduces the strength calculation formula of the Composite Rock-Bolt Bearing Structur...

  6. Inflorescence Development and the Role of LsFT in Regulating Bolting in Lettuce (Lactuca sativa L.)

    Science.gov (United States)

    Chen, Zijing; Han, Yingyan; Ning, Kang; Ding, Yunyu; Zhao, Wensheng; Yan, Shuangshuang; Luo, Chen; Jiang, Xiaotang; Ge, Danfeng; Liu, Renyi; Wang, Qian; Zhang, Xiaolan

    2018-01-01

    Lettuce (Lactuca sativa L.) is one of the most important leafy vegetable that is consumed during its vegetative growth. The transition from vegetative to reproductive growth is induced by high temperature, which has significant economic effect on lettuce production. However, the progression of floral transition and the molecular regulation of bolting are largely unknown. Here we morphologically characterized the inflorescence development and functionally analyzed the FLOWERING LOCUS T (LsFT) gene during bolting regulation in lettuce. We described the eight developmental stages during floral transition process. The expression of LsFT was negatively correlated with bolting in different lettuce varieties, and was promoted by heat treatment. Overexpression of LsFT could recover the late-flowering phenotype of ft-2 mutant. Knockdown of LsFT by RNA interference dramatically delayed bolting in lettuce, and failed to respond to high temperature. Therefore, this study dissects the process of inflorescence development and characterizes the role of LsFT in bolting regulation in lettuce. PMID:29403510

  7. Inflorescence Development and the Role of LsFT in Regulating Bolting in Lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Chen, Zijing; Han, Yingyan; Ning, Kang; Ding, Yunyu; Zhao, Wensheng; Yan, Shuangshuang; Luo, Chen; Jiang, Xiaotang; Ge, Danfeng; Liu, Renyi; Wang, Qian; Zhang, Xiaolan

    2017-01-01

    Lettuce ( Lactuca sativa L.) is one of the most important leafy vegetable that is consumed during its vegetative growth. The transition from vegetative to reproductive growth is induced by high temperature, which has significant economic effect on lettuce production. However, the progression of floral transition and the molecular regulation of bolting are largely unknown. Here we morphologically characterized the inflorescence development and functionally analyzed the FLOWERING LOCUS T (LsFT) gene during bolting regulation in lettuce. We described the eight developmental stages during floral transition process. The expression of LsFT was negatively correlated with bolting in different lettuce varieties, and was promoted by heat treatment. Overexpression of LsFT could recover the late-flowering phenotype of ft-2 mutant. Knockdown of LsFT by RNA interference dramatically delayed bolting in lettuce, and failed to respond to high temperature. Therefore, this study dissects the process of inflorescence development and characterizes the role of LsFT in bolting regulation in lettuce.

  8. The Experimental Study of the Temperature Effect on the Interfacial Properties of Fully Grouted Rock Bolt

    Directory of Open Access Journals (Sweden)

    Fuhai Li

    2017-03-01

    Full Text Available This study analyzes the phenomenon of performance deterioration in fully grouted rock bolts in tunnels with a dry, hot environment and high geothermal activity with a focus on temperature effects on interfacial bond performance. Three groups of fully grouted rock bolt specimens were designed based on similar mechanical principles. They were produced and maintained at 20 °C, 35 °C, and 50 °C. Through the indoor gradual loading tensile test of specimens, variations of axial force and shear stress between the rock bolt and mortar adhesive interface were obtained under different environmental temperatures. Distribution of the axial force and shear stress on the anchorage section were found under different tensile forces. Results showed that, with an increase in specimen environmental temperature, maximum shear stress of the rock bolt section became smaller, while shear stress distribution along the rock bolt segment became more uniform. In addition, the axial force value at the same position along the pull end was greater, while axial stress along the anchorage’s length decayed faster. With an increase in tensile force under different temperatures, the axial force and maximum shear stress of rock bolt specimens along the anchorage section has a corresponding increase.

  9. Pull-out test of stud bolts embedded in concrete under an in-plane force

    International Nuclear Information System (INIS)

    Inada, Y.; Saito, H.; Torita, H.; Takiguchi, K.; Ibe, Y.; Taira, T.

    1995-01-01

    There are many steel plates with stud bolts embedded in the R C walls of a nuclear reactor building to support equipment and piping. Under a earthquake, the steel plates are submitted to an out-of-plane force due to the inertia force acting upon equipment and piping. Furthermore, the walls are submitted to an in-plane force, and cracks may occur. A large number of experimental studies have been carried out on the pull-out strength of stud bolts embedded in concrete. Few studies have been performed to understand the strength of stud bolts embedded in concrete under an in-plane force and, further, not any one on the strength for concrete under in-plane force simultaneously to stud bolts under out-of-plane force. This paper describes a test performed to understand the pull-out strength determined by this interaction of in-plane and out-of-plane forces. (author). 5 refs., 9 figs., 5 tabs

  10. Identification of flowering-related genes responsible for differences in bolting time between two radish inbred lines

    Directory of Open Access Journals (Sweden)

    Hye Sun Cho

    2016-12-01

    Full Text Available Late bolting after cold exposure is an economically important characteristic of radish (Raphanus sativus L., an important Brassicaceae root vegetable crop. However, little information is available regarding the genes and pathways that govern flowering time in this species. We performed high-throughput RNA sequencing analysis to elucidate the molecular mechanisms that determine the differences in flowering times between two radish lines, NH-JS1 (late bolting and NH-JS2 (early bolting. In total, 71,188 unigenes were identified by reference-guided assembly, of which 309, 788, and 980 genes were differentially expressed between the two inbred lines after 0, 15, and 35 days of vernalization, respectively. Among these genes, 218 homologs of Arabidopsis flowering-time (Ft genes were identified in the radish, and 49 of these genes were differentially expressed between the two radish lines in the presence or absence of vernalization treatment. Most of the Ft genes up-regulated in NH-JS1 vs NH-JS2 were repressors of flowering, such as RsFLC, consistent with the late-bolting phenotype of NH-JS1. Although the functions of genes down-regulated in NH-JS1 were less consistent with late-bolting characteristics than the up-regulated Ft genes, several Ft enhancer genes, including RsSOC1, a key floral integrator, showed an appropriate expression to the late-bolting phenotype. In addition, the patterns of gene expression related to the vernalization pathway closely corresponded with the different bolting times of the two inbred lines. These results suggest that the vernalization pathway is conserved between radish and Arabidopsis.

  11. Pyroshock Prediction of Ridge-Cut Explosive Bolts Using Hydrocodes

    Directory of Open Access Journals (Sweden)

    Juho Lee

    2016-01-01

    Full Text Available Pyrotechnic release devices such as explosive bolts are prevalent for many applications due to their merits: high reliability, high power-to-weight ratio, reasonable cost, and more. However, pyroshock generated by an explosive event can cause failures in electric components. Although pyroshock propagations are relatively well understood through many numerical and experimental studies, the prediction of pyroshock generation is still a very difficult problem. This study proposes a numerical method for predicting the pyroshock of a ridge-cut explosive bolt using a commercial hydrocode (ANSYS AUTODYN. A numerical model is established by integrating fluid-structure interaction and complex material models for high explosives and metals, including high explosive detonation, shock wave transmission and propagation, and stress wave propagation. To verify the proposed numerical scheme, pyroshock measurement experiments of the ridge-cut explosive bolts with two types of surrounding structures are performed using laser Doppler vibrometers (LDVs. The numerical analysis results provide accurate prediction in both the time (acceleration and frequency domains (maximax shock response spectra. In maximax shock response spectra, the peaks due to vibration modes of the structures are observed in both the experimental and numerical results. The numerical analysis also helps to identify the pyroshock generation source and the propagation routes.

  12. Non-linear finite element modelling and analysis of the effect of gasket creep-relaxation on circular bolted flange connections

    International Nuclear Information System (INIS)

    Luyt, P.C.B.; Theron, N.J.; Pietra, F.

    2017-01-01

    It is well known that gasket creep-relaxation results in a reduction of contact pressure between the surface of a gasket and the face of a flange over an extended period of time. This reduction may result in the subsequent failure of the circular bolted flange connection due to leakage. In this paper a pair of flat and raised face integral flanges, PN 10 DN 50 (in accordance with the European EN 1092-1 standard), with non-asbestos compressed fibre ring gaskets with aramid and a nitrile rubber binder were considered. Finite element modelling and analyses were done, for both the circular bolted flange configurations, during the seating condition. The results of the finite element analyses were experimentally validated. It was found that the number of bolt tightening increments as well as the time between the bolt tightening increments had a significant impact on the effect which gasket creep-relaxation had after the seating condition. An increase in either the number of bolting increments or the time between the bolting increments will reduce the effect which gasket creep-relaxation has once the bolts had been fastened. Based on these results it is possible to develop an optimisation scheme to minimize the effect which gasket creep-relaxation has on the contact pressure between the face of the flange and the gasket, after seating, by either increasing or decreasing the number of bolt tightening increments or the time between the bolt tightening increments. - Highlights: • Number of bolt tightening increments and time between bolt tightening increments had significant impact on effect of gasket creep-relaxation after the seating condition. • Impact of gasket creep-relaxation during seating and operating phases investigated by means of finite element analysis and experimentally verified. • Possible to develop optimisation scheme to minimize effect ofh gasket creep-relaxation on contact pressure between flange face and gasket. • Knowing the contact pressure is

  13. Influence of Thread Root Radius on Maximum Local Stresses at Large Diameter Bolts under Axial Loading

    Directory of Open Access Journals (Sweden)

    Cojocaru Vasile

    2014-06-01

    Full Text Available In the thread root area of the threaded bolts submitted to axial loading occur local stresses, higher that nominal stresses calculated for the bolts. These local stresses can generate failure and can reduce the fatigue life of the parts. The paper is focused on the study of the influence of the thread root radius on the maximum local stresses. A large diameter trapezoidal bolt was subjected to a static analysis (axial loading using finite element simulation.

  14. Transcriptomic analysis reveals the roles of gibberellin-regulated genes and transcription factors in regulating bolting in lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Liu, Xueying; Lv, Shanshan; Liu, Ran; Fan, Shuangxi; Liu, Chaojie; Liu, Renyi; Han, Yingyan

    2018-01-01

    A cool temperature is preferred for lettuce cultivation, as high temperatures cause premature bolting. Accordingly, exploring the mechanism of bolting and preventing premature bolting is important for agriculture. To explore this relationship in depth, morphological, physiological, and transcriptomic analyses of the bolting-sensitive line S39 at the five-leaf stage grown at 37°C were performed in the present study. Based on paraffin section results, we observed that S39 began bolting on the seventh day at 37°C. During bolting in the heat-treated plants, GA3 and GA4 levels in leaves and the indoleacetic acid (IAA) level in the stem reached a maximum on the sixth day, and these high contents were maintained. Additionally, bolting begins in the fifth day after GA3 treatment in S39 plants, GA3 and GA4 increased and then decreased, reaching a maximum on the fourth day in leaves. Similarly, IAA contents reached a maximum in the stem on the fifth day. No bolting was observed in the control group grown at 25°C, and significant changes were not observed in GA3 and GA4 levels in the controls during the observation period. RNA-sequencing data implicated transcription factors (TFs) in regulating bolting in lettuce, suggesting that the high GA contents in the leaves and IAA in the stem promote bolting. TFs possibly modulate the expression of related genes, such as those encoding hormones, potentially regulating bolting in lettuce. Compared to the control group, 258 TFs were identified in the stem of the treatment group, among which 98 and 156 were differentially up- and down-regulated, respectively; in leaves, 202 and 115 TFs were differentially up- and down-regulated, respectively. Significant changes in the treated group were observed for C2H2 zinc finger, AP2-EREBP, and WRKY families, indicating that these TFs may play important roles in regulating bolting.

  15. Site ultrasonic measurement on RPV stud-bolt loading under hot transient of Qinshan NPP

    International Nuclear Information System (INIS)

    Qu Jiadi; Dou Yikang; Zhu Shiming

    1994-08-01

    It expounds that the key of solving thermal transient sealing problem is to obtain the thermal increment of stud-bolt loading. This loading, as a primary stress loading, is directly related to the bolt fatigue life and transient loading spectrum for vessel analysis. The fundamental works and main results of ultrasonic measurement on RPV stud-bolt loading on Qinshan site are also presented. The measuring capability has exceeded 1 m in length and temperature of 280 degree C, therefore, it is possible to be used in the field of NPP. The paper is the continuation of research work for sealing analysis and tests on the RPV (see SMiRT-9, 10)

  16. Response of garlic (Allium sativum L. bolting and bulbing to temperature and photoperiod treatments

    Directory of Open Access Journals (Sweden)

    Cuinan Wu

    2016-04-01

    Full Text Available This research was conducted to evaluate the effect of temperature and photoperiod treatments on the bolting and bulb formation of three local garlic cultivars (cvs in two consecutive years. Naturally vernalized plants of cvs G107, G025 and G064 were transplanted into growth chambers and subjected to various combinations of temperature [T15/10, 15°C/10°C; T20/15, 20°C/15°C and T25/18, 25°C/18°C (day/night] and photoperiod (L8, 8 h and L14,14 h treatments. Plant growth, endogenous phytohormone and methyl jasmonate (MeJA levels, along with the bolting and yield of garlic were evaluated. The experimental results from two consecutive years indicated that higher temperature (20°C or 25°C and longer photoperiod (14 h treatments significantly enhanced the garlic bolting, bulbing and cloving with a shorter growth period and a higher bulb weight. Moreover, the endogenous phytohormone and MeJA levels in the test plants were significantly increased by the higher temperature (25°C for the phytohormone level; 20°C for the MeJA level and longer photoperiod [14 h, except for abscisic acid (ABA, which had the highest level at 8 h] conditions and were decreased by the lowest test temperature (15°C and shorter photoperiod (8 h, except for ABA conditions. This response coincided with that of the bulbing index, bolting rate, growth period and bulb weight. In addition, plants treated under the conditions of 20°C/15°C–14 h and 25°C/18°C–14 h produced the highest phytohormone levels (except for ABA for cvs G025 and G064, respectively, and showed the best bolting and bulbing behavior. It is reasonable to assume that endogenous phytohormone (especially gibberellic acid and MeJA levels are highly related to garlic bolting and bulbing, which might lead to the different responses of the three studied cultivars to the combination of temperature and photoperiod treatments. Furthermore, cvs G107 and G025 bolt well and have better bulb

  17. Application of Long Expansion Rock Bolt Support in the Underground Mines of Legnica–Głogów Copper District

    Directory of Open Access Journals (Sweden)

    Skrzypkowski Krzysztof

    2017-09-01

    Full Text Available In the underground mines of the Legnica–Głogów Copper District (LGOM the main way to protect the room excavation is the use of a rock bolt support. For many years, it has proven to be an efficient security measure in excavations which met all safety standards and requirements. The article presents the consumption of the rock bolt support in the Mining Department “Polkowice–Sieroszowice” in the years 2010–2015 as well as the number of bolt supports that were used to secure the excavations. In addition, it shows the percentage of bolt supports that were used to conduct rebuilding work and cover the surface of exposed roofs. One of the factors contributing to the loss of the functionality of bolt supports is corrosion whose occurrence may lead directly to a reduction in the diameter of rock bolt support parts, in particular rods, bearing plates and nuts. The phenomenon of the corrosion of the bolt support and its elements in underground mining is an extremely common phenomenon due to the favorable conditions for its development in mines, namely high temperature and humidity, as well as the presence of highly aggressive water. This involves primarily a decrease in the capacity of bolt support construction, which entails the need for its strengthening, and often the need to perform the reconstruction of the excavation.

  18. Evaluation of Many Load Tests of Passive Rock Bolts in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Holý Ondřej

    2017-03-01

    Full Text Available Within the research project “FR-TI4/329 Research and development - creating an application system for the design and analysis of soil and rock anchors including the development of monitoring elements”, an extensive stage of field load tests of rock bolts was carried out. The tests were conducted at 14 locations with varied rock composition. Before the initial tests, a loading stand was designed and constructed. A total of 201 pieces of tensile tests of bolts having lengths from 0.5 up to 2.5 m, a diameter of 22-32 mm, were performed. These were fully threaded rods, self-drilling rods, and fiberglass rods. The bolts were clamped into the cement and resin. The loading tests were always performed until material failure of bolts or shear stress failure at the interface cement-rock. At each location, basic geotechnical survey was carried out in the form of core drilling in a length of 3.0 metres with the assessment of the rock mass in situ, and laboratory testing of rock mechanics. Upon the completion of testing protocols, rock mass properties analysis was performed focusing on the evaluation of shear friction at the grouting-rock interface.

  19. Design and analysis of push pipe joint under internal pressure and temperature loading

    International Nuclear Information System (INIS)

    Abid, M.; Alam, K.

    2005-01-01

    Pipe joints flanged or welded are commonly used in industry for different applications ranging from sewerage to the high pressure and temperature applications. However, with the rapidly changing technological trends, for optimized space such as for heat exchanger applications, pipe joint design needs special consideration, especially for the internal pipe where no flanged/bolted joint due to space constraint can be used. In addition, where joint opening/closing is the requirement for maintenance or other functional purposes, it becomes inevitable to use some special design. In this paper, a push joint proposed is designed, analyzed, optimized and tested for safe stress and operating conditions. An experimental test rig is designed and tests are performed for internal pressure and temperature separately and joint's behaviour is analyzed in detail for any leaks. FEA results are compared and verified with the mathematical results. Based on the experimental observations, the joint is safe as no leaks are observed. (author)

  20. Analytical design method for a truss-bolt system for reinforcement of fractured coal mine roofs - illustrated with a case study

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B.; Yue, Z.Q.; Tham, L.G. [University of Hong Kong, Hong Kong (China). Dept. of Civil Engineering

    2005-02-01

    This paper presents an analytical design method for the truss-bolt system in reinforcing underground fractured rock roofs in coal mines. The analytical design method is based on the mechanical analysis of the fractured rock roof with reinforcement by inclined roof bolts and a horizontal tie-rod. The mechanical analysis for the system includes a non-linear bending model for the laterally inclined roof bolts and three upper and lower bounds. The lateral resistance of the inclined roof bolts in a truss-bolt-supported roadway is examined using classical theory of a non-linear beam in bending. The paper analyses the arching action by lateral behavior of the inclined roof bolts in reinforcing the fractured roof. Based on mechanical models, the design formula concerning the lateral bolt forces, tensions in the tie-rod in the truss system, as well as the reinforcement behavior have been derived. In order to ensure that the roof truss-bolt system reinforces the coal roof effectively, a lower bound of pre-tightening forces must be applied on the tie-rod for stabilizing the fractured roof by arching action. The pre-tightening forces exerted via the tie-rod also cannot be greater than its upper bound, since the excessive tightening force will cause localized failure in the rock near the bolt tail at the abutment of the fractured roof beam. The analytical formulas for both lower and upper bounds for truss pre-tightening forces are put forward in this paper. Furthermore, the paper also presents analytical equations for designing the axial forces and dimensions for bolts in this kind of system.

  1. Special remote tooling developed and utilized to tighten TFTR TF coil casing bolts

    International Nuclear Information System (INIS)

    Burgess, T.W.; Walton, G.R.; Meighan, T.G.; Paul, B.L.

    1993-01-01

    Special tooling has been developed and used to tighten toroidal field (TF) coil casing bolts that have loosened from years of Tokamak Fusion Test Reactor (TFTR) operation. Due to their location, many of the TF casing bolts cannot be directly accessed or viewed; their condition was first discovered during unrelated inspections in 1988. Engineering solutions were, sought until 1992, when a remotely operated wrench concept was successfully demonstrated on a TF coil mockup. The concept was developed into several working tools that have successfully been applied to tighten several thousand TF casing bolts during recent scheduled outages. This effort has improved the integrity and reliability of the TF coil system in preparing for the final experimental phase of the TFTR. This paper discusses the design and application of this tooling

  2. X-ray measurement of residual stress on bolt threads

    International Nuclear Information System (INIS)

    Hagiwara, Masaya; Nakahara, Kanefumi; Yoshimoto, Isamu.

    1989-01-01

    This study deals with X-ray measurement of residual stress at the local area around the thread root of a bolt. Residual stress in the 0.5 mm x 5 mm area was measured using a method of stepped scanning and parabolic approximation. The conditions of measurement had been determined and evaluated through the preliminary measurement of compressive stress acting on the cylindrical surface. Furthermore, the fatigue strength estimated by applying the residual stress data to the previously presented hypothesis was compared with the experimental results. The main conclusions obtained were as follows: (1) The residual stress in a relatively small area on the cylindrical surface with large curvature can be measured by X-ray using a method of stepped scanning and parabolic approximation; (2) The compressive residual stress measured at the thread root was larger for the bolt manufactured by thread rolling after heat treatment than for one manufactured by thread rolling before heat treatment; (3) The distribution of residual stress along the axial direction from the thread root to the portion under crest did not represent remarkable change in its value; (4) The residual stress of a bolt was somewhat decreased by fatigue loading on the condition of low mean stress; (5) The fatigue strength estimated using residual stress data showed the tendency of experimental results well. (author)

  3. Lower limit of strength wedge-type anchor bolts

    International Nuclear Information System (INIS)

    Arnedo Pena, A.; Frances Urmeneta, M.

    1998-01-01

    Simple expansion bolts, with a split expansion ring and a threaded bolt with an integral cone expander, called wedge type, are very used in securing and anchoring structures. The anchorage is obtained by a mechanism of torque-controlled expansion. Although less resistant than other types, its easy installation and low cost make them very competitive in light structures. In this paper, the minimum capacity values are analysed, when they are used to anchor safety-related equipment in NPP. The EPRI criteria developed in response to USI A-46 are applied and complemented by the new CEB Anchorage Design Guide. The results are compared with the information from european manufactures, adopting different safety factors for cracked and non-cracked concrete. With adequate control and inspection measures, including areas of noticeable cracking of concrete. minimum values for equipment can be obtained satisfying the strictest seismic validation requirements. (Author) 5 refs

  4. Experimental Study on Bond-Slip Behavior of Bamboo Bolt-Modified Slurry Interface under Pull-Out Load

    Directory of Open Access Journals (Sweden)

    Wei Lu

    2018-01-01

    Full Text Available This paper presents an analysis of bamboo bolt-modified slurry interfaces based on 26 in situ axial pull-out tests intended to highlight the mechanical behavior of interface under a fracture mode. Three impact factors are analyzed: anchorage length, bolt diameter, and bolt hole diameter, using the same materials of bamboo and modified slurry. The result shows that the interface between the bamboo bolt and anchoring agent is the control interface of an anchorage system, and the local behavior of the interface involves four stages: elastic, soften, friction, and decoupling. Distribution law and change trend of slippage, stress, and strain of anchoring interface along with the axial direction of an anchor bolt were analyzed. The result shows that there is effective anchoring length limit in this kind of interface, and that the complete decoupling phenomenon should not be neglected. Through a comparative analysis of the existing bond-slip model and interface bond-slip curve, and considering the correspondence of the strain-slip curve and trilinear bond-slip model simultaneously, a modified trilinear bond-slip model has been proposed. The friction section of this model is limited, and shearing stress in the complete decoupling section is zero.

  5. A Design Method for the Tension Side of Statically Loaded, Bolted Beam-to-Column Connections

    NARCIS (Netherlands)

    Zoetemeijer, P.

    1974-01-01

    In this paper a design method for the tension side of statically loaded, bolted beam-to-column connections is developed based on the plastic behaviour of the flanges and the bolts under the assumption that the plastification is large enough to allow the adoption of the most favourable static

  6. Bolting state-building fault lines with social capital

    African Journals Online (AJOL)

    2013-12-15

    Dec 15, 2013 ... Keywords: State-building, social capital, ethnic supremacy, Dinka, Nuer,. South Sudan. * Robert Gerenge is the Head of Special Programmes at the Electoral Institute for Sustainable. Democracy in Africa (EISA). South Sudan's December 2013 conflict: Bolting state-building fault lines with social capital.

  7. Apparatus For Eddy-Current Inspection Of Bolts

    Science.gov (United States)

    Amos, Jay M.

    1994-01-01

    Eddy-current apparatus for inspection of bolts, studs, and other threaded fasteners detects flaws in threads, shanks, and head fillets. With help of apparatus, technician quickly inspects fasteners of various dimensions. Accommodates fasteners with diameters from 0.190 in. to 1 in. and with lengths up to 5 in. Basic design modified to accommodate fasteners of other sizes.

  8. A Smart Washer for Bolt Looseness Monitoring Based on Piezoelectric Active Sensing Method

    Directory of Open Access Journals (Sweden)

    Heyue Yin

    2016-10-01

    Full Text Available Piezoceramic based active sensing methods have been researched to monitor preload on bolt connections. However, there is a saturation problem involved with this type of method. The transmitted energy is sometimes saturated before the maximum preload which is due to it coming into contact with flat surfaces. When it comes to flat contact surfaces, the true contact area will easily saturate with the preload. The design of a new type of bolt looseness monitoring sensor, a smart washer, is to mitigate the saturation problem. The smart washer is composed of two annular disks with contact surfaces that are machined into convex and concave respectively, to eliminate the complete flat contact surfaces and to reduce the saturation effect. One piezoelectric patch is bonded on the non-contact surface of each annular disk. These two mating annular disks form a smart washer. One of the two piezoelectric patches serves as an actuator to generate an ultrasonic wave that propagates through the contact surface; the other one serves as a sensor to detect the propagated waves. The wave energy propagated through the contact surface is proportional to the true contact area which is determined by the bolt preload. The time reversal method is used to extract the peak of the focused signal as the index of the transmission wave energy; then, the relationship between the signal peak and bolt preload is obtained. Experimental results show that the focused signal peak value changes with the bolt preload and presents an approximate linear relationship when the saturation problem is experienced. The proposed smart washer can monitor the full range of the rated preload.

  9. High-strength bolt-forming of fine-grained aluminum alloy 6061 with a continuous hybrid process

    International Nuclear Information System (INIS)

    Kim, Ji Hun; Hwang, Sun Kwang; Im, Yong-Taek; Son, Il-Heon; Bae, Chul Min

    2012-01-01

    Highlights: ► Fine-grained AA6061-O was produced by a continuous hybrid process. ► It consists of rolling, ECAP, and drawing. ► High-strength bolt was manufactured with the fine-grained AA6061-O. ► The UTS and micro-hardness of the bolt was increased by 50%. ► The route C was better in making a uniform micro-hardness distribution in the bolt. - Abstract: It is well known that the development of a continuous manufacturing process to apply severe plastic deformation (SPD) is a major challenge for industrial usages to improve the mechanical properties of the material through grain refinement. In this study, fine-grained AA6061-O wire was manufactured by a two-pass hybrid process consisting of drawing, equal channel angular pressing and rolling in a continuous manner to investigate the effects of processing routes for two different routes, A and C, on the variation of ultimate tensile strength (UTS) and micro-hardness distribution. The UTS value (185 MPa) of the specimen processed by the two-pass hybrid process with route A was higher than that of 171 MPa obtained from the two-pass wire-drawing process and was equivalent to the level of 184 MPa processed by the three-pass wire-drawing process. The average micro-hardness value (Hv 58.0) obtained from the two-pass hybrid process through route C was the highest among all the cases. According to transmission electron microscopy, the original grain was subdivided and elongated owing to deformation during the processes. The specimen processed by the two-pass hybrid process through route C showed smaller deformation bands and had potentially higher angle grain boundaries compared to the specimen processed by the two-pass wire-drawing process. Finally, the high-strength bolt was manufactured using the fine-grained AA6061-O wire prepared by the continuous hybrid process to check its formability. A ductile fracture at the first thread right above the jaw was observed in the bolt tension test of the manufactured bolt

  10. Investigation of corrosion and stress corrosion cracking in bolting materials on light water reactors

    International Nuclear Information System (INIS)

    Czajkowski, C.J.

    1985-01-01

    Laboratory experiments performed at BNL have shown that the concentration of boric acid to a moist paste at approximately the boiling point of water can produce corrosion rates of the order of several tenths of an inch per year on bolting and piping materials, which values are consistent with service experience. Other failure evaluation experience has shown that primary coolant/lubricant interaction may lead to stress corrosion cracking (SCC) of steam generator manway studs. An investigation was also performed on eleven lubricants and their effects on A193 B7 and A540 B24 bolting materials. H 2 S generation by the lubricants, coefficient of friction results and transgranular SCC of the bolting materials in steam are discussed. 13 refs

  11. Investigation of corrosion and stress corrosion cracking in bolting materials on light water reactors

    International Nuclear Information System (INIS)

    Czajkowski, C.J.

    1986-01-01

    Laboratory experiments performed at Brookhaven National Laboratory have shown that the concentration of boric acid to a moist paste at approximately the boiling point of water can produce corrosion rates of the order of approximately 3.5mm per year on bolting and piping materials, which values are consistent with service experience. Other failure evaluation experience has shown that primary coolant-lubricant interaction may lead to stress corrosion cracking (SCC) of steam generator manway studs. An investigation was also performed on eleven lubricants and their effects on A193 B7 and A540 B24 bolting materials. H 2 S generation by the lubricants, coefficient of friction results and transgranular SCC of the bolting materials in steam are discussed. (author)

  12. Bearing Stress at Failure of Double-Lap Hybrid Joints in Woven Fabric Kenaf Fiber Composite Plates under Quasi-static Loading

    Directory of Open Access Journals (Sweden)

    Lee Sim Yee

    2017-01-01

    Full Text Available The present paper is focused on the bearing stress at failure of double-lap woven fabric kenaf fiber reinforced polymer (KFRP hybrid bonded-bolted joints in experimental frameworks. The effects of different normalized plate width (plate width/hole diameter, W/d, lay-up types and bolt loads were incorporated in current study as specified in testing series. Generally, hybrid joint coupons separated within adhesive layer prior to net-tension failure or bearing/net-tension failure. The bearing stress at failure increased as W/d ratio increment, critical W/d is given as four and three in clamped and finger tight condition respectively. Lay-up types present insignificant effect to bearing stress at failure due to low volume fiber fraction in kenaf fiber composites. Combination of thicker and clamped conditions plate demonstrated greater bearing stress than equivalent finger-tight (FT conditions due to higher load transferred from friction, as expected.

  13. Application of Long Expansion Rock Bolt Support in the Underground Mines of Legnica-Głogów Copper District

    Science.gov (United States)

    Skrzypkowski, Krzysztof; Korzeniowski, Waldemar; Zagórski, Krzysztof; Dudek, Piotr

    2017-09-01

    In the underground mines of the Legnica-Głogów Copper District (LGOM) the main way to protect the room excavation is the use of a rock bolt support. For many years, it has proven to be an efficient security measure in excavations which met all safety standards and requirements. The article presents the consumption of the rock bolt support in the Mining Department "Polkowice-Sieroszowice" in the years 2010-2015 as well as the number of bolt supports that were used to secure the excavations. In addition, it shows the percentage of bolt supports that were used to conduct rebuilding work and cover the surface of exposed roofs. One of the factors contributing to the loss of the functionality of bolt supports is corrosion whose occurrence may lead directly to a reduction in the diameter of rock bolt support parts, in particular rods, bearing plates and nuts. The phenomenon of the corrosion of the bolt support and its elements in underground mining is an extremely common phenomenon due to the favorable conditions for its development in mines, namely high temperature and humidity, as well as the presence of highly aggressive water. This involves primarily a decrease in the capacity of bolt support construction, which entails the need for its strengthening, and often the need to perform the reconstruction of the excavation. The article presents an alternative for steel bearing plates, namely plates made using the spatial 3D printing technology. Prototype bearing plates were printed on a 3D printer Formiga P100 using the "Precymit" material. The used printing technology was SLS (Selective Laser Sintering), which is one of the most widely used technologies among all the methods of 3D printing for the short series production of the technical parts of the final product. The article presents the stress-strain characteristic of the long expansion connected rock bolt support OB25 with a length of 3.65 m. A rock bolt support longer than 2.6 m is an additional bolt support in

  14. Thermal and electrical joint test for the helical field coils in the Advanced Toroidal Facility

    International Nuclear Information System (INIS)

    Brown, R.L.; Johnson, R.L.

    1985-01-01

    Initial feasibility studies of a number of configurations for the Advanced Toroidal Facility (ATF) resulted in the selection of a resistive copper continuous-coil torsatron as the optimum device considering the physics program, cost, and schedule. Further conceptual design work was directed toward optimization of this configuration and, if possible, a shorter schedule. It soon became obvious that in order to shorten the schedule, a number of design and fabrication activities should proceed in parallel. This was most critical for the vacuum vessel and the helical field (HF) coils. If the HF coils were wound in place on a completed vacuum vessel, the overall schedule would be significantly (greater than or equal to12 months) longer. The approach of parallel scheduel paths requires that the HF coils be segmented into parts of less than or equal to180 0 of poloidal angle and that joints be made on a turn-by-turn basis when the segments are installed. It was obvious from the outset that the compact and complex geometry of the joint design presented a special challenge in the areas of reliability, assembly, maintenance, disassembly, and cost. Also, electrical, thermal, and force excursions are significant for these joints. A number of soldered, welded, brazed, electroplated, and bolted joints were evaluated. The evaluations examined fabrication feasibility and complexity, thermal-electrical performance at approximately two-thirds of the steady-state design conditions, and installation and assembly processes. Results of the thermal-electrical tests were analyzed and extrapolated to predict performance at peak design parameters. The final selection was a lap-type joint clamped with insulated bolts that pass through the winding packing. 3 refs., 4 figs

  15. Ultrasonic extensometry for determining bolt preload in heavy industry - from petrochemical to reactors

    International Nuclear Information System (INIS)

    Erdman, D.C.

    1981-01-01

    Use of ultrasonic extensometers has found wide application for bolt preload determination in airborne and aerospace applications where elongation measurement accuracy is often required to .0001 in. Experience has now been gained in heavy industry with fasteners up to 12 feet long, often on studs and bolts with relatively rough head surfaces. Here, accuracy may be reduced to .001 inch, a figure far better than available from torque wrenches. This paper describes some of these heavy industry applications

  16. Study on reactor building structure using ultrahigh strength materials - Part 6: Tests for joints of SC-frames and PCa-panels

    International Nuclear Information System (INIS)

    Uchiyama, T.; Ishimura, K.; Takahashi, T.; Kei, T.

    1993-01-01

    A mixed structure composed of reinforced concrete precast panels and frames of steel beams and concrete filled steel tube columns using ultrahigh strength materials was proposed for reactor buildings. The paper describes the structural characteristics of the high tension bolt joints between the panels and the frames. (author)

  17. Taub–Bolt heat engines

    Science.gov (United States)

    Johnson, Clifford V.

    2018-02-01

    It is shown that aspects of the extended thermodynamic properties of the Taub–Bolt–AdS spacetime in four dimensions are similar to those of the Schwarzschild–AdS black hole. In a high temperature expansion, the equations of state begin to deviate only at next-to-subleading orders. By analogy with what has been done for black holes, Taub–Bolt’s thermodynamic equations are used to define holographic heat engines, the first examples of gravitational heat engines defined using a spacetime that is not a black hole. As a further comparison, the Taub–Bolt engine efficiency is computed for two special kinds of engine cycle and compared to the results for analogous Schwarzschild black hole engine cycles.

  18. Holographic description of Kerr-Bolt-AdS-dS spacetimes

    International Nuclear Information System (INIS)

    Chen, B.; Ghezelbash, A.M.; Kamali, V.; Setare, M.R.

    2011-01-01

    We show that there exists a holographic 2D CFT description of a Kerr-Bolt-AdS-dS spacetime. We first consider the wave equation of a massless scalar field propagating in extremal Kerr-Bolt-AdS-dS spacetimes and find in the 'near region', the wave equation in extremal limit could be written in terms of the SL(2,R) quadratic Casimir. This suggests that there exist dual CFT descriptions of these black holes. In the probe limit, we compute the scattering amplitudes of the scalar off the extremal black holes and find perfect agreement with the CFT prediction. Furthermore we study the holographic description of the generic four-dimensional non-extremal Kerr-Bolt-AdS-dS black holes. We find that if focusing on the near-horizon region, for the massless scalar scattering in the low-frequency limit, the radial equation could still be rewritten as the SL(2,R) quadratic Casimir, suggesting the existence of dual 2D description. We read the temperatures of the dual CFT from the conformal coordinates and obtain the central charges by studying the near-horizon geometry of near-extremal black holes. We recover the macroscopic entropy from the microscopic counting. We also show that for the super-radiant scattering, the retarded Green's functions and the corresponding absorption cross sections are in perfect match with CFT prediction.

  19. Behaviour of high stretch bolts in tension working as part of elements of steel structures, and their tendency to delayed fracturing

    Directory of Open Access Journals (Sweden)

    Moyseychik Evgeniy Alekseevich

    2014-12-01

    Full Text Available In the article, the author has proven that manufacturing and installation errors, as well as contact deformations of high strength bolts, if analyzed as part of tensile connections of steel structures, work in eccentric tension. In pursuance of the effective state standards, the analysis of these bolts is based on the axial tension. The author has analyzed the failure of a steel structure, caused by the fracture of eccentrically loaded bolts made of steel grade XC 42 (France, or C40 (Germany, that later followed the delayed fracturing pattern. The author provides the findings of the lab tests, whereby the above bolts were tested in the presence of an angle washer. The author has also analyzed the findings of low-temperature tests of bolts in tension. The author demonstrates that the strength of high strength bolts is driven by the material, the structure shape, and the thermal treatment pattern. Eccentric tension tests of bolts have proven that cracks emerge in the areas of maximal concentration of stresses (holes in shafts, etc. that coincide with the areas where fibers are in tension; cracks tend to follow the delayed fracturing pattern, and their development is accompanied by the deformation-induced metal heating in the fracture area. Therefore, the analysis of high strength bolts shall concentrate on the eccentric tension with account for contact-induced loads, while the tendency to delayed fracturing may be adjusted through the employment of both metallurgical and process techniques.

  20. Structural optimization of an alternate design for the Space Shuttle solid rocket booster field joint

    Science.gov (United States)

    Barthelemy, Jean-Francois M.; Rogers, James L., Jr.; Chang, Kwan J.

    1987-01-01

    A structural optimization procedure is used to determine the shape of an alternate design for the Shuttle's solid rocket booster field joint. In contrast to the tang and clevis design of the existing joint, this alternate design consists of two flanges bolted together. Configurations with 150 studs of 1 1/8 in diameter and 135 studs of 1 3/16 in diameter are considered. Using a nonlinear programming procedure, the joint weight is minimized under constraints on either von Mises or maximum normal stresses, joint opening and geometry. The procedure solves the design problem by replacing it by a sequence of approximate (convex) subproblems; the pattern of contact between the joint halves is determined every few cycles by a nonlinear displacement analysis. The minimum weight design has 135 studs of 1 3/16 in diameter and is designed under constraints on normal stresses. It weighs 1144 lb per joint more than the current tang and clevis design.

  1. Discussion about effecting of stiffener in four bolts in a row end plate connection for long span and heavy load steel structures in Vietnam

    Science.gov (United States)

    Huong, Khang T.; Nguyen, Cung H.

    2018-04-01

    Nowadays, steel structure industry in Vietnam is in strong development. The construction of steel structure becomes larger span and heavier load. The issue spawned a number of issues arise from optimizing connections. Typical of steel connections in prefabricated steel structure that is an end plate (face plate) bolted connection. When the connection carried a heavy load, then the number of bolts is required much more. Increasing the number of rows bolts will less effective because can still not enough strength requirements, the bolts in row near rotational center will level arm reduction, then it cannot carry heavy loads. The current solution is doing multiple bolts in a row. Current standards such as EN [1], AISC [2] are no specific guidelines for calculating the connection four bolts in a row that primarily assumes the way works like a T-stub of the two bolts a row. Some articles studied T-stub four bolts in a row [3], [4], [5], [6] by component method but it has some components which weren’t considered. In this paper, in order to provide a contribution to improve the T-stub four bolts in a row, the stiffener component in T-stub will be added and compared with T-stub without stiffener by the finite element model to demonstrate effectiveness in reducing stress and displacement of T-stub. It gives ideas for the economic design of four bolts in a row end plate connection in Vietnam for future.

  2. Bolted flanged connections subjected to longitudinal bending moments

    International Nuclear Information System (INIS)

    Blach, A.E.

    1992-01-01

    Flanges in piping systems and also pressure vessel flanges on tall columns are often subjected to longitudinal bending moments of considerable magnitude, be it from thermal expansion stresses in piping systems or from wind or seismic loadings on tall vertical pressure vessels. Except for the ASME Code, Section III, Subsections NB, NC, and ND, other pressure vessel and piping codes do not contain design ASME Nuclear Power Plant Code (Section III), an empirical formula is given, expressing a longitudinal bending moment in bolted flanged connections in terms of an equivalent internal pressure to be added to the design pressure of the flange. In this paper, an attempt is made to analyse the stresses on flanges and bolting due to external bending moments and to compare flange thicknesses thus obtained with thicknesses required using the equivalent design pressure specified in Subsections NB, NC, and ND. A design method is proposed, based on analysis and experimental work, which may be suitable for flange bending moment analysis when the rules of the Nuclear Power Plant Code are not mandatory. (orig.)

  3. Performance of Link-To-Stub Bolted Connection in Column-Tree Moment Resisting Frames under Fire Conditions

    Directory of Open Access Journals (Sweden)

    Mahmood Yahyai

    2015-12-01

    Full Text Available Column-tree moment resisting frames, as the efficient shop-welded and field-bolted structural systems, are used in many countries. Very limited research has been carried out on such systems under fire conditions. This paper presents experimental investigations of the behavior of beam and bolted splice connections in steel column-tree moment resisting frames exposed to fire. Two full-scale steel sub-frames with different splice connections were tested under ISO 834 standard fire. The flange splice plates were configured as a single plate with single shear bolts in first specimen, and as double plates with double shear bolts in second specimen. The observation of thermal and structural fire behaviors including temperature histories, temperature-deflection of the beam, temperature-rotation of splice connections and failure modes were investigated. The temperature-deflection and temperature-rotation curves remained in the elastic range until about 600°C. Beyond 600°C, the behavior would be highly nonlinear plastic. The beam splice connection failed due to shear fracture of top bolts at temperatures beyond 750°C. Consequently, stub beam web failed at those temperatures because of block-shear. Using double plates with double shear bolts for flange splices would enhance the temperature resistance and rotational capacity of the beam splice connections. Both tests results confirmed that specimens retain the capacity to support the design load when the average beam temperature does not exceed 600°C. This temperature limit confirms the temperature criteria provided by ASTM E119 and ANSI/UL 263 for a restrained beam, and can be used to specify the minimum fire resistance criteria for beams in column-tree MRFs. The measured time-deflection curves showed that the restrained fire resistance rating for both unprotected specimens obtained about 15 minutes in both tests.

  4. Ultrasonic measurement on RPV stud-bolt loading under hot transient of Qinshan NPP

    International Nuclear Information System (INIS)

    Qu Jiadi; Dou Yikang; Zhu Shiming; Lu Jie; Wang Yingguan

    1994-01-01

    It is a continuation of research work for sealing analysis and tests on the PRV of PWR. It expounds that the key of solving thermal transient sealing problem lies in giving the thermal increment of stud-bolt fatigue life and transient loading spectrum for vessel analysis. The authors recounted the fundamental works and main results of ultrasonic measurement on RPV stud-bolt loading on the reactor of Qinshan Nuclear Power Plant. The measuring capability exceeds 1 m length and 300 degree C temperature. Therefore, it is possible to be used in the field of NPP

  5. An analysis of bolted opening structure and development of analysis expert system using ANSYS

    International Nuclear Information System (INIS)

    Jun, S. M.; Suh, E. K.; Shim, H. B.; Kim, T. W.; Lee, B. Y.

    1998-01-01

    Bolted opening structures is widely applied for class 1 machinery of nuclear plant with strict design requirement. As the shape of the bolted opening structure is non-axisymmetric due to the existence of stud bolts although it is almost axi-symmetric, 3D analysis is required to satisfy such kind of design requirements. Because as much as possible trial computations are need to get an optimal design condition in the limited period of basic design, an easy and fast analysis tool is useful in the design stage. In the paper, a transformation technique of non-axisymmetric problem into quasi-axisymmetric has been proposed based on the general purpose commercial code ANSYS. Both the pre-processor which incorporates the technique and prepares data and post-processor which prepares arranged results from the huge output of commercial code have been developed to help the design engineers. (author)

  6. Simulation and design of ECT differential bobbin probes for the inspection of cracks in bolts

    International Nuclear Information System (INIS)

    Ra, S W; Im, K H; Woo, Y D; Lee, S G; Kim, H J; Song, S J; Kim, S K; Cho, Y T; Jung, J A

    2015-01-01

    All Various defects could be generated in bolts for a use of oil filters for the manufacturing process and then may affect to the safety and quality in bolts. Also, fine defects may be imbedded in oil filter system during multiple forging manufacturing processes. So it is very important that such defects be investigated and screened during the multiple manufacturing processes. Therefore, in order effectively to evaluate the fine defects, the design parameters for bobbin-types were selected under a finite element method (FEM) simulations and Eddy current testing (ECT). Especially the FEM simulations were performed to make characterization in the crack detection of the bolts and the parameters such as number of turns of the coil, the coil size and applied frequency were calculated based on the simulation results. (paper)

  7. Simulation and design of ECT differential bobbin probes for the inspection of cracks in bolts

    Science.gov (United States)

    Ra, S. W.; Im, K. H.; Lee, S. G.; Kim, H. J.; Song, S. J.; Kim, S. K.; Cho, Y. T.; Woo, Y. D.; Jung, J. A.

    2015-12-01

    All Various defects could be generated in bolts for a use of oil filters for the manufacturing process and then may affect to the safety and quality in bolts. Also, fine defects may be imbedded in oil filter system during multiple forging manufacturing processes. So it is very important that such defects be investigated and screened during the multiple manufacturing processes. Therefore, in order effectively to evaluate the fine defects, the design parameters for bobbin-types were selected under a finite element method (FEM) simulations and Eddy current testing (ECT). Especially the FEM simulations were performed to make characterization in the crack detection of the bolts and the parameters such as number of turns of the coil, the coil size and applied frequency were calculated based on the simulation results.

  8. Ultrasonic inspection of studs (bolts) using dynamic predictive deconvolution and wave shaping.

    Science.gov (United States)

    Suh, D M; Kim, W W; Chung, J G

    1999-01-01

    Bolt degradation has become a major issue in the nuclear industry since the 1980's. If small cracks in stud bolts are not detected early enough, they grow rapidly and cause catastrophic disasters. Their detection, despite its importance, is known to be a very difficult problem due to the complicated structures of the stud bolts. This paper presents a method of detecting and sizing a small crack in the root between two adjacent crests in threads. The key idea is from the fact that the mode-converted Rayleigh wave travels slowly down the face of the crack and turns from the intersection of the crack and the root of thread to the transducer. Thus, when a crack exists, a small delayed pulse due to the Rayleigh wave is detected between large regularly spaced pulses from the thread. The delay time is the same as the propagation delay time of the slow Rayleigh wave and is proportional to the site of the crack. To efficiently detect the slow Rayleigh wave, three methods based on digital signal processing are proposed: wave shaping, dynamic predictive deconvolution, and dynamic predictive deconvolution combined with wave shaping.

  9. Holographic description of Kerr-Bolt-AdS-dS spacetimes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, B., E-mail: bchen01@pku.edu.c [Department of Physics, and State Key Laboratory of Nuclear Physics and Technology, and Center for High Energy Physics, Peking University, Beijing 100871 (China); Ghezelbash, A.M., E-mail: masoud.ghezelbash@usask.c [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada); Kamali, V., E-mail: vkamali1362@gmail.co [Department of Campus of Bijar, Kurdistan University, Bijar (Iran, Islamic Republic of); Setare, M.R., E-mail: rezakord@ipm.i [Department of Campus of Bijar, Kurdistan University, Bijar (Iran, Islamic Republic of)

    2011-07-01

    We show that there exists a holographic 2D CFT description of a Kerr-Bolt-AdS-dS spacetime. We first consider the wave equation of a massless scalar field propagating in extremal Kerr-Bolt-AdS-dS spacetimes and find in the 'near region', the wave equation in extremal limit could be written in terms of the SL(2,R) quadratic Casimir. This suggests that there exist dual CFT descriptions of these black holes. In the probe limit, we compute the scattering amplitudes of the scalar off the extremal black holes and find perfect agreement with the CFT prediction. Furthermore we study the holographic description of the generic four-dimensional non-extremal Kerr-Bolt-AdS-dS black holes. We find that if focusing on the near-horizon region, for the massless scalar scattering in the low-frequency limit, the radial equation could still be rewritten as the SL(2,R) quadratic Casimir, suggesting the existence of dual 2D description. We read the temperatures of the dual CFT from the conformal coordinates and obtain the central charges by studying the near-horizon geometry of near-extremal black holes. We recover the macroscopic entropy from the microscopic counting. We also show that for the super-radiant scattering, the retarded Green's functions and the corresponding absorption cross sections are in perfect match with CFT prediction.

  10. Resolution of Surveillance Report No. PAD-BDW-95-004 for suspect bolts installed in the 105 KW roof addition structure

    International Nuclear Information System (INIS)

    Frier, W.A.

    1995-01-01

    A DOE RL surveillance determined that a test report (WHC-SD-NR-TRP-020) was less than adequate. As a result, WHC removed nine of the previous in-situ tested A325 suspect bolts and contracted with Koon-Hall Testing Corporation to perform hardness and tensile testing and chemical composition analysis of the removed bolts. WHC also contracted with ADVENT Engineering, Inc., to perform an evaluation of the Koon-Hall test results and to respond to the concerns identified in the DOE RL surveillance. The Koon-Hall Laboratory test results and the assessments strongly support the conclusion that the suspect bolts are indeed the equivalent of A325 high-strength, Type-1 bolts and have been properly heat-treated

  11. Preliminary Design and Analysis of an In-plane PRSEUS Joint

    Science.gov (United States)

    Lovejoy, Andrew E.; Poplawski, Steven

    2013-01-01

    As part of the National Aeronautics and Space Administration's (NASA's) Environmentally Responsible Aviation (ERA) program, the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) has been designed, developed and tested. However, PRSEUS development efforts to date have only addressed joints required to transfer bending moments between PRSEUS panels. Development of in-plane joints for the PRSEUS concept is necessary to facilitate in-plane transfer of load from PRSEUS panels to an adjacent structure, such as from a wing panel into a fuselage. This paper presents preliminary design and analysis of an in-plane PRSEUS joint for connecting PRSEUS panels at the termination of the rod-stiffened stringers. Design requirements are provided, the PRSEUS blade joint concept is presented, and preliminary design changes and analyses are carried out to examine the feasibility of the proposed in-plane PRSEUS blade joint. The study conducted herein focuses mainly on the PRSEUS structure on one side of the joint. In particular, the design requirements for the rod shear stress and bolt bearing stress are examined. A PRSEUS blade joint design was developed that demonstrates the feasibility of this in-plane PRSEUS joint concept to terminate the rod-stiffened stringers. The presented design only demonstrates feasibility, therefore, some areas of refinement are presented that would lead to a more optimum and realistic design.

  12. Fatigue behavior of a bolted assembly - a comparison between numerical analysis and experimental analysis

    International Nuclear Information System (INIS)

    Bosser, M.; Vagner, J.

    1987-01-01

    The fatigue behavior of a bolted assembly can be analysed, either by fatigue tests, or by computing the stress variations and using a fatigue curve. This paper presents the fatigue analysis of a stud-bolt and stud-flange of a steam generator manway carried out with the two methods. The experimental analysis is performed for various levels of load, according to the recommandations of the ASME code section III appendix II. The numerical analysis of the stresses is based on the results of a finite element analysis performed with the program SYSTUS. The maximum stresses are obtained in the first bolt threads. In using these stresses, the allowable number of cycles for each level of loading analysed, is obtained from fatigue curves, as defined in appendix I section III of the ASME code. The analysis underlines that, for each level of load the purely numerical approach is highly conservative, compared to the experimental approach. (orig.)

  13. Impedance-based damage assessment using piezoelectric sensors

    Science.gov (United States)

    Rim, Mi-Sun; Yoo, Seung-Jae; Lee, In; Song, Jae-Hoon; Yang, Jae-Won

    2011-04-01

    Recently structural health monitoring (SHM) systems are being focused because they make it possible to assess the health of structures at real-time in many application fields such as aircraft, aerospace, civil and so on. Piezoelectric materials are widely used for sensors of SHM system to monitor damage of critical parts such as bolted joints. Bolted joints could be loosened by vibration, thermal cycling, shock, corrosion, and they cause serious mechanical failures. In this paper, impedance-based method using piezoelectric sensors was applied for real-time SHM. A steel beam specimen fastened by bolts was tested, and polymer type piezoelectric materials, PVDFs were used for sensors to monitor the condition of bolted joint connections. When structure has some damage, for example loose bolts, the impedance of PVDF sensors showed different tendency with normal structure which has no loose bolts. In the case of loose bolts, impedance values are decreased and admittance values are increased.

  14. LCM-seq reveals the crucial role of LsSOC1 in heat-promoted bolting of lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Chen, Zijing; Zhao, Wensheng; Ge, Danfeng; Han, Yingyan; Ning, Kang; Luo, Chen; Wang, Shenglin; Liu, Renyi; Zhang, Xiaolan; Wang, Qian

    2018-05-17

    Lettuce (Lactuca sativa L.) is one of the most economically important vegetables. The floral transition in lettuce is accelerated under high temperatures, which can significantly decrease yields. However, the molecular mechanism underlying the floral tranition in lettuce is poorly known. Using laser capture microdissection coupled with RNA sequencing, we isolated shoot apical meristem cells from the bolting-sensitive lettuce line S39 at four critical stages of development. Subsequently, we screened specifically for the flowering-related gene LsSOC1 during the floral transition through comparative transcriptomic analysis. Molecular biology, developmental biology, and biochemical tools were combined to investigate the biological function of LsSOC1 in lettuce. LsSOC1 knockdown by RNA interference resulted in a significant delay in the timing of bolting and insensitivity to high temperature, which indicated that LsSOC1 functions as an activator during heat-promoted bolting in lettuce. We determined that two heat-shock transcription factors, HsfA1e and HsfA4c, bound to the promoter of LsSOC1 to confirm that LsSOC1 played an important role in heat-promoted bolting. This study indicates that LsSOC1 plays a crucial role in the heat-promoted bolting process in lettuce. Further investigation of LsSOC1 may be useful for clarification of the bolting mechanism in lettuce. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  15. Finite element analysis of beam-to-column joints in steel frames under cyclic loading

    Directory of Open Access Journals (Sweden)

    Elsayed Mashaly

    2011-03-01

    Full Text Available The aim of this paper is to present a simple and accurate three-dimensional (3D finite element model (FE capable of predicting the actual behavior of beam-to-column joints in steel frames subjected to lateral loads. The software package ANSYS is used to model the joint. The bolted extended-end-plate connection was chosen as an important type of beam–column joints. The extended-end-plate connection is chosen for its complexity in the analysis and behavior due to the number of connection components and their inheritable non-linear behavior. Two experimental tests in the literature were chosen to verify the finite element model. The results of both the experimental and the proposed finite element were compared. One of these tests was monotonically loaded, whereas the second was cyclically loaded. The finite element model is improved to enhance the defects of the finite element model used. These defects are; the long time need for the analysis and the inability of the contact element type to follow the behavior of moment–rotation curve under cyclic loading. As a contact element, the surface-to-surface element is used instead of node-to-node element to enhance the model. The FE results show good correlation with the experimental one. An attempt to improve a new technique for modeling bolts is conducted. The results show that this technique is supposed to avoid the defects above, give much less elements number and less solution time than the other modeling techniques.

  16. The Guidelines for Modelling the Preloading Bolts in the Structural Connection Using Finite Element Methods

    OpenAIRE

    Paulina Krolo; Davor Grandić; Mladen Bulić

    2016-01-01

    The aim of this paper is the development of the two different numerical techniques for the preloading of bolts by the finite element method using the software Abaqus Standard. Furthermore, this paper gave detailed guidelines for modelling contact, method for solving the numerical error problems such as numerical singularity error and negative eigenvalues due to rigid body motion or the problem of the extensive elongation of bolts after pretension which is occurring during the analysis. The be...

  17. Measurement of the Length of Installed Rock Bolt Based on Stress Wave Reflection by Using a Giant Magnetostrictive (GMS) Actuator and a PZT Sensor.

    Science.gov (United States)

    Luo, Mingzhang; Li, Weijie; Wang, Bo; Fu, Qingqing; Song, Gangbing

    2017-02-23

    Rock bolts, as a type of reinforcing element, are widely adopted in underground excavations and civil engineering structures. Given the importance of rock bolts, the research outlined in this paper attempts to develop a portable non-destructive evaluation method for assessing the length of installed rock bolts for inspection purposes. Traditionally, piezoelectric elements or hammer impacts were used to perform non-destructive evaluation of rock bolts. However, such methods suffered from many major issues, such as the weak energy generated and the requirement for permanent installation for piezoelectric elements, and the inconsistency of wave generation for hammer impact. In this paper, we proposed a portable device for the non-destructive evaluation of rock bolt conditions based on a giant magnetostrictive (GMS) actuator. The GMS actuator generates enough energy to ensure multiple reflections of the stress waves along the rock bolt and a lead zirconate titantate (PZT) sensor is used to detect the reflected waves. A new integrated procedure that involves correlation analysis, wavelet denoising, and Hilbert transform was proposed to process the multiple reflection signals to determine the length of an installed rock bolt. The experimental results from a lab test and field tests showed that, by analyzing the instant phase of the periodic reflections of the stress wave generated by the GMS transducer, the length of an embedded rock bolt can be accurately determined.

  18. Design of Multiple Bolted Connections for Laminated Veneer Lumber

    Science.gov (United States)

    Borjen Yeh; Douglas Rammer; Jeff Linville

    2014-01-01

    The design of multiple bolted connections in accordance with Appendix E of the National Design Specification for Wood Construction (NDS) has incorporated provisions for evaluating localized member failure modes of row and group tear-out when the connections are closely spaced. Originally based on structural glued laminated timber (glulam) members made with all L1...

  19. A Study of the Bolt Connection System for a Concrete Barrier of a Modular Bridge

    Directory of Open Access Journals (Sweden)

    Doo-Yong Cho

    2018-04-01

    Full Text Available Modular technology has been recently studied to reduce the construction periods in the field of bridge construction. However, this method is restricted to the pier, girder, and deck, which are the main members of a bridge, and incidental facilities such as concrete barriers have been rarely studied. Thus, in this study, the connection system of a concrete barrier for modular bridges was developed, and a static loading experiment was performed to verify the structural capacity of the proposed system. The variables of the experiment were the vertical and horizontal bolt connections and the construction method. The barrier and plate were fabricated using match casting methods in which nuts were first inserted into the plates rather than anchor bolts using the conservative method. Moreover, a comparison with the conventional in situ barrier was also performed. The experiments were conducted according to the AASHTO LRFD standard. Consequently, the specimen using the vertical bolt connection had a structural capacity that was equal to 85% of that of the conventional specimen and exhibited similar crack patterns compared with the conventional specimen. In the case of the horizontal bolt connection, the separation in the connection area occurred with the application of the initial load and this specimen exhibited a poor performance because of the increase in the separation distance with the application of the maximum load.

  20. Gradient material model in analysis of mechanical joints of CFRP laminate

    Science.gov (United States)

    Puchała, Krzysztof; ElŻbieta, Szymczyk; Jachimowicz, Jerzy; Bogusz, Paweł

    2018-01-01

    Mechanical joints (e.g. bolted) used for decades are proved to be reliable. They can be assembled and applied in very rough conditions since they are less sensitive to environmental effects than other types of joints (e.g. adhesive). Therefore, they are still employed in aircraft design. High specific stiffness and strength of composite materials (especially CFRP) cause a continuous increase in their usage in aircraft structures. In general, composites are brittle materials and more notch sensitive than metal alloys. Hole making is a necessary stage in manufacturing of a mechanical joint. Holes vicinities are the areas of high stress concentrations and determine load capability of the whole structure. Therefore, mechanical joints of composite parts require a special focus during both a designing and a manufacturing process. The aim of the paper is analysis of potential local material weakness/deterioration caused by a drilling process and its influence on the global response of a mechanical joint. The specimen in the form of a double-shear joint was analyzed. The weakened areas were identified on the basis of NDT ultrasonic analysis. A simple gradient material model was proposed to describe the hole vicinity. Numerical simulations were performed and compared to experimental results.

  1. Strength of Glued-in Bolts after Full Scale Loading

    DEFF Research Database (Denmark)

    Pedersen, Martin Bo Uhre; Clorius, Christian Odin; Damkilde, Lars

    1999-01-01

    with a length of 500 mm had a special hollow tapering giving them a higher load bearing capacity than solid bolts of equal dimensions. A FEM-analysis confirms the higher load bearing capacity. The mean residual strength was found to be 362 kN with a standard deviation of 37 kN, which is 95% of the predicted...

  2. Detection and depth determination of corrosion defects in embedded bolts using ultrasonic testing technique

    International Nuclear Information System (INIS)

    Lin, Shan; Fukutomi, Hiroyuki; Yuya, Hideki; Ito, Keisuke

    2011-01-01

    A great number of anchor bolts are used to fix various components to concrete foundation in thermal and nuclear power plants. As aging power plants degrade, it is feared that defects resulted from corrosion may occur underground. In this paper, a measurement method utilizing the phased array technique is developed to detect such defects. Measurement results show that this method can detect local and circumferential corrosion defects introduced artificially, but defect echo position appears to be farther away from the bolt head than is actually the case. A finite element simulation of wave propagation shows that longitudinal waves excited by a phased array probe are mode converted and reflected at the defect and at bolt wall, which results in the position of the defect echo appearing to be farther away than the defect actually is. Moreover, an approach for determining the depth of defects using measurement results is also proposed based on numerical results. The depths determined by the proposed approach agree with the actual depths with a maximum error of 1.8 mm and a RMSE of 1.06 mm. (author)

  3. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari; Gerard T. Pittard

    2005-07-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. Bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple castiron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs with the pipe in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, minimize excavation, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of old cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct safe repair operations on live mains.

  4. Testing of nuclear grade lubricants and their effects on A540 B24 and A193 B7 bolting materials

    International Nuclear Information System (INIS)

    Czajkowski, C.J.

    1985-01-01

    An investigation was performed on eleven commonly used lubricants by the nuclear power industry. The investigation included EDS analysis of the lubricants, notched-tensile constant extension rate testing of bolting materials with the lubricants, frictional testing of the lubricants and weight loss testing of a bonded solid film lubricant. The report generally concludes that there is a significant amount of variance in the mechanical properties of common bolting materials; that MoS 2 can hydrolyze to form H 2 S at 100 0 C and cause stress corrosion cracking (SCC) of bolting materials, and that the use of copper-containing lubricants can be potentially detrimental to high strength steels in an aqueous environment. Additionally, the testing of various lubricants disclosed that some lubricants contain potentially detrimental elements (e.g. S, Sb) which can promote SCC of the common bolting materials. One of the most significant findings of this report is the observation that both A193 B7 and A540 B24 bolting materials are susceptible to transgranular stress corrosion cracking in demineralized H 2 O at 280 0 C in notched tensile tests

  5. Critical Joints in Large Composite Primary Aircraft Structures. Volume 3: Ancillary Test Results

    Science.gov (United States)

    Bunin, Bruce L.; Sagui, R. L.

    1985-01-01

    A program was conducted to develop the technology for critical structural joints for composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of a comprehensive ancillary test program are summarized, consisting of single-bolt composite joint specimens tested in a variety of configurations. These tests were conducted to characterize the strength and load deflection properties that are required for multirow joint analysis. The composite material was Toray 300 fiber and Ciba-Geigy 914 resin, in the form of 0.005 and 0.01 inch thick unidirectional tape. Tests were conducted in single and double shear for loaded and unloaded hole configurations under both tensile and compressive loading. Two different layup patterns were examined. All tests were conducted at room temperature. In addition, the results of NASA Standard Toughness Test (NASA RP 1092) are reported, which were conducted for several material systems.

  6. On the performance of Usain Bolt in the 100 m sprint

    Science.gov (United States)

    Hernández Gómez, J. J.; Marquina, V.; Gómez, R. W.

    2013-09-01

    Many university texts on mechanics consider the effect of air drag force, using the slowing down of a parachute as an example. Very few discuss what happens when the drag force is proportional to both u and u2. In this paper we deal with a real problem to illustrate the effect of both terms on the speed of a runner: a theoretical model of the world-record 100 m sprint of Usain Bolt during the 2009 World Championships in Berlin is developed, assuming a drag force proportional to u and to u2. The resulting equation of motion is solved and fitted to the experimental data obtained from the International Association of Athletics Federations, which recorded Bolt's position with a laser velocity guard device. It is worth noting that our model works only for short sprints.

  7. Energy Neutral Wireless Bolt for Safety Critical Fastening.

    Science.gov (United States)

    Seyoum, Biruk B; Rossi, Maurizio; Brunelli, Davide

    2017-09-26

    Thermoelectric generators (TEGs) are now capable of powering the abundant low power electronics from very small (just a few degrees Celsius) temperature gradients. This factor along with the continuously lowering cost and size of TEGs, has contributed to the growing number of miniaturized battery-free sensor modules powered by TEGs. In this article, we present the design of an ambient-powered wireless bolt for high-end electro-mechanical systems. The bolt is equipped with a temperature sensor and a low power RF chip powered from a TEG. A DC-DC converter interfacing the TEG with the RF chip is used to step-up the low TEG voltage. The work includes the characterizations of different TEGs and DC-DC converters to determine the optimal design based on the amount of power that can be generated from a TEG under different loads and at temperature gradients typical of industrial environments. A prototype system was implemented and the power consumption of this system under different conditions was also measured. Results demonstrate that the power generated by the TEG at very low temperature gradients is sufficient to guarantee continuous wireless monitoring of the critical fasteners in critical systems such as avionics, motorsport and aerospace.

  8. Energy Neutral Wireless Bolt for Safety Critical Fastening

    Directory of Open Access Journals (Sweden)

    Biruk B. Seyoum

    2017-09-01

    Full Text Available Thermoelectric generators (TEGs are now capable of powering the abundant low power electronics from very small (just a few degrees Celsius temperature gradients. This factor along with the continuously lowering cost and size of TEGs, has contributed to the growing number of miniaturized battery-free sensor modules powered by TEGs. In this article, we present the design of an ambient-powered wireless bolt for high-end electro-mechanical systems. The bolt is equipped with a temperature sensor and a low power RF chip powered from a TEG. A DC-DC converter interfacing the TEG with the RF chip is used to step-up the low TEG voltage. The work includes the characterizations of different TEGs and DC-DC converters to determine the optimal design based on the amount of power that can be generated from a TEG under different loads and at temperature gradients typical of industrial environments. A prototype system was implemented and the power consumption of this system under different conditions was also measured. Results demonstrate that the power generated by the TEG at very low temperature gradients is sufficient to guarantee continuous wireless monitoring of the critical fasteners in critical systems such as avionics, motorsport and aerospace.

  9. Comportamiento mecánico de las juntas tipo T-bolt en materiales compuestos gruesos

    OpenAIRE

    Martínez Moll, Víctor

    2003-01-01

    En aquest treball s'ha realitzat una anàlisi de la junta T-bolt aplicada a la unió de laminats gruixuts amb elements metàl·lics. Més concretament, l'estudi es centra en el tipus de juntes T-bolt emprades en la unió entre les pales i la boixa de grans aerogeneradors, que constitueix una de les principals aplicacions d'aquest tipus de junta.En primer lloc, s'ha realitzat una anàlisi simplificada dels factors que influeixen al comportament de la junta, a partir del qual es justifica la necessit...

  10. A review on model updating of joint structure for dynamic analysis purpose

    Directory of Open Access Journals (Sweden)

    Zahari S.N.

    2016-01-01

    Full Text Available Structural joints provide connection between structural element (beam, plate etc. in order to construct a whole assembled structure. There are many types of structural joints such as bolted joint, riveted joints and welded joints. The joints structures significantly contribute to structural stiffness and dynamic behaviour of structures hence the main objectives of this paper are to review on method of model updating on joints structure and to discuss the guidelines to perform model updating for dynamic analysis purpose. This review paper firstly will outline some of the existing finite element modelling works of joints structure. Experimental modal analysis is the next step to obtain modal parameters (natural frequency & mode shape to validate and improve the discrepancy between results obtained from experimental and the simulation counterparts. Hence model updating will be carried out to minimize the differences between the two results. There are two methods of model updating; direct method and iterative method. Sensitivity analysis employed using SOL200 in NASTRAN by selecting the suitable updating parameters to avoid ill-conditioning problem. It is best to consider both geometrical and material properties in the updating procedure rather than choosing only a number of geometrical properties alone. Iterative method was chosen as the best model updating procedure because the physical meaning of updated parameters are guaranteed although this method required computational effort compare to direct method.

  11. Estimation of the thermal neutron flux in a PET cyclotron room via radioactive analysis of the bolts of a wall socket in the room

    International Nuclear Information System (INIS)

    Ogata, Y.; Ishigure, N.; Mochizuki, S.; Ito, K.; Hatano, K.; Abe, J.; Miyahara, H.; Masumoto, K.; Nakamura, H.; Matsumura, H.

    2008-01-01

    Full text: Since positron emission nuclides for PET (Positron Emission Tomography) have short half-lives, they are mainly produced by on-site cyclotrons. Significant amounts of neutrons are generated together with the operating of the cyclotron, and then materials in the room are activated. To quantify the neutron flux density will lead the prediction of the extent of the activation. We tried to estimate the neutron flux of the room via the radioactive analysis of bolts in the room. The cyclotron (Cypris HM-18, Sumitomo Heavy Industry) is able to accelerate protons and deuterons up to 18 and 10 MeV, respectively. The routine charge current is 20μA. The cyclotron is housed in a room with 1 m thickness concrete wall. A couple of bolts of a wall socket were removed to investigate the components and the radioactivities, which were analyzed by fluorescent X-ray spectroscopy and by gamma-ray spectroscopy, respectively. We compared the neutron flux estimated by the bolts analysis with the results measured by the gold foil activation method. The weight sum of the bolts was 1.257 g. They were made of nickel plated brass, and predominantly consisted of Cu (63%) and Zn (34%). Four nuclides, 69m Zn, 65 Zn, 64 Cu, and 60 Co, were detected in the bolts. The activity of 64 Cu half-life of 12.7 h, led the last few days history of neutron flux, and the activity of 65 Zn, 244 d, led the last few years history. The analysis of the bolts activity estimated the thermal neutron flux at 4∼6x10 5 cm -2 s -1 . This figure agreed with the value, 6∼9x10 5 cm -2 s -1 , computed from the activated gold foil near the bolts. Bolts are quite generally installed in such a room. Therefore, the radioactive analysis of the bolts leads convenient and effective estimation of neutron flux there. Consequently, the radioactive analysis of the bolts in the cyclotron room allowed us to estimate the neutron flux in the room. (author)

  12. Efficiency of low versus high airline pressure in stunning cattle with a pneumatically powered penetrating captive bolt gun.

    Science.gov (United States)

    Oliveira, Steffan Edward Octávio; Gregory, Neville George; Dalla Costa, Filipe Antonio; Gibson, Troy John; Paranhos da Costa, Mateus José Rodrigues

    2017-08-01

    The efficiency of stunning cattle was assessed in 443 animals (304 pure Zebu and 139 crossbred cattle), being mainly mature bulls and cows. Cattle were stunned using a Jarvis pneumatically powered penetrating captive bolt gun operating with low (160-175psi, N=82) and high (190psi, N=363) airline pressure, which was within the manufactures specifications. Signs of brain function and the position of the shots on the heads were recorded after stunning. Velocity of the captive bolt and its physical parameters were calculated. Cattle shot with low pressures showed more rhythmic respiration (27 vs. 8%, P<0.001), less tongue protrusion (4 vs. 12%, P=0.03) and less masseter relaxation (22 vs. 48%, P<0.001). There was an increased frequency of shots in the ideal position when cattle were shot with the low compared to high airline pressures (15.3 vs. 3.1%). Bolt velocity and its physical parameters were significantly (P<0.01) higher when using high pressure. Airline pressures below 190psi are inappropriate when shooting adult Zebu beef cattle with pneumatically powered penetrating captive bolt guns. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Complication assessment and prevention strategies using midfoot fusion bolt for medial column stabilization in Charcot's osteoarthropathy

    DEFF Research Database (Denmark)

    Mehlhorn, Alexander T; Walther, Markus; Iblher, Niklas

    2016-01-01

    and stabilization using midfoot fusion bolt and lateral lag screws. Age, gender, presence of preoperative osteomyelitis or ulcer, number of complications and operative revisions, Hba1c value, consolidation of arthrodesis, presence of a load-bearing foot and period to bolt dislocation was assessed. The mean follow......-up was 21.4±14.6 (mean±SDM) months, 64% of patients suffered from diabetes with a preoperative Hba1c of 8.5±2.4. The mean number of revisions per foot was 3.6±4.1. Bolt dislocation was seen in 57% of the patients following 11.3±8.5 months; in 75% of these patients bony healing occurred before dislocation....... There was a significant association between preoperative increased Hba1c value, presence of preoperative ulcer and wound infection. Healing of arthrodesis was demonstrated in 57% and a permanent weight-bearing foot without recurrent ulcer was achieved in 79%. The early and late postoperative complications could...

  14. Investigating the effect of clamping force on the fatigue life of bolted plates using volumetric approach

    International Nuclear Information System (INIS)

    Esmaeili, F.; Chakherlou, T. N.; Zehsaz, M.; Hasanifard, S.

    2013-01-01

    In this paper, the effects of bolt clamping force on the fatigue life for bolted plates made from Al7075-T6 have been studied on the values of notch strength reduction factor obtained by volumetric approach. To attain stress distribution around the notch (hole) which is required for volumetric approach, nonlinear finite element simulations were carried out. To estimate the fatigue life, the available smooth S-N curve of Al7075-T6 and the notch strength reduction factor obtained from volumetric method were used. The estimated fatigue life was compared with the available experimental test results. The investigation shows that there is a good agreement between the life predicted by the volumetric approach and the experimental results for various specimens with different amount of clamping forces. Volumetric approach and experimental results showed that the fatigue life of bolted plates improves because of the compressive stresses created around the plate hole due to clamping force.

  15. Unloading performances and stabilizing practices for columnar jointed basalt: A case study of Baihetan hydropower station

    Directory of Open Access Journals (Sweden)

    Qixiang Fan

    2017-12-01

    Full Text Available The columnar jointed rock mass (CJR, composed of polygonal cross-sectional columns cut by several groups of joints in various directions, was exposed during the excavations of the Baihetan hydropower station, China. In order to investigate the unloading performances and the stability conditions during excavation of the columns, an experimental field study was performed. Firstly, on-site investigations indicated that the geotechnical problems, including rock relaxation, cracking and collapse, were the most prominent for the CJR Class I that contains intensive joint network and the smallest column sizes. Comprehensive field tests, including deformation measurement by multi-point extensometers, ultrasonic wave testing, borehole television observation and stress monitoring of rock anchors, revealed that the time-dependent relaxation of the CJRs was marked. The practical excavation experiences for the Baihetan columnar jointed rock masses, such as blasting scheme, supporting time of shotcrete and rock bolts, were presented in the excavations of the diversion tunnels. These detailed investigations and practical construction experiences can provide helpful information for similar geotechnical works in jointed rock mass.

  16. Finite element model study of the effect of corner rounding on detectability of corner cracks using bolt hole eddy current

    Science.gov (United States)

    Underhill, P. R.; Krause, T. W.

    2017-02-01

    Recent work has shown that the detectability of corner cracks in bolt-holes is compromised when rounding of corners arises, as might occur during bolt-hole removal. Probability of Detection (POD) studies normally require a large number of samples of both fatigue cracks and electric discharge machined notches. In the particular instance of rounding of bolt-hole corners the generation of such a large set of samples representing the full spectrum of potential rounding would be prohibitive. In this paper, the application of Finite Element Method (FEM) modeling is used to supplement the study of detection of cracks forming at the rounded corners of bolt-holes. FEM models show that rounding of the corner of the bolt-hole reduces the size of the response to a corner crack to a greater extent than can be accounted for by loss of crack area. This reduced sensitivity can be ascribed to a lower concentration of eddy currents at the rounded corner surface and greater lift-off of pick-up coils relative to that of a straight-edge corner. A rounding with a radius of 0.4 mm (.016 inch) showed a 20% reduction in the strength of the crack signal. Assuming linearity of the crack signal with crack size, this would suggest an increase in the minimum detectable size by 25%.

  17. Enhancement of tendon–bone healing via the combination of biodegradable collagen-loaded nanofibrous membranes and a three-dimensional printed bone-anchoring bolt

    Directory of Open Access Journals (Sweden)

    Chou YC

    2016-08-01

    Full Text Available Ying-Chao Chou,1,2 Wen-Lin Yeh,2 Chien-Lin Chao,1 Yung-Heng Hsu,1,2 Yi-Hsun Yu,1,2 Jan-Kan Chen,3 Shih-Jung Liu1,2 1Department of Mechanical Engineering, Chang Gung University, 2Department of Orthopedic Surgery, Chang Gung Memorial Hospital, 3Department of Physiology and Pharmacology, Chang Gung University, Taoyuan, Taiwan Abstract: A composite biodegradable polymeric model was developed to enhance tendon graft healing. This model included a biodegradable polylactide (PLA bolt as the bone anchor and a poly(D,L-lactide-co-glycolide (PLGA nanofibrous membrane embedded with collagen as a biomimic patch to promote tendon–bone interface integration. Degradation rate and compressive strength of the PLA bolt were measured after immersion in a buffer solution for 3 months. In vitro biochemical characteristics and the nanofibrous matrix were assessed using a water contact angle analyzer, pH meter, and tetrazolium reduction assay. In vivo efficacies of PLGA/collagen nanofibers and PLA bolts for tendon–bone healing were investigated on a rabbit bone tunnel model with histological and tendon pullout tests. The PLGA/collagen-blended nanofibrous membrane was a hydrophilic, stable, and biocompatible scaffold. The PLA bolt was durable for tendon–bone anchoring. Histology showed adequate biocompatibility of the PLA bolt on a medial cortex with progressive bone ingrowth and without tissue overreaction. PLGA nanofibers within the bone tunnel also decreased the tunnel enlargement phenomenon and enhanced tendon–bone integration. Composite polymers of the PLA bolt and PLGA/collagen nanofibrous membrane can effectively promote outcomes of tendon reconstruction in a rabbit model. The composite biodegradable polymeric system may be useful in humans for tendon reconstruction. Keywords: polylactide–polyglycolide nanofibers, PLGA, collagen, 3D printing, polylactide, PLA, bone-anchoring bolts, tendon healing

  18. Thermodynamics of Taub-NUT/bolt black holes in Einstein-Maxwell gravity

    International Nuclear Information System (INIS)

    Dehghani, M.H.; Khodam-Mohammadi, A.

    2006-01-01

    First, we construct the Taub-NUT/bolt solutions of (2k+2)-dimensional Einstein-Maxwell gravity, when all the factor spaces of 2k-dimensional base space B have positive curvature. These solutions depend on two extra parameters, other than the mass and the NUT charge. These are electric charge q and electric potential at infinity V. We investigate the existence of Taub-NUT solutions and find that in addition to the two conditions of uncharged NUT solutions, there exist two extra conditions. These two extra conditions come from the regularity of vector potential at r=N and the fact that the horizon at r=N should be the outer horizon of the NUT charged black hole. We find that the NUT solutions in 2k+2 dimensions have no curvature singularity at r=N, when the 2k-dimensional base space is chosen to be CP 2k . For bolt solutions, there exists an upper limit for the NUT parameter which decreases as the potential parameter increases. Second, we study the thermodynamics of these spacetimes. We compute temperature, entropy, charge, electric potential, action and mass of the black hole solutions, and find that these quantities satisfy the first law of thermodynamics. We perform a stability analysis by computing the heat capacity, and show that the NUT solutions are not thermally stable for even k's, while there exists a stable phase for odd k's, which becomes increasingly narrow with increasing dimensionality and wide with increasing V. We also study the phase behavior of the 4 and 6 dimensional bolt solutions in canonical ensemble and find that these solutions have a stable phase, which becomes smaller as V increases

  19. Usage of prestressed vertical bolts for retrofitting flat slabs damaged due to punching shear

    Directory of Open Access Journals (Sweden)

    Hamed S. Askar

    2015-09-01

    An experimental investigation with the objective of retrofitting flat slabs damaged due to punching shear using prestressed vertical bolts is presented in this paper. The parameters examined in this study are vertical prestressed bolts with different ratios within the slab thickness, slab thickness and central column size. Through the experimental tests the load carrying capacity, deformation characteristics and the cracking behavior have been investigated. A comparison between the behavior of retrofitted slabs and their references showed that the proposed system of repair is effective and could be used in practice. A comparison between the experimental results and calculated punching failure load based on the formulas adopted by different codes, showed a reasonable agreement.

  20. Critical joints in large composite primary aircraft structures. Volume 2: Technology demonstration test report

    Science.gov (United States)

    Bunin, Bruce L.

    1985-01-01

    A program was conducted to develop the technology for critical structural joints in composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of four large composite multirow bolted joint tests are presented. The tests were conducted to demonstrate the technology for critical joints in highly loaded composite structure and to verify the analytical methods that were developed throughout the program. The test consisted of a wing skin-stringer transition specimen representing a stringer runout and skin splice on the wing lower surface at the side of the fuselage attachment. All tests were static tension tests. The composite material was Toray T-300 fiber with Ciba-Geigy 914 resin in 10 mil tape form. The splice members were metallic, using combinations of aluminum and titanium. Discussions are given of the test article, instrumentation, test setup, test procedures, and test results for each of the four specimens. Some of the analytical predictions are also included.

  1. Use of the cylindrically guided wave technique for the inspection of stud bolts, valve stems and pump shafts

    International Nuclear Information System (INIS)

    Light, G.M.; Bloom, E.A.; Ruescher, E.H.; Lui, S.N.

    1989-01-01

    Over the last several years, nuclear power plants have expressed concern about failures of bolting, valve stems, and pump shafts. This paper reports on the development of an ultrasonic technique to inspect these components. The authors have successfully demonstrated the cylindrically guided wave technique (CGWT) on a wide range of stud bolts. The CGWT employs zero-degree longitudinal waves constrained to travel within the boundary of the cylindrically shaped components during inspection. Theoretically explained, mode conversion occurs because the ultrasonic wave is guided down the length of the component. These mode-converted signals are dependent upon the diameter of the component under inspection and the longitudinal- and shear-wave velocities of the component material. This technique has also been successfully used on valve stems in the field. The geometry of the valve stem is very similar to that of the stud bolt

  2. Failure Analysis Of The Bolt From Turn Table Tightening On The Heavy Lifting Equipment System

    International Nuclear Information System (INIS)

    Hatta, IIham

    2000-01-01

    This paper provides the results of failure analysis of the bolt from the turn table tightening which usually using on the heavy lifting equipment or as a equipment tor the material handling with the maximum load about 25 ton. The process of the failure analysis from the series of laboratory testing such as chemical composition, tensile testing, hardness, fracture surtace and microstructure. The results of the analysis we see this bolt have suffered fatigue failure and the initiation, cracking from the manufacture defect. This defect in the form like the folding on the screw surface which maybe happen at the screw forming process. This folding as a part of metal which not bonding together, so could act as a initial crack, and got the creasing of the strength too which cause from oxidation and decarburization at the moment of heat treatment process. So this material got the changein the strength too which oxidation and decarburization at the moment of heat treatment process. So this material got the change in the microstructure, from the martensite temper to the coarse ferrite and finally reduces the strength of the bolt

  3. Special requirements for bolting material for nuclear and other special applications

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    A specification that provides special requirements for bolting material for use in nuclear and other special applications is presented. The requirements of the specification are supplemental to the requirements of the basic material specifications and they include tempering, welding, elimination of surface defects, certification and identification, quality assurance and various examination methods

  4. Stress evaluation of baffle former bolt for IASCC failure prediction

    International Nuclear Information System (INIS)

    Matsubara, T.; Tsutsui, T.; Kamei, Y.; Kitsu, M.

    2011-01-01

    Baffle structure in PWRs Reactor is quite important assembly for the core safety, and Baffle Former Bolts (BFBs) are fastener members for maintaining Baffle structure. It has been reported worldwide that some of BFBs were cracked due to IASCC (Irradiation Assisted Stress Corrosion Cracking) because BFBs are located at core region under severe environments, high neutron flux, high temperature and high stress. According to the material studies of IASCC on austenitic stainless steel, a crack initiation of IASCC is strongly related with the stress and the neutron fluence. For this reason, it is very important for IASCC failure prediction to simulate the stress of BFBs. However, the stress of BFBs are considered to be influenced by several factors and to be changed complexly as operational time increases, by irradiation creep of Bolt itself, swelling of Baffle structure, and so on. Therefore, it is difficult to estimate the stress histories of BFBs (Bolt stress as a function of operational time) precisely. Then, the author has developed the calculation method of the stress histories of BFBs considering irradiation effects (swelling and irradiation creep). In this method, the stress histories of BFBs are calculated by combining two kinds of FE models, Global model (modeled whole Baffle structure which consists of Baffle plates, Former plates and Core Barrel) and Local model (modeled around BFB finely). The whole Baffle structure deformation changes as a function of heat, swelling and irradiated creep are calculated by Global model, and the stress histories of BFBs are calculated by Local model using the outputs (deformations on driving nodes) of Global model. In the FE analysis of Local model, the stress of BFBs are calculated considering irradiation effects and elastic-plastic characteristics depending on neutron fluence, so this method enables to calculate precisely the stress of extreme small area of BFBs surface. This paper shows the outline of the calculation method

  5. Tapered joint design for power transmission of MW-grade wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jong Hun; Bae, Jun Woo; Oh, Han Yong [Dept. of Mechatronics, Jungwon University, Geosan (Korea, Republic of); Kwon, Yong Chul [Kyeongnam Technopark, Changwon (Korea, Republic of)

    2015-11-15

    This study focuses on the design of the tapered joints of a wind power turbine. The main variables of the tapered joint are the transmitted torque, shaft diameter, contact area of the tapered ring, and tightening torque of the bolts, which applies a compressive pressure from the hub to the shaft. The stress distribution of the taper fit was calculated under axisymmetric plane strain conditions because of the small taper angle. The axial displacement of the clamp can be calculated from the radial elastic deformation and the taper angle. The stress field of each ring is obtained from the cylinder stress equation. To verify the accuracy of the calculation, finite element (FE) analysis was performed, and the results of the calculation and FE analysis were compared. The hoop stress of the tapered surface showed a discrepancy of approximately 10, but the trends of the stress distributions of each component and the relative movement obtained by FE analysis were in good agreement with the analytical calculation results.

  6. Bolted Ribs Analysis for the ITER Vacuum Vessel using Finite Element Submodelling Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Zarzalejos, José María, E-mail: jose.zarzalejos@ext.f4e.europa.eu [External at F4E, c/Josep Pla, n.2, Torres Diagonal Litoral, Edificio B3, E-08019, Barcelona (Spain); Fernández, Elena; Caixas, Joan; Bayón, Angel [F4E, c/Josep Pla, n.2, Torres Diagonal Litoral, Edificio B3, E-08019, Barcelona (Spain); Polo, Joaquín [Iberdrola Ingeniería y Construcción, Avenida de Manoteras 20, 28050 Madrid (Spain); Guirao, Julio [Numerical Analysis Technologies, S L., Marqués de San Esteban 52, Entlo, 33209 Gijon (Spain); García Cid, Javier [Iberdrola Ingeniería y Construcción, Avenida de Manoteras 20, 28050 Madrid (Spain); Rodríguez, Eduardo [Mechanical Engineering Department EPSIG, University of Oviedo, Gijon (Spain)

    2014-10-15

    Highlights: • The ITER Vacuum Vessel Bolted Ribs assemblies are modelled using Finite Elements. • Finite Element submodelling techniques are used. • Stress results are obtained for all the assemblies and a post-processing is performed. • All the elements of the assemblies are compliant with the regulatory provisions. • Submodelling is a time-efficient solution to verify the structural integrity of this type of structures. - Abstract: The ITER Vacuum Vessel (VV) primary function is to enclose the plasmas produced by the ITER Tokamak. Since it acts as the first radiological barrier of the plasma, it is classified as a class 2 welded box structure, according to RCC-MR 2007. The VV is made of an inner and an outer D-shape, 60 mm-thick double shell connected through thick massive bars (housings) and toroidal and poloidal structural stiffening ribs. In order to provide neutronic shielding to the ex-vessel components, the space between shells is filled with borated steel plates, called In-Wall Shielding (IWS) blocks, and water. In general, these blocks are connected to the IWS ribs which are connected to adjacent housings. The development of a Finite Element model of the ITER VV including all its components in detail is unaffordable from the computational point of view due to the large number of degrees of freedom it would require. This limitation can be overcome by using submodelling techniques to simulate the behaviour of the bolted ribs assemblies. Submodelling is a Finite Element technique which allows getting more accurate results in a given region of a coarse model by generating an independent, finer model of the region under study. In this paper, the methodology and several simulations of the VV bolted ribs assemblies using submodelling techniques are presented. A stress assessment has been performed for the elements involved in the assembly considering possible types of failure and including stress classification and categorization techniques to analyse

  7. Review and synthesis of stress intensity factor solutions applicable to cracks in bolts

    International Nuclear Information System (INIS)

    James, L.A.; Mills, W.J.

    1988-01-01

    The available literature for stress intensity factor solutions for cracks in round bars, both threaded and unthreaded, subjected to either tension or bending, is reviewed. The results are synthesized into a form that is appropriate for the analysis of bolts and studs. (author)

  8. Effect of CO2 enrichment on the glucosinolate contents under different nitrogen levels in bolting stem of Chinese kale (Brassica alboglabra L.).

    Science.gov (United States)

    La, Gui-xiao; Fang, Ping; Teng, Yi-bo; Li, Ya-juan; Lin, Xian-yong

    2009-06-01

    The effects of CO(2) enrichment on the growth and glucosinolate (GS) concentrations in the bolting stem of Chinese kale (Brassica alboglabra L.) treated with three nitrogen (N) concentrations (5, 10, and 20 mmol/L) were investigated. Height, stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO(2) concentration was elevated from 350 to 800 microl/L at each N concentration. In the edible part of the bolting stem, 11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO(2) concentration, N concentration, and CO(2)xN interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those of indolyl GSs were not affected, by elevated atmospheric CO(2). However, at 20 mmol N/L, elevated CO(2) had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon (C) content increased, whereas the N and sulfur (S) contents decreased under elevated CO(2) concentration in the three N treatments, resulting in changes in the C/N and N/S ratios. Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO(2) concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO(2) condition.

  9. Effect of CO2 enrichment on the glucosinolate contents under different nitrogen levels in bolting stem of Chinese kale (Brassica alboglabra L.)*

    Science.gov (United States)

    La, Gui-xiao; Fang, Ping; Teng, Yi-bo; Li, Ya-juan; Lin, Xian-yong

    2009-01-01

    The effects of CO2 enrichment on the growth and glucosinolate (GS) concentrations in the bolting stem of Chinese kale (Brassica alboglabra L.) treated with three nitrogen (N) concentrations (5, 10, and 20 mmol/L) were investigated. Height, stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO2 concentration was elevated from 350 to 800 μl/L at each N concentration. In the edible part of the bolting stem, 11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO2 concentration, N concentration, and CO2×N interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those of indolyl GSs were not affected, by elevated atmospheric CO2. However, at 20 mmol N/L, elevated CO2 had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon (C) content increased, whereas the N and sulfur (S) contents decreased under elevated CO2 concentration in the three N treatments, resulting in changes in the C/N and N/S ratios. Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO2 concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO2 condition. PMID:19489111

  10. Remote controlled stud bolt handling device for reactor pressure vessel

    International Nuclear Information System (INIS)

    Shindo, Takenori; Shigehiro, Katsuya; Ito, Morio; Okada, Kenji

    1988-01-01

    In nuclear power stations, at the time of regular inspection, the works of opening and fixing the upper covers of reactor pressure vessels are carried out for inspecting the inside of reactor pressure vessels and exchanging fuel rods. These upper covers are fastened with many stud bolts, therefore, the works of opening and fixing require a large amount of labor, and are done under the restricted condition of wearing protective clothings and masks. Babcock Hitachi K.K. has completed the development of a remotely controlled automatic bolt tightenig device for this purpose, therefore, its outline is reported. The conventional method of these works and the problems in it are described. The design of the new device aimed at the parallel execution of cleaning screw threads, loosening and tightening nuts, and taking off and putting on nuts and washers, thus contributing to the shortening of regular inspection period, the reduction of the radiation exposure of workers, and the decrease of the number of workers. The function, reliability and endurance of the new device were confirmed by the verifying test using a device made for trial. The device is composed of a stand, a rail and four stations each with a cleaning unit, a stud tensioner and a nut handling unit. (K.I.)

  11. Ultrasonic testing of core baffle former bolts of the core tanks of pressurised water reactors; Ultraschallpruefung von Kernumfassungsschrauben der Kernbehaelter von Druckwasserreaktoren

    Energy Technology Data Exchange (ETDEWEB)

    Bies, Christian M.; Alaerts, Louis; Bonitz, Frank W. [Westinghouse Electric Germany GmbH, Mannheim (Germany); Devlin, Russell S.; Minogue, Patrick [WesDyne International, Madison, PA (United States)

    2013-07-01

    This article presents the MIDAS VI testing robot used by Westinghouse / WesDyne. This is a remotely operated underwater vehicle which positions ultrasonic probes under camera control. This vehicle makes it possible to substantially reduce the time required for setting up and preparing ultrasonic tests on core baffle former bolts. It has also accelerated the test procedure itself. Test methods have also been developed for bolt types which were hitherto considered incapable of being tested. One of these methods is based on a phased array probe. The article also reports on experiences gained over the course of years in testing core baffle former bolts in European nuclear power plants using the SUPREEM testing robot.

  12. Residual Strength of Glued-in Bolts After 9 Years In Situ Loading

    DEFF Research Database (Denmark)

    Pedersen, Martin Bo Uhre; Clorius, Christian Odin; Damkilde, Lars

    1996-01-01

    In 1993 one of the wooden blades of the Nibe-B windmill was struck by lightning and subsequently demounted after 9 years of use. The mishap offered a unique opportunity to investigate the residual strength of the 28 glued-in bolts used to form the blade to rotor hub connection.The test method...

  13. Rotor characteristics experiments with cooling pipe/fender bolt-groups, HTR-500

    International Nuclear Information System (INIS)

    Froening.

    1990-01-01

    For the design of composite liners for prestressed concrete pressure vessels of high temperature reactors, the force-displacement relationship of rotor elements is required. The rotor elements link the liner with the vessel concrete and transfer loads between liner and concrete. The liner is mainly stressed only at the sheet level due to concrete upsetting because of external load, including creeping due to prestress, internal pressure and temperature, shrinkage and temperature difference between liner and concrete. In the region of planned peripheral disturbances (penetrations, sheet/transfers, etc.), and at places with unintentional imperfections (dents, points of impact with slightly different sheet thicknesses), the liner sheet may be displaced against the concrete. Such displacements lead to a shear load on fender bolts and cooling pipes. The strains develop slowly. They can also be cyclical owing to internal pressure and temperature changes, the amplitudes being low, however. In addition, tensile stress may be applied to the fender bolt rotors by the driving effect of the shear-stressed cooling pipes, by the liner bending strain at the edges of dented fields, or by external loads. (orig.) [de

  14. An impedance-based approach for detection and quantification of damage in cracked plates and loose bolts in bridge structures

    Science.gov (United States)

    Rabiei, Masoud; Sheldon, Jeremy; Palmer, Carl

    2012-04-01

    The applicability of Electro-Mechanical Impedance (EMI) approach to damage detection, localization and quantification in a mobile bridge structure is investigated in this paper. The developments in this paper focus on assessing the health of Armored Vehicle Launched Bridges (AVLBs). Specifically, two key failure mechanisms of the AVLB to be monitored were fatigue crack growth and damaged (loose) rivets (bolts) were identified. It was shown through experiment that bolt damage (defined here as different torque levels applied to bolts) can be detected, quantified and located using a network of lead zirconate titanate (PZT) transducers distributed on the structure. It was also shown that cracks of various sizes can be detected and quantified using the EMI approach. The experiments were performed on smaller laboratory specimens as well as full size bridge-like components that were built as part of this research. The effects of various parameters such as transducer type and size on the performance of the proposed health assessment approach were also investigated.

  15. Nonlinear characterization of a bolted, industrial structure using a modal framework

    Science.gov (United States)

    Roettgen, Daniel R.; Allen, Matthew S.

    2017-02-01

    This article presents measurements from a sub assembly of an off-the-shelf automotive exhaust system containing a bolted-flange connection and uses a recently proposed modal framework to develop a nonlinear dynamic model for the structure. The nonlinear identification and characterization methods used are reviewed to highlight the strengths of the current approach and the areas where further development is needed. This marks the first use of these new testing and nonlinear identification tools, and the associated modal framework, on production hardware with a realistic joint and realistic torque levels. To screen the measurements for nonlinearities, we make use of a time frequency analysis routine designed for transient responses called the zeroed early-time fast Fourier transform (ZEFFT). This tool typically reveals the small frequency shifts and distortions that tend to occur near each mode that is affected by the nonlinearity. The damping in this structure is found to be significantly nonlinear and a Hilbert transform is used to characterize the damping versus amplitude behavior. A model is presented that captures these effects for each mode individually (e.g. assuming negligible nonlinear coupling between modes), treating each mode as a single degree-of-freedom oscillator with a spring and viscous damping element in parallel with a four parameter Iwan model. The parameters of this model are identified for each of the structure's modes that exhibited nonlinearity and the resulting nonlinear model is shown to capture the stiffness and damping accurately over a large range of response amplitudes.

  16. 3-D Analysis of Flanged Joints Through Various Preload Methods Using ANSYS

    Science.gov (United States)

    Murugan, Jeyaraj Paul; Kurian, Thomas; Jayaprakash, Janardhan; Sreedharapanickar, Somanath

    2015-10-01

    Flanged joints are being employed in aerospace solid rocket motor hardware for the integration of various systems or subsystems. Hence, the design of flanged joints is very important in ensuring the integrity of motor while functioning. As these joints are subjected to higher loads due to internal pressure acting inside the motor chamber, an appropriate preload is required to be applied in this joint before subjecting it to the external load. Preload, also known as clamp load, is applied on the fastener and helps to hold the mating flanges together. Generally preload is simulated as a thermal load and the exact preload is obtained through number of iterations. Infact, more iterations are required when considering the material nonlinearity of the bolt. This way of simulation will take more computational time for generating the required preload. Now a days most commercial software packages use pretension elements for simulating the preload. This element does not require iterations for inducing the preload and it can be solved with single iteration. This approach takes less computational time and thus one can study the characteristics of the joint easily by varying the preload. When the structure contains more number of joints with different sizes of fasteners, pretension elements can be used compared to thermal load approach for simulating each size of fastener. This paper covers the details of analyses carried out simulating the preload through various options viz., preload through thermal, initial state command and pretension element etc. using ANSYS finite element package.

  17. Thermomechanical behaviour of bolted assemblies

    International Nuclear Information System (INIS)

    Scliffet, L.

    1995-01-01

    This paper presents first results obtained in an R and D study on the thermomechanical behaviour of bolted assemblies. Thermal shocks during operating transients both severely distort such assemblies and cause variations in stud pre-loads. So during a hot shock, the thermal gradient in the flange induced over-tightening due to the differential thermal expansion involved. Over-tightening can reach 70% of the nominal value, usually after 10 to 15 mn, after which the stress relaxes as soon as the heating affects the stud. A series of hot shocks causes assembly fatigue, notably resulting in thread plasticization, making it impossible to tighten the studs. In the case of cold transients, the reverse phenomenon is observed. The hot flange contracts sharply upon contact with the cold fluid, causing stress relief in the expanded studs. The resulting loss of tensile stress, which reaches up to 50%, can then cause severe leakage, especially if the nominal tightening capacity is already impaired. The study presented is based on tests and modelling. (author). 16 figs

  18. Analytical and numerical investigation of bolted steel ring flange connection for offshore wind monopile foundations

    DEFF Research Database (Denmark)

    Madsen, C.A.; Kragh-Poulsen, Jens-Christian; Tage, K.J.

    2017-01-01

    The monopile foundation is the dominant solution for support of wind turbines in offshore wind farms. It is normally grouted to the transition piece which connects the foundation to the turbine. Currently, the bolted steel ring flange connection is investigated as an alternative. The monopile......--transition piece connection has specific problems, such as out-of-verticality and installation damage from driving the MP into the seabed and it is not fully known how to design for these. This paper presents the status of the ongoing development work and an estimate of what still needs to be covered in order...... to use the connection in practice. This involves presentation of an analytical and non-linear FE analysis procedure for the monopile-transition piece connection composed of two L flanges connected with preloaded bolts. The connection is verified for ultimate and fatigue limit states based...

  19. Analytical and numerical investigation of bolted steel ring flange connection for offshore wind monopile foundations

    DEFF Research Database (Denmark)

    Madsen, C.A.; Kragh-Poulsen, Jens-Christian; Tage, K.J.

    The monopile foundation is the dominant solution for support of wind turbines in offshore wind farms. It is normally grouted to the transition piece which connects the foundation to the turbine. Currently, the bolted steel ring flange connection is investigated as an alternative. The monopile......--transition piece connection has specific problems, such as out-of-verticality and installation damage from driving the MP into the seabed and it is not fully known how to design for these. This paper presents the status of the ongoing development work and an estimate of what still needs to be covered in order...... to use the connection in practice. This involves presentation of an analytical and non-linear FE analysis procedure for the monopile-transition piece connection composed of two L flanges connected with preloaded bolts. The connection is verified for ultimate and fatigue limit states based...

  20. Intergranular cracking mechanism in baffle former bolt materials for PWR core internals

    Energy Technology Data Exchange (ETDEWEB)

    Yonezawa, Toshio; Arioka, Koji; Kanasaki, Hiroshi; Fujimoto, Koji [Takasago R and D Center, Mitsubishi Heavy Industries Ltd., Takasago, Hyogo (Japan); Ajiki, Kazuhide [Kobe Shipyard and Machinery, Mitsubishi Heavy Industries Ltd., Kobe, Hyogo (Japan); Matsuoka, Takanori [Nuclear Development Corp., Tokai, Ibaraki (Japan); Urata, Sigeru; Mizuta, Hitoshi [Kansai Electric Power Co., Inc., Osaka (Japan)

    2000-03-01

    In this study, the cause of intergranular cracking in baffle former bolts(BFBs) was estimated from metallurgical and chemical viewpoints based upon the experimental data and information published by EdF. At first, five kinds of possibilities were estimated as the cause of intergranular cracking in BFBs. Five possibilities estimated were (1) mechanical cracking caused by high strain in irradiation hardened austenitic stainless steels, (2) O{sub 2} SCC due to residual oxygen in the bolt stagnant region, (3) caustic SCC due to dry and wet phenomenon, (4) low pH SCC due to oxygen concentration cell, and (5) PWSCC due to radiation induced segregation. In this study each possibility was evaluated by the calculation and some out of pile tests. And also, the cause of the intergranular cracking in BFBs was estimated by the data of the post-irradiation examinations and basic out of pile tests for Type 316CW and Type 347 stainless steels in the authors' previous study. From these evaluation, the intergranular cracking in BFBs seems to be caused by the PWSCC, but not caused by mechanical cracking O{sub 2} SCC, caustic SCC or low pH SCC. (author)

  1. Experimental analysis of mechanical joints strength by means of energy dissipation

    Science.gov (United States)

    Wolf, Alexander; Lafarge, Remi; Kühn, Tino; Brosius, Alexander

    2018-05-01

    Designing complex structures with the demand for weight reduction leads directly to a multi-material concept. This mixture has to be joined securely and welding, mechanical joining and the usage of adhesives are commonly used for that purpose. Sometimes also a mix of at least two materials is useful to combine the individual advantages. The challenge is the non-destructive testing of these connections because destructive testing requires a lot of preparation and expensive testing equipment. The authors show a testing method by measuring and analysing the energy dissipation in mechanical joints. Known methods are radiography, thermography and ultrasound testing. Unfortunately, the usage of these methods is difficult and often not usable in fibre-reinforced-plastics. The presented approach measures the propagation of the elastic strain wave through the joint. A defined impact strain is detected with by strain-gauges whereby the transmitter is located on one side of the joint and the receiver on the other, respectively. Because of different mechanisms, energy dissipates by passing the joint areas. Main reasons are damping caused by friction and material specific damping. Insufficient performed joints lead to an effect especially in the friction damping. By the measurement of the different strains and the resulting energy loss a statement to the connection quality is given. The possible defect during the execution of the joint can be identified by the energy loss and strain vs. time curve. After the description of the method, the authors present the results of energy dissipation measurements at a bolted assembly with different locking torques. By the adjustable tightening torques for the screw connections easily a variation of the contact pressure can be applied and analysed afterwards. The outlook will give a statement for the usability for other mechanical joints and fibre-reinforced-plastics.

  2. Un mejor posicionamiento para un mejor Bolt : concurso Effie Colombia

    OpenAIRE

    Carvajal, Martin; Jaramillo, Isabella; Pedraza, Carlos; Rodriguez, Natalia; Amezquita, Juan José

    2017-01-01

    En este trabajo, se realiza una estrategia de marketing y comunicación para el proyecto Chevrolet en el mercado colombiano, teniendo en cuenta la información suministrada por la empresa y la investigación externa. El trabajo muestra 5 etapas diferentes: Desafío Estratégico, Perspectivas y Objetivos; Idea creativa; Medición de resultados; Viabilidad; y material gráfico. El objetivo de este trabajo es proponer una estrategia de marketing integral para la llegada del nuevo Chevrolet Bolt al merc...

  3. Drop Tests Results Of Revised Closure Bolt Configuration Of The Standard Waste Box, Standard Large Box 2, And Ten Drum Overpack Packagings

    International Nuclear Information System (INIS)

    May, C.; Opperman, E.; Mckeel, C.

    2010-01-01

    The Transuranic (TRU) Disposition Project at Savannah River Site will require numerous transfers of radioactive materials within the site boundaries for sorting and repackaging. The three DOT Type A shipping packagings planned for this work have numerous bolts for securing the lids to the body of the packagings. In an effort to reduce operator time to open and close the packages during onsite transfers, thus reducing personnel exposure and costs, an evaluation was performed to analyze the effects of reducing the number of bolts required to secure the lid to the packaging body. The evaluation showed the reduction to one-third of the original number of bolts had no effect on the packagings capability to sustain vibratory loads, shipping loads, internal pressure loads, and the loads resulting from a 4-ft drop. However, the loads caused by the 4-ft drop are difficult to estimate and the study recommended each of the packages be dropped to show the actual effects on the package closure. Even with reduced bolting, the packagings were still required to meet the 49 CFR 178.350 performance criteria for Type A packaging. This paper discusses the effects and results of the drop testing of the three packagings.

  4. Fretting fatigue cracking of a center guide bolt supporting the combustion chamber in a heavy-duty gas turbine engine

    Energy Technology Data Exchange (ETDEWEB)

    Neidel, Andreas; Fischer, Boromir; Gaedicke, Tobias [Siemens AG, Energy Sector, Gasturbinenwerk Berlin (Germany). Werkstoffprueflabor

    2018-04-01

    The slotted center guide bolt of the center guide feature of the lower part of the outer shell of an annular combustion chamber was found fractured in a heavy-duty gas turbine engine used for power generation, after approximately 5.500 operating hours. The incident was a one-off event and not a recurring incident. No similar events were reported from the fleet; hence the failure was not considered a field issue. The metallurgical root cause investigation that was ordered to determine the failure mechanism revealed that the incident center guide bolt failed by fretting fatigue cracking, a high cycle fatigue (HCF) phenomenon.

  5. Suicide with two makes of captive-bolt guns (livestock stunners) fired simultaneously to the forehead.

    Science.gov (United States)

    Pircher, Rebecca; Geisenberger, Dorothee; Große Perdekamp, Markus; Neukamm, Merja; Pollak, Stefan; Schmidt, Ulrike; Thierauf-Emberger, Annette

    2017-11-01

    In humans, most fatalities from slaughterer's guns are suicides committed by persons familiar with stunning devices. The great majority of cases accounts for shots to the head, especially the frontal region. Only a small number of two subsequent cranial shots from captive-bolt humane killers have been reported up to now. In the case presented by the authors, a suicide by simultaneous shots to the head fired from two different makes of captive-bolt guns (one of them having two separate outlets for the combustion gases in the muzzle plane, the other type having no additional openings) is described for the first time. One of the shooting devices remained in firm contact with the left hand and produced patterned staining from rust corresponding to the surface relief of the gun. The medicolegal and criminalistic aspects of this unique case are discussed with reference to the pertinent literature.

  6. Analysis of Modeling Parameters on Threaded Screws.

    Energy Technology Data Exchange (ETDEWEB)

    Vigil, Miquela S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brake, Matthew Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Vangoethem, Douglas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-06-01

    Assembled mechanical systems often contain a large number of bolted connections. These bolted connections (joints) are integral aspects of the load path for structural dynamics, and, consequently, are paramount for calculating a structure's stiffness and energy dissipation prop- erties. However, analysts have not found the optimal method to model appropriately these bolted joints. The complexity of the screw geometry cause issues when generating a mesh of the model. This paper will explore different approaches to model a screw-substrate connec- tion. Model parameters such as mesh continuity, node alignment, wedge angles, and thread to body element size ratios are examined. The results of this study will give analysts a better understanding of the influences of these parameters and will aide in finding the optimal method to model bolted connections.

  7. Rate of driving a ventilation tunnel by means of the GPK heading machine using roof bolting and steel supports. [USSR

    Energy Technology Data Exchange (ETDEWEB)

    Cheremnov, V.I.; Kruglyak, A.S.; Miroshnikova, L.A.; Sharov, V.N.

    1983-05-01

    The paper discusses a method for strata control during mine drivage tested in the im. Voroshilov coal mine in 1982. A ventilation tunnel with a crosscut of 16.4 m/sup 2/ was driven in coal with compression strength coefficient from 0.8 to 1.0, argillites and aleurites in the floor and the roof with compression strength coefficient from 4 to 6. Mining depth was 150 m, water influx was low. The tunnel was driven by means of the GPK heading machine with a 1PNB-2 loader. The AMK support system which consisted of arched steel supports, steel beams for joining steel arches and of roof bolts was used. Arched supports were installed each 0.8 m. The roof between the arches was supported by a system of roof bolts and junction beams. Support design is shown in a scheme. Increasing support spacing to 0.8 m (instead of 0.5 m) and roof bolting permitted drivage rate to be increased and steel consumption to be significantly reduced (by 244 kg/m). (3 refs.)

  8. Further development of remote testing of submerged bolts and screws in reactors

    International Nuclear Information System (INIS)

    Mohr, F.; Schirner, G.; Meier, R.; Wiesinger, W.

    2007-01-01

    Since the eighties, intelligeNDT has been carrying out ultrasonic tests of bolts in reactor containments and pressure vessels both in Germany and abroad. The ultrasonic equipment used belonged to the SAPHIR/SAPHIRplus line. The recording and online evaluation software was adapted to the test requirements and optimized for high test rates and quality-assured documentation. As test manipulator, the ''SUSI'' submarine by AREVA NP was used with good results. (orig.)

  9. Behavior of four-bolt extended end-plate connection subjected to lateral loading

    Directory of Open Access Journals (Sweden)

    Elsayed Mashaly

    2011-03-01

    Full Text Available A considerable number of literatures have been published on the behavior of end-plate connections in ordinary moment-resisting frames. It was found, experimentally, that this type of connection might act as either a fully-rigid or a semi-rigid connection depending mainly on the thickness of the end plate and the diameter of bolts. In recent years, due to their good ductility and their good ability of energy dissipation, extended end-plate connections are recommended to be widely used in special moment-resisting frames subjected to lateral loads. The purpose of this study is to investigate the effect of both the material and geometric properties of four-bolt extended end-plate connections upon their behavior when subjected to lateral loading. This is done through a parametric study upon a finite element model using the multi-purpose software package ANSYS. The parametric study takes into account 12 parameters which are expected to be effective on the behavior of the studied connection. The results are presented by the relation between the storey drift, which represents the rotation of the connection and the applied lateral load, which simulates the moment on the connection. The results verify that the chosen parameters are considered effective depending on the energy dissipation of the connection.

  10. Crack-depth effects in the cylindrically guided wave technique for bolt and pump-shaft inspections

    International Nuclear Information System (INIS)

    Tsai, Y.M.; Liu, S.N.; Light, G.M.

    1991-01-01

    Nuclear power plants have experienced the failures of bolts and pump shafts. The industry is concerned about nondestructive evaluation (NDE) techniques that can be applied to these components. The cylindrically guided wave technique (CGWT) has been developed to detect the simulated circumferential defects in long bolts and studs. The ultrasonic CGWT employs the zero-degree longitudinal waves constrained to travel within the boundary of the components with cylindrical shape during inspection. When longitudinal waves are guided to travel along a cylinder, and impinge onto a circumferential defect, the waves are scattered at the crack on the cylinder surface. In this work, the wave scattering at the circumferential crack on a long cylinder is investigated. The transfer factor of the scattered waves is calculated for a wide range of frequency spectra. The scattered waveform at a distance away from a crack is calculated. The effect that crack depth exerts to the waveform in CGWT is shown. CGWT signals, waveform calculation and so on are reported. (K.I.)

  11. Analytical and numerical investigation of bolted steel ring flange connection for offshore wind monopile foundations

    Science.gov (United States)

    Madsen, C. A.; Kragh-Poulsen, J.-C.; Thage, K. J.; Andreassen, M. J.

    2017-12-01

    The monopile foundation is the dominant solution for support of wind turbines in offshore wind farms. It is normally grouted to the transition piece which connects the foundation to the turbine. Currently, the bolted steel ring flange connection is investigated as an alternative. The monopile--transition piece connection has specific problems, such as out-of-verticality and installation damage from driving the MP into the seabed and it is not fully known how to design for these. This paper presents the status of the ongoing development work and an estimate of what still needs to be covered in order to use the connection in practice. This involves presentation of an analytical and non-linear FE analysis procedure for the monopile-transition piece connection composed of two L flanges connected with preloaded bolts. The connection is verified for ultimate and fatigue limit states based on an integrated load simulation carried out by the turbine manufacturer.

  12. A real-time visual inspection method of fastening bolts in freight car operation

    Science.gov (United States)

    Nan, Guo; Yao, JunEn

    2015-10-01

    A real-time inspection of the key components is necessary for ensuring safe operation of freight car. While traditional inspection depends on the trained human inspectors, which is time-consuming and lower efficient. With the development of machine vision, vision-based inspection methods get more railway on-spot applications. The cross rod end fastening bolts are important components on both sides of the train body that fixing locking plates together with the freight car main structure. In our experiment, we get the images containing fastening bolt components, and accurately locate the locking plate position using a linear Support Vector Machine (SVM) locating model trained with Histograms of Oriented Gradients (HOG) features. Then we extract the straight line segment using the Line Segment Detector (LSD) and encoding them in a range, which constitute a straight line segment dataset. Lastly we determine the locking plate's working state by the linear pattern. The experiment result shows that the localization accurate rate is over 99%, the fault detection rate is over 95%, and the module implementation time is 2f/s. The overall performance can completely meet the practical railway safety assurance application.

  13. Estimation for bolt fastening conditions of thin aluminum structure using PZT sensors

    International Nuclear Information System (INIS)

    Hong, Yong; Han, Byeong Hee; Kim, Byung Jin; Hong, Dong Pyo; Kim, Young Moon

    2007-01-01

    This work presents a study on PZT impedance-based method, it is one of the NDT(Non-Destructive Technique). We study about assessment of the square-structure health condition by impedance-based technique using PZT patches, associated with longitudinal wave propagation. Health conditions of the square-structure controlled by bolt fastening condition is adjusted by torque wrench. In order to estimate the damage condition numerically, we suggest the evaluation method of impedance peak frequency shift

  14. Mechanical characteristics of connection for GFRP plates using tapping screws

    Science.gov (United States)

    Inoue, Yuya; Duong, Nguyen Ngoc; Satake, Chito; Matsumoto, Yukihiro

    2017-10-01

    FRP material has good characteristics such as light-weight, high-strength and high-corrosion resistance. Light-weight structure possesses some advantages over the rational constructing procedure such as self-building structures. In recent years, mechanical characteristics of FRP joints using bolts and/or rivet are investigated in detail, and they are used in many FRP structures. However, the bolts lack bearing strength compared with material strength and the joint needs the prepared bolt hole. In this paper, an alternative joint system for FRP structures using tapping screw is proposed and mechanical characteristics are investigated through experiment. Tapping screw has some advantages; easy-to-use, light-weight and high bearing strength. Then, the results of double-lapped tensile shear tests having one, four and eight tapping screws along longitudinal direction are shown. Moreover, it is shown that longitudinal stress distribution is approximately corresponding to the theoretical stress distribution of double-lapped adhesively bonded joints. Based on these, it is proposed that joint strength can be estimated by using the present calculation method.

  15. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari; Gerard T. Pittard

    2005-01-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple cast-iron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1 (Program Management) and Task 2 (Establishment of Detailed Design Specifications) were completed in prior quarters while Task 3 (Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves) has progressed to installing prototype sleeves in cast-iron test pipe segments. Efforts in the current quarter continued to focus on Tasks 4-8. Highly valuable lessons were learned from field tests of the 4-inch gas pipe repair robot in cast-iron pipe at Public Service Electric & Gas. (These field tests were conducted and reported last quarter.) These tests identified several design issues which need to be implemented in both the small- and large

  16. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari; Gerard T. Pittard

    2004-11-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple castiron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1 (Program Management) and Task 2 (Establishment of Detailed Design Specifications) were completed in prior quarters while Task 3 (Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves) has progressed to installing prototype sleeves in cast iron test pipe segments. Efforts in this quarter continued to focus on Tasks 4-8, with significant progress made in each as well as field testing of the 4-inch gas pipe repair robot in cast iron pipe at Public Service Electric & Gas. The field tests were conducted August 23-26, 2004 in Oradell, New Jersey. The field tests identified several design issues which need to be implemented in both the small

  17. Review of research on the hygrothermal environmental durability of structural adhesively bonded joints

    Directory of Open Access Journals (Sweden)

    Xiao HAN

    2017-06-01

    Full Text Available In recent years, structural adhesive bonding technology has been widely used in many industrial fields, with many advantages over traditional mechanical connection methods, such as riveting, welding and bolt connection. Due to the adhesive characteristics of polymer materials, the environmental durability of adhesive joint becomes the key problems in engineering structure connection feasibility and long-term service reliability. On the basis of the review of the research of the hot-humid environmental durability of structural adhesive joints, the effects of temperature, moisture and coupled condition on the structural mechanical behaviour are discussed, introducing the published research progress and results both at home and abroad. The prospects are provided: the future research work can be combined with a variety of observation scales of environmental aging test and numerical simulation method, delve into sub hygroscopic, creep, thermal expansion and hygroscopic expansion aging behavior, such as the environment of model prediction method simulation in more than a variety of mechanical performance degradation behavior of coupling conditions, and provide more reliable theoretical modeling and experimental data for engineering design and application of cementing structure.

  18. محاكاة لوصلة ربط البراغي تحت تأثير قوة شد احادية وعوامل متغيرة

    Directory of Open Access Journals (Sweden)

    أناهيد حسين جبر

    2017-06-01

    Full Text Available This research aims to simulate preloaded bolted joint made of steel by finite element method (FEM by studying the structural response of bolted joint. The bolted joint is made up of two pieces shaped L , each piece is made up of vertical section fixed with horizontal section by Edge Weld method ,weld size is (5mm and they link by bolt (M30*3.5 ,it has been confirmed from weld size by using features (Weld Check Plot and ( Pin/bolt Check in Solid work Simulation to find out the accuracy of design result. Designed a widget on the maximum tensile strength unilateral exposed it the link to ward the top on the first piece of (20 KN has been installed the second piece from the bottom. In this research were studied torque pre-pregnancy bolt or (pre tensions torque with different values (588,882,1225 N.m on the structural response of the connection link, the study showed that the increase in pre-pregnancy bolt lead to a decrease in displacement between the end edges of the link-prone external download and installation and this confirms the increase in pre-pregnancy bolt increases the pressure on the two pieces and thus an increase in power to install and link connectivity and prevent its separation from each other. As it has been the study of stress and strain on the surface of the link connectivity and showed that the increase of pre-pregnancy screw increases stress especially in the vicinity of slot screw areas and emotions, either friction forces (Contact / Friction between the bolt and the surface of the interface in contact with him becoming more and increase the pre-load of the bolt, as well as broad this research impact of increased pre-pregnancy to bolt the welding area, which accounted for as (Beam where increasing stress the welding area, but not for large have been clarified all the forces acting on the welding area mentioned in the tables. Finally, research the reliability of simulation program , the analytical Solidwork Simulation, which

  19. Mechanical tests of the bolt of the gripper latch on the control rod cluster

    International Nuclear Information System (INIS)

    Lemaire, E.; Couet, D.; Molinie, D.; Grandjean, Y.; Radat, M.P.; Guttmann, D.

    1998-01-01

    Failure analysis and mechanical testing indicate that control rod drive mechanisms malfunctioning by 1995-96 is due to rupture by fatigue of a bolt inside the stationary gripper assembly. Fatigue is enhanced by free working following surface adaptation and unscrewing of the assembly. These results are taken into account for the choice of a new anti-rotation device. (authors)

  20. The use of hydraulic bolts for coupling in order to shorten the maintenance critical path in turbo generator sites; Uso de tornillos hidraulicos para acoplamiento a fin de acortar la ruta critica del mantenimiento en sitios de turbogeneradores

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Arelle, Carlos [Turbomaquinas S. A. de C.V., La Piedad, Michoacan (Mexico)

    2007-11-15

    The use of hydraulic bolts has permitted to diminish the time in the critical path of the maintenance, attaining to reduce the total costs and avoiding that some bolts are stuck, benefits the on time planning of the maintenance. The bolts of radial adjustment provide significant benefits to the General Turbine operator. The hydraulic bolts avoid the normal problems of the conventional coupling bolts and rapidly help to re-establish the couple concentricity. The bolts are individually designed to meet a specific geometry and are a direct replacement of the conventional bolts. [Spanish] El uso de tornillos hidraulicos ha permitido disminuir el tiempo de la ruta critica del mantenimiento, logrando reducir los costos totales y al evitar que algun tornillo se atore, beneficia la planeacion de mantenimientos a tiempo. Los tornillos de ajuste radial proveen beneficios significativos al operador de la Turbina General. Los tornillos hidraulicos eliminan los problemas normales de los tornillos de acoplamiento convencionales y rapidamente ayudan a restablecer la concentridad del cople. Los tornillos son disenados individualmente para completar una geometria especifica y son un reemplazo directo de los tornillos convencionales.

  1. Turning caring into business: the nuts and bolts of starting a private-duty home care business.

    Science.gov (United States)

    Smith, Cheryl

    2007-10-01

    As baby boomers age and home care grows in popularity as an alternative to institutionalized care, opportunities abound for entrepreneurs to meet the demand through professional private-duty businesses. This article examines the nuts and bolts of launching and operating a successful private-duty agency.

  2. Failure analysis of the stud bolt of a canned motor pump of heavy water plant, Talcher

    International Nuclear Information System (INIS)

    Kumar, Sunil; Sethumadhavan, V.; Sah, D.N.; Sivaramakrishnan, K.S.; Kain, Vivekanand; Gadiyar, H.S.

    1990-01-01

    Detailed investigations have been carried out on the failed stud bolts (made of DIN 1.4021 X 20Cr 13) of a canned motor pump of Heavy Water Plant, Talcher, using metallographic, microhardness testing, scanning electron microscopy and electron probe micro-analysis(EPMA) techniques. The studs had failed in a brittle manner in the mid-length portion. The origin of the fracture has been identified to be a corroded region on the stud surface. Branching cracks propagating through silicon rich inclusions have been noted. Two types of inclusions, one containing Mn and S and other containing S, Mn and O 2 have been found in the material. Clusters of large and small inclusions of the above types have been found near the origin of the fracture. It has been concluded that the fracture was caused by corrosion fatigue, initiating at the cluster of inclusions present on the surface of the stud bolts. (author). 7 refs., 5 figs

  3. Probability of detection for bolt hole eddy current in extracted from service aircraft wing structures

    Science.gov (United States)

    Underhill, P. R.; Uemura, C.; Krause, T. W.

    2018-04-01

    Fatigue cracks are prone to develop around fasteners found in multi-layer aluminum structures on aging aircraft. Bolt hole eddy current (BHEC) is used for detection of cracks from within bolt holes after fastener removal. In support of qualification towards a target a90/95 (detect 90% of cracks of depth a, 95% of the time) of 0.76 mm (0.030"), a preliminary probability of detection (POD) study was performed to identify those parameters whose variation may keep a bolt hole inspection from attaining its goal. Parameters that were examined included variability in lift-off due to probe type, out-of-round holes, holes with diameters too large to permit surface-contact of the probe and mechanical damage to the holes, including burrs. The study examined the POD for BHEC of corner cracks in unfinished fastener holes extracted from service material. 68 EDM notches were introduced into two specimens of a horizontal stabilizer from a CC-130 Hercules aircraft. The fastener holes were inspected in the unfinished state, simulating potential inspection conditions, by 7 certified inspectors using a manual BHEC setup with an impedance plane display and also with one inspection conducted utilizing a BHEC automated C-Scan apparatus. While the standard detection limit of 1.27 mm (0.050") was achieved, given the a90/95 of 0.97 mm (0.039"), the target 0.76 mm (0.030") was not achieved. The work highlighted a number of areas where there was insufficient information to complete the qualification. Consequently, a number of recommendations were made. These included; development of a specification for minimum probe requirements; criteria for condition of the hole to be inspected, including out-of-roundness and presence of corrosion pits; statement of range of hole sizes; inspection frequency and data display for analysis.

  4. Vibration-based testing of bolted joints

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel; Sah, Si Mohamed; Fidlin, Alexander

    2017-01-01

    hammer, whichtriggers measurement and data processing. However, experimental results revealed that this technique encounters twoproblems, for it to be presently useful in real applications: First the variability in results is too large, about twice that for a torque wrench. Figure 2(a) shows...

  5. A feasibility study for experimentally determining dynamic force distribution in a lap joint

    Energy Technology Data Exchange (ETDEWEB)

    Mayes, Randall Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2013-11-01

    Developing constitutive models of the physics in mechanical joints is currently stymied by inability to measure forces and displacements within the joint. The current state of the art estimates whole joint stiffness and energy loss per cycle from external measured force input and one or two acceleration responses. To validate constitutive models beyond this state requires a measurement of the distributed forces and displacements at the joint interface. Unfortunately, introducing measurement devices at the interface completely disrupts the desired physics. A feasibility study is presented for a non-intrusive method of solving for the interface dynamic forces from an inverse problem using full field measured responses. The responses come from the viewable surface of a beam. The noise levels associated with digital image correlation and continuous scanning laser Doppler velocimetry are evaluated from typical beam experiments. Two inverse problems are simulated. One utilizes the extended Sum of Weighted Accelerations Technique (SWAT). The second is a new approach dubbed the method of truncated orthogonal forces. These methods are much more robust if the contact patch geometry is well identified. Various approaches to identifying the contact patch are investigated, including ion marker tracking, Prussian blue and ultrasonic measurements. A typical experiment is conceived for a beam which has a lap joint at one end with a single bolt connecting it to another identical beam. In a virtual test using the beam finite element analysis, it appears that the SWAT inverse method requires evaluation of too many coefficients to adequately identify the force distribution to be viable. However, the method of truncated orthogonal forces appears viable with current digital image correlation (and probably other) imaging techniques.

  6. Low-Friction, Low-Profile, High-Moment Two-Axis Joint

    Science.gov (United States)

    Lewis, James L.; Le, Thang; Carroll, Monty B.

    2010-01-01

    The two-axis joint is a mechanical device that provides two-degrees-of-freedom motion between connected components. A compact, moment-resistant, two-axis joint is used to connect an electromechanical actuator to its driven structural members. Due to the requirements of the overall mechanism, the joint has a low profile to fit within the allowable space, low friction, and high moment-reacting capability. The mechanical arrangement of this joint can withstand high moments when loads are applied. These features allow the joint to be used in tight spaces where a high load capability is required, as well as in applications where penetrating the mounting surface is not an option or where surface mounting is required. The joint consists of one base, one clevis, one cap, two needle bearings, and a circular shim. The base of the joint is the housing (the base and the cap together), and is connected to the grounding structure via fasteners and a bolt pattern. Captive within the housing, between the base and the cap, are the rotating clevis and the needle bearings. The clevis is attached to the mechanical system (linear actuator) via a pin. This pin, and the rotational movement of the clevis with respect to the housing, provides two rotational degrees of freedom. The larger diameter flange of the clevis is sandwiched between a pair of needle bearings, one on each side of the flange. During the assembly of the two-axis joint, the circular shims are used to adjust the amount of preload that is applied to the needle bearings. The above arrangement enables the joint to handle high moments with minimal friction. To achieve the high-moment capability within a low-profile joint, the use of depth of engagement (like that of a conventional rotating shaft) to react moment is replaced with planar engagement parallel to the mounting surface. The needle bearings with the clevis flange provide the surface area to react the clevis loads/moments into the joint housing while providing minimal

  7. 77 FR 32698 - Proposed Extension of Existing Information Collection; Safety Standards for Roof Bolts in Metal...

    Science.gov (United States)

    2012-06-01

    ... are used to prevent the fall of roof, face, and rib. Advancements in technology of roof and rock bolts... information technology (e.g., permitting electronic submissions of responses), to minimize the burden of the...-0121. Affected Public: Business or other for-profit. Cite/Reference/Form/ etc. 30 CFR 56.3203, 57.3203...

  8. A Noble Approach of Process Automation in Galvanized Nut, Bolt Manufacturing Industry

    Directory of Open Access Journals (Sweden)

    Akash Samanta

    2012-05-01

    Full Text Available Corrosion costs money”, The Columbus battle institute estimates that corrosion costs Americans more than $ 220 billion annually, about 4.3% of the gross natural product [1].Now a days due to increase of pollution, the rate of corrosion is also increasing day-by-day mainly in India, so, to save the steel structures, galvanizing is the best and the simplest solution. Due to this reason galvanizing industries are increasing day-by-day since mid of 1700s.Galvanizing is a controlled metallurgical combination of zinc and steel that can provide a corrosion resistance in a wide variety of environment. In fact, the galvanized metal corrosion resistance factor can be some 70 to 80 times greater that the base metal material. Keeping in mind the importance of this industry, a noble approach of process automation in galvanized nut-bolt  manufacturing plant is presented here as nuts and bolts are the prime ingredient of any structure. In this paper the main objectives of any industry like survival, profit maximization, profit satisfying and sales growth are fulfilled. Furthermore the environmental aspects i.e. pollution control and energy saving are also considered in this paper. The whole automation process is done using programmable logic controller (PLC which has number of unique advantages like being faster, reliable, requires less maintenance and reprogrammable. The whole system has been designed and tested using GE, FANUC PLC.

  9. Cylindrically guided wave technique for detection of stress corrosion cracking and corrosion wastage in long stud-bolts

    International Nuclear Information System (INIS)

    Light, G.M.; Joshi, N.R.

    1986-01-01

    The authors discuss how, when performing an ultrasonic inspection of a cylindrical body, the sound waves, or pulses, will interact with the boundaries of the cylinder and produce mode-converted as well as normal longitudinal waves. The elastic energy of the wave propagating along the length of the cylinder is concentrated and produces strong echoes from shallow defects in the specimen. In threaded specimens, the guided wave produces signals from the threads that can be differentiated from defects in the cylinder. This paper reports on a study using the guided wave theory conducted to determine the optimum inspection transducer size and frequency relative to stud-bolt diameter and length. Bolts ranging from 25 to 285 cm (10 to 112 in.) in length and 2.5 to 11.5 cm (1 to 4.5 in.) in diameter were tested. For all cases, theoretical predictions agreed well with the experimental data. In this paper, the theory, experimental apparatus, and testing results are discussed

  10. Fracture of an industrial steam turbine horizontal joint nut upon tightening; Bruch der Mutter einer Horizontalteilfugenverschraubung einer Industriedampfturbine beim Anziehen

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Boromir; Giller, Madeleine; Neidel, Andreas; Riesenbeck, Susanne [Siemens AG - Gasturbinenwerk Berlin (Germany). Energy Sector Werkstoffprueflabor

    2017-11-01

    The nut of a horizontal joint fastener cracked upon tightening during assembly in an industrial steam turbine factory. It was previously used in an over-pressure test, but was otherwise not yet used in service. Nut and bolt were made of the nickel-based superalloy Nimonic 80A, a precipitation-hardenable wrought high-strength alloy with excellent creep and corrosion properties. Such alloys usually get a complex heat treatment after hot-rolling, comprising homogenizing and multiple ageing cycles. The subject nut failed due to an extreme case of mixed grain size which detrimentally affected mechanical properties and was attributed to an insufficient degree of deformation during hot rolling.

  11. Ultrasonic Detection of Small Crack in Studs[Bolts] by Time Difference of Thread Signals(TDTS)

    International Nuclear Information System (INIS)

    Suh, D. M.; Park, D. Y.; Kim, C. K.

    1990-01-01

    It is difficult to detect such flaws as stress - corrosion cracking or corrosion wastage(loss of bolt diameter) in the threads. In many cases the critical size of a flaw is very small(1-2 mm order). This paper describes how it is possible to discriminate small flaw indications in threads using the time difference or thread signals(TDTS) by a signal-conditioning technique

  12. A multi-feature integration method for fatigue crack detection and crack length estimation in riveted lap joints using Lamb waves

    Science.gov (United States)

    He, Jingjing; Guan, Xuefei; Peng, Tishun; Liu, Yongming; Saxena, Abhinav; Celaya, Jose; Goebel, Kai

    2013-10-01

    This paper presents an experimental study of damage detection and quantification in riveted lap joints. Embedded lead zirconate titanate piezoelectric (PZT) ceramic wafer-type sensors are employed to perform in situ non-destructive evaluation (NDE) during fatigue cyclical loading. PZT wafers are used to monitor the wave reflection from the boundaries of the fatigue crack at the edge of bolt joints. The group velocity of the guided wave is calculated to select a proper time window in which the received signal contains the damage information. It is found that the fatigue crack lengths are correlated with three main features of the signal, i.e., correlation coefficient, amplitude change, and phase change. It was also observed that a single feature cannot be used to quantify the damage among different specimens since a considerable variability was observed in the response from different specimens. A multi-feature integration method based on a second-order multivariate regression analysis is proposed for the prediction of fatigue crack lengths using sensor measurements. The model parameters are obtained using training datasets from five specimens. The effectiveness of the proposed methodology is demonstrated using several lap joint specimens from different manufactures and under different loading conditions.

  13. A multi-feature integration method for fatigue crack detection and crack length estimation in riveted lap joints using Lamb waves

    International Nuclear Information System (INIS)

    He, Jingjing; Guan, Xuefei; Peng, Tishun; Liu, Yongming; Saxena, Abhinav; Celaya, Jose; Goebel, Kai

    2013-01-01

    This paper presents an experimental study of damage detection and quantification in riveted lap joints. Embedded lead zirconate titanate piezoelectric (PZT) ceramic wafer-type sensors are employed to perform in situ non-destructive evaluation (NDE) during fatigue cyclical loading. PZT wafers are used to monitor the wave reflection from the boundaries of the fatigue crack at the edge of bolt joints. The group velocity of the guided wave is calculated to select a proper time window in which the received signal contains the damage information. It is found that the fatigue crack lengths are correlated with three main features of the signal, i.e., correlation coefficient, amplitude change, and phase change. It was also observed that a single feature cannot be used to quantify the damage among different specimens since a considerable variability was observed in the response from different specimens. A multi-feature integration method based on a second-order multivariate regression analysis is proposed for the prediction of fatigue crack lengths using sensor measurements. The model parameters are obtained using training datasets from five specimens. The effectiveness of the proposed methodology is demonstrated using several lap joint specimens from different manufactures and under different loading conditions. (paper)

  14. Upon bolting the GTR1 and GTR2 transporters mediate transport of glucosinolates to the inflorescence rather than roots

    DEFF Research Database (Denmark)

    Andersen, Tonni Grube; Halkier, Barbara Ann

    2014-01-01

    We recently described the glucosinolate transporters GTR1 and GTR2 as actively contributing to the establishment of tissue-specific distribution of the defense compounds glucosinolates in vegetative Arabidopsis plants. Upon bolting and thereby development of the inflorescence and initiation of seed...

  15. Numerical probabilistic analysis for slope stability in fractured rock masses using DFN-DEM approach

    Directory of Open Access Journals (Sweden)

    Alireza Baghbanan

    2017-06-01

    Full Text Available Due to existence of uncertainties in input geometrical properties of fractures, there is not any unique solution for assessing the stability of slopes in jointed rock masses. Therefore, the necessity of applying probabilistic analysis in these cases is inevitable. In this study a probabilistic analysis procedure together with relevant algorithms are developed using Discrete Fracture Network-Distinct Element Method (DFN-DEM approach. In the right abutment of Karun 4 dam and downstream of the dam body, five joint sets and one major joint have been identified. According to the geometrical properties of fractures in Karun river valley, instability situations are probable in this abutment. In order to evaluate the stability of the rock slope, different combinations of joint set geometrical parameters are selected, and a series of numerical DEM simulations are performed on generated and validated DFN models in DFN-DEM approach to measure minimum required support patterns in dry and saturated conditions. Results indicate that the distribution of required bolt length is well fitted with a lognormal distribution in both circumstances. In dry conditions, the calculated mean value is 1125.3 m, and more than 80 percent of models need only 1614.99 m of bolts which is a bolt pattern with 2 m spacing and 12 m length. However, as for the slopes with saturated condition, the calculated mean value is 1821.8 m, and more than 80 percent of models need only 2653.49 m of bolts which is equivalent to a bolt pattern with 15 m length and 1.5 m spacing. Comparison between obtained results with numerical and empirical method show that investigation of a slope stability with different DFN realizations which conducted in different block patterns is more efficient than the empirical methods.

  16. Structural safety test and analysis of type IP-2 transport packages with bolted lid type and thick steel plate for radioactive waste drums in a NPP

    International Nuclear Information System (INIS)

    Kim, Dong Hak; Seo, Ki Seog; Lee, Sang Jin; Lee, Kyung Ho; Kim, Jeong Mook

    2007-01-01

    If a type IP-2 transport package were to be subjected to a free drop test and a penetration test under the normal conditions of transport, it should prevent a loss or dispersal of the radioactive contents and a more than 20% increase in the maximum radiation level at any external surface of the package. In this paper, we suggested the analytic method to evaluate the structural safety of a type IP-2 transport package using a thick steel plate for a structure part and a bolt for tying a bolt. Using an analysis a loss or disposal of the radioactive contents and a loss of shielding integrity were confirmed for two kinds of type IP-2 transport packages to transport radioactive waste drums from a waste facility to a temporary storage site in a nuclear power plant. Under the free drop condition the maximum average stress at the bolts and the maximum opening displacement of a lid were compared with the tensile stress of a bolt and the steps in a lid, which were made to avoid a streaming radiation in the shielding path, to evaluate a loss or dispersal of radioactive waste contents. Also a loss of shielding integrity was evaluated using the maximum decrease in a shielding thickness. To verify the impact dynamic analysis for free drop test condition and evaluate experimentally the safety of two kinds of type IP-2 transport packages, free drop tests were conducted with various drop directions

  17. SCC life estimation based on cracks initiated from the corrosion pits of bolting material SCM435 used in steam turbine

    International Nuclear Information System (INIS)

    Itoh, Hitomi; Ochi, Mayumi; Fujiwara, Isao; Momoo, Takashi

    2003-01-01

    Life estimation was performed for the stress corrosion cracking (SCC) that occurs in deaerated and wet hot pure steam at the bottoms of the threads of bolts made of SCM435 (equivalent to AISI 4137) used in steam turbine. SCC is believed to occur when corrosion pits are formed and grow to critical size, after which SCC is initiated and cracks propagate until the critical fracture toughness value is reached. Calculations were performed using laboratory and field data. The results showed that, for a 40mm diameter bolt with 0.2% offset strength of 820MPa, the critical crack depth for straight-front cracks was 5.4mm. The SCC life depends on the lubricant used; the SCC life estimated from this value is approximately 70,000 hours when graphite is used as a lubricant. (author)

  18. Design and Analytical Evaluation of a New Self-Centering Connection with Bolted T-Stub Devices

    Directory of Open Access Journals (Sweden)

    Mahbobeh Mirzaie Aliabadi

    2013-01-01

    Full Text Available A new posttensioned T-stub connection (PTTC for earthquake resistant steel moment resisting frames (MRFs is introduced. The proposed connection consists of high strength posttensioned (PT strands and bolted T-stubs. The post-tensioning strands run through the column and are anchored against the flange of the exterior column. The T-stubs, providing energy dissipation, are bolted to the flange of beam and column and no field welding is required. The strands compress the T-stub against the column flange to develop the resisting moment to service loads and to provide a restoring force that returns the structure to its initial position following an earthquake. An analytical model based on fiber elements is developed in OpenSees to model PTTCs. The analytical model can predict the expected behavior of the new proposed connection under cyclic loading. PTTC provides similar characteristic behavior of the posttensioned connections. Both theoretical behavior and design methods are proposed, and the design methods are verified based on parametric studies and comparison to analytical results. The parametric studies prove the desired self-centering behavior of PTTC and show that this connection can reduce or eliminate the plastic rotation by its self-centering behavior as well as providing required strength and stiffness under large earthquake rotations.

  19. Application of shape memory alloys in bolted flanged connections

    International Nuclear Information System (INIS)

    Zhu Shichun; Lu Xiaofeng

    2009-01-01

    The Shape Memory Effect (SME) and super elasticity of the Shape Memory Alloys (SMA) can make up the clamping force decreasing caused by the creep and relaxation behavior in Bolted Flanged Connections (BFC), and improve the reliability of the BFC. Advances in the research of SMA in BFC home and abroad is summarized in this paper. The application prospects of Ti-Ni-Pd, Ti-Ni-Hf, Fe-Mn-Si, Cu-Al-Ni and Ni-Al-Mn in the BFC are also discussed. It is considered that the compressive characteristics of the parent phase of SMA should be studied further for the application of SMA to BFC besides the design of sealing structure. When more basic research data is accumulated, BFC with high sealing performance for the critical engineering applications can be developed based on the comprehensive consideration of the stability and reliability of the clamping force. (authors)

  20. Development of rock bolt grout and shotcrete for rock support and corrosion of steel in low-pH cementitious materials

    Energy Technology Data Exchange (ETDEWEB)

    Boden, Anders (Vattenfall Power Consultant AB, Vaellingby (Sweden)); Pettersson, Stig (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden))

    2011-04-15

    It is foreseen that cementitious products will be utilized in the construction of the final repository. The use of conventional cementitious material creates pulses in the magnitude of pH 12.13 in the leachates and release alkalis. Such a high pH is detrimental mainly to impairment of bentonite functioning, but also to possibly enhanced dissolution of spent fuel and alteration of fracture filling materials. It also complicates the safety analysis of the repository, as the effect of a high pH-plume should be considered in the evaluation. As no reliable pH-plume models exist, the use of products giving a pH below 11 in the leachates facilitates the safety analysis, although limiting the amount of low-pH cement is recommended. In earlier studies it was found that shotcreting, standard casting and rock bolting with low-pH cement (pH . 11 in the leachate) should be possible without any major development work. This report summarizes the results of development work done during 2008 and 2009 in the fields of low-pH rock bolt grout, low-pH shotcrete and steel corrosion in low-pH concrete. Development of low-pH rock bolt grout mixes and laboratory testing of the selected grout was followed by installation of twenty rock bolts for rock support at Aspo HRL using the chosen low-pH grout. The operation was successful and the bolts and grout are subject to follow up the next ten years. Low-pH shotcrete for rock support was initially developed within the ESDRED project, which was an Integrated Project within the European Commission sixth framework for research and technological development. ESDRED is an abbreviation for Engineering Studies and Demonstrations of Repository Designs. ESDRED was executed from 1st February 2004 to 31st January 2009. The development of the mix design described in this report was based on the results from ESDRED. After laboratory testing of the chosen mix, it was field tested in niche NASA 0408A at Aspo HRL. Further, some areas in the TASS-tunnel were

  1. Development of rock bolt grout and shotcrete for rock support and corrosion of steel in low-pH cementitious materials

    International Nuclear Information System (INIS)

    Boden, Anders; Pettersson, Stig

    2011-04-01

    It is foreseen that cementitious products will be utilized in the construction of the final repository. The use of conventional cementitious material creates pulses in the magnitude of pH 12.13 in the leachates and release alkalis. Such a high pH is detrimental mainly to impairment of bentonite functioning, but also to possibly enhanced dissolution of spent fuel and alteration of fracture filling materials. It also complicates the safety analysis of the repository, as the effect of a high pH-plume should be considered in the evaluation. As no reliable pH-plume models exist, the use of products giving a pH below 11 in the leachates facilitates the safety analysis, although limiting the amount of low-pH cement is recommended. In earlier studies it was found that shotcreting, standard casting and rock bolting with low-pH cement (pH . 11 in the leachate) should be possible without any major development work. This report summarizes the results of development work done during 2008 and 2009 in the fields of low-pH rock bolt grout, low-pH shotcrete and steel corrosion in low-pH concrete. Development of low-pH rock bolt grout mixes and laboratory testing of the selected grout was followed by installation of twenty rock bolts for rock support at Aspo HRL using the chosen low-pH grout. The operation was successful and the bolts and grout are subject to follow up the next ten years. Low-pH shotcrete for rock support was initially developed within the ESDRED project, which was an Integrated Project within the European Commission sixth framework for research and technological development. ESDRED is an abbreviation for Engineering Studies and Demonstrations of Repository Designs. ESDRED was executed from 1st February 2004 to 31st January 2009. The development of the mix design described in this report was based on the results from ESDRED. After laboratory testing of the chosen mix, it was field tested in niche NASA 0408A at Aspo HRL. Further, some areas in the TASS-tunnel were

  2. How joint characteristics between a piezoelectric beam and the main structure affect the performance of an energy harvester

    Science.gov (United States)

    Jahani, K.; Rafiei, M. M.; Aghazadeh, P.

    2017-09-01

    In this paper, the influence of the joint region between a piezoelectric energy harvesting beam and the vibratory main structure is studied. The investigations are conducted in two separate sections, namely numerical and experimental studies. In numerical studies, the effects of nonlinear parameters on generated power are investigated while the joint characteristics the between vibrating base and a piezoelectric energy harvester are taken into consideration. A unimorph beam with a tip mass and a nonlinear piezoelectric layer that undergoes a large-amplitude deflection is considered as an energy harvester. By applying the Euler-Lagrange equation and Gauss’s law the mechanical and electrical equations of motion are obtained, respectively. The excitation frequency is assumed to be close to the first natural frequency. Thus, a unimodal response is considered to be like that of a system with a single degree of freedom (SDOF). The joint between the vibrating main structure and the cantilevered beam is then added to the SDOF model. The joint characteristics are simulated with a light mass, mj , linear spring stiffness, kj , and equivalent viscous damper, cj . In two scenarios, i.e. with a rigid joint and with a flexible one, a numerical approach is followed to investigate the effects of each nonlinear parameter of the harvester (stiffness, damping and piezoelectric coefficient) on the harvested power. In experimental studies, the influence of a bolted joining technique and a flexible adhesive bonding method on the harvested power is investigated. The results achieved experimentally confirm those obtained numerically, i.e. a stiffer joint leads to a greater power produced by the harvester. In other words, neglecting the joint characteristics will cause the performance (maximum output power and the range of excitation frequency) of the harvester to be overestimated in numerical simulations.

  3. European development Rock bolting; Desarrollo Europeo del Bulonaje

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-01

    The project European Development Rockbolting which was developed during the period 1994-1997 and carried out within the OCICARBON Action Program (OCICARBON-ITGE agreement dated September 1, 1994, Code C-13-438) as well as within the framework of the Coal Technical research Program of the D. G. XVII of the EEC, n 7220/AB/143. The project has had the following external partners: DMT (Germany), BCC (UK) and CDF (France), and the collaboration of INERIS (France), RMT (UK) and GEOCONTROL S. A. (Spain). The objective of the investigation was to improve the techniques and design currently used in the application of rockbolts for supporting of both infrastructure and beds in the European coal mining. The most important result, besides that derived from the sharing of experiences and knowledge, was the technological design of a supporting system, which was carried out by each partner for the various proposed exploitations. The Spanish part carried out the works of designing and estimation of the bolting system corresponding to the exploitations of: -Carbones de Pedraforca SA. Saldes mine. -U. E. Provence. Pit Y. Morandat.

  4. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari; Gerard T. Pittard

    2005-04-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple cast-iron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of old cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1 (Program Management) and Task 2 (Establishment of Detailed Design Specifications) were completed previously. Task 3 (Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves) has progressed to installing prototype sleeves in test cast-iron pipe segments. Efforts in the current quarter continued to be focused on Tasks 4-8. Highly valuable lessons were learned from field tests of the 4-inch gas pipe repair robot in cast-iron pipe at Public Service Electric & Gas. (These field tests were conducted and reported previously.) Several design issues were identified which need to be implemented in both the small- and large-diameter repair

  5. Integrity of Bolted Angle Connections Subjected to Simulated Column Removal

    Science.gov (United States)

    Weigand, Jonathan M.; Berman, Jeffrey W.

    2016-01-01

    Large-scale tests of steel gravity framing systems (SGFSs) have shown that the connections are critical to the system integrity, when a column suffers damage that compromises its ability to carry gravity loads. When supporting columns were removed, the SGFSs redistributed gravity loads through the development of an alternate load path in a sustained tensile configuration resulting from large vertical deflections. The ability of the system to sustain such an alternate load path depends on the capacity of the gravity connections to remain intact after undergoing large rotation and axial extension demands, for which they were not designed. This study experimentally evaluates the performance of steel bolted angle connections subjected to loading consistent with an interior column removal. The characteristic connection behaviors are described and the performance of multiple connection configurations are compared in terms of their peak resistances and deformation capacities. PMID:27110059

  6. Application of the cylindrically guided wave technique for bolt and pump shaft inspections

    International Nuclear Information System (INIS)

    Light, G.M.; Ruescher, E.H.; Bloom, E.A.; Joshi, N.R.; Tsai, Y.M.; Liu, S.N.

    1993-01-01

    Elastic wave propagation in a bounded medium significantly differs from that in an unbounded medium. The bounded medium in the form of a cylinder acts like a solid waveguide directing the wave with its geometry. A continuous or a pulsed wave interacts with cylindrical boundaries producing mode-converted signals in addition to the backwall echo. The signals are received at constant time intervals directly proportional to the diameter of a solid cylindrical object such as a bolt or an anchor stud. The Cylindrically Guided Wave Technique (CGWT) makes intelligent use of the mode-converted signals, or trailing pulses, to detect corrosion wastages and cracks in cylindrical objects. (orig.)

  7. INFORMATION FOR USERS OF NUTS, BOLTS, SCREWS, NAILS AND RIVETS (SCEM GROUP 47)

    CERN Multimedia

    Logistics Group

    2002-01-01

    We should like to remind users that, since the closure of the self-service stores, nuts, bolts, screws, nails and rivets (Group 47 of the Stores Catalogue) can be obtained, in smaller packages than via EDH, from the 'Emergency Counter' in the Central Stores (Building 73, R-002) upon presentation of a duly completed hard-copy Materials Request form. The 'Emergency Counter' is open Mondays to Fridays from 7.30 a.m. to 11.50 a.m. and from 1.00 p.m. to 4.20 p.m. Information concerning the available packages can be found under the appropriate SCEM reference number in the Stores Catalogue. Logistics Group SPL Division

  8. Behavior of Equipment Support Beam Joint Directly Connected to A Steel-plate Concrete(SC) Wall

    International Nuclear Information System (INIS)

    Kim, K. S.; Kwon, K. J.

    2008-01-01

    To decrease the time for building nuclear power plants, a modular construction method, 'Steel-plate Concrete(SC)', has been investigated for over a decade. To construct a SC wall, a pair of steel plates are placed in parallel similar to a form-work in conventional reinforced concrete (RC) structures, and concrete is filled between the steel plates. Instead of removing the steel plates after the concrete has cured, the steel plates serve as components of the structural member. The exposed steel plate of SC structures serves as the base plate for the equipment support, and the headed studs welded to the steel plates are used as anchor bolts. Then, a support beam can be directly welded to the surface of the steel plate in any preferred position. In this study, we discuss the behavior and evaluation method of the equipment support joint directly connected to exposed steel plate of SC wall

  9. Analysis of the Seismic Performance of Site-Bolted Beam to Column Connections in Modularized Prefabricated Steel Structures

    Directory of Open Access Journals (Sweden)

    Xuechun Liu

    2017-01-01

    Full Text Available This paper proposes a site-bolted connection that is suitable for modularized prefabricated steel structures. Excellent ductility is achieved by various structural measures. Six connection specimens with different parameters were subjected to quasi-static loading tests and finite element analysis (FEA to determine the seismic performance of the proposed connection (e.g., hysteretic behavior, skeleton curve, ductility, and failure mode. The results of the tests and FEA showed that the connection underwent sufficient plastic deformation under cyclic loading and that its ultimate rotation angle could reach 0.09 rad. A clear plastic hinge formed on the beam before the connection failed, which suggests a ductile failure mode. The connection exhibited a wide hysteresis loop, which indicated good seismic performance. The results also showed that the connection does not slip under small earthquakes and could dissipate energy through slippage in the connection region under a moderate earthquake and through slippage in the connection region as well as plastic deformation at the beam end under a severe earthquake. The number of bolts was the main parameter that affected the seismic performance of the connection. The test and FEA results demonstrated that all six specimens had excellent seismic and ductile performance and an exceptional plastic rotation capacity.

  10. Examination of pulsed eddy current for inspection of second layer aircraft wing lap-joint structures using outlier detection methods

    Energy Technology Data Exchange (ETDEWEB)

    Butt, D.M., E-mail: Dennis.Butt@forces.gc.ca [Royal Military College of Canada, Dept. of Chemistry and Chemical Engineering, Kingston, Ontario (Canada); Underhill, P.R.; Krause, T.W., E-mail: Thomas.Krause@rmc.ca [Royal Military College of Canada, Dept. of Physics, Kingston, Ontario (Canada)

    2016-09-15

    Ageing aircraft are susceptible to fatigue cracks at bolt hole locations in multi-layer aluminum wing lap-joints due to cyclic loading conditions experienced during typical aircraft operation, Current inspection techniques require removal of fasteners to permit inspection of the second layer from within the bolt hole. Inspection from the top layer without fastener removal is desirable in order to minimize aircraft downtime while reducing the risk of collateral damage. The ability to detect second layer cracks without fastener removal has been demonstrated using a pulsed eddy current (PEC) technique. The technique utilizes a breakdown of the measured signal response into its principal components, each of which is multiplied by a representative factor known as a score. The reduced data set of scores, which represent the measured signal, are examined for outliers using cluster analysis methods in order to detect the presence of defects. However, the cluster analysis methodology is limited by the fact that a number of representative signals, obtained from fasteners where defects are not present, are required in order to perform classification of the data. Alternatively, blind outlier detection can be achieved without having to obtain representative defect-free signals, by using a modified smallest half-volume (MSHV) approach. Results obtained using this approach suggest that self-calibrating blind detection of cyclic fatigue cracks in second layer wing structures in the presence of ferrous fasteners is possible without prior knowledge of the sample under test and without the use of costly calibration standards. (author)

  11. Examination of pulsed eddy current for inspection of second layer aircraft wing lap-joint structures using outlier detection methods

    International Nuclear Information System (INIS)

    Butt, D.M.; Underhill, P.R.; Krause, T.W.

    2016-01-01

    Ageing aircraft are susceptible to fatigue cracks at bolt hole locations in multi-layer aluminum wing lap-joints due to cyclic loading conditions experienced during typical aircraft operation, Current inspection techniques require removal of fasteners to permit inspection of the second layer from within the bolt hole. Inspection from the top layer without fastener removal is desirable in order to minimize aircraft downtime while reducing the risk of collateral damage. The ability to detect second layer cracks without fastener removal has been demonstrated using a pulsed eddy current (PEC) technique. The technique utilizes a breakdown of the measured signal response into its principal components, each of which is multiplied by a representative factor known as a score. The reduced data set of scores, which represent the measured signal, are examined for outliers using cluster analysis methods in order to detect the presence of defects. However, the cluster analysis methodology is limited by the fact that a number of representative signals, obtained from fasteners where defects are not present, are required in order to perform classification of the data. Alternatively, blind outlier detection can be achieved without having to obtain representative defect-free signals, by using a modified smallest half-volume (MSHV) approach. Results obtained using this approach suggest that self-calibrating blind detection of cyclic fatigue cracks in second layer wing structures in the presence of ferrous fasteners is possible without prior knowledge of the sample under test and without the use of costly calibration standards. (author)

  12. Investigation on the Influence of Abutment Pressure on the Stability of Rock Bolt Reinforced Roof Strata Through Physical and Numerical Modeling

    Science.gov (United States)

    Kang, Hongpu; Li, Jianzhong; Yang, Jinghe; Gao, Fuqiang

    2017-02-01

    In underground coal mining, high abutment loads caused by the extraction of coal can be a major contributor to many rock mechanic issues. In this paper, a large-scale physical modeling of a 2.6 × 2.0 × 1.0 m entry roof has been conducted to investigate the fundamentals of the fracture mechanics of entry roof strata subjected to high abutment loads. Two different types of roof, massive roof and laminated roof, are considered. Rock bolt system has been taken into consideration. A distinct element analyses based on the physical modeling conditions have been performed, and the results are compared with the physical results. The physical and numerical models suggest that under the condition of high abutment loads, the massive roof and the laminated roof fail in a similar pattern which is characterized as vertical tensile fracturing in the middle of the roof and inclined shear fracturing initiated at the roof and rib intersections and propagated deeper into the roof. Both the massive roof and the laminated roof collapse in a shear sliding mode shortly after shear fractures are observed from the roof surface. It is found that shear sliding is a combination of tensile cracking of intact rock and sliding on bedding planes and cross joints. Shear sliding occurs when the abutment load is much less than the compressive strength of roof.

  13. Finite element analysis of an extended end-plate connection using the T-stub approach

    Energy Technology Data Exchange (ETDEWEB)

    Muresan, Ioana Cristina; Balc, Roxana [Technical University of Cluj-Napoca, Faculty of Civil Engineering. 15 C Daicoviciu Str., 400020, Cluj-Napoca (Romania)

    2015-03-10

    Beam-to-column end-plate bolted connections are usually used as moment-resistant connections in steel framed structures. For this joint type, the deformability is governed by the deformation capacity of the column flange and end-plate under tension and elongation of the bolts. All these elements around the beam tension flange form the tension region of the joint, which can be modeled by means of equivalent T-stubs. In this paper a beam-to-column end-plate bolted connection is substituted with a T-stub of appropriate effective length and it is analyzed using the commercially available finite element software ABAQUS. The performance of the model is validated by comparing the behavior of the T-stub from the numerical simulation with the behavior of the connection as a whole. The moment-rotation curve of the T-stub obtained from the numerical simulation is compared with the behavior of the whole extended end-plate connection, obtained by numerical simulation, experimental tests and analytical approach.

  14. Impact of Different Standard Type A7A Drum Closure-Ring Practices on Gasket Contraction and Bolt Closure Distance– 15621

    Energy Technology Data Exchange (ETDEWEB)

    Ketusky, Edward [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Blanton, Paul [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Bobbitt, John H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-03-11

    The Department of Energy, the Savannah River National Laboratory, several manufacturers of specification drums, and the United States Department of Transportation (DOT) are collaborating in the development of a guidance document for DOE contractors and vendors who wish to qualify containers to DOT 7A Type A requirements. Currently, the effort is focused on DOT 7A Type A 208-liter (55-gallons) drums with a standard 12-gauge bolted closure ring. The U.S. requirements, contained in Title 49, Part 178.350 “Specification 7A; general packaging, Type A specifies a competent authority review of the packaging is not required for the transport of (Class 7) radioactive material containing less than Type A quantities of radioactive material. For Type AF drums, a 4 ft. regulatory free drop must be performed, such that the drum “suffers maximum damage.” Although the actual orientation is not defined by the specification, recent studies suggest that maximum damage would result from a shallow angle top impact, where kinetic energy is transferred to the lid, ultimately causing heavy damage to the lid, or even worse, causing the lid to come off. Since each vendor develops closure recommendations/procedures for the drums they manufacture, key parameters applied to drums during closing vary based on vendor. As part of the initial phase of the collaboration, the impact of the closure variants on the ability of the drum to suffer maximum damage is investigated. Specifically, closure testing is performed varying: 1) the amount of torque applied to the closure ring bolt; and, 2) stress relief protocol, including: a) weight of hammer; and, b) orientation that the hammer hits the closure ring. After closure, the amount of drum lid gasket contraction and the distance that the closure bolt moves through the closure ring is measured.

  15. Fuel element clusters for nuclear reactors

    International Nuclear Information System (INIS)

    Anthony, A.J.; Hutchinson, J.J.

    1975-01-01

    In the fuel element assembly for nuclear reactors the influence of temperature cycles upon the stability of the joints between the individual components, especially between the control rod guide tubes and the connecting rods and end plates, respectively, is reduced. For this purpose, the connection is designed as a bolted connection connecting, on the one hand, the guide tubes and guide bolts and, on the other hand, these two components and the end plates. Moreover, the materials of the guide tubes, bolts and end plates are selected so that their respective thermal expansion coefficients differ. The material which can be used for the end plates and the guide bolts is stainless steel and stainless steel plus inconel (nickel-chrome-iron alloy), respectively; for the guide tubes it is a zirconium alloy (zircaloy). In addition to some technical designs of the bolted connections the materials and lengths of the components are selected in such a way that the expansion path of the components held by a bolted connection is equal to that of the stressing part. (DG/RF) [de

  16. On the Process-Related Rivet Microstructural Evolution, Material Flow and Mechanical Properties of Ti-6Al-4V/GFRP Friction-Riveted Joints

    Science.gov (United States)

    Borba, Natascha Z.; Afonso, Conrado R. M.; Blaga, Lucian; dos Santos, Jorge F.; Canto, Leonardo B.; Amancio-Filho, Sergio T.

    2017-01-01

    In the current work, process-related thermo-mechanical changes in the rivet microstructure, joint local and global mechanical properties, and their correlation with the rivet plastic deformation regime were investigated for Ti-6Al-4V (rivet) and glass-fiber-reinforced polyester (GF-P) friction-riveted joints of a single polymeric base plate. Joints displaying similar quasi-static mechanical performance to conventional bolted joints were selected for detailed characterization. The mechanical performance was assessed on lap shear specimens, whereby the friction-riveted joints were connected with AA2198 gussets. Two levels of energy input were used, resulting in process temperatures varying from 460 ± 130 °C to 758 ± 56 °C and fast cooling rates (178 ± 15 °C/s, 59 ± 15 °C/s). A complex final microstructure was identified in the rivet. Whereas equiaxial α-grains with β-phase precipitated in their grain boundaries were identified in the rivet heat-affected zone, refined α′ martensite, Widmanstätten structures and β-fleck domains were present in the plastically deformed rivet volume. The transition from equiaxed to acicular structures resulted in an increase of up to 24% in microhardness in comparison to the base material. A study on the rivet material flow through microtexture of the α-Ti phase and β-fleck orientation revealed a strong effect of shear stress and forging which induced simple shear deformation. By combining advanced microstructural analysis techniques with local mechanical testing and temperature measurement, the nature of the complex rivet plastic deformational regime could be determined. PMID:28772545

  17. On the Process-Related Rivet Microstructural Evolution, Material Flow and Mechanical Properties of Ti-6Al-4V/GFRP Friction-Riveted Joints

    Directory of Open Access Journals (Sweden)

    Natascha Z. Borba

    2017-02-01

    Full Text Available In the current work, process-related thermo-mechanical changes in the rivet microstructure, joint local and global mechanical properties, and their correlation with the rivet plastic deformation regime were investigated for Ti-6Al-4V (rivet and glass-fiber-reinforced polyester (GF-P friction-riveted joints of a single polymeric base plate. Joints displaying similar quasi-static mechanical performance to conventional bolted joints were selected for detailed characterization. The mechanical performance was assessed on lap shear specimens, whereby the friction-riveted joints were connected with AA2198 gussets. Two levels of energy input were used, resulting in process temperatures varying from 460 ± 130 °C to 758 ± 56 °C and fast cooling rates (178 ± 15 °C/s, 59 ± 15 °C/s. A complex final microstructure was identified in the rivet. Whereas equiaxial α-grains with β-phase precipitated in their grain boundaries were identified in the rivet heat-affected zone, refined α′ martensite, Widmanstätten structures and β-fleck domains were present in the plastically deformed rivet volume. The transition from equiaxed to acicular structures resulted in an increase of up to 24% in microhardness in comparison to the base material. A study on the rivet material flow through microtexture of the α-Ti phase and β-fleck orientation revealed a strong effect of shear stress and forging which induced simple shear deformation. By combining advanced microstructural analysis techniques with local mechanical testing and temperature measurement, the nature of the complex rivet plastic deformational regime could be determined.

  18. Ground Support Strategies at the Turquoise Ridge Joint Venture, Nevada

    Science.gov (United States)

    Sandbak, L. A.; Rai, A. R.

    2013-05-01

    Weak rock masses of high grade Carlin-trend gold mineralization are encountered in the Turquoise Ridge Joint Venture underground mine. The sediments consist of very weak and altered limestone, mudstone, and carbon-rich clays. The rock mass ratings are described as very poor to poor (Bieniawski in Proceedings of the symposium on exploration for rock engineering, Johannesburg, South Africa, pp. 97-106, 1976). The undercut and fill or boxes stoping mining methods are used because of the low dipping ore body geometry, complex geology, and weak rock mass. Design criteria are chosen to keep openings in weak rock as small as possible to prevent unraveling and to minimize supplementary support. Typical ground support for drifting includes the use of bolts, mesh, spiling, and shotcrete. Quality control of cemented rock fill (CRF) through sampling and aggregate sieve testing is necessary to insure high support strength. Specific support may include shotcrete arches with steel ring sets and CRF "arches" as a replacement of weak rock masses around long-term mine openings. Movement monitoring is utilized in problem areas and is needed to quantify and validate computer modeling.

  19. Development of an eddy current inspection technique for sleeved engine disk bolt holes

    International Nuclear Information System (INIS)

    Palanisamy, R.; Lakin, K.M.

    1983-01-01

    Recent research programs have concentrated mainly on developing techniques to characterize surface breaking cracks and very little has been done towards characterizing subsurface flaws in conducting materials. Presented in this paper are the results of some initial theoretical work aimed at the development of a reliable eddy current technique to detect and characterize defects in engine disk bolt holes under a 0.05'' stainless steel sleeve. The change in impedance of an absolute eddy current coil with and without ferrite core, and the distribution of eddy currents around a second layer crack with and without a thin insulating film between the two conducting layers have been predicted numerically. The overall system development goals and methods to accomplish them are outlined briefly

  20. Structural health monitoring for bolt loosening via a non-invasive vibro-haptics human-machine cooperative interface

    Science.gov (United States)

    Pekedis, Mahmut; Mascerañas, David; Turan, Gursoy; Ercan, Emre; Farrar, Charles R.; Yildiz, Hasan

    2015-08-01

    For the last two decades, developments in damage detection algorithms have greatly increased the potential for autonomous decisions about structural health. However, we are still struggling to build autonomous tools that can match the ability of a human to detect and localize the quantity of damage in structures. Therefore, there is a growing interest in merging the computational and cognitive concepts to improve the solution of structural health monitoring (SHM). The main object of this research is to apply the human-machine cooperative approach on a tower structure to detect damage. The cooperation approach includes haptic tools to create an appropriate collaboration between SHM sensor networks, statistical compression techniques and humans. Damage simulation in the structure is conducted by releasing some of the bolt loads. Accelerometers are bonded to various locations of the tower members to acquire the dynamic response of the structure. The obtained accelerometer results are encoded in three different ways to represent them as a haptic stimulus for the human subjects. Then, the participants are subjected to each of these stimuli to detect the bolt loosened damage in the tower. Results obtained from the human-machine cooperation demonstrate that the human subjects were able to recognize the damage with an accuracy of 88 ± 20.21% and response time of 5.87 ± 2.33 s. As a result, it is concluded that the currently developed human-machine cooperation SHM may provide a useful framework to interact with abstract entities such as data from a sensor network.

  1. A 3D regression surface for the room temperature tightness gasket data reduction and bolt load design

    International Nuclear Information System (INIS)

    Jolly, Pascal; Marchand, Luc

    2008-01-01

    The purpose of the present work is to propose a new approach for modelling the tightness behaviour of the gaskets used in bolted flange joints. This new approach consists of developing a mathematical model for a three-dimensional (3D) representation of the gasket tightness performance. Rather than considering a 2D graph for characterizing the complete gasket behaviour, a third axis is added to the S g vs. Tp plot to dissociate the unloading cycles from initial gasket tightening. This leads to the definition of a surface that is represented by a simple polynomial equation that contains six coefficients that are determined by a simple regression calculation. In the first part of the paper, the new approach is tested through a database of 406 room temperature tightness (ROTT) tests performed on different gasket styles. Then, a statistical analysis of the predictions made with the new model demonstrates its ability to predict gasket leak rates much more accurately than it was previously possible with the gasket constants derived from the ROTT Draft 9 or 10 methods. It is also demonstrated that the new approach can be used to model successfully complex gasket behaviours such as the tightness hardening phenomenon. Secondly, the effect of gas pressure change on the leak rate is analysed. It turns out that at high gasket stresses, the actual scheme of the ROTT tests may not allow enough time for reaching a stabilized leak rate value because of a transitory time effect in the porous structure of gaskets. Then, in order to evaluate the characteristic waiting period (dwell time) before a stabilized flow rate is achieved following a change in the gas pressure level, a simple phenomenological analysis of the flow is performed

  2. A modeling study of dynamic characteristic analysis of isolated structure for seismic exciting tests

    International Nuclear Information System (INIS)

    Lee, Jae Han; Koo, G. H.; Yoo, Bong

    1998-04-01

    The fundamental frequency of the isolated superstructure for seismic exciting tests was calculated by 16 Hz with a initial modal analysis model. but the actual modal test resulted in 5 Hz. This large difference was resulted from some uncertainties in analysis modeling of several connection parts between column and upper beam, cross bars of each face of the isolated superstructure. When the stiffness of cross-bars are larger than certain level in all the analyses, the joint stiffness between main slab and columns does not effect to the fundamental frequency. So the fundamental frequency of the isolated superstructure was governed by the cross-bar's stiffness. In actual tests the first and second frequencies show a little difference regardless of the cross section characteristics (inertia moments) of four columns because the joint stiffness between column and main slab is less than 10 8 1b f in/radian. The mounting device of each column to main slab, and the bolting device of each column to upper beam are fabricated with lower stiffness compared to design value. The bolting of cross-bars and the fitness of bolt-hole to bolt were loosed during the modal tests. In the future the tight connecting and the precise assembling of isolated superstructure are required to reduce the difference of the fundamental frequencies obtained from the modal analysis and actual test. (author). 4 refs

  3. Use of a Non-Penetrating Captive Bolt for Euthanasia of Neonate Goats

    Directory of Open Access Journals (Sweden)

    Andrew Grist

    2018-04-01

    Full Text Available A non-penetrating captive bolt device, powered by a 1 grain 0.22″ cartridge delivering a calculated kinetic energy of 47 Joules was tested as a euthanasia method on 200 neonate goats (Capra aegagrus hircus of mean dead weight = 4.425 kg (SD (Standard deviation ± 0.4632, to assess effectiveness and shot position. Evaluation of the method was conducted using behavioural indicators of brain dysfunction followed by post mortem examination of the heads. Once correct shot position had been established, 100% of 158 kids (95% confidence interval 97.5% to 100% were successfully stunned/killed with a shot positioned on the midline, between the ears, with the chin tucked into the neck. The use of the Accles and Shelvoke CASH Small Animal Tool can therefore be recommended for the euthanasia of neonate goats with a 1 grain cartridge and a specific shooting position.

  4. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari, Gerard T. Pittard

    2004-01-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple cast iron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1--Program Management and Task 2--were completed in prior quarters while Task 3--Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves has progressed to installing prototype sleeves in cast iron test pipe segments. Efforts in this quarter continued to focus on Tasks 4--8, with significant progress made in each. Task 4 (Design, Fabricate and Test Patch Setting Robotic Train) progressed to the design of the control electronics and pneumatic system to inflate the bladder robotic patch setting module. Task 5 (Design & Fabricate Pipe-Wall Cleaning Robot Train with Pan/Zoom/Tilt Camera) continued with additional in-pipe testing required to

  5. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M Kothari; Gerard T. Pittard

    2004-07-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple castiron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1 (Program Management) and Task 2 (Establishment of Detailed Design Specifications) were completed in prior quarters while Task 3 (Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves) has progressed to installing prototype sleeves in cast iron test pipe segments. Efforts in this quarter continued to focus on Tasks 4-8, with significant progress made in each. Task 4 (Design, Fabricate and Test Patch Setting Robotic Train) progressed to the design of the control electronics and pneumatic system to inflate the bladder robotic patch setting module. Task 5 (Design & Fabricate Pipe-Wall Cleaning Robot Train with Pan/Zoom/Tilt Camera

  6. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari; Gerard T. Pittard

    2004-04-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple cast-iron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1--Program Management and Task 2--were completed in prior quarters while Task 3--Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves has progressed to installing prototype sleeves in cast iron test pipe segments. Efforts in this quarter continued to focus on Tasks 4--8, with significant progress made in each. Task 4 (Design, Fabricate and Test Patch Setting Robotic Train) progressed to the design of the control electronics and pneumatic system to inflate the bladder robotic patch setting module. Task 5 (Design & Fabricate Pipe-Wall Cleaning Robot Train with Pan/Zoom/Tilt Camera) continued with additional in-pipe testing required to

  7. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari; Gerard T. Pittard

    2003-06-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple cast-iron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and attaching a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service (which results in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1-Program Management was previously completed. Two reports, one describing the program management plan and the other consisting of the technology assessment, were submitted to the DOE COR in the first quarter. Task 2-Establishment of Detailed Design Specifications and Task 3-Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves are now well underway. First-quarter activities included conducting detailed analyses to determine the capabilities of coiled-tubing locomotion for entering and repairing gas mains and the first design iteration of the joint-sealing sleeve. The maximum horizontal reach of coiled tubing inside a pipeline before buckling prevents further access was calculated for a wide

  8. Development of stiffer and ductile glulam portal frame

    Science.gov (United States)

    Komatsu, Kohei

    2017-11-01

    Portal frame structures, which are constituted of straight glulam beams and columns connected semi-rigidly by steel insert gusset plate with a lot of drift pins, were the first successful glulam structures widely used in Japan. In addition to this connection system, the author invented also a new type of jointing devise for glulam structures named as "Lagscrewbolt" which had a full threaded portion at inner part to grip wooden member as well as another thread part at the end of shank to connect with other member. The initial type of "Lagscrewbolt" was successfully applied to a various types of glulam buildings which could be rapidly built-up on construction site. Its strength performance, however, was rather brittle therefore the improvement of the ductility was a crucial research subject. In order to give a sufficient ductility on the "Lagscrewbolted joint system", so-called "Slotted Bolted Connection" concept was adopted for making use of large energy dissipation characteristics due to high-tension bolted steel connection with slotted bolt holes. Static & dynamic performance of glulam portal frame specimens was evaluated by static cyclic loading test as well as shaking table test. Current latest form of the jointing system can show very high ductility as well as stable hysteretic cyclic loops by inserting brass-shim between steel-to-steel friction interfaces

  9. Experimental Research on Seismic Performance of a New-Type of R/C Beam-Column Joints with End Plates

    Directory of Open Access Journals (Sweden)

    Shufeng Li

    2017-01-01

    Full Text Available This paper presents a new-type of fabricated beam-column connections with end plates. The joint details are as follows: the concrete beams are connected to column by end plates and six high strength long bolts passing through the core area. In addition, in order to increase the stiffness and shear strength, stirrups are replaced by the steel plate hoop in the core zone. To examine the fail behavior of the fabricated beam-column connection specimens, a quasi-static test is conducted for nine full-scale models to obtain the hysteresis curves, skeleton curves, ductility, energy dissipation capacity, and other seismic indicators. The experimental results show that all specimens failed in bending in a malleable way with a beam plastic hinge and the hysteresis curves are excellently plump for the end plate connections. From the seismic indexes, the fabricated connection specimens exhibit better seismic performance, which can provide reference for the application of prefabricated frame structure in the earthquake area.

  10. Optimally analyzing and implementing of bolt fittings in steel structure based on ANSYS

    Science.gov (United States)

    Han, Na; Song, Shuangyang; Cui, Yan; Wu, Yongchun

    2018-03-01

    ANSYS simulation software for its excellent performance become outstanding one in Computer-aided Engineering (CAE) family, it is committed to the innovation of engineering simulation to help users to shorten the design process. First, a typical procedure to implement CAE was design. The framework of structural numerical analysis on ANSYS Technology was proposed. Then, A optimally analyzing and implementing of bolt fittings in beam-column join of steel structure was implemented by ANSYS, which was display the cloud chart of XY-shear stress, the cloud chart of YZ-shear stress and the cloud chart of Y component of stress. Finally, ANSYS software simulating results was compared with the measured results by the experiment. The result of ANSYS simulating and analyzing is reliable, efficient and optical. In above process, a structural performance's numerical simulating and analyzing model were explored for engineering enterprises' practice.

  11. Continuous miner and friction bolts play key roles in Highland's move underground

    International Nuclear Information System (INIS)

    Scott, J.J.; Jackson, D.

    1977-01-01

    Exxon has added underground mining operations to the open pits at its Highland uranium mine and mill complex 60 mi northeast of Casper in the Powder River Basin and has, in the process, adopted some innovative mining techniques. A continuous shield miner is being used in conjunction with continuous ground support--thought to be the first truly successful combination of these techniques in a US uranium mine. Highland miners are also making extensive use of ''Split Sets,'' a patented friction rock bolt system invented in 1973, which has proven to be a successful cost-saving substitute for timber supports in Highland's soft, water-saturated, extremely unstable sediments. Initial mine production at Highland began in July 1972, and the mill started up the following October. Design capacity at startup was 2,000 tpd, a figure that has since been expanded to 3,000 tpd through mill modifications but without a major construction program. Current production is about 2 million lb per year of U 3 O 8

  12. The possibility of tribopair lifetime extending by welding of quenched and tempered stainless steel with quenched and tempered carbon steel

    Directory of Open Access Journals (Sweden)

    V. Marušić

    2015-04-01

    Full Text Available In the conditions of tribocorrosion wear, extending of parts lifetime could be achieved by using stainless steel,which is hardened to sufficiently high hardness. In the tribosystem bolt/ bushing shell/link plate of the bucket elevator transporter conveyor machine, the previously quenched and tempered martensitic stainless steel for bolts is hardened at ≈47 HRC and welded with the quenched and tempered high yield carbon steel for bolts. Additional material, based on Cr-Ni-Mo (18/8/6 is used. The microstructure and hardness of welded samples are tested. On the tensile tester, resistance of the welded joint is tested with a simulated experiment. Dimensional control of worn tribosystem elements was performed after six months of service.

  13. Anchorage fatigue. Vermoeiing in verankeringen

    Energy Technology Data Exchange (ETDEWEB)

    Liemberg, B J

    1983-01-01

    Modern wind turbines are equipped with slender and slack masts with low eigenfrequency, fastened with anchor bolts to a concrete foundation. As a result of wind loads and the behavior of the turbine these joints are subjected to strongly and irregularly fluctuating forces. This aspect of wind turbine design, mostly somewhat neglected, is investigated by the Sima Stevin laboratory at Delft. Static tests and even normal dynamic tests with loads fluctuating with constant amplitude and frequency are not in accordance with the facts and consequently of limited value. S-N diagrams are made up and discussed. Knowledge of stress concentration lines is necessary for further computations and tests. The case of bolted joints anchored in concrete and under strain of tension (the critical point for these constructions) is elaborated in detail.

  14. Resolution of Generic Safety Issue 29: Bolting degradation or failure in nuclear power plants

    International Nuclear Information System (INIS)

    Johnson, R.E.

    1990-06-01

    This report describes the US Nuclear Regulatory Commission's (NRC's) Generic Safety Issue 29, ''Bolting Degradation or Failure in Nuclear Power Plants,'' including the bases for establishing the issue and its historical highlights. The report also describes the activities of the Atomic Industrial Forum (AIF) relevant to this issue, including its cooperation with the Materials Properties Council (MPC) to organize a task group to help resolve the issue. The Electric Power Research Institute, supported by the AIF/MPC task group, prepared and issued a two-volume document that provides, in part, the technical basis for resolving Generic Safety Issue 29. This report presents the NRC's review and evaluation of the two-volume document and NRC's conclusion that this document, in conjunction with other information from both industry and NRC, provides the bases for resolving this issue

  15. Nuts and Bolts of the Ion Band State Theory

    Science.gov (United States)

    Chubb, Scott R.

    2005-12-01

    The nuts and bolts of our ion band state theory of low energy nuclear reactions (LENR's) in palladium-deuteride (PdD) and palladium-hydride (PdH) are the electrons that hold together or tear apart the bonds (or lack of bonds) between deuterons (d's) or protons (p's) and the host material. In PdDx and PdHx, this bonding is strongly correlated with loading. In ambient loading conditions (x ≲ 0.6), bonding inhibits ion band state occupation. As x → 1, slight increases and decreases in loading can induce "vibrations" (which have conventionally been thought to occur from phonons) that can induce potential losses or increases of p/d. Naive assumptions about phonons fail to include these losses and increases. These effects can occur because neither H or D has core electrons and because in either PdD or PdH, the electrons near the Fermi energy have negligible overlap with the nucleus of either D or H. In the past, implicitly, we have used these facts to justify our ion band state theory. Here, we present a more formal justification, based on the relationship between H(D) ion band states (IBS's) and H(D) phonons that includes a microscopic picture that explains why occupation of IBS's can occur in PdD and PdH and how this can lead to nuclear reactions.

  16. [Suicide by double bolt gunshot wound to the head: case report and review of the literature].

    Science.gov (United States)

    Grellner, W; Buhmann, D; Wilske, J

    2000-01-01

    Suicidal gunshot wounds from a livestock stunner with infliction of two shots against the head are extremely rare events. A case with these characteristics is presented and the corresponding literature is reviewed. A 61-year-old butcher was found dead with two entry wounds of the forehead on the right side and in the centre being typical for captive bolt pistols (symmetrically localized powder burns). The issues of the sequence of shots and the capacity of action are discussed on the basis of morphological findings and pathophysiological considerations. A literature review revealed only 4 case reports with double gunshot wounds of the skull caused by "humane killers" (Tovo 1956, Wolff and Laufer 1965, Schiermeyer 1973, Pollak 1977).

  17. An analysis of a joint shear model for jointed media with orthogonal joint sets

    International Nuclear Information System (INIS)

    Koteras, J.R.

    1991-10-01

    This report describes a joint shear model used in conjunction with a computational model for jointed media with orthogonal joint sets. The joint shear model allows nonlinear behavior for both joint sets. Because nonlinear behavior is allowed for both joint sets, a great many cases must be considered to fully describe the joint shear behavior of the jointed medium. An extensive set of equations is required to describe the joint shear stress and slip displacements that can occur for all the various cases. This report examines possible methods for simplifying this set of equations so that the model can be implemented efficiently form a computational standpoint. The shear model must be examined carefully to obtain a computationally efficient implementation that does not lead to numerical problems. The application to fractures in rock is discussed. 5 refs., 4 figs

  18. Study on Utilization of LVL Sengon (Paraserianthes falcataria for Three-Hinged Gable Frame Structures

    Directory of Open Access Journals (Sweden)

    Ali Awaludin

    2016-07-01

    Full Text Available This study focuses on the utilization of non-prismatic LVL members of wood species Sengon (Paraserianthes falcataria for three-hinged gable frame structures. This wood species matures in 6 to 8 years, and the innovative application as LVL product for these structures is evaluated. A full-scale model of a beam-column connection is produced and tested to validate the moment-rotation response predicted by the numerical study using ABAQUS. The FEM results showed a linear-elastic moment-rotation curve response up to a joint rotation of 0.015 radians which is in very good agreement with the experiment. This validated FE model for the beam-column joint was further utilized to generate predictions for the moment-rotation relation using different bolt diameters and configurations. The last part of this study presents an evaluation of the maximum load bearing capacity of three-hinged gable frame timber structures considering a rigid and semi-rigid beam-column joint model. If the load carrying capacity is governed by the yielding of the bolt, the gable frame structure with the rigid beam-column joint overestimates the load bearing capacity by 17% to 25%.

  19. Improving the transient response of a bolt-clamped Langevin transducer using a parallel resistor.

    Science.gov (United States)

    Chang, Kuo Tsi

    2003-08-01

    This paper suggests a parallel resistor to reduce DC time constant and DC response time of the transient response, induced immediately after an AC voltage connected to a bolt-clamped Langevin transducer (BLT) is switched off. An equivalent circuit is first expressed. Then, an open-circuit transient response at the terminals induced by initial states is derived and measured, and thus parameters for losses of the BLT device are estimated by DC and AC time constants of the transient response. Moreover, a driving and measuring system is designed to determine transient response and steady-state responses of the BLT device, and a parallel resistor is connected to the BLT device to reduce the DC time constant. Experimental results indicate that the DC time constant greatly exceeds the AC time constant without the parallel resistor, and greatly decreases from 42 to 1 ms by a 100-kOmega parallel resistor.

  20. MR diagnosis of temporomandibular joint. A study of joint effusion

    International Nuclear Information System (INIS)

    Kaneda, Takashi; Yamashiro, Mitsuaki; Ozawa, Kaoru; Suzuki, Hiromi; Okada, Hiroyuki; Yamamoto, Hirotsugu

    1998-01-01

    The purposes of this study were to evaluate the relationship between correlation of MR joint effusion of the temporomandibular joint and disk position, to evaluate the relationship between joint effusion and aging, and to assess the frequency of MR joint effusion of bilateral temporomandibular joints. The temporomandibular joints of 192 patients with clinical symptoms of temporomandibular joint disorders were imaged bilaterally using high field, surface-coil MR imaging. Oblique sagittal and coronal proton density-weighted and T2-weighted images were obtained. Imaging findings of joint effusion were correlated with disk position, aging, and bilateral temporomandibular joints. MR showed effusion in 4% of the joints with normal superior disk position, 36% of the joints with disk displacement with reduction, and 45% of the joints with disk displacement without reduction. There were significant differences in the incidence of joint effusion between normal disk position and anterior disk displacement with or without reduction. Younger patients less than 40 years were significant higher the incidence of joint effusion than those of older patients. A significant association was seen between joint effusion and aging. MR showed effusion in 17% of the unilateral temporomandibular joint, 24% of the bilateral temporomandibular joints. There was no significant difference between unilateral and bilateral case. These results indicated that joint effusion using MR imaging was associated with varied temporomandibular joint pathologic states. (author)

  1. Reversible fastener clamp load monitor with continuous visual or remote readout

    Science.gov (United States)

    Hodge, Malcolm H.; Kausel, Theodore C., Jr.; Begley, Matthew R.

    1998-03-01

    SIMS has developed a simple means for detecting and monitoring both absolute and relative clamp load, or bolt tension, in fastener systems. More than twenty-five percent of automotive failures are known to be due to undetected loss of fastener clamp load. While the equivalent aerospace maintenance statistics are not known, the average automobile has 3,500 fasteners while a Boeing 747 has closer to one million. It is therefore anticipated that the new SensaBolt clamp load tracking system could find wide applications in the aerospace arena. We describe a visually-evident and retrofitted clamp load monitoring design which is based on the differential joint substrate compression at, and immediately adjacent to, the fastener location. This intrinsically-accurate indicator does not necessarily require alteration in either the bolt or nut geometries, thereby facilitating product introduction and retrofit in aging aircraft applications. In addition, SensaBolt's sole reliance on substrate compression renders it more accurate then torque wrench or turn-of-nut techniques. Readout may be accomplished by any of three principal methods: for those applications with ease of access to the sensor, loss of tension can be determined by direct visual inspection. Application of a standard wrench can then be made to restore the fastener's proper tightness, per the SensaBolt indicators. In those instances where line-of-sight is unimpeded and more formal inspection is desired, the SensaBolt may be interrogated by a laser scanner bar code reader. Finally, SensaBolt may be addressed by the SIMS fiber optic harness for those instances where full-time remote interrogation is desired.

  2. Effect of tree species and end seal on attractiveness and utility of cut bolts to the redbay Ambrosia beetle and granulate Ambrosia beetle (Coleoptera: Curculionidae: Scolytinae)

    Science.gov (United States)

    Albert E. Mayfield; James L. Hanula

    2012-01-01

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is a non-native invasive pest and vector of the fungus that causes laurel wilt disease in certain trees of the family Lauraceae. This study assessed the relative attractiveness and suitability of cut bolts of several tree species to X. glabratus. In 2009, female X. glabratus were equally attracted to traps...

  3. Contact with friction modeling for the study of a bolted junction

    International Nuclear Information System (INIS)

    Lebon, F.; Raous, M.; Boulegues, D.

    1987-01-01

    Many structural analysis problems are concerned by contact phenomena. A good knowledge of the contact displacements and the contact forces between the different parts of the structure is generally essential in structure assembling. The special boundary behaviour has a strong influence on the distribution of the stresses in the whole structure and on his total fiability. The contact behaviour is strongly non linear because of the non penetration conditions on the one hand, and because of the friction on the other. On such problems the real contact zone and the contact forces are unknown 'a priori' and have to be determined during the resolution. The non-penetration is characterized by unilateral conditions and the friction is described by a constitutive law (Coulomb friction law). The application presented here concerns the assembling of the three parts of a bolted junction using a pressing ring. There are three contact zones in this program. A good description of the contact phenomena is essential to ensure tightness. Our methods are based on projection techniques coupled with overrelaxed Gauss-Seidel methods including condensation procedures (reduction of the number of variables). Non linear programming methods and iterative procedures on special boundary conditions are also used. (orig./HP)

  4. Application of the cylindrically guided wave technique for bolt and pump-shaft inspections

    International Nuclear Information System (INIS)

    Light, G.M.; Ruescher, E.H.; Bloom, E.A.; Tsai, Y.M.

    1990-01-01

    Southwest Research Institute (SwRI) has been working with the cylindrically guided wave technique (CGWT) since late 1982. The initial work was aimed at inspecting reactor pressure vessel hold-down studs. The CGWT was shown to be able to detect defects as small as 0.060 inch (1.5 mm) deep through metal paths up to 120 inches (304 cm) in stud bolt carbon steel. Later developments in the application of CGWT were aimed at inspecting reactor coolant pump (RCP) shafts. The RCP shafts are usually approximately 2 meters long and have changing diameters along the length, from approximately 12 cm to 23 cm in discrete steps. The pump shafts have been susceptible to small cracks and can be inspected most cost-effectively from the top of the shaft. A matrix transducer composed of six 1-inch (2.54-cm) diameter transducers along with pulsing and receiving electronics (EPRI Pump-Shaft Inspection System) was developed during 1988. A patent application for this technology has been made. This report describes the work conducted during 1989 and the results obtained

  5. Statistical time series methods for damage diagnosis in a scale aircraft skeleton structure: loosened bolts damage scenarios

    International Nuclear Information System (INIS)

    Kopsaftopoulos, Fotis P; Fassois, Spilios D

    2011-01-01

    A comparative assessment of several vibration based statistical time series methods for Structural Health Monitoring (SHM) is presented via their application to a scale aircraft skeleton laboratory structure. A brief overview of the methods, which are either scalar or vector type, non-parametric or parametric, and pertain to either the response-only or excitation-response cases, is provided. Damage diagnosis, including both the detection and identification subproblems, is tackled via scalar or vector vibration signals. The methods' effectiveness is assessed via repeated experiments under various damage scenarios, with each scenario corresponding to the loosening of one or more selected bolts. The results of the study confirm the 'global' damage detection capability and effectiveness of statistical time series methods for SHM.

  6. Fractures in high-strength bolts due to hydrogen induced stress corrosion. Causes and corrective actions

    International Nuclear Information System (INIS)

    Hoche, Holger; Oechsner, Matthias

    2017-01-01

    Delayed brittle fractures of high-strength bolts of the strength class 10.9 are presented, taking the example of three damage cases. The respective damage mechanisms could be attributed to hydrogen induced stress corrosion which was caused, in turn, by hydrogen absorption during operation. The examples were chosen with a particular focus on the material condition's susceptibility which explains the cause for the occurrence of the damage mechanism. However, in only one of the three cases the susceptibility was evident and could be explained by violations of normative specifications and an unfavorable material choice. Whereas in the two other examples, only slight or no deviations from the standards and/or regulations could be found. The influencing parameters that caused the damage, those that further promoted the damage, as well as possible corrective actions are discussed taking into account the three exemplary damage cases.

  7. Aircraft Fatigue - with Particular Emphasis on Australian Operations and Research.

    Science.gov (United States)

    1983-04-01

    its research on the fatigue behaviour of full-scale alluminium -alloy structures by undertaking a major investigation using surplus wings from North...on the corrosion fatigue of Taper-Lok bolted joints in D6AC steel. In March 1973 the RAAF finally took delivery of its first F-IliC, and among the...development of multiple defects, corrosion /stress corrosion , detvrirrat- ion of bonded joints, undetected cracks or damage, inadquate repairs 2r untested

  8. Determination of Parachute Joint Factors using Seam and Joint Testing

    Science.gov (United States)

    Mollmann, Catherine

    2015-01-01

    This paper details the methodology for determining the joint factor for all parachute components. This method has been successfully implemented on the Capsule Parachute Assembly System (CPAS) for the NASA Orion crew module for use in determining the margin of safety for each component under peak loads. Also discussed are concepts behind the joint factor and what drives the loss of material strength at joints. The joint factor is defined as a "loss in joint strength...relative to the basic material strength" that occurs when "textiles are connected to each other or to metals." During the CPAS engineering development phase, a conservative joint factor of 0.80 was assumed for each parachute component. In order to refine this factor and eliminate excess conservatism, a seam and joint testing program was implemented as part of the structural validation. This method split each of the parachute structural joints into discrete tensile tests designed to duplicate the loading of each joint. Breaking strength data collected from destructive pull testing was then used to calculate the joint factor in the form of an efficiency. Joint efficiency is the percentage of the base material strength that remains after degradation due to sewing or interaction with other components; it is used interchangeably with joint factor in this paper. Parachute materials vary in type-mainly cord, tape, webbing, and cloth -which require different test fixtures and joint sample construction methods. This paper defines guidelines for designing and testing samples based on materials and test goals. Using the test methodology and analysis approach detailed in this paper, the minimum joint factor for each parachute component can be formulated. The joint factors can then be used to calculate the design factor and margin of safety for that component, a critical part of the design verification process.

  9. Temporomandibular joint space in children without joint disease

    International Nuclear Information System (INIS)

    Larheim, T.A.

    1981-01-01

    Bilateral assessment of the temporomandibular joint space in children without joint disease is reported. Twenty-eight children were examined with conventional radiography and 23 with tomography. High prevalence of asymmetric joint spaces with both techniques indicated that great care should be taken when using narrowing or widening of the joint space as a diagnostic criterion in children with juvenile rheumatoid arthritis. Other signs, such as restricted translation of the mandibular head, and clinical symptoms should be evaluated. (Auth.)

  10. Fracture Mechanics Models for Brittle Failure of Bottom Rails due to Uplift in Timber Frame Shear Walls

    Directory of Open Access Journals (Sweden)

    Joergen L. Jensen

    2016-01-01

    Full Text Available In partially anchored timber frame shear walls, hold-down devices are not provided; hence the uplift forces are transferred by the fasteners of the sheathing-to-framing joints into the bottom rail and via anchor bolts from the bottom rail into the foundation. Since the force in the anchor bolts and the sheathing-to-framing joints do not act in the same vertical plane, the bottom rail is subjected to tensile stresses perpendicular to the grain and splitting of the bottom rail may occur. This paper presents simple analytical models based on fracture mechanics for the analysis of such bottom rails. An existing model is reviewed and several alternative models are derived and compared qualitatively and with experimental data. It is concluded that several of the fracture mechanics models lead to failure load predictions which seem in sufficiently good agreement with the experimental results to justify their application in practical design.

  11. Fabrication of a full-size mock-up for inboard 10o section of ITER vacuum vessel thermal shield

    International Nuclear Information System (INIS)

    Chung, W.; Nam, K.; Noh, C.H.; Kang, D.K.; Kang, S.M.; Oh, Y.G.; Choi, S.W.; Kang, S.H.; Utin, Y.; Ioki, K.; Her, N.; Yu, J.

    2011-01-01

    A full-scale mock-up of VVTS inboard section was made in order to validate its manufacturing processes before manufacturing the vacuum vessel thermal shield (VVTS) for ITER tokamak. VVTS inboard 10 o section consists of 20 mm shells on which cooling tubes are welded and flange joints that connect adjacent thermal shield sectors. The whole VVTS inboard is divided into two by bisectional flange joint located at the center. All the manufacturing processes except silver coating were tested and verified in the fabrication of mock-up. For the forming and the welding, pre-qualification tests were conducted to find proper process conditions. Shell thickness change was measured after bending, forming and buffing processes. Shell distortion was adjusted after the welding. Welding was validated by non-destructive examination. Bisectional flange joint was successfully assembled by inserting pins and tightening with bolt/nut. Bolt hole margin of 2 mm for sector flange was revealed to be sufficient by successful sector assembly of upper and lower parts of mock-up. Handling jig was found to be essential because the inboard section was flexible. Dimensional inspection of the fabricated mock-up was performed with a 3D laser scanner.

  12. Aging considerations for pressurizers in nuclear power plants

    International Nuclear Information System (INIS)

    Ware, A.G.

    1988-01-01

    This paper discusses the degradation mechanisms affecting the residual life of the nuclear pressurized water reactor (PWR) pressurizer and its subcomponents. The major sources of degradation for pressurizers are thermal transients such as plant heatups and cooldowns, internal pressure within the vessel, high intermittent flow through the spray nozzle, differential thermal movement causing rubbing of the immersion heater sheathes, and prolonged exposure to chemical and thermal conditions that can potentially lead to degradation. The latter includes thermal embrittlement of cast stainless steel spray heads and chemically assisted intergranular stress corrosion cracking of stainless steel. Steam leakage that interacts with lubricants used to assemble manway bolted joints can cause corrosion of bolts

  13. Micromechanics-Based Damage Analysis of Fracture in Ti5553 Alloy with Application to Bolted Sectors

    Science.gov (United States)

    Bettaieb, Mohamed Ben; Van Hoof, Thibaut; Minnebo, Hans; Pardoen, Thomas; Dufour, Philippe; Jacques, Pascal J.; Habraken, Anne Marie

    2015-03-01

    A physics-based, uncoupled damage model is calibrated using cylindrical notched round tensile specimens made of Ti5553 and Ti-6Al-4V alloys. The fracture strain of Ti5553 is lower than for Ti-6Al-4V in the full range of stress triaxiality. This lower ductility originates from a higher volume fraction of damage sites. By proper heat treatment, the fracture strain of Ti5553 increases by almost a factor of two, as a result of a larger damage nucleation stress. This result proves the potential for further optimization of the damage resistance of the Ti5553 alloy. The damage model is combined with an elastoviscoplastic law in order to predict failure in a wide range of loading conditions. In particular, a specific application involving bolted sectors is addressed in order to determine the potential of replacing the Ti-6Al-4V by the Ti5553 alloy.

  14. An Application of Retroduction to Analyzing and Testing the Backing off of Nuts and Bolts During Dynamic Loading

    Science.gov (United States)

    Kerley, James J.

    1987-01-01

    The method of retroduction, adapted from the doctoral thesis of Dr. A. Croce, relies on a process of dialectic questioning that begins with the information sought, proceeds to Given items (either in the form of dimensions or limits of research). and to Known mathematical forms of analysis in design or to principles of study in research. Finally, analysis and synthesis are used to abstract the dielectic questions and to arrive at the information desired. This method is used to solve the engineering design problem of a beam and to determine why bolts and nuts vibrate apart. Both mathematical analysis and dialectic logical analysis are utilized. Results are provided of tests conducted to check the retroductive study of why and how nuts back off.

  15. Damage Assessment of a Steel Lattice Mast under Natural Excitation

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Rytter, A.

    1994-01-01

    . These diagonals were cut and provided with a bolted joint implying that a damage could be simulated. Based on 20 periodical measurements during 6 months the sensitivity of the modal parameters, identified by an ARMA-model, to environmental conditions such as wind-direction, wind-speed and air-temperature have...

  16. Joint Replacement (Finger and Wrist Joints)

    Science.gov (United States)

    ... All Topics A-Z Videos Infographics Symptom Picker Anatomy Bones Joints Muscles Nerves Vessels Tendons About Hand Surgery What is a Hand Surgeon? What is a Hand Therapist? Media Find a Hand Surgeon Home Anatomy Joint Replacement Email to a friend * required fields ...

  17. Joint Operation Planning

    National Research Council Canada - National Science Library

    2006-01-01

    .... It sets forth joint doctrine to govern the joint operation planning activities and performance of the Armed Forces of the United States in joint operations, and provides the joint doctrinal basis...

  18. Jointness for the Rest of Us: Reforming Joint Professional Development

    Science.gov (United States)

    2016-06-10

    transferred to the Joint Staff. 13 DOD’s instinct to “overly centralize planning, organization, and management.”20 The authors contend that this...2. 3 John F. Schank and others, Who is Joint? Reevaluating the Joint Duty Assignment List : A Study Prepared for the Joint Staff, by the RAND...and code those billets as such. Once identified, DOD must expand the Joint Duty Assignment List (JDAL) to include billets that offer enlisted personnel

  19. The Use of a Non-Penetrating Captive Bolt for the Euthanasia of Neonate Piglets.

    Science.gov (United States)

    Grist, Andrew; Lines, Jeff A; Knowles, Toby G; Mason, Charles W; Wotton, Stephen B

    2018-04-02

    The most common method for the on-farm euthanasia of neonate piglets is reported to be manual blunt force trauma. This paper presents the results of research to evaluate a mechanical non-penetrating captive bolt (the Accles and Shelvoke CASH small animal tool, Birmingham, UK) to produce an immediate stun/kill with neonate piglets. One hundred and forty-seven piglets (average dead weight = 1.20 kg ± 0.58 (standard deviation, SD), mean age = 5.8 days (median = 3)) were euthanized with the device and demonstrated immediate loss of consciousness, subjectively assessed by behavioural signs and no recovery. The result that 147 out of 147 animals were effectively stun/killed gives a 95% confidence interval for the true percentage of animals that would be effectively stun/killed of 97.5-100% with the use of the CASH small animal tool under the conditions of the current study. This research concludes that the CASH small animal tool, using a 1 grain brown coded cartridge, is suitable for producing a stun/kill in neonate piglets when applied in a frontal/parietal position.

  20. Periprosthetic joint infection: are patients with multiple prosthetic joints at risk?

    Science.gov (United States)

    Jafari, S Mehdi; Casper, David S; Restrepo, Camilo; Zmistowski, Benjamin; Parvizi, Javad; Sharkey, Peter F

    2012-06-01

    Patients who present with a periprosthetic joint infection in a single joint may have multiple prosthetic joints. The risk of these patients developing a subsequent infection in another prosthetic joint is unknown. Our purposes were (1) to identify the risk of developing a subsequent infection in another prosthetic joint and (2) to describe the time span and organism profile to the second prosthetic infection. We retrospectively identified 55 patients with periprosthetic joint infection who had another prosthetic joint in place at the time of presentation. Of the 55 patients, 11 (20%) developed a periprosthetic joint infection in a second joint. The type of organism was the same as the first infection in 4 (36%) of 11 patients. The time to developing a second infection averaged 2.0 years (range, 0-6.9 years). Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Coracoclavicular joint

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kun Sang; Park, Chan Il; Ahn, Jae Doo; Lim, Chong Won [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1970-10-15

    The coracoclvicular joint, a rear abnormality which may be the cause of pain in the shoulder and limitation of motion of the shoulder joint, is discussed. A case of coracoclvicular joint with shoulder pain was observed in 65 yrs old Korean male.

  2. Ultraprecision XY stage using a hybrid bolt-clamped Langevin-type ultrasonic linear motor for continuous motion.

    Science.gov (United States)

    Lee, Dong-Jin; Lee, Sun-Kyu

    2015-01-01

    This paper presents a design and control system for an XY stage driven by an ultrasonic linear motor. In this study, a hybrid bolt-clamped Langevin-type ultrasonic linear motor was manufactured and then operated at the resonance frequency of the third longitudinal and the sixth lateral modes. These two modes were matched through the preload adjustment and precisely tuned by the frequency matching method based on the impedance matching method with consideration of the different moving weights. The XY stage was evaluated in terms of position and circular motion. To achieve both fine and stable motion, the controller consisted of a nominal characteristics trajectory following (NCTF) control for continuous motion, dead zone compensation, and a switching controller based on the different NCTFs for the macro- and micro-dynamics regimes. The experimental results showed that the developed stage enables positioning and continuous motion with nanometer-level accuracy.

  3. Analysis of WWER 440 SG primary collector bolted joint damage

    Energy Technology Data Exchange (ETDEWEB)

    Matocha, K.; Wozniak, J. [Vitkovice J.S.C., Ostrava (Switzerland); Pochman, K. [NPP Dukovany (Switzerland)

    1997-12-31

    The susceptibility of CHN35VT-VD and 08CH18N10T stainless steels to stress corrosion cracking in water environment, simulating water solution found in threaded holes, was investigated using rising load line displacement tests of precracked C(T) specimens. To judge the role of oxidant on stress corrosion cracking of both stainless steels, the effect of dissolved oxygen content (fully deaerated water, water aerated at the beginning of the test) was studied. 7 refs.

  4. Analysis of WWER 440 SG primary collector bolted joint damage

    Energy Technology Data Exchange (ETDEWEB)

    Matocha, K; Wozniak, J [Vitkovice J.S.C., Ostrava (Switzerland); Pochman, K [NPP Dukovany (Switzerland)

    1998-12-31

    The susceptibility of CHN35VT-VD and 08CH18N10T stainless steels to stress corrosion cracking in water environment, simulating water solution found in threaded holes, was investigated using rising load line displacement tests of precracked C(T) specimens. To judge the role of oxidant on stress corrosion cracking of both stainless steels, the effect of dissolved oxygen content (fully deaerated water, water aerated at the beginning of the test) was studied. 7 refs.

  5. Temporomandibular joint

    International Nuclear Information System (INIS)

    Westesson, P.L.; Hatala, M.; Tallents, R.H.; Katzberg, R.W.; Musgrave, M.; Levitt, S.

    1990-01-01

    This paper determines the frequency of MR signs of abnormal temporomandibular joints (TMJs) in asymptomatic volunteers. Forty-two volunteers with 84 clinically normal TMJs were imaged in the sagittal and coronal planes with surface coil MR imaging. Sagittal closed and open and coronal closed views were obtained bilaterally in all volunteers. The images were classified as normal (superior disk position) or abnormal (disk displacement of degenerative joint disease). Eighteen joints in 11 volunteers were abnormal; 12 had disk displacement with reduction and six had disk displacement without reduction, with associated degenerative joint disease in three of the six. Asymptomatic internal derangement and degenerative joint disease occur in about one-fourth of asymptomatic volunteers

  6. Joint resistance measurements of pancake and terminal joints for JT-60SA EF coils

    Energy Technology Data Exchange (ETDEWEB)

    Obana, Tetsuhiro, E-mail: obana.tetsuhiro@LHD.nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Takahata, Kazuya; Hamaguchi, Shinji; Mito, Toshiyuki; Imagawa, Shinsaku [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Kizu, Kaname; Murakami, Haruyuki; Yoshida, Kiyoshi [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan)

    2013-11-15

    Highlights: • To evaluate the joint fabrication technology for the JT-60SA EF coils, joint resistance measurements were conducted with a joint sample. • The joint sample was composed of pancake and terminal joints. • The measurements demonstrated that both joints fulfilled the design requirement. • Considering the measurements, the characteristics of both joints were investigated using an analytical model that represents the joints. -- Abstract: To evaluate the joint fabrication technology for the JT-60SA EF coils, joint resistance measurements were conducted using a sample consisting of pancake and terminal joints. Both joints are shake-hands lap joints composed of cable-in-conduit conductors and a pure copper saddle-shaped spacer. The measurements demonstrated that both joints fulfilled the design requirement. Considering these measurements, the characteristics of both joints were investigated using analytical models that represent the joints. The analyses indicated that the characteristics of the conductors used in the joints affect the characteristics of the joints.

  7. Joint instability and osteoarthritis.

    Science.gov (United States)

    Blalock, Darryl; Miller, Andrew; Tilley, Michael; Wang, Jinxi

    2015-01-01

    Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA). Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA.

  8. Joint Instability and Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Darryl Blalock

    2015-01-01

    Full Text Available Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA. Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA.

  9. International joint ventures

    DEFF Research Database (Denmark)

    Sørensen, Karsten Engsig

    2001-01-01

    The article analysis problems connected with corporate joint ventures. Among others the possible conflicts between the joint venture agreement and the statutes of the companies is examined, as well as certain problems connected to the fact that the joint venture partners have created commen control...... over their joint company....

  10. Joint Chiefs of Staff > About > The Joint Staff > Senior Enlisted Advisor

    Science.gov (United States)

    Skip to main content (Press Enter). Toggle navigation Joint Chiefs of Staff Joint Chiefs of Staff Joint Chiefs of Staff Facebook Twitter YouTube Flickr Blog Instagram Search JCS: Search Search Search JCS: Search Home Media News Photos Videos Publications About The Joint Staff Chairman Vice Chairman

  11. A joint-constraint model for human joints using signed distance-fields

    DEFF Research Database (Denmark)

    Engell-Nørregård, Morten Pol; Abel, Sarah Maria Niebe; Erleben, Kenny

    2012-01-01

    We present a local joint-constraint model for a single joint which is based on distance fields. Our model is fast, general, and well suited for modeling human joints. In this work, we take a geometric approach and model the geometry of the boundary of the feasible region, i.e., the boundary of all...... allowed poses. A region of feasible poses can be built by embedding motion captured data points in a signed distance field. The only assumption is that the feasible poses form a single connected set of angular values. We show how signed distance fields can be used to generate fast and general joint......-joint dependencies, or joints with more than three degrees of freedom. The resolution of the joint-constraints can be tweaked individually for each degree of freedom, which can be used to optimize memory usage. We perform a comparative study of the key-properties of various joint-constraint models, as well...

  12. FLANGE: a computer program for the analysis of flanged joints with ring-type gaskets

    International Nuclear Information System (INIS)

    Rodabaugh, E.C.; O'Hara, F.M. Jr.; Moore, S.E.

    1976-01-01

    The computer program FLANGE was written to calculate not only the stresses due to moment loads on the flange ring but also stresses due to internal pressure; stresses due to a temperature difference between the hub and ring; and stresses due to the variations in bolt load that result from pressure, hub-ring temperature gradient, and/or bolt-ring temperature difference. The program FLANGE is applicable to tapered-hub, straight, and blind flanges. The analysis method is based on the differential equations for thin plates and shells. The stresses due to moment loading calculated by the two methods are essentially identical for identical boundary conditions. A description of the general model of flanges used in the theoretical development of the computer code is provided. The actual mathematical expressions for calculating stresses and displacements due to moment and pressure loads are derived. Example calculations, listings, and flowcharts of the program and its subroutines are included as appendices

  13. Estimation of Joint types and Joint Limits from Motion capture data

    DEFF Research Database (Denmark)

    Engell-Nørregård, Morten Pol; Erleben, Kenny

    2009-01-01

    It is time-consuming for an animator to explicitly model joint types and joint limits of articulated figures. In this paper we describe a simple and fast approach to automated joint estimation from motion capture data of articulated figures. Our method will make the joint modeling more efficient ...

  14. Design of a bolted flange subjected to severe nuclear system thermal transients - A case study

    International Nuclear Information System (INIS)

    Palmer, W.J.; Tomawski, R.J.; Ezekoye, L.I.; Lacey, M.L.

    1986-01-01

    Flange design standards recognize that flanged joints may develop leakage should they be exposed to severe thermal gradients and recommend that such operating conditions be avoided. In nuclear power plants, severe thermal transients may be encountered in many plant and system operating and test conditions. In such applications, conformance with standard design practice may not ensure a leak-tight joint. This paper describes the proper consideration of thermal effects on flanged joints and how that can lead to the development of a successful leak-tight design. Similar procedures may be applied generally to evaluate and upgrade flanged joints in thermal shock applications

  15. Development on application of ultrasonic sealing techniques to plutonium transportation cask

    International Nuclear Information System (INIS)

    Hayakawa, Tsuyoshi; Akiba, Mitsunori; D'Agraives, B.C.

    1994-01-01

    In a cooperation research between Power Reactor and Nuclear Fuel Development Corporation and Commission of the European Communities, Joint Research Centre, Ispra establishment, application of ultrasonic sealing techniques to a plutonium container is developed in Ispra. The seal is derived from the sealing-bolt technology currently in use at the BNFL site of sellafield (UK) for the safeguarding of underwater spent fuel storage containers called MEBs. In this technique, one of the normal bolts closing the lid of the container is replaced by a special ultrasonically verifiable sealing-bolt. In the application to the plutonium container, it is proposed to attach a clamping seal which has the same internal configuration as a MEB sealing-bolt but is fastened with a 'one-way' mechanism to one of the protruding pins of the container. Similarly the seal is provided with an identity and integrity features. The uniqueness of the identity, as well as the integrity can be checked on the spot by an inspector carrying a reading equipment. Thus, in a few minutes, one identifies the seal and knows whether its integrity is intact, which tells that the container has not been opened or attempted to open illeagally. By application of the seal to the plutonium container, the containment/surveillance during the transportation will be upgraded. (author)

  16. Laboratory results gained from cold worked type 316Ti under simulated PWR primary environment

    International Nuclear Information System (INIS)

    Devrient, B.; Kilian, R.; Koenig, G.; Widera, M.; Wermelinger, T.

    2015-01-01

    Beginning in 2005, intergranular stress corrosion cracking (IGSCC) of barrel bolts made from cold worked type 316Ti (German Material No. 1.4571 K) was observed in several S/KWU type PWRs. This mechanism was so far less understood for PWR primary conditions. Therefore an extended joint research program was launched by AREVA GmbH and VGB e.V. to clarify the specific conditions which contributed to the observed findings on barrel bolts. In the frame of this research program beneath the evaluation of the operational experience also laboratory tests on the general cracking behavior of cold worked type 316Ti material, which followed the same production line as for barrel bolt manufacturing in the eighties, with different cold work levels covering up to 30 % were performed to determine whether there is a specific susceptibility of cold worked austenitic stainless steel specimens to suffer IGSCC under simulated PWR primary conditions. All these slow strain rate tests on tapered specimens and component specimens came to the results that first, much higher cold work levels than used for the existing barrel bolts are needed for IGSCC initiation. Secondly, additional high active plastic deformation is needed to generate and propagate intergranular cracking. And thirdly, all specimens finally showed ductile fracture at the applied strain rates. (authors)

  17. The Use of a Non-Penetrating Captive Bolt for the Euthanasia of Neonate Piglets

    Directory of Open Access Journals (Sweden)

    Andrew Grist

    2018-04-01

    Full Text Available The most common method for the on-farm euthanasia of neonate piglets is reported to be manual blunt force trauma. This paper presents the results of research to evaluate a mechanical non-penetrating captive bolt (the Accles and Shelvoke CASH small animal tool, Birmingham, UK to produce an immediate stun/kill with neonate piglets. One hundred and forty-seven piglets (average dead weight = 1.20 kg ± 0.58 (standard deviation, SD, mean age = 5.8 days (median = 3 were euthanized with the device and demonstrated immediate loss of consciousness, subjectively assessed by behavioural signs and no recovery. The result that 147 out of 147 animals were effectively stun/killed gives a 95% confidence interval for the true percentage of animals that would be effectively stun/killed of 97.5–100% with the use of the CASH small animal tool under the conditions of the current study. This research concludes that the CASH small animal tool, using a 1 grain brown coded cartridge, is suitable for producing a stun/kill in neonate piglets when applied in a frontal/parietal position.

  18. Reliability of Tubular Joints

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    In this paper the preliminary results obtained by tests on tubular joints are presented. The joints are T-joints and the loading is static. It is the intention in continuation of these tests to perform tests on other types of joints (e.g. Y-joints) and also with dynamic loading. The purpose...... of the test is partly to obtain empirical data for the ultimate load-carrying capacity of tubular T-joints and partly to obtain some experience in performing tests with tubular joints. It is well known that tubular joints are usually designed in offshore engineering on the basis of empirical formulas obtained...... by experimental test results. Therefore, there is a need for performing experimental tests in this area....

  19. Analytical and experimental evaluation of the capacity of the bottom rail in partially anchored timber shear walls

    OpenAIRE

    Caprolu, Giuseppe; Källsner, Bo; Girhammar, Ulf Arne; Vessby, Johan

    2012-01-01

    Källsner and Girhammar have developed plastic design methods for light-frame timber shear walls that can be used for determining the load-carrying capacity when the shear walls are partially anchored. For such walls, the leading stud is not fully anchored against uplift and tying down forces are developed in the sheathing-to-framing joints. Since the forces in the anchor bolts and the sheathing-to-framing joints do not act in the same vertical plane, the bottom rail will be subjected to cross...

  20. Does generalized joint hypermobility predict joint injury in sport? A review.

    LENUS (Irish Health Repository)

    Donaldson, Peter R

    2012-02-01

    OBJECTIVE: To determine whether persons with generalized joint hypermobility have an increased risk of lower limb joint injury during sport. DATA SOURCES: PubMed, CINAHL, EMBASE, and SportDiscus were searched through February 2009, without language restrictions, using terms related to risk; hip, ankle, and knee injuries; and joint instability. Reference lists of included studies and relevant reviews were searched by hand. STUDY SELECTION: Selection criteria were peer-reviewed studies with a prospective design that used an objective scale to measure generalized joint hypermobility; the participants were engaged in sport activity, and the injury data were quantitative and based on diagnosis by a health professional, were self-reported, or resulted in time lost to athletic participation. The studies were screened by 1 researcher and checked by a second. Study methods were independently assessed by 2 investigators using the 6-point scale for prognostic studies developed by Pengel. Disagreements were resolved through discussion. Of 4841 studies identified, 18 met inclusion criteria. Of these, 8 were included in random-effects meta-analyses. DATA EXTRACTION: The data extracted by 2 reviewers included participant and sport characteristics and details of joint hypermobility and injury measurements. More detailed data for 4 investigations were obtained from the study authors. Where possible, hypermobility was defined as >\\/=4 of 9 points on the British Society of Rheumatology Scale (BSRS). MAIN RESULTS: Lower limb joint injuries (3 studies, 1047 participants) occurred in 14% of participants. Using the BSRS of joint hypermobility, any lower limb injury was not associated with hypermobility [odds ratio (OR), 1.43; 95% confidence interval (CI), 0.56-3.67]. Using the original authors\\' definitions, hypermobility was associated with risk of knee joint injuries (OR, 2.62; 95% CI, 1.04-6.58) in 5 studies. In 4 studies in which the BSRS could be used (1167 participants; incidence

  1. A computational model for three-dimensional jointed media with a single joint set

    International Nuclear Information System (INIS)

    Koteras, J.R.

    1994-02-01

    This report describes a three-dimensional model for jointed rock or other media with a single set of joints. The joint set consists of evenly spaced joint planes. The normal joint response is nonlinear elastic and is based on a rational polynomial. Joint shear stress is treated as being linear elastic in the shear stress versus slip displacement before attaining a critical stress level governed by a Mohr-Coulomb faction criterion. The three-dimensional model represents an extension of a two-dimensional, multi-joint model that has been in use for several years. Although most of the concepts in the two-dimensional model translate in a straightforward manner to three dimensions, the concept of slip on the joint planes becomes more complex in three dimensions. While slip in two dimensions can be treated as a scalar quantity, it must be treated as a vector in the joint plane in three dimensions. For the three-dimensional model proposed here, the slip direction is assumed to be the direction of maximum principal strain in the joint plane. Five test problems are presented to verify the correctness of the computational implementation of the model

  2. The joint flanker effect and the joint Simon effect: On the comparability of processes underlying joint compatibility effects.

    Science.gov (United States)

    Dittrich, Kerstin; Bossert, Marie-Luise; Rothe-Wulf, Annelie; Klauer, Karl Christoph

    2017-09-01

    Previous studies observed compatibility effects in different interference paradigms such as the Simon and flanker task even when the task was distributed across two co-actors. In both Simon and flanker tasks, performance is improved in compatible trials relative to incompatible trials if one actor works on the task alone as well as if two co-actors share the task. These findings have been taken to indicate that actors automatically co-represent their co-actor's task. However, recent research on the joint Simon and joint flanker effect suggests alternative non-social interpretations. To which degree both joint effects are driven by the same underlying processes is the question of the present study, and it was scrutinized by manipulating the visibility of the co-actor. While the joint Simon effect was not affected by the visibility of the co-actor, the joint flanker effect was reduced when participants did not see their co-actors but knew where the co-actors were seated. These findings provide further evidence for a spatial interpretation of the joint Simon effect. In contrast to recent claims, however, we propose a new explanation of the joint flanker effect that attributes the effect to an impairment in the focusing of spatial attention contingent on the visibility of the co-actor.

  3. Joint ventures

    DEFF Research Database (Denmark)

    Sørensen, Karsten Engsig

    Afhandlingen analysere de konkurrenceretlige og selskabsretlige regler som er bestemmende for hvordan et joint venture samarbejde er struktureret......Afhandlingen analysere de konkurrenceretlige og selskabsretlige regler som er bestemmende for hvordan et joint venture samarbejde er struktureret...

  4. A New Method for Determination of Joint Roughness Coefficient of Rock Joints

    Directory of Open Access Journals (Sweden)

    Shigui Du

    2015-01-01

    Full Text Available The joint roughness coefficient (JRC of rock joints has the characteristic of scale effect. JRC measured on small-size exposed rock joints should be evaluated by JRC scale effect in order to obtain the JRC of actual-scale rock joints, since field rock joints are hardly fully exposed or well saved. Based on the validity analysis of JRC scale effect, concepts of rate of JRC scale effect and effective length of JRC scale effect were proposed. Then, a graphic method for determination of the effective length of JRC scale effect was established. Study results show that the JRC of actual-scale rock joints can be obtained through a fractal model of JRC scale effect according to the statistically measured results of the JRC of small-size partial exposed rock joints and by the selection of fractal dimension of JRC scale effect and the determination of effective length of JRC scale effect.

  5. Laboratory characterization of rock joints

    International Nuclear Information System (INIS)

    Hsiung, S.M.; Kana, D.D.; Ahola, M.P.; Chowdhury, A.H.; Ghosh, A.

    1994-05-01

    A laboratory characterization of the Apache Leap tuff joints under cyclic pseudostatic and dynamic loads has been undertaken to obtain a better understanding of dynamic joint shear behavior and to generate a complete data set that can be used for validation of existing rock-joint models. Study has indicated that available methods for determining joint roughness coefficient (JRC) significantly underestimate the roughness coefficient of the Apache Leap tuff joints, that will lead to an underestimation of the joint shear strength. The results of the direct shear tests have indicated that both under cyclic pseudostatic and dynamic loadings the joint resistance upon reverse shearing is smaller than that of forward shearing and the joint dilation resulting from forward shearing recovers during reverse shearing. Within the range of variation of shearing velocity used in these tests, the shearing velocity effect on rock-joint behavior seems to be minor, and no noticeable effect on the peak joint shear strength and the joint shear strength for the reverse shearing is observed

  6. THE RELATIONSHIP BETWEEN TEMPOROMANDIBULAR-JOINT MOBILITY AND PERIPHERAL JOINT MOBILITY RECONSIDERED

    NARCIS (Netherlands)

    Dijkstra, P.U.; DEBONT, L.G.M.; VANDERWEELE, L.T.; Boering, G.

    The purpose of this paper was to study the relationship between temporomandibular joint (TMJ) mobility and mobility of joints and to study the general character of joint mobility in 83 subjects, 55 females and 28 males (mean age 26.7, range 13-46 years). The subjects were recruited from the

  7. Dual joint space arthrography in temporomandibular joint disorders: Comparison with single inferior joint space arthrography

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyung Sik; Chang, Duk Soo; Lee, Kyung Soo; Kim, Woo Sun; Sung, Jung Ho; Jun, Young Hwan [Capital Armed Forces General Hospital, Seoul (Korea, Republic of)

    1989-02-15

    The temporomandibular joint(TMJ) is really a complex of two synovial space separated by fibrocartilaginous disc. Single inferior joint space arthrography is commonly performed for evaluation of TMJ disorders, which is known to be superior in demonstrating joint dynamics. But it reveals only the inferior surface of the disc. Therefore, dual space arthrography is superior to demonstrate the soft tissue anatomic feature of the joint such as disc position and shape. Authors performed 83 TMJ arthrograms in TMJ problems. Initially, the inferior joint space was done and then the superior space was sequentially contrasted. The follow results were noted: 1. In all cases, dual space arthrography revealed accurate disc shape and positions. 2. Concordant findings between the two techniques: 68 cases (82%). Discordance between the two techniques: 15 cases (18%) 3. Possible causes of discordance between inferior and dual space arthrography. a) Normal varians of anterior recess: 3 cases b) Posterior disc displacement: 4 cases c) Influence of the patient's head position change :4 cases d) False perforation: 2 cases e) Reduction change: 2 cases 4. In 5 cases with anterior displacement, dual space arthrography gave additional findings such as adhesion within the superior space, which could not be evaluated by single inferior space.

  8. Experimental study on effects of drilling parameters on respirable dust production during roof bolting operations.

    Science.gov (United States)

    Jiang, Hua; Luo, Yi; McQuerrey, Joe

    2018-02-01

    Underground coalmine roof bolting operators exhibit a continued risk for overexposure to airborne levels of respirable coal and crystalline silica dust from the roof drilling operation. Inhaling these dusts can cause coal worker's pneumoconiosis and silicosis. This research explores the effect of drilling control parameters, specifically drilling bite depth, on the reduction of respirable dust generated during the drilling process. Laboratory drilling experiments were conducted and results demonstrated the feasibility of this dust control approach. Both the weight and size distribution of the dust particles collected from drilling tests with different bite depths were analyzed. The results showed that the amount of total inhalable and respirable dust was inversely proportional to the drilling bite depth. Therefore, control of the drilling process to achieve proper high-bite depth for the rock can be an important approach to reducing the generation of harmful dust. Different from conventional passive engineering controls, such as mist drilling and ventilation approaches, this approach is proactive and can cut down the generation of respirable dust from the source. These findings can be used to develop an integrated drilling control algorithm to achieve the best drilling efficiency as well as reducing respirable dust and noise.

  9. Joint Electromagnetic Spectrum Management Operations

    Science.gov (United States)

    2012-03-20

    promulgate command-specific policy and guidance for EMS use, the joint restricted frequency list (JRFL) process, the joint communications–electronics...joint communications–electronics operating instructions (JCEOI) and joint restricted frequency list (JRFL). Examples of FM include providing the...joint restricted frequency list Figure III-4. Joint Frequency Management Office Spectrum Management Process Chapter III III-10 JP 6-01 assignments

  10. Joint diseases

    International Nuclear Information System (INIS)

    Weissman, S.D.

    1989-01-01

    The authors discuss how x-ray examination is essential in the diagnosis and evaluation of the arthritides. Most arthritides are first suspected by the clinician, and x-ray evaluation of these entities along with laboratory testing is important for confirmation of the clinical diagnosis and in staging of the disease process. Several arthritides are often diagnosed first by the podiatrist on x-ray evaluation, including pseudogout, ankylosing spondylitis, early rheumatoid arthritis, degenerative joint disease, and tuberculosis of bone. The joint responds to insult in only a limited number of ways that become apparent on x-ray. The soft tissues surrounding the joint, the articulating bones, and alignment of the joint space may all be involved by the arthritic process. On roentgenographic examination, the soft tissues must be examined for edema, masses, calcifications, and atrophy. The articulating bones must be examined for demineralization, erosions, osteophytes, periosteal reaction, cysts and sclerosis

  11. Imaging findings of charcot joint

    International Nuclear Information System (INIS)

    Meng Quanfei; Zhou Chunxiang; Chen Yingming; Jiang Bo

    2003-01-01

    Objective: To analyze the MRI characters of Charcot joint, and to evaluate the diagnostic value of X-ray, CT, and MRI on Charcot joint. Methods: Eight patients with 8 Charcot joints underwent X-ray, CT, and MR examinations. 6 of them had syringomyelia, 1 patient had injury of the spinal cord, and 1 case had diabetes. All 8 patients had sensory reduction or deficit in the sick extremities. Results: There were two types of Charcot joint, hypertrophic and atrophic. Radiographic and CT features of hypertrophic joint (n=3) showed hyperostotic osteosclerosis and mammoth osteophytes in the sick bones, periarticular ossification, and articular disorganization. Radiographic and CT features of atrophic joint (n=5) showed extensive bone resorption (destruction), periarticular debris, and articular disorganization. Main MRI features of Charcot joint included hydrarthrosis within joint capsule, thickened, loose, and elongated joint capsule with para-joint, peri-diaphysis, and inter-muscular extension in a pseudopodia pattern. The irregular joint capsule wall was presented as mild hypointensity on T 1 WI, slight hyper-intensity on T 2 WI, and was markedly enhanced after Gd-DTPA was administrated, which was considered as a characteristic manifestation of the lesion. Soft tissue mass containing hypo-intense stripes on both T 1 WI and T 2 WI was commonly noted adjacent to the involved joint. Conclusion: X-rays plain film is the first choice for the diagnosis of Charcot joint, and MRI is pretty useful in the diagnosis of Charcot joint

  12. Formation of tough composite joints

    International Nuclear Information System (INIS)

    Brun, M.K.

    1997-05-01

    Joints which exhibit tough fracture behavior were formed in a composite with a Si/SiC matrix reinforced with Textron SCS-6 fibers with either boron nitride or silicon nitride fiber coatings. In composites with BN coatings fibers were aligned uniaxially, while composites with Si 3 N 4 -coated fibers had a 0/90 degree architecture. Lapped joints (joints with overlapping fingers) were necessary to obtain tough behavior. Geometrical requirements necessary to avoid brittle joint failure have been proposed. Joints with a simple overlap geometry (only a few fingers) would have to be very long in order to prevent brittle failure. Typical failure in these joints is caused by a crack propagating along the interfaces between the joint fingers. Joints of the same overall length, but with geometry changed to be symmetric about the joint centerline and with an extra shear surface exhibited tough fractures accompanied with extensive fiber pullout. The initial matrix cracking of these joints was relatively low because cracks propagated easily through the ends of the fingers. Joints with an optimized stepped sawtooth geometry produced composite-like failures with the stress/strain curves containing an elastic region followed by a region of rising stress with an increase of strain. Increasing the fiber/matrix interfacial strength from 9 to 25 MPa, by changing the fiber coating, increased matrix cracking and ultimate strength of the composite significantly. The best joints had matrix cracking stress and ultimate strength of 138 and 240 MPa, respectively. Joint failure was preceded by multiple matrix cracking in the entire composite. The high strength of the joints will permit building of structures containing joints with only a minor reduction of design stresses

  13. Automated detection of cracks on the faying surface within high-load transfer bolted speciments

    Science.gov (United States)

    Wheatley, Gregory; Kollgaard, Jeffrey R.

    2003-07-01

    Boeing is currently conducting evaluation testing of the Comparative Vacuum Monitoring (CVMTM) system offered by Structural Monitoring Systems, Ltd (SMS). Initial testing has been conducted by SMS, with further test lab validations to be performed at Boeing in Seattle. Testing has been conducted on dog bone type specimens that have been cut at the center line. A notch was cut at one of the bolt holes and a CVM sensor installed on both sides of the plate. The doublers were added and a single line of 4 bolts along the longitudinal center line were used to attach the doubler plates to the dog bone type specimen. In this way, a high load transfer situation exists between the two halves of the dog bone specimen and the doubler plates. The CVM sensors are slightly over 0.004" (0.1mm) in thickness and are installed directly upon the faying surface of the dog bone specimen. Testing was conducted on an Instron 8501 Servohydraulic testing machine at the Department of Mechanical and Materials Engineering, University of Western Australia. The standard laboratory equipment offered by Structural Monitoring Systems, Ltd was used for crack detection. This equipment included the Kvac (vacuum supply) and the Sim8 (flow meter). The Sim8 was electrically connected to the Instron machine so that as soon as a crack was detected, fatigue loading was halted. The aim of the experiment was for CVM to detect a crack on the faying surface of the specimens at a length of 0.050" +/- 0.010". This was accomplished successfully. CVM has been developed on the principle that a small volume maintained at a low vacuum is extremely sensitive to any ingress of air. In addition to the load bearing sensors described above, self-adhesive, elastomeric sensors with fine channels on the adhesive face have been developed. When the sensors have been adhered to the structure under test, these fine channels, and the structure itself, form a manifold of galleries alternately at low vacuum and atmospheric pressure

  14. Experimental joint immobilization in guinea pigs. Effects on the knee joint

    Science.gov (United States)

    Marcondesdesouza, J. P.; Machado, F. F.; Sesso, A.; Valeri, V.

    1980-01-01

    In young and adult guinea pigs, the aftermath experimentally induced by the immobilization of the knee joint in hyperextended forced position was studied. Joint immobilization which varied from one to nine weeks was attained by plaster. Eighty knee joints were examined macro and microscopically. Findings included: (1) muscular hypotrophy and joint stiffness in all animals, directly proportional to the length of immobilization; (2) haemoarthrosis in the first week; (3) intra-articular fibrous tissue proliferation ending up with fibrous ankylosis; (4) hyaline articular cartilage erosions; (5) various degrees of destructive menisci changes. A tentative explanation of the fibrous tissue proliferation and of the cartilage changes is offered.

  15. Prosthesis of the wrist-joint

    Energy Technology Data Exchange (ETDEWEB)

    Feldmeier, C.

    1983-02-25

    Function of the hand-joint and the well-being of patients can be severely affected by arthrosis of the wrist-joint. Therapeutically, arthrodesis usually results in a painfree status of stiffness. A painless and well functioning joint can be achieved by alloplastic joint replacement or resurfacing. The possibilities and clinical results in cases of arthrosis of the carpo-metacarpal joint of the thumb, pseudarthrosis of the scaphoid, aseptic necrosis of the Lunate and severe arthrosis of the radio-carpal joint are demonstrated.

  16. [Short-term effectiveness of Swanson artificial joint replacement in treating posttraumatic metacarpophalangeal joint stiffness].

    Science.gov (United States)

    Lu, Hui; Shen, Xiangqian; Xu, Jihua; Huang, Xin; Ye, Po; Wu, Shoucheng

    2011-11-01

    To investigate the short-term effectiveness of Swanson artificial joint replacement in treating post-traumatic metacarpophalangeal joint stiffness. Between August 2007 and May 2010, 11 cases (13 fingers) of metacarpophalangeal joint stiffness with soft tissue defects underwent Swanson artificial joint replacement. There were 7 males (9 fingers) and 4 females (4 fingers), aged 43 to 65 years with an average of 49 years. The involved fingers included 4 thumbs, 4 index fingers, 3 middle fingers, and 2 ring fingers. The types of injury included open and crush injury in 8 fingers, fracture of the metacarpophalangeal joint in 3 fingers, metacarpophalangeal joint severing in 2 fingers. The time from joint stiffness to hospitalization was 12 to 48 weeks (mean, 24 weeks). The joint activity was (136.82 +/- 28.96) degrees. According to total active motion (TAM) assessment, included good in 1 finger, fair in 6 fingers, and poor in 6 fingers before operation. The activities of daily living were assessed by Sollerman score, which was 45.64 +/- 11.04. The X-ray films and CT scan showed traumatic arthritis of the metacarpophalangeal joint. The incision healed by first intention. All patients were followed up 12 to 34 months (mean, 24.1 months). At last follow-up, the joint activity was (194.64 +/- 28.86) degrees, showing significant difference when compared with preoperative value (t = 25.214, P = 0.000). According to TAM assessment, including excellent in 1 finger, good in 4 fingers, fair in 7 fingers, and poor in 1 finger. The Sollerman score was 67.45 +/- 8.20 postoperatively, showing significant difference when compared with the preoperative score (t = -10.470, P = 0.000). X-ray examination showed no prosthesis fracture, periprosthetic fracture, or joint dislocation occurred at last follow-up. Swanson artificial joint replacement can be applied to treat post-traumatic metacarpophalangeal joint stiffness, which can improve the joint activity and has satisfactory short

  17. A Review of Natural Joint Systems and Numerical Investigation of Bio-Inspired GFRP-to-Steel Joints

    Directory of Open Access Journals (Sweden)

    Evangelos I. Avgoulas

    2016-07-01

    Full Text Available There are a great variety of joint types used in nature which can inspire engineering joints. In order to design such biomimetic joints, it is at first important to understand how biological joints work. A comprehensive literature review, considering natural joints from a mechanical point of view, was undertaken. This was used to develop a taxonomy based on the different methods/functions that nature successfully uses to attach dissimilar tissues. One of the key methods that nature uses to join dissimilar materials is a transitional zone of stiffness at the insertion site. This method was used to propose bio-inspired solutions with a transitional zone of stiffness at the joint site for several glass fibre reinforced plastic (GFRP to steel adhesively bonded joint configurations. The transition zone was used to reduce the material stiffness mismatch of the joint parts. A numerical finite element model was used to identify the optimum variation in material stiffness that minimises potential failure of the joint. The best bio-inspired joints showed a 118% increase of joint strength compared to the standard joints.

  18. Prosthesis of the wrist-joint

    International Nuclear Information System (INIS)

    Feldmeier, C.

    1983-01-01

    Function of the hand-joint and the well-being of patients can be severely affected by arthrosis of the wrist-joint. Therapeutically, arthrodesis usually results in a painfree status of stiffness. A painless and well functioning joint can be achieved by alloplastic joint replacement or resurfacing. The possibilities and clinical results in cases of arthrosis of the carpo-metacarpal joint of the thumb, pseudarthrosis of the scaphoid, aseptic necrosis of the Lunate and severe arthrosis of the radio-carpal joint are demonstrated. (orig.) [de

  19. Part I. Remembering No. 2 (Ladislav Loerinc). EMO joint venture, joint-stock company - really completely useless organ?

    International Nuclear Information System (INIS)

    Blaha, M.

    2008-01-01

    In this chapter author reviewed the story of the EMO joint venture, joint-stock company, between Slovenske elektrarne, a. s. and EdF. EMO joint venture, joint-stock company, was established to complete the Mochovce nuclear power plant. EMO joint venture, joint-stock company was closed after one year of work. History of EMO joint venture, joint-stock company, was described by its former general manager Mr. Ladislav Loerinc.

  20. Effect of Strain Rate on Joint Strength and Failure Mode of Lead-Free Solder Joints

    Science.gov (United States)

    Lin, Jian; Lei, Yongping; Fu, Hanguang; Guo, Fu

    2018-03-01

    In surface mount technology, the Sn-3.0Ag-0.5Cu solder joint has a shorter impact lifetime than a traditional lead-tin solder joint. In order to improve the impact property of SnAgCu lead-free solder joints and identify the effect of silver content on tensile strength and impact property, impact experiments were conducted at various strain rates on three selected SnAgCu based solder joints. It was found that joint failure mainly occurred in the solder material with large plastic deformation under low strain rate, while joint failure occurred at the brittle intermetallic compound layer without any plastic deformation at a high strain rate. Joint strength increased with the silver content in SnAgCu alloys in static tensile tests, while the impact property of the solder joint decreased with increasing silver content. When the strain rate was low, plastic deformation occurred with failure and the tensile strength of the Sn-3.0Ag-0.5Cu solder joint was higher than that of Sn-0.3Ag-0.7Cu; when the strain rate was high, joint failure mainly occurred at the brittle interface layer and the Sn-0.3Ag-0.7Cu solder joint had a better impact resistance with a thinner intermetallic compound layer.

  1. Forming a multinational joint venture

    International Nuclear Information System (INIS)

    Bhatia, N.K.; Garb, R.H.; Statton, T.D.

    1990-01-01

    This paper discusses the basis and mechanics for forming a multinational joint venture. The topics of the paper include the motivations for a joint venture, selection of the appropriate co-venturer, management of the multinational joint venture, and the joint venture agreement. The authors state that a joint venture is not applicable or desirable in all instances and to be successful, must be carefully planned

  2. Joint imaging

    International Nuclear Information System (INIS)

    Hengst, W.

    1984-01-01

    Joint imaging is a proven diagnostic procedure which has become indispensable to the detection and treatment of different joint diseases in almost all disciplines. The method is suited for early diagnosis of joint affections both in soft tissue and bone which cannot be detected by X-ray or other procedures. The local activity accumulation depends on the rate of metabolism and is visualized in the scan, which in turn enables the extension and floridity of focal lesions to be evaluated and followed-up. Although joint scans may often give hints to probabilities relevant to differential diagnosis, the method is non-specific and only useful if based on the underlying clinical picture and X-ray finding, if possible. The radiation exposure is very low and does not represent a hazard in cases of adequate assessment of indication. In pregnant women and children the assessment of indication has to be based on very strict principles. The method is suited for out-patient diagnosis and can be applied in all installations equipped with a gamma camera and a technetium generator. (orig.) [de

  3. Managing Joint Production Motivation

    DEFF Research Database (Denmark)

    Lindenberg, Siegwart; Foss, Nicolai Juul

    2011-01-01

    We contribute to the microfoundations of organizational performance by proffering the construct of joint production motivation. Under such motivational conditions individuals see themselves as part of a joint endeavor, each with his or her own roles and responsibilities; generate shared...... representations of actions and tasks; cognitively coordinate cooperation; and choose their own behaviors in terms of joint goals. Using goal-framing theory, we explain how motivation for joint production can be managed by cognitive/symbolic management and organizational design....

  4. Mechanics of Suture Joints

    Science.gov (United States)

    Li, Yaning; Song, Juha; Ortiz, Christine; Boyce, Mary; Ortiz Group/DMSE/MIT Team; Boyce Group/ME/MIT Team

    2011-03-01

    Biological sutures are joints which connect two stiff skeletal or skeletal-like components. These joints possess a wavy geometry with a thin organic layer providing adhesion. Examples of biological sutures include mammalian skulls, the pelvic assembly of the armored fish Gasterosteus aculeatus (the three-spined stickleback), and the suture joints in the shell of the red-eared slider turtle. Biological sutures allow for movement and compliance, control stress concentrations, transmit loads, reduce fatigue stress and absorb energy. In this investigation, the mechanics of the role of suture geometry in providing a naturally optimized joint is explored. In particular, analytical and numerical micromechanical models of the suture joint are constructed. The anisotropic mechanical stiffness and strength are studied as a function of suture wavelength, amplitude and the material properties of the skeletal and organic components, revealing key insights into the optimized nature of these ubiquitous natural joints.

  5. Generalised joint hypermobility and knee joint hypermobility: prevalence, knee joint symptoms and health-related quality of life in a Danish adult population.

    Science.gov (United States)

    Junge, Tina; Henriksen, Peter; Hansen, Sebrina; Østengaard, Lasse; Golightly, Yvonne M; Juul-Kristensen, Birgit

    2017-10-27

    Several biomechanical factors, such as knee joint hypermobility (KJH), are suggested to play a role in the etiology of knee joint symptoms and knee osteoarthritis. Nevertheless, the prevalence or consequences of KJH solely or included in the classification of generalized joint hypermobility (GJHk) is unknown for a general population. Therefore, the objectives were to report the prevalence of self-reported GJHk and KJH, as well as the association of these conditions to knee joint symptoms, severity and duration of symptoms, and health-related quality of life (HRQoL) in a Danish adult population. This study is a cross-sectional population-based survey of 2056 Danish adults. Respondents received online questionnaires of GJHk and KJH, knee joint symptoms, the severity and duration of these, as well as HRQoL. Total response rate was 49% (n = 1006). The prevalence of self-reported GJHk and KJH was 13% and 23%, mostly representing women. More than half of the respondents with GJHk and KJH had knee joint symptoms. The odds for reporting knee joint symptoms, severity of knee joint symptoms and duration of knee joint symptoms were twice as high for respondents with GJHk and KJH. Respondents with GJHk and KJH reported lower HRQoL. GJHk and KJH were frequently reported in the Danish adult population, mostly in women. Respondents with GJHk and KJH were two times more likely to report knee joint-related symptoms such as pain, reduced performance of usual activity and lower HRQoL. The impact of these conditions on HRQoL is comparable with knee osteoarthritis. © 2017 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.

  6. Joint Intentionality

    Directory of Open Access Journals (Sweden)

    Koreň Ladislav

    2016-03-01

    Full Text Available According to the shared intentionality hypothesis proposed by Michael Tomasello, two cognitive upgrades – joint and collective intentionality, respectively – make human thinking unique. Joint intentionality, in particular, is a mindset supposed to account for our early, species-specific capacity to participate in collaborative activities involving two (or a few agents. In order to elucidate such activities and their proximate cognitive-motivational mechanism, Tomasello draws on philosophical accounts of shared intentionality. I argue that his deference to such cognitively demanding accounts of shared intentional activities is problematic if his theoretical ambition is in part to show that and how early (prelinguistic and precultural capacities for joint action contribute to the development of higher cognitive capacities.

  7. Analysis Of Effect Of Mechanical Properties Of Aluminum Alloy Addition Of Zinc Corrosion Resistance Of Carbon Steel A325 Bolts Process Of Hot Dip Galvanizing

    Directory of Open Access Journals (Sweden)

    Ery Diniardi

    2015-08-01

    Full Text Available The world oil industry are common in offshore areas that are included in a corrosive environment so that the low-carbon steel bolts A325 will gradually corroded. Therefore an alternative that can be done to reduce the corrosion rate that is by coating with a Hot dip galvanizing method. The purpose of this study to improve the quality of products from low carbon steel bolts A325 with the addition of Zinc Aluminium alloy on the results of the Hot Dip Galvanizing. Results of testing the hardness of the lowest obtained in quenching time of 30 seconds is 162 037 HVN and the highest hardness obtained on quenching time of 60 seconds is 203 688 HVN. To microstructure shows that the phase Eta which is soft on the surface of the outermost started a little not as much time quenching 30 seconds so that the nature of its decline and violence increased the phase Zeta that are hard are widely spread meet the layer of phase resulting in hardness of the coating while quenching 45 seconds exceed the hardness of quenching time of 30 seconds. Results of analysis of the rate of corrosion that galvanized coating on each test is different and the structure of ferrite and pearlite it looks clear. For quenching time of 30 seconds obvious difference in galvanized layer thicker than quenching time of 45 and 60 seconds. This happens because of the influence of factors zinc layer that coats the base material so that decreased levels of corrosion is comparable to the time Salt Spray Test SST performed.

  8. The temporomandibular joint

    International Nuclear Information System (INIS)

    Campbell, W.

    1984-01-01

    Whilst the temporomandibular joint is in many ways unique, it is subject to all the diseases and disorders found in joints in other parts of the human skeleton. By far the most common disorder is injury, followed by arthropathy, acute and chronic dislocations, ankylosis, and in rare instances, neoplasms. The diagnosis and management of the temporomandibular joint are the primary responsibility of the oral surgeon. Nevertheless, this anatomical region is an area in which the cooperation of medical and dental disciplines may be required for the satisfactory conclusion of treatment. The more so when the disease process involves either associated psychosomatic illness or malignancy. The mainstay of the diagnosis is a careful radiological examination of the joint. There exists a delicate relationship between the dentition, the muscles of mastication, and the temporomandibular articulation, which is controlled by arthrokinetic reflex activity of the branches of the 5th cranial nerve. Imbalance between one or more of the components of this integrated system frequently leads to disturbances in function. Pain-dysfunction disorders constitute the larger part of temporomandibular joint disturbances generally encountered

  9. Benign joint hypermobility syndrome

    Directory of Open Access Journals (Sweden)

    Iwona Słowińska

    2014-11-01

    Full Text Available Benign joint hypermobility syndrome (BJHS, commonly known as loose ligament syndrome, is a non-inflammatory rheumatic condition. It is characterised by a greater than normal range of motion of the joints of the limbs and spine. The prevalence of the syndrome in preschool-age children is estimated to be between 2% and 30%, depending on ethnic background (with higher prevalence in Asian and African populations, occurring most often in families with a history of the condition and more frequently in girls. This paper presents a case report of a 12-year-old girl. A broad differential diagnostic approach to recurrent joint inflammation with joint effusion and pain made it possible to establish a diagnosis of benign joint hypermobility syndrome. The child met the Brighton criteria; her Beighton score was 7 out of 9. Patient education aimed at eliminating abnormal joint movement and an appropriate rehabilitation programme play key roles in the treatment of BJHS.

  10. Sacroiliac joint dysfunction.

    Science.gov (United States)

    Ilaslan, Hakan; Arslan, Ahmet; Koç, Omer Nadir; Dalkiliç, Turker; Naderi, Sait

    2010-07-01

    Sacroiliac joint dysfunction is a disorder presenting with low back and groin pain. It should be taken into consideration during the preoperative differential diagnosis of lumbar disc herniation, lumbar spinal stenosis and facet syndrome. Four cases with sacroiliac dysfunction are presented. The clinical and radiological signs supported the evidence of sacroiliac dysfunction, and exact diagnosis was made after positive response to sacroiliac joint block. A percutaneous sacroiliac fixation provided pain relief in all cases. The mean VAS scores reduced from 8.2 to 2.2. It is concluded that sacroiliac joint dysfunction diagnosis requires a careful physical examination of the sacroiliac joints in all cases with low back and groin pain. The diagnosis is made based on positive response to the sacroiliac block. Sacroiliac fixation was found to be effective in carefully selected cases.

  11. Metallic joints for very high vacuum; Joints metalliques pour ultra-vide

    Energy Technology Data Exchange (ETDEWEB)

    Paigne, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1961-07-01

    After defining three main types of joint; three types of distribution of the tightening force in the clamps are demonstrated; the distribution of stresses, distortion and displacements in these clamps is then calculated by means of the theory of elasticity. This is followed by experimental results on a particular means of tightening (i.e. screw-clamps). From a brief discussion on the behaviour of the clamps it is possible finally to define other types of joint deriving from the main types originally foreseen. (author) [French] Apres avoir defini trois principaux types de joints, on met en evidence trois types de distribution des forces de serrage des brides; puis on calcule a l'aide de la theorie de l'elasticite la distribution des contraintes, deformations et deplacements dans ces brides. On donne ensuite des resultats experimentaux sur un mode de serrage particulier (cas des serres-joints). Une discussion sommaire sur le comportement des brides permet de definir finalement d'autres types de joints derivant des types principaux envisages initialement. (auteur)

  12. Acromioclavicular joint separation

    Directory of Open Access Journals (Sweden)

    Devan Pandya, BS

    2018-04-01

    Full Text Available History of present illness: A 30-year-old male was brought in by ambulance to the emergency department as a trauma activation after a motorcycle accident. The patient was the helmeted rider of a motorcycle traveling at an unknown speed when he lost control and was thrown off his vehicle. He denied loss of consciousness, nausea, or vomiting. The patient’s vital signs were stable and his only complaint was pain around his left shoulder. On exam, the patient had a prominent left clavicle without skin compromise. He had adequate range of motion in the left shoulder with moderate pain, and his left upper extremity was neurovascularly intact. Significant findings: Plain films of the left shoulder showed elevation of the left clavicle above the acromion. There was an increase in the acromioclavicular (AC and coracoclavicular (CC distances (increased joint distances marked with red and blue arrows, respectively. A normal AC joint measures 1-3 mm whereas a normal CC distance measures 11-13 mm.1 The injury was classified as a Rockwood type III AC joint separation. Discussion: The AC joint is a synovial joint between an oval facet on the acromion and a similar facet on the distal end of the clavicle. Horizontal stability is provided by the AC joint while axial stability is provided by the CC joint.2,3 AC joint injuries account for about 9%-12% of shoulder girdle injuries, and the most common mechanism is direct trauma.4,5 Initial evaluation with imaging includes plain films with three views: the anterior-posterior (AP view with the shoulder in internal and external rotation as well as an axillary, or scapula-Y view (sensitivity 40%, specificity 90% for all films.6,7 AC joint injuries are classified by the Rockwood system.8 Type I involves a sprain or incomplete tear of the AC ligaments with an intact CC ligament. The AC joint appears normal on X-ray, but can become widened with stress, achieved by having the patient hold a 10-15 pound weight from each

  13. Hip joint injection

    Science.gov (United States)

    ... medicine into the joint. The provider uses a real-time x-ray (fluoroscopy) to see where to place ... Wakefield RJ. Arthrocentesis and injection of joints and soft tissue. In: Firestein GS, Budd RC, Gabriel SE, ...

  14. Local reinforcement of magnesium components by friction processing. Determination of bonding mechanisms and assessment of joint properties

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, G.A. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Materialforschung

    2008-07-01

    The development of new creep-resistant and cost effective die casting magnesium alloys, such as AE, MRI, MEZ, ACM, AXJ, AJ, WE, have emerged as an alternative, to fulfil the modern demands in structurally relevant applications, such as engine blocks, gears and converter boxes. However, in most cases, magnesium components are screwed with aluminium and steel bolts, which lead the screwed joints to lose the preload force, due to relaxation. This barrier thereby limits the broad use of magnesium within this segment and should somehow find an adequate solution to help overcome this limitation. Furthermore, together with alloy development and the addition of reinforcement (MMCs), local material engineering processes have been conceived and are considered a method to improve the properties and therefore expand the number of potential applications for magnesium alloys. In this context, Friction Welding (FW) and particularly Friction Hydro Pillar Processing (FHPP), which can be described as a drill and fill process, appear to be an alternative to make the use of magnesium more widespread. For this reason, FHPP is intended to be used, to locally reinforce the mechanically fastened magnesium components. With this approach, regions submitted to the stresses imposed by tightening forces can be compensated by the use of a material with superior properties. It is not required to fabricate the whole structure from an expensive material, thus saving costs and thereby satisfying the economic pressures of an increasingly competitive global market. In the present work, a preliminary experimental matrix was defined and used to determine the optimal welding conditions for each specific material combination selected. Further, elaborate experimental techniques are used to describe the process parameters-microstructure-properties relationships and the consequent mechanisms leading to bonding in FHPP welds in similar and dissimilar configurations. The welds were performed using a hydraulic

  15. Parameter identification for joint elements in a revolute-joint detector manipulator

    International Nuclear Information System (INIS)

    Preissner, C.; Shu, D.; Royston, T.

    2005-01-01

    A revolute-joint robot is being developed for the spatial positioning of an x-ray detector at the Advanced Photon Source. Commercially available revolute-joint manipulators do not meet our size, positioning, or payload specifications. One idea being considered is the modification of a commercially available robot, with the goal of improving the repeatability and trajectory accuracy. Theoretical, computational, and experimental procedures are being used to (1) identify, (2) simulate the dynamics of an existing robot system using a multibody approach, and eventually (3) design an improved version, with low dynamic positioning uncertainty. A key aspect of the modeling and performance prediction is accurate stiffness and damping values for the robot joints. This paper discusses the experimental identification of the stiffness and damping parameters for one robot harmonic drive joint

  16. A GBT-framework towards modal modelling of steel structures

    DEFF Research Database (Denmark)

    Hansen, Anders Bau; Jönsson, Jeppe

    2017-01-01

    In modern structural steel frame design, the modelling of joints between beams and columns are based on very simple assumptions. The joints are most often assumed to behave as a perfect hinge or as a rigid joint. This means that in the overall static analysis relative rotations and changes...... the rotational stiffness of a connection. Based on a modelling of any beam-to-column joint using finite shell elements and springs for single components such as bolts, it is the primary hypothesis that it is possible to formulate a generalized connection model with few degrees of freedom related to a relevant...... set of deformation modes. This hypothesis is based on the idea of modal decomposition performed in generalized beam theories (GBT). The question is – is it possible to formulate an eigenvalue problem with a solution corresponding to mode shapes for the deformation of the joint by using the finite...

  17. Quantifying the impact of transient joint symptoms, chronic joint symptoms, and arthritis: a population-based approach.

    Science.gov (United States)

    Busija, Lucy; Buchbinder, Rachelle; Osborne, Richard H

    2009-10-15

    To estimate the prevalence and co-occurrence of self-reported doctor-diagnosed arthritis, chronic joint symptoms (pain, aching, stiffness, or swelling on most days for a month), and transient joint symptoms (pain, aching, stiffness, or swelling but not on most days for a month), and to compare the sociodemographic characteristics, activity limitations, and health-related quality of life (HRQOL) of people with joint conditions with those who have no self-reported doctor-diagnosed arthritis and no joint symptoms. Data from the 2004 population-based South Australian Health Omnibus Survey (n = 2,840, ages 18-96 years) were used in the study. Activity limitations were assessed using 10 activity limitations questions from the Short Form 36 health survey. HRQOL was assessed using the Assessment of Quality of Life scale. Half of all respondents reported having joint problems, with 26%, 11%, and 13% reporting self-reported doctor-diagnosed arthritis, chronic joint symptoms, and transient joint symptoms, respectively. Chronic joint conditions (self-reported doctor-diagnosed arthritis and chronic joint symptoms) accounted for 74% of all joint problems and were associated with higher odds of activity limitations and poorer HRQOL. The frequency of transient and chronic joint symptoms was highest among middle-aged participants (ages 45-54 years for transient and 45-64 years for chronic joint symptoms) and those who had a body mass index in the obese range. Prevalence of self-reported doctor-diagnosed arthritis increased with age and was higher among women and those who were overweight or obese. This study documented the high prevalence and impact of joint conditions in the community. Chronic joint conditions affect daily life and are substantial barriers for effective public health interventions aimed at reducing obesity and inactivity.

  18. Analysis of the Behaviour of Semi Rigid Steel End Plate Connections

    Directory of Open Access Journals (Sweden)

    Bahaz A.

    2018-01-01

    Full Text Available The analysis of steel-framed building structures with full strength beam to column joints is quite standard nowadays. Buildings utilizing such framing systems are widely used in design practice. However, there is a growing recognition of significant benefits in designing joints as partial strength/semi-rigid. The design of joints within this partial strength/semi-rigid approach is becoming more and more popular. This requires the knowledge of the full nonlinear moment-rotation behaviour of the joint, which is also a design parameter. The rotational behaviour of steel semi rigid connections can be studied using the finite element method for the following three reasons: i such models are inexpensive; ii they allow the understanding of local effects, which are difficult to measure accurately physically, and iii they can be used to generate extensive parametric studies. This paper presents a three-dimensional finite element model using ABAQUS software in order to identify the effect of different parameters on the behaviour of semi rigid steel beam to column end plate connections. Contact and sliding between different elements, bolt pretension and geometric and material non-linearity are included in this model. A parametric study is conducted using a model of two end-plate configurations: flush and extended end plates. The studied parameters were as follows: bolts type, end plate thickness and column web stiffener. Then, the model was calibrated and validated with experimental results taken from the literature and with the model proposed by Eurocode3. The procedure for determining the moment–rotation curve using finite element analysis is also given together with a brief explanation of how the design moment resistance and the initial rotational stiffness of the joint are obtained.

  19. Laboratory Method for Evaluating the Characteristics of Expansion Rock Bolts Subjected to Axial Tension / Laboratoryjna Metoda Badania Charakterystyk Kotew Rozprężnych Poddanych Rozciąganiu Osiowemu

    Science.gov (United States)

    Korzeniowski, Waldemar; Skrzypkowski, Krzysztof; Herezy, Łukasz

    2015-03-01

    Rock bolts have long been used in Poland, above all in the ore mining. Worldwide experience (Australia, Chile, Canada, South Africa, Sweden, and USA) provides evidence of rock bolt supports being used for loads under both static and dynamic conditions. There are new construction designs dedicated to the more extreme operating conditions, particularly in mining but also in tunneling. Appreciating the role and significance of the rock bolt support and its use in Polish conditions amounting to millions of units per year, this article describes a new laboratory test facility which enables rock bolt testing under static load conditions. Measuring equipment used as well as the possibilities of the test facility were characterized. Tests were conducted on expansion rock bolt supports installed inside a block simulating rock mass with compression strength of 80 MPa, which was loaded statically as determined by taking account of the load in order to maintain the desired axial tension, which was statically burdened in accordance with determined program load taking into consideration the maintenance of set axial tension strength at specified time intervals until capacity was exceeded. As an experiment the stress-strain characteristics of the rock bolt support were removed showing detailed dependence between its geometrical parameters as well as actual rock bolt deformation and its percentage share in total displacement and deformation resulting from the deformation of the bolt support elements (washer, thread). Two characteristic exchange parts with varying intensity of deformation /displacement per unit were highlighted with an increase in axial force static rock bolt supports installed in the rock mass. Obudowa kotwowa jest już od dawna stosowana w Polsce, przede wszystkim w górnictwie rudnym. Światowe doświadczenia (Australia, Chile, Kanada, RPA, Szwecja,USA) świadczą o stosowaniu obudowy kotwowej zarówno w warunkach obciążeń o charakterze statycznym jak i

  20. Can symptomatic acromioclavicular joints be differentiated from asymptomatic acromioclavicular joints on 3-T MR imaging?

    Science.gov (United States)

    Choo, Hye Jung; Lee, Sun Joo; Kim, Jung Han; Cha, Seong Sook; Park, Young Mi; Park, Ji Sung; Lee, Jun Woo; Oh, Minkyung

    2013-04-01

    To evaluate retrospectively whether symptomatic acromioclavicular joints can be differentiated from asymptomatic acromioclavicular joints on 3-T MR imaging. This study included 146 patients who underwent physical examination of acromioclavicular joints and 3-T MR imaging of the shoulder. Among them, 67 patients showing positive results on physical examination were assigned to the symptomatic group, whereas 79 showing negative results were assigned to the asymptomatic group. The following MR findings were compared between the symptomatic and asymptomatic groups: presence of osteophytes, articular surface irregularity, subchondral cysts, acromioclavicular joint fluid, subacromial fluid, subacromial bony spurs, joint capsular distension, bone edema, intraarticular enhancement, periarticular enhancement, superior and inferior joint capsular distension degree, and joint capsular thickness. The patients were subsequently divided into groups based on age (younger, older) and the method of MR arthrography (direct MR arthrography, indirect MR arthrography), and all the MR findings in each subgroup were reanalyzed. The meaningful cutoff value of each significant continuous variable was calculated using receiver operating characteristic analysis. The degree of superior capsular distension was the only significant MR finding of symptomatic acromioclavicular joints and its meaningful cutoff value was 2.1mm. After subgroup analyses, this variable was significant in the older age group and indirect MR arthrography group. On 3-T MR imaging, the degree of superior joint capsular distension might be a predictable MR finding in the diagnosis of symptomatic acromioclavicular joints. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  1. MP Joint Arthritis

    Science.gov (United States)

    ... All Topics A-Z Videos Infographics Symptom Picker Anatomy Bones Joints Muscles Nerves Vessels Tendons About Hand Surgery What is a Hand Surgeon? What is a Hand Therapist? Media Find a Hand Surgeon Home Anatomy MP Joint Arthritis Email to a friend * required ...

  2. Functional disorders of the temporomandibular joints: Internal derangement of the temporomandibular joint.

    Science.gov (United States)

    Chang, Chih-Ling; Wang, Ding-Han; Yang, Mu-Chen; Hsu, Wun-Eng; Hsu, Ming-Lun

    2018-04-01

    Temporomandibular joint (TMJ) is one of the most complex joints of the human body. Due to its unique movement, in terms of combination of rotation and translator movement, disc of the joint plays an important role to maintain its normal function. In order to sustain the normal function of the TMJ, disc must be kept in proper position as well as maintain normal shape in all circumstances. Once the disc is not any more in its normal position during function of the joint, disturbance of the joint can be occurred which will lead to subsequent distortion of the disc. Shape of the disc can be influenced by many factors i.e.: abnormal function or composition of the disc itself. Etiology of the internal derangement of the disc remains controversial. Multifactorial theory has been postulated in most of previous manuscripts. Disc is composed of mainly extracellular matrix. Abnormal proportion of collagen type I & III may also leads to joint hypermobility which may be also a predisposing factor of this disorder. Thus it can be recognized as local manifestation of a systemic disorder. Different treatment modalities with from conservative treatment to surgical intervention distinct success rate have been reported. Recently treatment with extracellular matrix injection becomes more and more popular to strengthen the joint itself. Since multifactorial in character, the best solution of the treatment modalities should be aimed to resolve possible etiology from different aspects. Team work may be indication to reach satisfied results. Copyright © 2018. Published by Elsevier Taiwan.

  3. Water flow in single rock joints

    International Nuclear Information System (INIS)

    Hakami, Eva

    1989-05-01

    To study the hydromechanical properties of single rock joints a technique to make transparent replicas of natural joint surfaces has been developed. Five different joint samples were replicated and studied. The aperture distribution of the joints were obtained through a measurement method provided by the transparent replicas. The principle behind the method is that a water drop with a known volume, which is placed inside a joint, will cover a certain area of the surface depending on the average size of aperture at the actual point. Flow tests were performed on the same joint replicas. The tortuousity of the flow and the velocity along single stream lines were measured using colour injections into the water flow through the joints. The equivalent hydraulic apertures determined from the flow tests where shown to be smaller than the average mechanical apertures. The velocity of the flow varies strongly between different paths over the joint depending on the spatial distribution of the apertures. The degree of matedness between the joint surfaces is an important factor influencing the channeling character of the joints. (author) (38 refs.)

  4. Effect of joint design on ballistic performance of quenched and tempered steel welded joints

    International Nuclear Information System (INIS)

    Balakrishnan, M.; Balasubramanian, V.; Madhusudhan Reddy, G.

    2014-01-01

    Highlights: • Traditional usage of austenitic stainless steel filler for armour steel welding shows poor ballistic performance. • Earlier efforts show dubious success on ballistic resistance of armour steel joints. • Comparative evaluation of equal/unequal joint design on ballistic performance. • Effect of joint design covers the main aspects of successful bullet stoppage. - Abstract: A study was carried out to evaluate the effect of joint design on ballistic performance of armour grade quenched and tempered steel welded joints. Equal double Vee and unequal double Vee joint configuration were considered in this study. Targets were fabricated using 4 mm thick tungsten carbide hardfaced middle layer; above and below which austenitic stainless steel layers were deposited on both sides of the hardfaced interlayer in both joint configurations. Shielded metal arc welding process was used to deposit for all layers. The fabricated targets were evaluated for its ballistic performance and the results were compared in terms of depth of penetration on weld metal. From the ballistic test results, it was observed that both the targets successfully stopped the bullet penetration at weld center line. Of the two targets, the target made with unequal double Vee joint configuration offered maximum resistance to the bullet penetration at weld metal location without any bulge at the rear side. The higher volume of austenitic stainless steel front layer and the presence of hardfaced interlayer after some depth of soft austenitic stainless steel front layer is the primary reason for the superior ballistic performance of this joint

  5. Determination of anatomic landmarks for optimal placement in captive-bolt euthanasia of goats.

    Science.gov (United States)

    Plummer, Paul J; Shearer, Jan K; Kleinhenz, Katie E; Shearer, Leslie C

    2018-03-01

    OBJECTIVE To determine the optimal anatomic site and directional aim of a penetrating captive bolt (PCB) for euthanasia of goats. SAMPLE 8 skulls from horned and polled goat cadavers and 10 anesthetized horned and polled goats scheduled to be euthanized at the end of a teaching laboratory. PROCEDURES Sagittal sections of cadaver skulls from 8 horned and polled goats were used to determine the ideal anatomic site and aiming of a PCB to maximize damage to the midbrain region of the brainstem for euthanasia. Anatomic sites for ideal placement and directional aiming were confirmed by use of 10 anesthetized horned and polled goats. RESULTS Clinical observation and postmortem examination of the sagittal sections of skulls from the 10 anesthetized goats that were euthanized confirmed that perpendicular placement and firing of a PCB at the intersection of 2 lines, each drawn from the lateral canthus of 1 eye to the middle of the base of the opposite ear, resulted in consistent disruption of the midbrain and thalamus in all goats. Immediate cessation of breathing, followed by a loss of heartbeat in all 10 of the anesthetized goats, confirmed that use of this site consistently resulted in effective euthanasia. CONCLUSIONS AND CLINICAL RELEVANCE Damage to the brainstem and key adjacent structures may be accomplished by firing a PCB perpendicular to the skull over the anatomic site identified at the intersection of 2 lines, each drawn from the lateral canthus of 1 eye to the middle of the base of the opposite ear.

  6. Bistable Articulated Joint

    Science.gov (United States)

    Graighead, Norwood D., II; Preliasco, R. J.; Hult, T. D.

    1986-01-01

    Joint with four-bar-linkage geometry has following attributes: Springs to fully extended fully folded positions. Automatically locks in its extended position. Joint combines zero backlash, positive locking, and centerline pivoting. Used in folding tool handles, portable antenna booms, and many other deployable structures.

  7. [Classification and Treatment of Sacroiliac Joint Dislocation].

    Science.gov (United States)

    Tan, Zhen; Huang, Zhong; Li, Liang; Meng, Wei-Kun; Liu, Lei; Zhang, Hui; Wang, Guang-Lin; Huang, Fu-Guo

    2017-09-01

    To develop a renewed classification and treatment regimen for sacroiliac joint dislocation. According to the direction of dislocation of sacroiliac joint,combined iliac,sacral fractures,and fracture morphology,sacroiliac joint dislocation was classified into 4 types. Type Ⅰ (sacroiliac anterior dislocation): main fracture fragments of posterior iliac wing dislocated in front of sacroiliac joint. Type Ⅱ (sacroiliac posterior dislocation): main fracture fragments of posterior iliac wing dislocated in posterior of sacroiliac joint. Type Ⅲ (Crescent fracturedislocation of the sacroiliac joint): upward dislocation of posterior iliac wing with oblique fracture through posterior iliac wing. Type ⅢA: a large crescent fragment and dislocation comprises no more than onethird of sacroiliac joint,which is typically inferior. Type ⅢB: intermediatesize crescent fragment and dislocation comprises between one and twothirds of joint. Type ⅢC: a small crescent fragment where dislocation comprises most,but not the entire joint. Different treatment regimens were selected for different types of fractures. Treatment for type Ⅰ sacroiliac joint dislocation: anterior iliac fossa approach pry stripping reset; sacroiliac joint fixed with sacroiliac screw through percutaneous. Treatment for type Ⅱ sacroiliac joint dislocation: posterior sacroiliac joint posterior approach; sacroiliac joint fixed with sacroiliac screw under computer guidance. Treatment for type ⅢA and ⅢB sacroiliac joint dislocation: posterior sacroiliac joint approach; sacroiliac joint fixed with reconstruction plate. Treatment for type ⅢC sacroiliac joint dislocation: sacroiliac joint closed reduction; sacroiliac joint fixed with sacroiliac screw through percutaneous. Treatment for type Ⅳ sacroiliac joint dislocation: posterior approach; sacroiliac joint fixed with spinal pelvic fixation. Results of 24 to 72 months patient follow-up (mean 34.5 months): 100% survival,100% wound healing,and 100

  8. Reliability of agriculture universal joint shafts based on temperature measuring in universal joint bearing assemblies

    Directory of Open Access Journals (Sweden)

    Аleksandar Asonja

    2015-03-01

    Full Text Available This paper presents a research into reliability calculations of agriculture double universal joint shafts based on temperature measuring in cardan-type universal joint bearing assemblies. Special laboratory equipment was developed for this research which is presented in the paper. The objective of this research was to test the real life span of universal joint shafts in the laboratory and in field, to obtain the results which can be used to improve the reliability of universal joint shafts. If the presented research were used along with maintenance measures recommended in the paper and with proper use, the level of reliability of the shafts would be 2.1 times higher. The presented results of the research showed that needle bearings, i.e. bearing assemblies of the joints, are the most critical elements on universal joint shafts and are possible causes of their lower reliability. The second universal joint is the part with the lowest reliability in the observed technical system.

  9. Facet joint syndrome

    International Nuclear Information System (INIS)

    Zigrai, M.; Zakovic, J.; Brezinova, M.; Pavlovicova, M.

    2002-01-01

    It is the purpose of the study to demonstrate the clinical relevance of degenerative changes in the facet joint of patients with low back pain irradiating to the lower extremities, and discuss some problems relating to diagnosis and different diagnosis. 119 patients presenting the listed bellow syndromes are covered by the study: scoliosis, polytopic pain vertebral syndrome, paresis and history of trauma. all patients undergo comprehensive neurological examination with special attention focused on the spine: CT and plain x-rays are taken of the lumbosacral segment to assess the condition of the facet joints. The neurological examination demonstrates in all cases pain syndrome in the lumbar spine referred to one or both lower extremities. In 56% it is a matter of persisting pain, and in 44% - recurrent. More than half of the patients complain of sacroiliac (SI) dislocation and palpatory pain. Unilateral or bilateral degenerative changes are documented by imaging studies in all patients, including: subchondral thickening, osteopathy narrowing the lateral or central part of the spinal canal with ensuing nerve root compression. The lumbosacral zygoapophyseal joints are source of pseudoradicular pain. A correlation between clinical picture and GT changes is noted in all patients with facet joint syndrome. CT is an indispensable method in diagnosing facet joint syndrome. (authors)

  10. Lower limb joint work and joint work contribution during downhill and uphill walking at different inclinations.

    Science.gov (United States)

    Alexander, Nathalie; Strutzenberger, Gerda; Ameshofer, Lisa Maria; Schwameder, Hermann

    2017-08-16

    Work performance and individual joint contribution to total work are important information for creating training protocols, but were not assessed so far for sloped walking. Therefore, the purpose of this study was to analyze lower limb joint work and joint contribution of the hip, knee and ankle to total lower limb work during sloped walking in a healthy population. Eighteen male participants (27.0±4.7yrs, 1.80±0.05m, 74.5±8.2kg) walked on an instrumented ramp at inclination angles of 0°, ±6°, ±12° and ±18° at 1.1m/s. Kinematic and kinetic data were captured using a motion-capture system (Vicon) and two force plates (AMTI). Joint power curves, joint work (positive, negative, absolute) and each joint's contribution to total lower limb work were analyzed throughout the stance phase using an ANOVA with repeated measures. With increasing inclination positive joint work increased for the ankle and hip joint and in total during uphill walking. Negative joint work increased for each joint and in total work during downhill walking. Absolute work was increased during both uphill (all joints) and downhill (ankle & knee) walking. Knee joint contribution to total negative and absolute work increased during downhill walking while hip and ankle contributions decreased. This study identified, that, when switching from level to a 6° and from 6° to a 12° inclination the gain of individual joint work is more pronounced compared to switching from 12° to an 18° inclination. The results might be used for training recommendations and specific training intervention with respect to sloped walking. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Intramedullary fixation of proximal humerus fractures: do locking bolts endanger the axillary nerve or the ascending branch of the anterior circumflex artery? A cadaveric study

    Directory of Open Access Journals (Sweden)

    Sermon An

    2008-12-01

    Full Text Available Abstract Background Proximal humerus fractures are one of the most common fractures. Intramedullary locked nailing is becoming a popular alternative treatment, especially for easier fracture patterns. Although axillary nerve injury has been reported, no study has compared the safety of the proximal locking options relative to the axillary nerve and the ascending branch of the anterior circumflex artery. Method Six different commercially available proximal humeral nails were implanted in 30 shoulders of 18 cadavers. After fluoroscopically guided implantation the shoulders were carefully dissected and the distance between the locking screws, the axillary nerve and the ascending branch of the anterior circumflex artery was measured. Results The course of the axillary nerve varies. A mean distance of 55.8 mm (SD = 5.3 between the lateral edge of the acromions and the axillary nerve at the middle of the humerus in a neutrally rotated position was observed. The minimum distance was 43.4 mm, the maximum 63.9 mm. Bent nails with oblique head interlocking bolts appeared to be the most dangerous in relation to the axillary nerve. The two designs featuring such a bend and oblique bolt showed a mean distance of the locking screw to the axillary nerve of 1 mm and 2.7 mm respectively Sirus (Zimmer® and (Stryker® T2 PHN (Proximal Humeral Nail. Regarding the ascending branch of the anterior circumflex artery, there was no difference between the nails which have an anteroposterior locking option. Conclusion It is of great importance for surgeons treating proximal humerus fractures to understand the relative risk of any procedure they perform. Since the designs of different nailing systems risk damaging the axillary nerve and ascending branch, blunt dissection, the use of protection sleeves during drilling and screw insertion, and individual risk evaluation prior to the use of a proximal humeral nail are advocated.

  12. [Temporo-mandibular joint. Morpho-functional considerations].

    Science.gov (United States)

    Scutariu, M D; Indrei, Anca

    2004-01-01

    The temporo-mandibular joint is distinguished from most other synovial joints of the body by two features: 1. the two jointed components carry teeth whose position and occlusion introduce a very strong influence on the movements of the temporo-mandibular joint and 2. its articular surfaces are not covered by hyaline cartilage, but by a dense, fibrous tissue. This paper describes the parts of the temporo-mandibular joint: the articular surfaces (the condylar process of the mandible and the glenoid part of the temporal bone), the fibrocartilaginous disc which is interposed between the mandibular and the temporal surface, the fibrous capsule of the temporo-mandibular joint and the ligaments of this joint. All these parts present a very strong adaptation at the important functions of the temporo-mandibular joint.

  13. Utilization of Facet Joint and Sacroiliac Joint Interventions in Medicare Population from 2000 to 2014: Explosive Growth Continues!

    Science.gov (United States)

    Manchikanti, Laxmaiah; Hirsch, Joshua A; Pampati, Vidyasagar; Boswell, Mark V

    2016-10-01

    Increasing utilization of interventional techniques in managing chronic spinal pain, specifically facet joint interventions and sacroiliac joint injections, is a major concern of healthcare policy makers. We analyzed the patterns of utilization of facet and sacroiliac joint interventions in managing chronic spinal pain. The results showed significant increase of facet joint interventions and sacroiliac joint injections from 2000 to 2014 in Medicare FFS service beneficiaries. Overall, the Medicare population increased 35 %, whereas facet joint and sacroiliac joint interventions increased 313.3 % per 100,000 Medicare population with an annual increase of 10.7 %. While the increases were uniform from 2000 to 2014, there were some decreases noted for facet joint interventions in 2007, 2010, and 2013, whereas for sacroiliac joint injections, the decreases were noted in 2007 and 2013. The increases were for cervical and thoracic facet neurolysis at 911.5 % compared to lumbosacral facet neurolysis of 567.8 %, 362.9 % of cervical and thoracic facet joint blocks, 316.9 % of sacroiliac joints injections, and finally 227.3 % of lumbosacral facet joint blocks.

  14. Pluralism in Theories of Responsibility: Joint Criminal Enterprise versus Joint Perpetration

    NARCIS (Netherlands)

    Cupido, M.; van Sliedregt, E.; Vasiliev, S.

    2014-01-01

    This paper scrutinizes the alleged pluralism between JCE and joint perpetration. It illustrates that the ICC and the ICTY in practice establish criminal responsibility under JCE and joint perpetration based on the participants’ cooperation in, and informed contribution to, a (criminal) organization

  15. Elbow joint instability

    DEFF Research Database (Denmark)

    Olsen, Bo Sanderhoff; Henriksen, M G; Søjbjerg, Jens Ole

    1994-01-01

    The effect of simultaneous ulnar and radial collateral ligament division on the kinematics of the elbow joint is studied in a cadaveric model. Severance of the anterior part of the ulnar collateral ligament and the annular ligament led to significant elbow joint instability in valgus and varus...

  16. Welding of Aluminum Alloys to Steels: An Overview

    Science.gov (United States)

    2013-08-01

    and deformations are a few examples of the unwanted consequences which somehow would lead to brittle fracture, fatigue fracture, shape instability...was made under the copper tips of the spot welding machine. The fatigue results showed higher fatigue strength of the joints with transition layer...kHz ultrasonic butt welding system with a vibration source applying eight bolt-clamped Langevin type PZT transducers and a 50 kW static induction

  17. Mechanical Design and Analysis of a 200 MHz, Bolt-together RFQ forthe Accelerator Driven Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Virostek, Steve; Hoff, Matt; Li, Derun; Staples, John; Wells,Russell

    2007-06-20

    A high-yield neutron source to screen sea-land cargocontainers for shielded Special Nuclear Materials (SNM) has been designedat LBNL [1,2]. The Accelerator-Driven Neutron Source (ADNS) uses theD(d,n)3He reaction to create a forward directed neutron beam. Keycomponents are a high-current radio-frequency quadrupole (RFQ)accelerator and a high-power target capable of producing a neutron fluxof>107 n/(cm2 cdot s) at a distance of 2.5 m. The mechanical designand analysis of the four-module, bolt-together RFQ will be presentedhere. Operating at 200 MHz, the 5.1 m long RFQ will accelerate a 40 mAdeuteron beam to 6 MeV. At a 5 percent duty factor, the time-average d+beam current on target is 1.5 mA. Each of the 1.27 m long RFQ moduleswill consist of four solid OFHC copper vanes. A specially designed 3-DO-ring will provide vacuum sealing between both the vanes and themodules. RF connections are made with canted coil spring contacts. Aseries of 60 water-cooled pi-mode rods provides quadrupole modestabilization. A set of 80 evenly spaced fixed slug tuners is used forfinal frequency adjustment and local field perturbationcorrection.

  18. Mathematical Modeling of Column-Base Connections under Monotonic Loading

    Directory of Open Access Journals (Sweden)

    Gholamreza Abdollahzadeh

    2014-12-01

    Full Text Available Some considerable damage to steel structures during the Hyogo-ken Nanbu Earthquake occurred. Among them, many exposed-type column bases failed in several consistent patterns, such as brittle base plate fracture, excessive bolt elongation, unexpected early bolt failure, and inferior construction work, etc. The lessons from these phenomena led to the need for improved understanding of column base behavior. Joint behavior must be modeled when analyzing semi-rigid frames, which is associated with a mathematical model of the moment–rotation curve. The most accurate model uses continuous nonlinear functions. This article presents three areas of steel joint research: (1 analysis methods of semi-rigid joints; (2 prediction methods for the mechanical behavior of joints; (3 mathematical representations of the moment–rotation curve. In the current study, a new exponential model to depict the moment–rotation relationship of column base connection is proposed. The proposed nonlinear model represents an approach to the prediction of M–θ curves, taking into account the possible failure modes and the deformation characteristics of the connection elements. The new model has three physical parameters, along with two curve-fitted factors. These physical parameters are generated from dimensional details of the connection, as well as the material properties. The M–θ curves obtained by the model are compared with published connection tests and 3D FEM research. The proposed mathematical model adequately comes close to characterizing M–θ behavior through the full range of loading/rotations. As a result, modeling of column base connections using the proposed mathematical model can give crucial beforehand information, and overcome the disadvantages of time consuming workmanship and cost of experimental studies.

  19. About the Joint Chiefs of Staff

    Science.gov (United States)

    Skip to main content (Press Enter). Toggle navigation Joint Chiefs of Staff Joint Chiefs of Staff Joint Chiefs of Staff Facebook Twitter YouTube Flickr Blog Instagram Search JCS: Search Search Search JCS: Search Home Media News Photos Videos Publications About The Joint Staff Chairman Vice Chairman

  20. Joint-2D-SL0 Algorithm for Joint Sparse Matrix Reconstruction

    Directory of Open Access Journals (Sweden)

    Dong Zhang

    2017-01-01

    Full Text Available Sparse matrix reconstruction has a wide application such as DOA estimation and STAP. However, its performance is usually restricted by the grid mismatch problem. In this paper, we revise the sparse matrix reconstruction model and propose the joint sparse matrix reconstruction model based on one-order Taylor expansion. And it can overcome the grid mismatch problem. Then, we put forward the Joint-2D-SL0 algorithm which can solve the joint sparse matrix reconstruction problem efficiently. Compared with the Kronecker compressive sensing method, our proposed method has a higher computational efficiency and acceptable reconstruction accuracy. Finally, simulation results validate the superiority of the proposed method.