Sample records for anchor bolts

1. ANCHORING EFFECT ANALYSIS OF TENSIONED BOLTS

夏建中

1997-01-01

The paper analyses quantitatively the anchoring effect of tensioned bolts on surrounding rock strength, and defines two concepts: one is the surrounding rock strength increased amount △τ13 and the other is the strength influence factor k. The anchoring effect of tensioned bolts is considered to increase a strength increased amount △τ13 where △τ13 is the product k and tensioned load p, i. e. △τ13= kp, where k is a function of two variables x and y. The distributive properties both △τ13 and k are also discussed in the paper, obtaining some useful results for designing bolting support parameters.

2. Estimation of maximum axial force of anchor bolts in consideration of random bolt failures

This paper proposes a method for structural reliability analysis of anchor bolts used in the support skirt of a reactor vessel. The method is based on the conservative assumption that a few anchor bolts within the skirt's inner-wall may fail in a random nature. Under the assumption, the maximum axial forces in the intact bolts are estimated. To reflect the uncertainty, random numbers are generated to simulate the possible failed bolts among a total of 60 bolts, which are circumferentially arranged along the inner side of the wall. Then the outcome of failed bolts together with their locations for every 60 bolts is defined as an experiment of a sample. The locations of failed bolt can significantly affect the stress analysis and its random outcomes require an efficient calculation scheme. In this paper we propose a rapid calculation algorithm, thus the direction of bending moment that causes the worst scenario in the stress analysis of bolts for each experiment can be rapidly found. Taking into consideration of design loads, the finite element method is further employed to calculate the maximum axial bolt force of each experiment. After statistical analysis of maximum axial forces from all experiments, the average maximum axial-force interval that the remaining bolts can withstand under a given random condition is estimated with a 95% confidence level. This interval can be used in conjunction with various results of structural integrity assessment to ensure the structural safety and reliability of a nuclear power plant component

3. Effects of Anchor Bolts Failures in Steam Explosion Analyses

Kim, Seung Hyun; Chang, Yoon-Suk [Kyung Hee University, Yongin (Korea, Republic of); Song, Sungchu; Cho, Yong-Jin [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2015-05-15

Steam explosion may occur in a nuclear power plant by molten core-coolant interactions when the external reactor vessel cooling strategy is failed. This phenomenon can threat the integrity of reactor cavity, penetration piping and support structures. Even though extensive researches have been performed to predict influences of the steam explosion, due to complexity of physical phenomena and environmental thermal hydraulic conditions, it is remained as one of possible hazards. A steam explosion can cause intensive and rapid heat transfer, and lead to the formation of pressure waves and production of missiles that may endanger surrounding reactor cavity wall and associate components due to resulting dynamic effects. The goal of this research is to examine structural integrity of RPV (Reactor Pressure Vessel) support structures and anchor bolts under typical ex-vessel steam explosion conditions through FE analyses. Particularly, influence due to the failure of anchor bolts connecting RPV and support structures was evaluated. In this paper, influence of RPV and support structure due to the anchor bolt failure were evaluated under typical steam explosion conditions and the following conclusions were derived. The highest maximum stresses were calculated at the support structures under the steam explosion condition with the SVF and anchor bolts non-failure. The all stress values did not exceed their yield strengths. The displacements were high under anchor bolt failure conditions. However, the vertical movements of major components were small comparing to the overall dimensions of them.

4. Analysis on the anchor mechanism of the full length resin bolt

宋彦波; 刘洪涛

2003-01-01

The purpose of this paper is to reveal the stress distribution characteristic along the full length anchor bolt. Based on the mechanic model set up, the author calculated the anchor mechanism of the full length resin rock-bolt. The stress distribution characteristic is different according to different type of surrounding-rock. The conclusion is important to optimize the roadway bolt support design.

5. Vibration Characteristic of Anchoring System of Bolt and Elastic Wave Propagation Law

WANG Cheng; LI Yi; NING Jian-guo; LIN Hua-chang

2006-01-01

Based on one-dimension wave theory, the propagation law of elastic wave along the rock bolt, rock medium and their coupling system are researched, and the attenuation law and propagation mechanism of wave in the anchoring system are obtained. Meanwhile, the studies on end reflection and dynamic response under load are also carried out experimentally, the relationship between anchoring length and excited wave length is obtained when the end reflection of bolt emerges, and it is concluded that under the condition of bolt loaded,as the load increases, the reflection of the upper interface of anchoring segment weakens while the end reflection strengthens relatively, hence the energy attenuation increases. These results provide some important theory basis for measuring the effective anchoring length of bolt, judging the bonding quality of anchoring end and surrounding rock, and estimating the utmost load force of bolt.

6. Parameter analysis of anchor bolt support for large-span and jointed rock mass

LI Xi-bing; ZHOU Zi-long; LI Qi-yue; HU Liu-qing

2005-01-01

In order to obtain the optimal parameters of anchor bolt supporting system for large-span and jointed rock mass in Kaiyang Phosphor Mine, it is expensive and unavailable with the method of in-situ experiments. This paper describes a numerical modeling with discrete element method for the supporting effects of different type of anchor bolts. The anchor bolts with variant length of 0.5 m, 0.8 m, 1.0 m, diameter of 10 mm, 15 mm, 20 mm, setting spacing of 3.0 m, 2.5 m, 2.0 m, and setting angle of 10°, 20°, 30°, are simulated respectively. The results show that there exist optimal parameters of anchor bolt support for large-span and jointed rock mass. For the bolt support of the concerning, the optimal length is 2.5-3.5 m, the diameter is 25-35 mm, the spacing is 0.5-0.6 m, and the setting angle is 105°.

7. Numerical simulation of the effect of coupling support of bolt-mesh-anchor in deep tunnel

SUN Xiao-ming; CAI Feng; YANG Jun; CAO Wu-fu

2009-01-01

The mechanical effects of bolt-mesh-anchor coupling support in deep tunnels were studied by using a numerical method, based on deep tunnel coupling supporting techniques and non-linear deformation mechanical theory of rock mass at great depths. It is shown that the potential of a rigid bolt support can be efficiently activated through the coupling effect between a bolt-net support and the surrounding rock. It is found that the accumulated plastic energy in the surrounding rock can be sufficiently transformed by the coupling effect of a bolt-mesh-tray support. The strength of the surrounding rock mass can be mobilized to control the deformation of the surrounding rock by a pre-stress and time-space effect of the anchor support. The high stress transformation effect can be realized by the mechanical coupling effect of the bolt-mesh-anchor support, whereby the force of the support and deformation of the surrounding rock tends to become uniform, leading to a sustained stability of the tunnel.

8. Applied on bolting-cable anchor support of full-seam roadway in weaker thick coal seam

赵庆彪; 张生华; 郭励生

2003-01-01

The designing method and the supporting mechanism of both bolt and small cable anchor for full-seam roadway in the weaker thick coal seam are systematically analyzed, and the construction technology and the supporting results are briefly summarized.

9. Fundamental study on pull-out strength of cast-in-place anchor bolt in concrete subjected to high temperature

Some recent research on high temperature behavior of concrete shows that its strength will decrease with further increase of temperature, and other mechanical properties also get worse, due to drying shrinkage, thermal stress and so on. Cast-in place anchor bolts are used in many structural applications. There is possibility that these anchor bolts will be exposed to high temperature in a short time by some accident, and that the pull-out strength will decrease. This paper describes a study on the pull-out strength of a cast-in-place anchor bolt installed in concrete which is subjected to high temperatures up to 500degC to obtain basic experimental data and to examine the response of cast-in-place anchor bolts to high temperature exposure. Tests results show that the pull-out strength under high temperature decreases significantly. The pull-out strength during heating and after heating up to 500degC was 20% and 50% of it in normal temperature, respectively. (author)

10. Development of ultrasonic testing technique for anchor bolts. Part 2. Development of nondestructive examination method for fatigue cracks by ultrasonic phased array technology

Cracks may initiate in anchor bolts in nuclear power plants due to a severe earthquake. Moreover, number of fatigue cracks have been found in the anchor bolts in aged nuclear and thermal power plants. Ultrasonic phased array technology is effective to detect such cracks, and a method is proposed to determine crack depth by using refection echo at the vicinity of crack according to simulation results of wave propagation within bolts. However, detectability of crack and applicability of this method for crack sizing are not known though they are essential to evaluation of crack in bolts by ultrasonic phased array technology. In this report, we prepared M24 and M30 bolt specimens with various slits and fatigue cracks introduced. Three linear array probes with respective frequency of 2, 5 and 10 MHz are used to measure these specimens. The investigation of fracture surface is also performed after finishing all measurements. Measurement results show the following: (1) the frequency of 10 MHz is more appropriate than frequencies of 5 and 2 MHz for detecting crack in bolts; (2) it is easy to detect 1-mm-deep cracks; and (3) it is possible to determine crack depth for M30 bolts with the deviation of 2 mm from actual depth by proposed method, but difficult for M24 bolts. (author)

11. Application of the Expansion Anchor Bolt and the Chemical Anchor to the Stair Lift%膨胀螺栓和化学锚栓在楼梯升降机中的应用

蔡祖光; 万海如

2012-01-01

This paper introduces the construction,principle,failure way, design and selection,installation quality and the evaluation for the expansion anchor bolt and the chemical anchor, and discusses key points of the stair lift installation with the expansion anchor bolt and the chemical anchor in detail.%介绍了膨胀螺栓和化学锚栓的结构、工作机理、失效方式、设计选用、安装质量及其评定方法，详细讨论了楼梯升降机安装施工中使用膨胀螺栓和化学螺栓时应注意的问题。

12. Stress Analysis of Building Curtain Wall Post Embedment Anchor Bolt%建筑幕墙后置埋件锚栓受力分析

陆新鑫; 吴强

2014-01-01

本文根据JGJ 145—2013《混凝土结构后锚固技术规程》第5.2.2条，对后置埋件在双向受弯矩、双向受剪力、以及扭矩、拉力的共同作用下进行的锚栓受力做了分析，提出了复合力作用下后置埋件锚栓的计算公式。%This paper, according to article 5.2.2 of JGJ 145 -2013 “technical specification for concrete structure of anch-oring force”, made an analysis of the force analysis of post anchor bolt under the interaction of bi-directional torque, shear force, bending, put ing forward the calculation formula of posts anchor bolt under composite force.

13. Structural Integrity Assessment of High-Strength Anchor Bolt in Nuclear Power Plant based on Fracture Mechanics Concept

Lim, Eunmo; Huh, Namsu [Seoul Nat' l Univ. of Science and Technology, Seoul (Korea, Republic of); Shim, Heejin; Oh, Changkyun; Kim, Hyunsu [KEPCO Engineering and Construction Company, Inc., Yongin (Korea, Republic of)

2013-07-15

The failure of a bolted joint owing to stress corrosion cracking (Succ) has been considered one of the most important structural integrity issues in a nuclear power plant. In this study, the failure possibility of bolting, which is used to support the steam generator of a pressurized water reactor, owing to Succ and brittle fracture was evaluated in accordance with guidelines proposed by the Electric Power Research Institute, which are called the Reference Flaw Factor method. For this evaluation, first, detailed finite element stress analyses were conducted to obtain the actual nominal stresses of bolting in which either service loads or bolt preload were considered. Based on these nominal stresses, the structural integrity of bolting was addressed from the viewpoints of Succ and toughness. In addition, the accuracy of the EPRI Reference Flaw Factor for assessing bolting failure was investigated using finite element fracture mechanics analyses.

14. 客运专线隧道内接触网基础预留锚栓组方案探讨%Investigation of Reserved Anchor Bolt Group Scheme for OCS Pole Foundation of Passenger Dedicated Railway Line Tunnel

谭晓燕

2014-01-01

阐述了客运专线隧道内采用预埋锚栓组方案将接触网吊柱固定于隧道壁的可实施性。此种方法的力学性能及经济性能均介于后植入化学锚栓及预埋轨槽方式之间。从接触网吊柱柱底荷载计算、锚栓组承载能力、锚栓组对混凝土锥体破坏区域影响及施工措施等方面进行论证。对3种隧道内接触网基础预留锚固形式即预埋轨槽、后植入化学锚栓、锚栓组方式进行简要比较。得出若能对隧道施工工艺进行优化，预埋锚栓组将比预埋轨槽、后植入化学锚栓这两种方法经济性能更高、结构安全可靠，可作为今后高速电气化铁路隧道内优先考虑的一种预留锚固方法。%The feasibility of an embedded anchor bolt group scheme which is used in fixing OCS davit on tunnel sidewall of passenger dedicated line is described.The mechanical performance and economic performance of this scheme are all between the post-install embedded chemical anchor bolt form and the embedded rail slot form.A brief comparison of three reserved anchorage forms is made,including embedded rail slot form,post-install chemical anchor bolt form and anchor bolt group form.The conclusion is,if the tunnel construction technology could be optimized,the implantation of anchor bolt group form would be more economic and reliable than the other forms,and in future it will be used as the priority reservation anchoring method in high-speed e-lectrified railway tunnel.

15. Degradation theories of concrete and development of a new deviatoric model in incremental tangent formulation: limit analysis applied to case of anchor bolts embedded in concrete

This research is achieved in the general framework of the study of the concrete behaviour. It has for objective the development of a new behaviour model satisfying to the particular requirements for an industrial exploitation. After the analysis of different existent models, a first development has concerned models based on the smeared crack theory. A new formulation of the theory permitted to overcome the stress locking problem. However, the analysis showed the persistence of some limits inert to this approach in spite of this improvement. Then, an analysis of the physical mechanisms of the concrete degradation has been achieved and permitted to develop the new damage model MODEV. The general formulation of this model is based on the theory of the thermodynamics and applied to the case of the heterogeneous and brittle materials. The MODEV model considers two damage mechanisms: extension and sliding. The model considers also that the relative tangent displacement between microcracks lips is responsible of the strain irreversibility. Thus, the rate of inelastic strain becomes function of the damage and the heterogeneity index of the material. The unilateral effect is taken in account as an elastic hardening or softening process according to re-closing or reopening of cracks. The model is written within the framework of non standard generalised materials in incremental tangent formulation and implemented in the general finite element code SYMPHONIE. The validation of the model has been achieved on the basis of several tests issued from the literature. The second part of this research has concerned the development of the CHEVILAB software. This simulation tool based on the limit analysis approach permit the evaluation of the ultimate load capacity of anchors bolts. The kinematics approach of the limit analysis has been adapted to the problem of anchors while considering several specific failure mechanisms. This approach has been validated then by comparison with the

16. 锚杆机节能降耗应用实践%Application of energy saving Anchor Bolt Machine

胡雨武; 杨晓勇

2011-01-01

锚杆机设备的驱动电机功率较大,在生产过程中电耗过大,通过技术改造,降低电机功率,加装变频器等措施实现了节能。改造投入约为14000元,系统运行一年左右就可收回投资,具有非常现实的指导及推广意义。%Anchor Equipment drive motor power greater power consumption in the production process too,by reducing the motor power,the installation of inverter and other measures to achieve energy-saving.

17. Bolting applications

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.

18. Performance of D-bolts Under Static Loading

Li, Charlie C.

2012-03-01

D-bolt is a type of energy-absorbing rock bolt. It is made of a smooth steel bar with anchors spaced along the bolt length. A typical section between adjacent anchors is approximately 1-m long, but it can be adjusted to adapt to the rock conditions. The bolt is fully encapsulated with either cement or resin grout in a borehole. The anchors are firmly fixed into the grout, while the smooth bolt sections can freely deform to absorb deformation energy. Full-scale static pull tests were carried out at different testing facilities in two laboratories. The tests show that a smooth bolt section between anchors may elongate by 110-167 mm depending on the section length. Field trials of the D-bolt were conducted in deep metal mines. The measurements showed that the D-bolts were equally loaded within every anchor-between section, avoiding load peaks and premature bolt failure due to stress concentrations caused by fracture/joint opening. The field trials of rebar and D-bolts in a largely deformed mine tunnel showed that the D-bolts behaved satisfactorily, with only a few failed bolts, while a number of the rebar bolts failed at the thread.

19. Assessment of rock bolt systems for underground waste storage

A review of existing rock bolting systems was undertaken to assess their suitability in underground design for storage of nuclear waste. Unique engineering considerations are required due to the thermal pulse generated by the waste causing additional stress to the support system and possibly affecting anchorage stability. Field visits were made to four underground projects to assess the performance of a wide variety of rock bolt systems. Cable bolts, point anchor bolts, locally debonded full column cement grout bolts, and yieldable bolt systems show promise. Full scale testing of bolt systems is recommended, together with assessing temperature effects on grout strength and grout longterm stability

20. A study of rock bolting failure modes

Cao Chen; Jan Nemcik; Ren Ting; Naj Aziz

2013-01-01

Rock bolting has advanced rapidly during the past 4 decades due to a better understanding of load transfer mechanisms and advances made in the bolt system technology.Bolts are used as permanent and temporary support systems in tunnelling and mining operations.A review of has indicated that three systems of reinforcement devices have evolved as part of rock bolt and ground anchor while the rock is not generally thought of as being a component of the reinforcement system.A classification of rock bolting reinforcement systems is presented,followed by the fundamental theory of the load transfer mechanism.The failure mode of two phases of rock bolting system is formularised.The failure modes of cable bolting are discussed using a bond strength model as well as an iterative method.Finally,the interfacial shear stress model for ribbed bar is introduced and a closed form solution is obtained using a tri-line stress strain relationship.

1. Rock bolt mechanical analysis and its application to engineering

GUO Ling-yun; XIAO Ming; XIAO Ying-chun

2008-01-01

Combined with the 3D FEM, end-anchored anchorage bolts were simulated by implicit anchorage bolt element. Implicit anchorage bolt elements hide in the elements of rock mass and extremely simplify the element subdivision. The calculated value of an-chorage bolt stress is larger than the measured one for the most time. we further analyzed the reciprocity of anchorage bolt and rock mass, and then deduced the analytical equa-tions of anchorage bolt stress and rock mass deformation under elasto-plastic state. The results indicate that it is essential to revise the anchorage bolts stress by using the formu-las deduced when rock mass is softened or significantly deformed. Finally, a case study indicates that the calculated results agree with those measured. Some helpful methods are offerd for more accurate simulation of the support effect and anchorage bolts real stress state.

2. Probabilistic designing of bolted support

Janas, P.; Krejsa, M.; Šňupárek, Richard; Krejsa, V.

Praha: Czech Tunelling Association ITA/AITES, 2010 - (Zlámal, J.; Butovič, A.; Hilar, M.), s. 746-752 ISBN 978-80-254-7054-1. [Transport and City Tunnels. Praha (CZ), 14.06.2010-16.06.2010] R&D Projects: GA ČR GA105/07/1265 Institutional research plan: CEZ:AV0Z30860518 Keywords : bolting * probabilistic design * anchoring reinforcement Subject RIV: DH - Mining, incl. Coal Mining

3. Stress wave propagation in supporting bolts: A test for bolt support quality

Wu Rui; Xu Jinhai; Li Chong; Zhou Baojing; Ma Qianqian; Wang Zhongliang

2012-01-01

A test method for the non-destructive determination of bolt length,anchoring length,and bolt body force is described.This addresses the problems of low accuracy,limited number of data,and untimely warning signs encountered with existing test methods.Numerical simulations of the bolt,resin,and rock system show that the length accuracy when using the velocity wave is lower than when using the acceleration wave.It is accepted practice to use the acceleration wave for length tests because of improved signal to noise ratios of the waveforms.Laboratory and in situ underground tests showed that the precision of the measurements meets field requirements.Using this method the anchor properties of each single bolt and,thus,the safety of the entire roadway support may be evaluated.

4. Plan for the use of anchor bolts as a strata control mechanism in mine workings; Plan paca la aplicacion de tornillos de anclaje como mechanismo de control de terrenos en obras mineras

Berlanga, J.M.

1992-01-01

The present study has two objectives. Firstly, to present the fundamental principles of the method of support with bolts. Secondly, to provide a plan for the preparation of tests, whose results will lead to the acceptance or rejection of the method of roof support with bolts in the mines of the Rio Escondido coal region. 10 refs., 9 figs., 3 tabs.

5. Behavior of Fiber Glass Bolts, Rock Bolts and Cable Bolts in Shear

Li, Xuwei; Aziz, Naj; Mirzaghorbanali, Ali; Nemcik, Jan

2016-07-01

This paper experimentally compares the shear behavior of fiber glass (FG) bolt, rock bolt (steel rebar bolt) and cable bolt for the bolt contribution to bolted concrete surface shear strength, and bolt failure mode. Two double shear apparatuses of different size were used for the study. The tensile strength, the shear strength and the deformation modulus of bolt control the shear behavior of a sheared bolted joint. Since the strength and deformation modulus of FG bolt, rock bolt and cable bolt obtained from uniaxial tensile tests are different, their shear behavior in reinforcing joints is accordingly different. Test results showed that the shear stiffness of FG bolted joints decreased gradually from the beginning to end, while the shear stiffness of joints reinforced by rock bolt and cable bolt decreased bi-linearly, which is clearly consistent with their tensile deformation modulus. The bolted joint shear stiffness was highly influenced by bolt pretension in the high stiffness stage for both rock bolt and cable bolt, but not in the low stiffness stage. The rock bolt contribution to joint shear strength standardised by the bolt tensile strength was the largest, followed by cable bolts, then FG bolts. Both the rock bolts and cable bolts tended to fail in tension, while FG bolts in shear due to their low shear strength and constant deformation modulus.

6. Piezoelectric Bolt Breakers and Bolt Fatigue Testers

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

7. Study on full-length recoverable resin-metal bolts

孙玉宁; 康全玉

2003-01-01

The paper introduces a kind of full-length recoverable resin-metal bolts, expounds its structural principle and stress features, and gives some instances in laboratory tests and underground tests. The results show that full-length recoverable resin-metal bolts can be used for supporting the walls of class Ⅰ～Ⅲ mining gateways, that the anchoring force is 50 kN or so, and that the recoverability rate is more than 80%, thus the supporting effect is better than that of split-set bolts.

8. Bolt Stress Monitor

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.

9. Failure mechanism of bolting support and high-strength bolt-grouting technology for deep and soft surrounding rock with high stress

李术才; 王洪涛; 王琦; 江贝; 王富奇; 郭念波; 刘文江; 任尧喜

2016-01-01

In deep underground mining, the surrounding rocks are very soft with high stress. Their deformation and destruction are serious, and frequent failures occur on the bolt support. The failure mechanism of bolt support is proposed to solve these problems. A calculation theory is established on the bond strength of the interface between the anchoring agent and surrounding rocks. An analysis is made on the influence law of different mechanical parameters of surrounding rocks on the interfacial bond strength. Based on the research, a new high-strength bolt-grouting technology is developed and applied on site. Besides, some helpful engineering suggestions and measures are proposed. The research shows that the serious deformation and failure, and the lower bond strength are the major factors causing frequent failures of bolt support. So, the bolt could not give full play to its supporting potential. It is also shown that as the integrity, strength, interface dilatancy and stress of surrounding rocks are improved, the bond strength will increase. So, the anchoring force on surrounding rocks can be effectively improved by employing an anchoring agent with high sand content, mechanical anchoring means, or grouting reinforcement. The new technology has advantages in a high strength, imposing pre-tightening force, and giving full play to the bolt supporting potential. Hence, it can improve the control effect on surrounding rocks. All these could be helpful references for the design of bolt support in deep underground mines.

10. Optimization of Bolt Stress

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....

11. Factors Influencing the Quality of Encapsulation in Rock Bolting

Aziz, Naj; Craig, Peter; Mirzaghorbanali, Ali; Nemcik, Jan

2016-08-01

Bolt installation quality is influenced by various factors, some are well known and others are less recognised. A programme of field and laboratory studies was undertaken to examine various factors of relevance to the load transfer mechanism between the bolt, resin and rock to ensure test methods truly represent field performance. Short encapsulation tests were undertaken as part of the Australian Coal Association Research Program (ACARP) funded project (C21011) with the ultimate aim of developing standard test methods for assessing bolt encapsulation with chemical resin anchor installations. The field study consisted of a series of Short Encapsulation Pull Tests (SEPT) carried out in three mines with different geological conditions to determine the most representative and practical method of SEPT. Additional field work included installation of bolts into threaded steel tubes for subsequent removal and laboratory evaluation. A series of pull tests was carried out by installing bolts in overhead rig mounted sandstone block, cast in concrete with controlled encapsulation length. Factors of importance considered included; borehole diameter, resin annulus thickness, installation time (including bolt spin to the back and "spin at back"), the effect of gloving and hole over drill. It was found that the borehole diameter had a detrimental effect on the encapsulation bonding strength. Bolt installation time of approximately 10 s constituted an acceptable time for effective bolt installation and within the resin manufacturers recommended time of 14 s. Maintaining constant length of encapsulation was paramount for obtaining consistency and repeatability of the test results. Finally, a numerical simulation study was carried out to assess the capabilities of FLAC 2D software in simulating the pull testing of rock bolts.

12. Degradation theories of concrete and development of a new deviatoric model in incremental tangent formulation: limit analysis applied to case of anchor bolts embedded in concrete; Theorie de degradation du beton et developpement d'un nouveau modele d'endommagement en formulation incrementale tangente: calcul a la rupture applique au cas des chevilles de fixation ancrees dans le beton

Ung Quoc, H

2003-12-15

This research is achieved in the general framework of the study of the concrete behaviour. It has for objective the development of a new behaviour model satisfying to the particular requirements for an industrial exploitation. After the analysis of different existent models, a first development has concerned models based on the smeared crack theory. A new formulation of the theory permitted to overcome the stress locking problem. However, the analysis showed the persistence of some limits inert to this approach in spite of this improvement. Then, an analysis of the physical mechanisms of the concrete degradation has been achieved and permitted to develop the new damage model MODEV. The general formulation of this model is based on the theory of the thermodynamics and applied to the case of the heterogeneous and brittle materials. The MODEV model considers two damage mechanisms: extension and sliding. The model considers also that the relative tangent displacement between microcracks lips is responsible of the strain irreversibility. Thus, the rate of inelastic strain becomes function of the damage and the heterogeneity index of the material. The unilateral effect is taken in account as an elastic hardening or softening process according to re-closing or reopening of cracks. The model is written within the framework of non standard generalised materials in incremental tangent formulation and implemented in the general finite element code SYMPHONIE. The validation of the model has been achieved on the basis of several tests issued from the literature. The second part of this research has concerned the development of the CHEVILAB software. This simulation tool based on the limit analysis approach permit the evaluation of the ultimate load capacity of anchors bolts. The kinematics approach of the limit analysis has been adapted to the problem of anchors while considering several specific failure mechanisms. This approach has been validated then by comparison with the

13. Anchor reinforcements

Levkovich, P.Ye.; Sal' nikov, V.K.; Savich, N.S.

1980-11-30

An anchor reinforcement includes an anchor shaft, an elastic jig with a separator wall having compartments placed parallely along it and filled with reinforcement material and a device for destroying the jig wall separator. To quickly put the anchor in place and increase the reliability of the reinforcement by mixing the reinforcement material components better, the device for destroying the jig separator wall was made in the shape of a shovel, fastened to the anchor shaft and the separator wall has a longitudinal hollow for holding the anchor shaft/shovel.

14. Overall bolt stress optimization

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...

15. Bolt Analysis Program

Travis, Brandon E.

2004-01-01

In designing and testing bolted joints there are multiple parameters to be considered and calculations that must be performed to predict the joint behavior. Each different set of parameters may call for a different set of equations. Determining every parameter in each bolted joint is impractical and in many cases impossible. On the other hand, it is much easier to reduce these calculations to a universal set that can be used for all bolted joints. This is the purpose of the Bolt Analysis Program. My project under the Mechanical and Rotating Systems branch of the Engineering Development and Analysis Division was to take the Bolt Analysis Program Version 2.0 and update the program to a modem and user-friendly format. Version 2.0 of the Bolt Analysis Program is a useful program, but lacks the dynamic capabilities that are needed for current applications. Version 2.0 of the Bolt Analysis Program was written in 1993 using the Pascal programming language in a DOS format. This program allows you to input data in a step-by-step format, calculates the data, and then on a final screen displays the input and the output fiom the calculations. Version 2.0 is still applicable for all bolted joint anaiysis, but has updates that are desired. First, the program runs in DOS format. With the applications available today, my mentor decided it would be best to update the program into Excel using Visual Basic for Applications (VBA). This would allow the program to have multiple Graphical User Interfaces (GUI s) while retaining all functions of the previous program. Version 2.0 only allows you to input data in a step-by-step process. If you make a mistake and need to go back, you must run through the entire program before you can return to fix your error. This becomes tedious when needing to change one parameter or test multiple sets of data. In Version 3.0, the program allows you to enter and change data at any time while displaying real-time output data. If you realize an error, it is

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

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.

17. Experimental study on the inorganic chemical anchor bolt property after high temperature effect%高温作用后无机化学锚栓性能试验研究

韩瑞昌; 冼兰

2009-01-01

考虑温度、冷却方式及静置时间的影响,对高温作用后无机化学锚栓的性能进行了试验研究,结果表明,随温度的升高,抗拔承载力先降低,后回升,再大幅度降低,自然冷却的抗拔承载力高于浇水冷却,随静置时间的推移,抗拔承载力略为降低.%Considered temperature, cooling form and stewing time influences, the progerty of inorganic chemical anchor holt was studied exper-imentally. The result indicated that the withdrawal resistance bearing capacity decreased first, then recovery, then decreased at wide range with temperature increasing, the withdrawal resistance bearing capacity of natural cooling was higher than watering cooling, the withdrawal resistance bearing capacity reduced litter with stewing time traction.

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

19. Bolt Thread Stress Optimization

Pedersen, Niels Leergaard

2012-01-01

Designs of threaded fasteners are controlled by different standards, and the number of different thread definitions is large. The most commonly used thread is probably the metric ISO thread, and this design is therefore used in this paper. Thread root design controls the stress concentration factor...... 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...

20. FEM analyses of stress and deformation of a flexible inner pressure bolt

CHEN Zhong-he; WANG Wei-qiang; ZHANG Le-wen

2008-01-01

The flexible inner pressure bolt is a new kind and new structural bolt (anchor rod). A number of structural improvements and performance test have been carried out. The bolt has superior compatibility to the soft crag and the large distortion tunnel with its flexibility. In order to study its stress, deformation and interaction mechanism thoroughly, a number of large distortion calculations and analyses have been carried out on the bolt by FEM (finite element method), especially with the ANSYS software, based on the updated Lagrangian law. The results show that the maximum stress of the inner wall of the bolt is consistent with an elastic analytic solution. The maximum stress on the body occurs in the vicinity of the enhancement material. The link enhancement of the body seems to be quite essential. The experimental results indicate that the maximum injection pressure in the bolt is 2.5 MPa without link enhancement and 8.3 MPa with the enhancement. This link enhancement effect is highly significant. These results provide some basis for the design, application and anchoring stress analysis of the holt.

1. Rock bolting and pull out test on rebar bolts

Kristjánsson, Gunnar

2014-01-01

Pull out tests were carried out in the laboratory of rock mechanics at Norwegian University of Science and Technology (NTNU) for the purpose of determining the critical embedment length of fully grouted rebar bolts. The 20-mm rebar bolts and the grouting material, the Rescon Zinc bolt cement used in the testing are widely used in underground projects in Norway. Different embedment lengths, ranging from 10 cm to 40 cm, were employed in the tests under different water-cement ratios ...

2. New bolting structure of fractured roof based on the Bossinesq equations

2010-01-01

Present support theories contain a number of shortcomings in the designation of fractured roof bolt parameters of rectangular or trapezoidal coal roadways.Roof fall accidents occur easily in this kind of roadway.Based on the Bossinesq equations and the Mohr strength theory,we propose a theory of an anchored cluster structure for fractured roofs and have investigated the formation of such an anchored cluster structure,its self stability mechanism and mechanical properties.The results show that an anchor and ...

3. Considerations on the design of through-wall anchors

Connections to existing buildings are often the most difficult planning challenge for the realization of construction measures in case of piping system replacements in nuclear power plants. This is due to restricted space or limited load reserves of the building structure. Usually the realization of support connections to the existing buildings is achieved by anchor bolts. But in critical cases the preferred alternative solution uses through-wall anchors. Up to now uniform assessment thresholds are not available, no technical guidelines or regulations for construction variants exist. Through-wall anchors allow significantly higher load capacities for tensile and shear loads but require enhanced planning and realization efforts.

4. Ultrasonic extensometer measures bolt preload

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.

5. Rock bolts - Improved design and possibilities

Thomas-Lepine, Capucine

2012-01-01

SummaryRock Bolts, improved design and possibilitiesMaster thesis NTNU 2012Student : Capucine Thomas-LepineSupervisor : Leif LiaKey words : rock foundation, small concrete dam, rock mass classification, rock joints, shear strength of rock discontinuities, fully grouted passive rock bolts designMasters Thesis : Rock bolts, improved design and possibilities is a continuation from the Masters Thesis NTNU 2011 Rock bolts in dams, expected capacity by Lars Kristian Neby. In...

6. Stud bolt handling equipment for reactor vessel

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)

7. 49 CFR 236.329 - Bolt lock.

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Bolt lock. 236.329 Section 236.329 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... § 236.329 Bolt lock. Bolt lock shall be so maintained that signal governing movements over switch...

8. Performance evaluation of bolt-cutter system on first Taurus launch

Baban, F.; Williams, R.; Amimoto, S.; Hansen, W.; Bixler, T.

1994-10-01

In rapid response to the request of the Space Test and Experimentation Directorate in Space Launch Operations, a launch-critical experimental investigation was conducted to evaluate the performance of a particular bolt-cutter system for separating stages on the first Taurus launch. The tests were to examine the variation of tension preloading on the bolt system and to demonstrate the tolerable margin on this parameter for such launches with the new types of bolts since the preloading was known to vary as much as 12% from a preset value before launch. We planned and carried out the experiment, designed and assembled the fixture to properly simulate flight application, and developed diagnostics. Four bolt cutters were purchased from the manufacturer for these tests, and one was provided by the contractor. In addition to the obvious requirement to demonstrate the successful severing of bolts under varying preloads, ignition-wire current and timing of chisel impact on the bolt were monitored. An optical diagnostic was designed to determine the flyout velocity and kinetic energy of the broken pieces. These latter measurements will be useful in anchoring performance codes simulating and assessing the structural dynamics of the bolt-cutter function for future missions. The tests were conducted successfully and the bolts were severed successfully in all five tests. The preloads were successively lowered from 2,500 lb to 2,250, 2,000, 1,500, and 1,000 lb These tests contributed in a timely manner to the STEP launch decision and to launch mission assurance. They demonstrated important margin to the nominally set 3,200 lb. preload. The entire complicated experimental program from inception to completion was accomplished in less than three weeks.

9. Test and application of hydraulic expansion bolts in a roadway under goaf with ultra-close separation

Wang Xiangyu; Bai Jianbiao; Guo Guanlong; Yu Yang

2014-01-01

The roof of a roadway under goaf with ultra-close separation consists of thin rock strata and rocks caving in upper goaf. Influenced by the mining of the upper coal seam, the roof is loose and broken, and its integ-rity is poor. Resin anchored bolts cannot provide an effective anchoring force in such roof conditions. By conducting free expansion tests and field pull-out tests on a hydraulic expansion bolt, this study has ana-lyzed the influencing factors and laws of radial expansion and anchoring force changes in the rod body. This has revealed the anchoring mechanism of such bolts, and has obtained reasonable water injection pressures and suitable drilling diameters (which are 20–25 MPa and 32–35 mm respectively) for the hydraulic expansion bolt (u28 mm) used in these tests. Based on pull-out tests at different interlayer spacing, the applicability of hydraulic expansion bolts had been verified for controlling the roof of road-ways under goaf with ultra-close distance. Combined with the deformation and failure characteristics of the test roadway roof, this paper proposes a united roof-control technology based on the use of hydraulic expansion bolts and advancing intubation for the roof. Engineering practice indicated that the roof of the test roadway did not generate leaking and caving phenomenon, and the amount of roof deformation was controlled to within 150 mm. Maintenance of the roadway roof has been improved significantly, which ensures safe mining in coal seams with ultra-close separation.

10. Non-Destructive Evaluation of Rock Bolts Associated With Optical Strain Sensors at the Homestake Gold Mine

Kogle, M. M.; Fratta, D.; Wang, H. F.; Geox^Tm

2010-12-01

Fiber-Bragg Grating (FBG) optical strain sensors have been installed in the former Homestake Gold Mine (Lead, SD) as part of an early science project at the Deep Underground Science and Engineering Laboratory (DUSEL). FBG sensors are anchored within an alcove at the 4100’ level of the mine using rock bolts and coupled to the rock mass with resin epoxy and cement grout. The quality of the coupling between the rock bolt and the rock mass is essential to assure that true rock mass strains are being recorded. To evaluate the integrity of the installed rock bolt system, guided ultrasonic waves can be used as a non-destructive monitoring system. The propagation of reflected ultrasonic waves capture information about the degree of coupling between the steel rock bolt and resin epoxy/cement grout and between the resin epoxy/cement grout and the surrounding rock mass, and hence the integrity of the installed rock bolt system. In this study, we use the phase velocity obtained from ultrasonic wave propagation to estimate the rock modulus. In our initial testing we generated a broadband elastic wave along the length of a rock bolt anchored in a concrete cylinder while monitoring multiple reflections with a single accelerometer affixed at the exposed end of the rock bolt. The captured waveforms include several reflections that were then analyzed to obtain frequency response, coherence, phase velocity, and damping between multiple reflections. As the wavelength increases, the response captures first elastic properties of the steel and then the combined elastic properties of the rock bolt/rock mass system. Challenges associated with implementing this non-destructive testing technique in rock masses include the generation of wide bandwidth signals having enough strength to produce multiple reflections with high enough signal-to-noise ratios to capture properties of multi-scale systems.

11. Barrel Bolt Cracking in a German PWR

Kilian, R.; Maussner, G. [AREVA GmbH (Germany); Koenig, G. [EnBW Kernkraft GmbH (Germany)

2011-07-01

In this paper, the results of failure analysis of cracked barrel bolts will be shown. The barrel bolts are made of German material number 1.4571 corresponding to 316 Ti. To ensure that the required mechanical properties are achieved, the material used was cold worked. At the end of the eighties, the bolts were installed to replace Inconel X- 750 bolts. The design used is a 'star bolt'. In 2005, cracking was first observed. In this report, the results of destructive examinations showing intergranular stress corrosion cracking will be presented. M16-Bolts exhibited cracking only in the area of cup, preventing unintentional loosening. All selected and examined M12-Bolts showed similar crack initiation in the head. Cracks may initiate on transition radii between the head and shank. The shank and thread of all bolts (M12 and M16) exhibited no indications of cracking. Bolts that experienced cracking could be clearly identified through visual inspection. The ultrasonic testing technique applied confirmed crack locations in the head. All cracks were attributed to Intergranular Stress Corrosion Cracking (IGSCC). Fracture surfaces exhibited relatively thin, dark layers and, in addition to corrosion products of the base metal, the debris on the shank and head also contained traces of Al, Si, Cu and Zn. (authors)

12. The new structure of fibre glass reinforced plastics bolt

马念杰; 刘社育

2003-01-01

The develop actuality and direction of FRP(fibre glass reinforced plastics) bolt in the world are analyzed. The new type structure of FRP bolt was designed. Trial data indicate that, all kinds of capability target of this FRP bolt all achieve and exceed the country standard, substitute present metal bolt,wood bolt and bamboo bolt and other side bolt, it can gain magnitude technology and economy benefit. FRP bolt mechanization product line produce efficiency is high, its throughput a day are 750 base, this can meet demand of hit-small mining company.

13. Acousto-optic Extensometer for Bolts

Maram, J.; Kuhr, G.

1985-01-01

Bolt torque or tension deduced from non contacting measurements. Pulsed Laser induces shockwave in bolthead while continuous-wave acousto-optic detector monitors distortion produced by shock. Shock travel time measured to determine bolt length. Solid-state position detector relatively inexpensive and keeps down cost of extensometer.

14. 49 CFR 236.756 - Lock, bolt.

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Lock, bolt. 236.756 Section 236.756 Transportation... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.756 Lock, bolt. A mechanical lock so arranged that if a switch, derail or movable-point frog is not in the proper position...

15. Hypersensitivity to Suture Anchors

Masafumi Goto

2013-01-01

Full Text Available Hypersensitivity to suture anchor is extremely rare. Herein, we present a case in which hypersensitivity to suture anchor was strongly suspected. The right rotator cuff of a 50-year-old woman was repaired with a metal suture anchor. Three weeks after the surgery, she developed erythema around her face, trunk, and hands, accompanied by itching. Infection was unlikely because no abnormalities were detected by blood testing or by medical examination. Suspicious of a metallic allergy, a dermatologist performed a patch testing 6 months after the first surgery. The patient had negative reactions to tests for titanium, aluminum, and vanadium, which were the principal components of the suture anchor. The anchor was removed 7 months after the first surgery, and the erythema disappeared immediately. When allergic symptoms occur and persist after the use of a metal anchor, removal should be considered as a treatment option even if the patch test result is negative.

16. Study on the material character steel big-end bolt

SHI Jian-jun; MA Nian-jie; ZHAN Ping; ZHANG Dian-li

2008-01-01

Based on the manufacturing method now used in our country,caused low bearing capacity in the bolt-end,which is a potential danger in the bolt supporting tunnel and a waste of money,and presented the new type strong steel big-end bolt can solve this problem.Analyzed the active state of the end of bolt by ANSYS,we can know that it is very disadvantage when bolt bore eccentric load.Contrasted with the different that common bolt and big-end bolt when they bore the same loading.The common bolt is bigger than the big-end bolt in stress value.Study on the processing technic of the new type of the strong steel big-end bolt,the new metal big-end bolt was produced by heat processing over big-end bolt and upset.From the microscopic examination on bolt metal,it is concluded that heat processing on the bolt-end refines the crystal grain of the metal material,which not only increase its extension but improve its property.Moreover the strength ability of the bolt material can be exerted completely.

17. Study on the material character steel big-end bolt

SHI Jian-jun; MA Nian-jie; ZHAN Ping; ZHANG Dian-li

2008-01-01

Based on the manufacturing method now used in our country, caused low bear-ing capacity in the bolt-end, which is a potential danger in the bolt supporting tunnel and a waste of money, and presented the new type strong steel big-end bolt can solve this problem. Analyzed the active state of the end of bolt by ANSYS, we can know that it is very disadvantage when bolt bore eccentric load. Contrasted with the different that com-mon bolt and big-end bolt when they bore the same loading. The common bolt is bigger than the big-end bolt in stress value. Study on the processing technic of the new type of the strong steel big-end bolt, the new metal big-end bolt was produced by heat processing over big-end bolt and upset. From the microscopic examination on bolt metal, it is con-cluded that heat processing on the bolt-end refines the crystal grain of the metal material, which not only increase its extension but improve its property. Moreover the strength ability of the bolt material can be exerted completely.

18. Computerized UT system for stud bolt

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

19. Susceptibility to anchoring effects

Todd McElroy

2007-02-01

Full Text Available Previous research on anchoring has shown this heuristic to be a very robust psychological phenomenon ubiquitous across many domains of human judgment and decision-making. Despite the prevalence of anchoring effects, researchers have only recently begun to investigate the underlying factors responsible for how and in what ways a person is susceptible to them. This paper examines how one such factor, the Big-Five personality trait of openness-to-experience, influences the effect of previously presented anchors on participants' judgments. Our findings indicate that participants high in openness-to-experience were significantly more influenced by anchoring cues relative to participants low in this trait. These findings were consistent across two different types of anchoring tasks providing convergent evidence for our hypothesis.

20. Experimental study and stress analysis of rock bolt anchorage performance

Yu Chen

2014-10-01

Full Text Available A new method was developed to apply pull-and-shear loads to the bolt specimen in order to evaluate the anchorage performance of the rebar bolt and the D-Bolt. In the tests, five displacing angles (0°, 20°, 40°, 60°, and 90°, two joint gaps (0 mm and 30 mm, and three kinds of host rock materials (weak concrete, strong concrete, and concrete-granite were considered, and stress–strain measurements were conducted. Results show that the ultimate loads of both the D-Bolt and the rebar bolt remained constant with any displacing angles. The ultimate displacement of the D-Bolt changed from 140 mm at the 0° displacing angle (pure pull to approximately 70 mm at a displacing angle greater than 40°. The displacement capacity of the D-Bolt is approximately 3.5 times that of the rebar bolt under pure pull and 50% higher than that of the rebar bolt under pure shear. The compressive stress exists at 50 mm from the bolt head, and the maximum bending moment value rises with the increasing displacing angle. The rebar bolt mobilises greater applied load than the D-Bolt when subjected to the maximum bending. The yielding length (at 0° of the D-Bolt is longer than that of the rebar bolt. The displacement capacity of the bolts increased with the joint gap. The bolt subjected to joint gap effect yields more quickly with greater bending moment and smaller applied load. The displacement capacities of the D-Bolt and the rebar bolt are greater in the weak host rock than that in the hard host rock. In pure shear condition, the ultimate load of the bolts slightly decreases in the hard rock. The yielding speed in the hard rock is higher than that in the weak rock.

1. Experimental study and stress analysis of rock bolt anchorage performance

Yu Chen

2014-01-01

A new method was developed to apply pull-and-shear loads to the bolt specimen in order to evaluate the anchorage performance of the rebar bolt and the D-Bolt. In the tests, five displacing angles (0?, 20?, 40?, 60?, and 90?), two joint gaps (0 mm and 30 mm), and three kinds of host rock materials (weak concrete, strong concrete, and concrete-granite) were considered, and stressestrain measurements were con-ducted. Results show that the ultimate loads of both the D-Bolt and the rebar bolt remained constant with any displacing angles. The ultimate displacement of the D-Bolt changed from 140 mm at the 0? displacing angle (pure pull) to approximately 70 mm at a displacing angle greater than 40?. The displacement capacity of the D-Bolt is approximately 3.5 times that of the rebar bolt under pure pull and 50%higher than that of the rebar bolt under pure shear. The compressive stress exists at 50 mm from the bolt head, and the maximum bending moment value rises with the increasing displacing angle. The rebar bolt mobilises greater applied load than the D-Bolt when subjected to the maximum bending. The yielding length (at 0?) of the D-Bolt is longer than that of the rebar bolt. The displacement capacity of the bolts increased with the joint gap. The bolt subjected to joint gap effect yields more quickly with greater bending moment and smaller applied load. The displacement capacities of the D-Bolt and the rebar bolt are greater in the weak host rock than that in the hard host rock. In pure shear condition, the ultimate load of the bolts slightly decreases in the hard rock. The yielding speed in the hard rock is higher than that in the weak rock.

2. Stress analysis of closure bolts for shipping casks

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

3. Anchoring visions in organizations

Simonsen, Jesper

1999-01-01

This paper introduces the term 'anchoring' within systems development: Visions, developed through early systems design within an organization, need to be deeply rooted in the organization. A vision's rationale needs to be understood by those who decide if the vision should be implemented as well as...... anchoring is considered to be a main activity, is outlined. The task of anchoring visions is described, and techniques and activities are suggested with respect to those actors that have to act on the visions and the recommendations from a design proposal. The paper concludes that obtaining appropriate...

4. Analytical large deformation shear strength for bolted rough discontinuous rock

LIU Bo(刘波); TAO Long-guang(陶龙光); YUE Zhong-qi(岳中琦)

2004-01-01

Presented a new analytical model for studying the shear-tensile large deformation behavior near the vicinity of joint interface for bolted rough discontinuous rock, and presented the formulation estimating global shear strength for bolted joints under shearing-tensile loads. The analytical strength curves of bolts contribution on reinforced discontinuous rocks as the function of joint displacements or deformation angle of a bolt at rock joints was obtained. Based on Barton's equation on JRC roughness profiles, the theoretical shearing strength of bolted rough joints was also established. Test results on bolted granite and marble specimen confirm the validity of the analytical approach.

5. Research on the bolt supporting principal of developing entry

XIONG Ren-qin

2004-01-01

Based on the principle of rock-soil mechanics, the bolt supporting technology of mine roadway were researched, it is pointed out that the roadway's four corner bolt, the prestressed bolt and the extensible bolt play an important role in keeping road stable; it is also indicated that the walls of roadway safeguarded well is important in keeping road stable, which can make the bolt and surrounding rock load-bearing together; bolt and grounting technology can increase anchorage capacity, which is very applicable for soft rock supporting and developing entry.

6. Simulation of the Load Evolution of an Anchoring System under a Blasting Impulse Load Using FLAC3D

Xigui Zheng

2015-01-01

Full Text Available A limitation in research on bolt anchoring is the unknown relationship between dynamic perturbation and mechanical characteristics. This paper divides dynamic impulse loads into engineering loads and blasting loads and then employs numerical calculation software FLAC3D to analyze the stability of an anchoring system perturbed by an impulse load. The evolution of the dynamic response of the axial force/shear stress in the anchoring system is thus obtained. It is revealed that the corners and middle of the anchoring system are strongly affected by the dynamic load, and the dynamic response of shear stress is distinctly stronger than that of the axial force in the anchoring system. Additionally, the perturbation of the impulse load reduces stress in the anchored rock mass and induces repeated tension and loosening of the rods in the anchoring system, thus reducing the stability of the anchoring system. The oscillation amplitude of the axial force in the anchored segment is mitigated far more than that in the free segment, demonstrating that extended/full-length anchoring is extremely stable and surpasses simple anchors with free ends.

7. Susceptibility to anchoring effects

Todd McElroy; Keith Dowd

2007-01-01

Previous research on anchoring has shown this heuristic to be a very robust psychological phenomenon ubiquitous across many domains of human judgment and decision-making. Despite the prevalence of anchoring effects, researchers have only recently begun to investigate the underlying factors responsible for how and in what ways a person is susceptible to them. This paper examines how one such factor, the Big-Five personality trait of openness-to-experience, influences the effect of previously p...

8. Decision Fusion System for Bolted Joint Monitoring

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.

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

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.)

10. High-Strength Bolt Corrosion Fatigue Life Model and Application

Wang Hui-li

2014-01-01

Full Text Available The corrosion fatigue performance of high-strength bolt was studied. Based on the fracture mechanics theory and the Gerberich-Chen formula, the high-strength bolt corrosion fracture crack model and the fatigue life model were established. The high-strength bolt crack depth and the fatigue life under corrosion environment were quantitatively analyzed. The factors affecting high-strength bolt corrosion fatigue life were discussed. The result showed that the high-strength bolt corrosion fracture biggest crack depth reduces along with the material yield strength and the applied stress increases. The material yield strength was the major factor. And the high-strength bolt corrosion fatigue life reduced along with the increase of material strength, the applied stress or stress amplitude. The stress amplitude influenced the most, and the material yield strength influenced the least. Low bolt strength and a low stress amplitude level could extend high-strength bolt corrosion fatigue life.

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

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-ν2) to accommodate small diameter flanges

12. Tension-loaded bolted connections in steel structures

Skavhaug, Elin Stensrud; Østhus, Svanhild Irene

2015-01-01

The purpose of this thesis is to study the behaviour of bolted steel connections subjected to tension. Quasi-static conditions have been considered. By performing laboratory tests on single bolts and simple T-stub connections the failure modes of the bolts have been examined. Finite element models are created and validated to represent the behaviour observed in the laboratory. Different grip length configurations have been tested for a single bolt and nut assembly subjected to pure tensio...

13. On prestress stiffness analysis of bolt-plate contact assemblies

Pedersen, Niels Leergaard; Pedersen, Pauli

2008-01-01

Bolt connections are among the most important connections used in structures. The stiffnesses of the bolt and of the connected members are the primary qualities that control the lifetime of the connection. The stiffness of the bolt can be estimated rather easily, in contrast to the member stiffness...

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

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.

15. Parameters determination and bolting control of gateway floor

GOU Pan-feng; XlN Ya-jun

2011-01-01

Gateway floor heave control is the key to guarantee mine safe and efficient production.Through analysis of floor instability characteristics and bolting control,gateway floor strata show second level stress under abutment pressure,which causes plastic flow failure in floor strata; gateway floor instability shows mainly shear-break slippage of “triangle sliding body”.Mechanics of floor bolting is mainly a function of connection and combination.Main area of bolting control lies in two gateway floor angles.The paper analyzes mechanics principle of gateway floor instability,constructs stability mechanics model of gateway floor bolting,obtains gateway floor stability criterion of different bolting angles and optimum formula of bolting parameters,carries out the engineering example,and guides better field application.It provides theoretical base for bolting gateway floor instability control.

16. Bolting Cabin Assistance System Using a Sensor Network

Yung-Hak Mo

2012-10-01

Full Text Available The bolting cabin assistance system prevents operators from facing dangerous situations. This system consists of a bolting robot control system and a top view supervisory system. In order to control the bolting robot, circular Hough transforms and fuzzy reasoning are used. First, the circular Hough transform roughly estimates the location of the bolt hole. After that, errors of estimation are compensated for using fuzzy reasoning. In order to track a bolt hole, a region of interest (ROI is used. By setting the region in which to search for a bolt hole, the algorithm tracks the location of the bolt hole. In order to choose an ROI, a template‐based matching algorithm is used. In order to make the top view supervisory system, four cameras are installed at the left, right, front and back of the robot. The four individual images from the various cameras are combined to make the top view image after correcting for distortion.

17. Anchoring the Deficit of the Anchor Deficit: Dyslexia or Attention?

Willburger, Edith; Landerl, Karin

2010-01-01

In the anchoring deficit hypothesis of dyslexia ("Trends Cogn. Sci.", 2007; 11: 458-465), it is proposed that perceptual problems arise from the lack of forming a perceptual anchor for repeatedly presented stimuli. A study designed to explicitly test the specificity of the anchoring deficit for dyslexia is presented. Four groups, representing all…

18. The design and testing of subscale smart aircraft wing bolts

Presently costly periodic inspection is vital in guaranteeing the structural integrity of aircraft. This investigation assesses the potential for significantly reducing aircraft maintenance costs without modification of aircraft structures by implementing smart wing bolts, manufactured from TRIP steel, which can be monitored for damage in situ. TRIP steels undergo a transformation from paramagnetic austenite to ferromagnetic martensite during deformation. Subscale smart aircraft wing bolts were manufactured from hot rolled TRIP steel. These wing bolts were used to demonstrate that washers incorporating embedded inductance coils can be utilized to measure the martensitic transformation occurring in the TRIP steel during bolt deformation. Early in situ warning of a critical bolt stress level was thereby facilitated, potentially reducing the costly requirement for periodic wing bolt removal and inspection. The hot rolled TRIP steels that were utilized in these subscale bolts do not however exhibit the mechanical properties required of wing bolt material. Thus warm rolled TRIP steel alloys were also investigated. The mechanical properties of the best warm rolled TRIP steel alloy tested almost matched those of AISI 4340. The warm rolled alloys were also shown to exhibit transformation before yield, allowing for earlier warning when overload occurs. Further work will be required relating to fatigue crack detection, environmental temperature fluctuation and more thorough material characterization. However, present results show that in situ early detection of wing bolt overload is feasible via the use of high alloy warm rolled TRIP steel wing bolts in combination with inductive sensor embedded washers. (paper)

19. The design and testing of subscale smart aircraft wing bolts

Vugampore, J. M. V.; Bemont, C.

2012-07-01

Presently costly periodic inspection is vital in guaranteeing the structural integrity of aircraft. This investigation assesses the potential for significantly reducing aircraft maintenance costs without modification of aircraft structures by implementing smart wing bolts, manufactured from TRIP steel, which can be monitored for damage in situ. TRIP steels undergo a transformation from paramagnetic austenite to ferromagnetic martensite during deformation. Subscale smart aircraft wing bolts were manufactured from hot rolled TRIP steel. These wing bolts were used to demonstrate that washers incorporating embedded inductance coils can be utilized to measure the martensitic transformation occurring in the TRIP steel during bolt deformation. Early in situ warning of a critical bolt stress level was thereby facilitated, potentially reducing the costly requirement for periodic wing bolt removal and inspection. The hot rolled TRIP steels that were utilized in these subscale bolts do not however exhibit the mechanical properties required of wing bolt material. Thus warm rolled TRIP steel alloys were also investigated. The mechanical properties of the best warm rolled TRIP steel alloy tested almost matched those of AISI 4340. The warm rolled alloys were also shown to exhibit transformation before yield, allowing for earlier warning when overload occurs. Further work will be required relating to fatigue crack detection, environmental temperature fluctuation and more thorough material characterization. However, present results show that in situ early detection of wing bolt overload is feasible via the use of high alloy warm rolled TRIP steel wing bolts in combination with inductive sensor embedded washers.

20. Optimization of bolt thread stress concentrations

Pedersen, Niels Leergaard

2013-01-01

Designs of threaded fasteners are controlled by different standards, and the number of different thread definitions is large. The most commonly used thread is probably the metric ISO thread, and this design is therefore used in the present paper. Thread root design controls the stress concentration...... factor 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 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...

1. Stiffness Analysis and Improvement of Bolt-Plate Contact Assemblies

Pedersen, Niels Leergaard; Pedersen, Pauli

2008-01-01

In a previous study it was shown that, a simplified expression for the stiffness of the plate member in a bolt-plate assembly can be found. The stiffnesses of the bolt and the connected plates are the primary quantities that control the lifetime of a dynamically loaded connection. The present study...... of stiffnesses is extended to include different material parameters by including the influence of Poisson's ratio. Two simple practical formulas are suggested and their accuracies are documented for different bolts and different material (Poisson's ratio). Secondly, the contact analysis between the...... bolt head and the plate is extended by the possibility of designing a gap, that is, a nonuniform distance between the bolt and plate before prestressing. Designing the gap function generates the possibility for a better stress field by which the stiffness of the bolt is lowered, and at the same time...

2. Apparatus for the ultrasonic examination of shroud hold down bolts

A process of testing hold down bolts depending from the sides of a steam separator within a nuclear reactor is described the process comprising the steps of: maintaining the steam separator under water; moving the bolts to unlatch the bolts from brackets on the shroud adjacent the steam separator; providing a shoe having a piezoelectric device mounted to the bottom of the shoe and exposed upwardly; providing a remotely actuated clamp attached to the shoe overlying the piezoelectric device; providing a mount to the shoe for manipulating the shoe underwater in a depending relationship at the bottom end of a pole; providing a pole and attaching the pole to the shoe; manipulating the shoe to the bottom of the bolt; and clamping the shoe to the bolt; and testing the bolt with the piezoelectric device

3. Characteristic Evaluation on Bolt Stress by Ultrasonic Nondestructive Methods

Qinxue Pan

2015-01-01

Full Text Available Based on the acoustoelasticity theory, a certain relationship exists between ultrasonic velocity and stress. By combining shear and longitudinal waves, this paper provides a nondestructive method of evaluating axial stress in a tightened bolt. For measuring the bolt axial stress in different situations, such as under low or high loads, this paper provides guidelines for calculating the stress for a given load factor. Experimental and calculated results were compared for three bolt test samples: an austenitic stainless steel bolt (A2-70 and low-carbon steel 4.8 and 8.8 bolts. On average, the experimental results were in good agreement with those obtained through calculations, thus providing a nondestructive method for bolt stress measurements.

4. Experimental study of friction in aluminium bolted joints

Vincenzi N.; De Agostinis M.; Croccolo D.

2010-01-01

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 desig...

5. High strength bolt failure analysis and integrity assessment. Lessons learned

Isolated failures have occurred in high strength bolting used in pressurized water reactor (PWR) component support applications. The U.S. nuclear industry component support bolting failure experience is described in this paper, focusing on materials specified intentionally as ''ultra-high-strength'' (minimum specified yield strength greater than 1034 MPa). The analysis and investigation of fabrication-induced problems with a bolt made from Carpenter Technology Alloy ''Custom 455'', (ASTM A 564 XM-16) a proprietary materials, are detailed, and the measures taken to assure integrity of these bolts during operation are discussed. Lessons learned to preclude future problems are presented as conclusions

6. The Anchoring Concept

Simonsen, Jesper

1998-01-01

This paper introduces the term 'anchoring' within systems development: Visions, developed through early systems design within an organization, need to be deeply rooted in the organization. A vision's rationale needs to be understood by those who decide if the vision should be implemented as well as...... by those involved in the actual implementation. A model depicting a recent trend within systems development is presented: Organizations rely on purchasing generic software products and/or software development outsourced to external contractors. A contemporary method for participatory design, where...

7. Testing and evaluation of Vespel up to 450 deg F when used in nuts and bolts as a self-locking element

Wood, C. M.

1984-01-01

The object of this investigation was to evaluate Vespel for potential application on the Solid Rocket Booster to replace all-metal deformed self-locking nuts and anchor nuts and be used as self-locking elements for bolts and screws. The Vespel self-locking elements were tested for prevailing torque retention at room temperature, after heating to 450 F and exposure for 3 hr, breakaway torque at 450 F and for vibration at a level consistent with the maximum expected on the SRB at lift-off and reentry. The investigation revealed Vespel has properties that can provide a self-locking capability for threaded fasteners up to 450 F and it can be used in nuts and anchor nuts for installation on the SRB. Vespel elements in bolts did not meet all our SRB requirements for reuse, however, we have defined a design for Vespel elements in nuts/anchor nuts that fully meets all requirements. It is recommended that No. 1, 1/4 in. and 5/16 in. nuts/anchor nuts be procured for use on the SRB. This system will eliminate the galling problems now encountered and achieve a much higher reuse life than the present deformed nut design.

8. Bolt Pull-Out Tests of Anchorage Body under Different Loading Rates

Tong-bin Zhao

2015-01-01

Full Text Available Based on the force analysis and mechanical transmission mechanism of grouting bolts, the self-developed test apparatus for interfacial mechanics is used to study the distribution rule of axial force and interfacial stress of bolts in anchorage body. At the same time, pull-out tests of anchorage body are simulated with the particle flow code software PFC2D, and stress distribution and failure patters are researched under different loading rates. The results show that the distribution of axial force and interfacial shear stress is nonuniform along the anchorage section: axial force decreases, shear force increases first and then decreases, and the maximum value of both of them is closed to the pull-out side; with the increase of loading rates, both of axial force and interfacial shear stress show a trend of increase in the upper anchorage section but changes are not obvious in the lower anchorage section, which causes serious stress concentration; failure strength of pull-out and loading rates show a linear correlation; according to loading rates’ impact on the anchoring effect, the loading rates’ scope can be divided into soft scope (v100 mm/s.

9. A marketing plan for Lightning Bolt

Silveira, Filipa Borges

2013-01-01

This project had as main goal to improve the perception of male surfers about the surf brand Lightning Bolt. It was proposed the creation of a collection of wetsuits as well as the “A Pure Source” Project to show the commitment of the brand with the surf community. To promote both several promotional activities are suggested such as the use of magazines, radio, banners and social media. To complement the distribution chain of the brand, a concept store and a mobile store are also recommended....

10. Structural analysis of closure bolts for shipping casks

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.

11. Accuracy of tunnelated vs. bolt-connected external ventricular drains

Bergdal, Ove; Springborg, Jacob Bertram; Holst, Anders Vedel;

2013-01-01

40%. As an alternative to the tunnelated EVD technique we often use a bolt-connected EVD. The aim of the present study was to investigate whether the use of bolt-connected EVDs would lead to higher accuracy, fewer passes and reoperations due to poor placement compared to tunnelated EVDs....

12. The effects of bolted joints on dynamic response of structures

Joint is an universal fastening technology for structural members; in particular bolted joints are extensively used in mechanical structures due to their simple maintenance and low cost. However, the components of bolted joints are imperative because failure could be catastrophic and endanger lives. Hence, in this study, the effects of bolted joints on vibrating structures are investigated by determining the structural dynamic properties, such as mode shapes, damping ratios and natural frequencies, and these are compared with the monolithic structures (welding). Two approaches of experimental rigs are developed: a beam and a frame where both are subjected to dynamic loading. The analysis reveals the importance of bolted joints in increasing the damping properties and minimizing the vibration magnitude of structures, this indicates the significant influence of bolted joints on the dynamic behaviour of assembled structures. The outcome of this study provides a good model for predicting the experimental variable response in different types of structural joints

13. Research on the mechanical property test of a new high-strength metal bolt

SHI Jian-jun; MA Nian-jie

2011-01-01

In order to study how to improve the overall performance of the operational metal bolt,based on the production process of an ordinary metal bolt used in understructure engineering,this paper focused on the existing problems of ordinary metal bolts identified by some survey and analysis.The results show that the structure of operational metal bolts is so unreasonable that the bolt tail is easily fractured by low load capacity.Furthermore,a new type of strong big-end metal bolt and its heat treatment and roughing processing technology were introduced.Through bolt tensile and metallographic tests,the property of the new big-end bolt was analyzed.The new findings indicate that after a special processing,the overall strength and plasticity of the bolt is greatly improved,and the grain of the bolt tail structure is refined,which would help build up favorable working conditions for bolt tails.

14. A development of numerical analysis model for tensile capacity evaluation of cast-in-place anchor

Numerical analysis is carried out to identify the appropriateness of the design codes that is available for the tensile design of fastening system at Nuclear Power Plant (NPP) in this study. This study is intended for the cast-in-place anchor that is widely used for the fastening of equipment in Korean NPPs. The microplane model and the elastic-perfectly plastic model are employed for the quasi-brittle material like concrete and for the ductile material like anchor bolt as constitutive model for numerical analysis and smeared crack model is employed for the crack and damage phenomena. The developed numerical model is verified on a basis of the various test data of cast-in-place anchor. The appropriateness of both ACI 349 Code and CCD approach of CEB-FIP Code is evaluated for the tensile design of cast-in-place anchor and it is proved that both design codes give a conservative results compared with real tensile capacity of cast-in-place anchor

15. Fretting fatigue mechanism of bearing cap bolted joints

Li, Xin; Zuo, Zhengxing; Qin, Wenjie

2014-05-01

Fretting fatigue is a common type of failure of the bearing cap bolted joints. This paper proposes a methodology to analyze the fretting fatigue mechanism of the bearing cap bolted joint. A biaxially loading system was designed to simulate fretting fatigue failure under typical engine working condition. Meanwhile, a submodel was developed in the finite element calculation to analyze the contact status and stress distribution of the structural models. The test result shows that long inclined cracks (about 650 μm long, orientation at 17°-34°) initiate at the middle region of the contact interface. As the increase of the bolt pretension load (from 6000 N to 10 000 N), the crack initial location is getting away from the bolt screw, and the fretting fatigue lives is increasing (from 7.8 × 105 to 6.0 × 106). With the fatigue phenomenon and the stress field analysis result, it concludes that the crack initiation is governed by the maximum shear stress; the bolt pretension load and the additional rotate torque caused by the bearing load are the two main factors which affect the fretting fatigue mechanism of the bearing cap bolted joints. It is beneficial to fretting fatigue lives of the bearing cap joints by increasing the bolt pretension load and restraining the oscillation of the bearing cap.

16. Epigenomics and bolting tolerance in sugar beet genotypes.

Hébrard, Claire; Peterson, Daniel G; Willems, Glenda; Delaunay, Alain; Jesson, Béline; Lefèbvre, Marc; Barnes, Steve; Maury, Stéphane

2016-01-01

In sugar beet (Beta vulgaris altissima), bolting tolerance is an essential agronomic trait reflecting the bolting response of genotypes after vernalization. Genes involved in induction of sugar beet bolting have now been identified, and evidence suggests that epigenetic factors are involved in their control. Indeed, the time course and amplitude of DNA methylation variations in the shoot apical meristem have been shown to be critical in inducing sugar beet bolting, and a few functional targets of DNA methylation during vernalization have been identified. However, molecular mechanisms controlling bolting tolerance levels among genotypes are still poorly understood. Here, gene expression and DNA methylation profiles were compared in shoot apical meristems of three bolting-resistant and three bolting-sensitive genotypes after vernalization. Using Cot fractionation followed by 454 sequencing of the isolated low-copy DNA, 6231 contigs were obtained that were used along with public sugar beet DNA sequences to design custom Agilent microarrays for expression (56k) and methylation (244k) analyses. A total of 169 differentially expressed genes and 111 differentially methylated regions were identified between resistant and sensitive vernalized genotypes. Fourteen sequences were both differentially expressed and differentially methylated, with a negative correlation between their methylation and expression levels. Genes involved in cold perception, phytohormone signalling, and flowering induction were over-represented and collectively represent an integrative gene network from environmental perception to bolting induction. Altogether, the data suggest that the genotype-dependent control of DNA methylation and expression of an integrative gene network participate in bolting tolerance in sugar beet, opening up perspectives for crop improvement. PMID:26463996

17. Explosive Bolt Dual-Initiated from One Side

Snow, Eric

2011-01-01

An explosive bolt has been developed that has a one-sided dual initiation train all the way down to the pyro charge for high reliability, while still allowing the other side of the bolt to remain in place after actuation to act as a thermal seal in an extremely high-temperature environment. This lightweight separation device separates at a single fracture plane, and has as much redundancy/reliability as possible. The initiation train comes into the explosive bolt from one side.

18. STUDY ON GATEWAY BOLTING EXCAVATED IN INCLINED COAL SEAM

陶连金; 王泳嘉; 张倬元

1997-01-01

A typical gateway is analyzed using fully-deformable discrete element method. The fractured zone around the gateway is measured in field. Based on the measurement results and theoretical analysis, a comprehensive support scheme adopting bolt and steel belt is proposed. Discrete element method is used to assess the bolting scheme, and displacement monitoring in field is also carried out. Having been put into practice, it is proved that the scheme is both successful and rational. According to theoretical analysis and monitoring in field, some importan tkeynotes that should be noticed in gateway bolting practice are presented as well.

19. Bone Anchored Hearing Treatment Procedure

Full Text Available ... skin to allow removal of some of the soft tissue where the screwlike fixture will be anchored. The ... screen, acting as a hinge. Beneath that the soft tissue consisting of fat and some muscle is removed. ...

20. Bone Anchored Hearing Treatment Procedure

Full Text Available ... to allow removal of some of the soft tissue where the screwlike fixture will be anchored. The ... series of slides demonstrates the removal of the tissue beneath the skin flap. You can see in ...

1. Bone Anchored Hearing Treatment Procedure

Full Text Available ... The Baha system consists of a bone-anchored titanium fixture that is implanted in the mastoid bone, ... the -- great. I'm going to grab the titanium implant. And what I want you to notice ...

2. Bone Anchored Hearing Treatment Procedure

Full Text Available ... of the bone oscillator is superficial on the skin, the transference of that energy is less efficient, ... slides, is to mark the location in the skin where the screwlike fixture will be anchored. Subsequent ...

3. An Experimental Method for Measuring the Clamping Force in Double Lap Simple Bolted and Hybrid (Bolted-Bonded) Joints

Goldarag, Firooz Esmaeili; Barzegar, Sajjad; Babaei, Alireza

2015-01-01

In this research, an experimental method for measuring the clamping force as a result of tightening torque in double lap simple bolted and hybrid (bolted-bonded) joints is proposed. Two types of joints, i.e. double lap simple and hybrid (bolted-bonded) joints were prepared for testing. In order to measure the clamping force or pretension resulting from the tightening torque at different applied torques, for both types of joints, a special experimental method was designed using a steel bush th...

4. Beam to Column Timber Joints with Pretensioned Bolts

Hayashikawa T.

2011-01-01

Full Text Available The effects of pretension in bolts on hysteretic response of timber joints exposed to a bending had been reported by the authors, but the cyclic tests were carried out at small displacement level which might not be applicable for earthquake-resistance design. In this study, similar cyclic tests but at large displacement levels were conducted. Beam to column timber joints with steel side plates were fabricated and continuously loaded until failure. At connection, the bolts were pretension in four different magnitudes: 0 kN, 5 kN, 10 kN and 15 kN. The results showed that frictional action between the steel side plates and wood member as a result of bolt pretensioning significantly increased the (frictional hysteretic damping and the equivalent viscous damping ratio. It is obvious from the test results that the pretension force in bolts has no influence on the maximum joint resistance but decreases the joint rotational deformation.

5. Preloading of bolted connections in nuclear reactor component supports

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.

6. What Makes Usain Bolt Unique as a Sprinter?

Shinabargar, A. J.; Hellrich, Matt; Baker, Blane

2010-09-01

For both casual and avid fans alike, Olympic and other sporting events can provide a wealth of data for simple physics analyses. One of the most impressive performances in recent Olympic history is that of Usain Bolt in the track-and-field sprinting events during the 2008 Summer Games. Over a seven-day span, Bolt set world records in the 100-m and 200-m individual sprints and in the 4 × 100-m sprint relay. In addition, Bolt left us all wondering what record time he might have run had he not eased into the finish line in the 100-m dash. Naturally, one question many fans and observers immediately ask is: What makes Usain Bolt unique as a sprinter?

7. Mechanics of Re-Torquing in Bolted Flange Connections

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. Eddy-Current Detection of Weak Bolt Heads

Messina, C. P.

1987-01-01

Electronic test identifies flawed units passing hardness tests. Eddy-current test detects weakness in head-to-shank junctions of 1/4-28 cup-washer lock bolts. Developed for alloy A286 steel bolts in Space Shuttle main engine fuel turbo-pump. Test examines full volume of head, including head-to-shank transition and nondestructively screens out potentially defective units. Test adapts to any other alloys.

9. An overview of bolt failures in nuclear systems

The S.M. Stoller Corporation (SMSC) conducted a survey a material failures in nuclear plant systems using two data bases, i.e., Operating Plant Experience Code and Nuclear Power Experience. Information from the data bases was used to classify material failures as a function of time, type of plant, and type of component. Bolting failures represented 2 percent of all pressurized water reactor (PWR) material failures and 1 percent of all boiling water reactor (BWR) material failures. The majority of the PWR bolt failures have been due to stress corrosion of Inconel X-750 control rod guide tube support pins in Westinghouse reactors and A-286 reactor core thermal shield and core barrel support bolts in B ampersand W reactors. An improved mechanical design and aging treatment are expected to improve the stress corrosion resistance of Inconel X-750 pins. The replacement A-286 bolts employ peening in the head to shank area, rounded thread radii, machining versus hot forging of the head, a locking device to prevent loose parts, and reduced stresses as product improvements. A portion of reactor external PWR bolt failures were due to inadvertent boric acid corrosion of carbon, low alloy, and martensitic steels. Other causes of outside reactor PWR bolting failures were excessive stress, chloride-induced stress corrosion, oxidation, and fatigue of various materials in a variety of applications. BWR bolt failures have been relatively few and apparently not generic. Stress corrosion failures of Inconel X-750 fuel channel fasteners are reported judged to be caused by excess stress, nonoptimal heat treatment, and nonoptimal material selection. No failures have been reported in BWR alloy X-750 channel fastener bolts loaded to approximately 50-percent yield. 3 figs., 6 tabs

10. What Makes Usain Bolt Unique as a Sprinter?

Shinabargar, A. J.; Hellrich, Matt; Baker, Blane

2010-01-01

For both casual and avid fans alike, Olympic and other sporting events can provide a wealth of data for simple physics analyses. One of the most impressive performances in recent Olympic history is that of Usain Bolt in the track-and-field sprinting events during the 2008 Summer Games. Over a seven-day span, Bolt set world records in the 100-m and…

11. Seismic response of unanchored and partially anchored liquid-storage tanks. Final report

Ground-mounted vertical storage tanks are important components of nuclear plant safety systems. A systematic study is made of the principal effects of base uplifting on the seismic response of laterally excited, unanchored and partially anchored cylindrical liquid-storage tanks. The study consists of two parts: the first deals with the static uplifting resistance of the flexible base plate, and the second deals with the dynamic response of the uplifting system. An insight into the behavior of the uplifting base plate is first gained with the help of a prismatic beam solution. In Section 2, the solution is implemented exactly, whereas in Section 3 it is implemented approximately by use of the Ritz energy procedure. Solutions are next presented for axisymmetrically and asymmetrically uplifted base plate of tanks, in Section 4. For the axisymmetric case the solution is implemented exactly, as well as approximately by modeling the plate by a series of semiinfinite prismatic beams. The accuracy of the latter approach is confirmed by comparing its predictions with those of the former. In Section 5, a highly efficient and rational method is presented for the dynamic response analysis of uplifting tanks. Both unanchored tanks and partially anchored tanks, for which the number of anchor bolts at the base is insufficient to ensure full fixity, are considered. It is shown that base uplifting may reduce significantly the hydrodynamic pressures, but these reductions may be associated with increased axial compressive stresses in the tank wall and large plastic rotations at the plate-shell junction. For partially anchored tanks, energy loss due to bolt yielding is found to be small

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

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 3m3 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 3m3 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 3m3 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

13. Bolt study - behaviour of bolts in drop accident scenarios of the Nirex 3m{sup 3} Box ILW package

Turner, G. [United Kingdom Nirex Ltd., Harwell (United Kingdom); Tso, C.F. [Arup, London (United Kingdom)

2004-07-01

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{sup 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{sup 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{sup 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.

14. Automatic Thickness and Volume Estimation of Sprayed Concrete on Anchored Retaining Walls from Terrestrial LIDAR Data

Martínez-Sánchez, J.; Puente, I.; GonzálezJorge, H.; Riveiro, B.; Arias, P.

2016-06-01

When ground conditions are weak, particularly in free formed tunnel linings or retaining walls, sprayed concrete can be applied on the exposed surfaces immediately after excavation for shotcreting rock outcrops. In these situations, shotcrete is normally applied conjointly with rock bolts and mesh, thereby supporting the loose material that causes many of the small ground falls. On the other hand, contractors want to determine the thickness and volume of sprayed concrete for both technical and economic reasons: to guarantee their structural strength but also, to not deliver excess material that they will not be paid for. In this paper, we first introduce a terrestrial LiDAR-based method for the automatic detection of rock bolts, as typically used in anchored retaining walls. These ground support elements are segmented based on their geometry and they will serve as control points for the co-registration of two successive scans, before and after shotcreting. Then we compare both point clouds to estimate the sprayed concrete thickness and the expending volume on the wall. This novel methodology is demonstrated on repeated scan data from a retaining wall in the city of Vigo (Spain), resulting in a rock bolts detection rate of 91%, that permits to obtain a detailed information of the thickness and calculate a total volume of 3597 litres of concrete. These results have verified the effectiveness of the developed approach by increasing productivity and improving previous empirical proposals for real time thickness estimation.

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

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.

16. Guideline for bolted joint design and analysis : version 1.0.

Brown, Kevin H.; Morrow, Charles W.; Durbin, Samuel; Baca, Allen

2008-01-01

This document provides general guidance for the design and analysis of bolted joint connections. An overview of the current methods used to analyze bolted joint connections is given. Several methods for the design and analysis of bolted joint connections are presented. Guidance is provided for general bolted joint design, computation of preload uncertainty and preload loss, and the calculation of the bolted joint factor of safety. Axial loads, shear loads, thermal loads, and thread tear out are used in factor of safety calculations. Additionally, limited guidance is provided for fatigue considerations. An overview of an associated Mathcad{copyright} Worksheet containing all bolted joint design formulae presented is also provided.

17. FEM modelling of fatigue loaded bolted flange joints

T. Smolnicki

2007-05-01

Full Text Available Purpose: The main purpose of this paper is to describe the modelling of large flexible objects in which bolted joints are used and also to present a new FEM calculation methodology of these objects.Design/methodology/approach: In bolted flange joints of flexible constructional elements, bolts are subject not only to tension and torsion but also to bending. Identification of straining of each bolt is only possible by means of numerical methods e.g. the finite element method FEM. In case of large objects, the calculation problem is faithful projection of the phenomena taking place in direct zone of the contact of screw-nut pair. The application of global equivalent models of the whole joint is necessary, to make it possible to precisely determine internal loads in individual bolts and then local models to determine stress fields necessary to assign durability.Calculation methodology based on the construction of two coherent models has been described: global - of an entire flange joint, and local - of a single bolt joint.Findings: The elaborated methodology was applied to estimate the flange joint in the heat exchanger with rotating heating surfaces that was subject to damage. The causes of damage of flange joint were found.Practical implications: Used methodology of FEM modelling of bolted flange joints based on two coherent models may be applied for different similar objects. The paper provides detailed description of methodology steps.Originality/value: The described methodology may be successfully applied to the analysis of large objects, however, significant geometric features with dimensions small in relation to dimensions of the whole object. Thanks to the application of two coherent models, it is possible to reflect all essential phenomena in the FEM model, both in the global scale - of the entire object, and local – a significant fragment of the joint.

18. Permanent ground anchors: Nicholson design criteria

Nicholson, P. J.; Uranowski, D. D.; Wycliffe-Jones, P. T.

1982-09-01

The methods used by Nicholson Construction Company in the design of permanent ground anchors specifically as related to retaining walls are discussed. Basic soil parameters, design concepts, drilling and grouting methods for ground anchors are discussed. Particular emphasis is placed on anchors founded in soil rather than rock formations. Also, soil properties necessary for the proper design of anchored retaining walls are detailed. The second chapter of the report is devoted to a general discussion of retaining wall and anchor design. In addition, a design example of an anchored retaining wall is presented in a step by step manner.

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

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.

20. The strength of Glued-in Bolts after 9 Years In Situ Loading

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

1996-01-01

An experimental determination of the remaining strength of glued-in bolts after 9 years is presented. The hollow tapered bolts served as the blade to rotor hub connection of a windmill with wooden blades. The test method is presented along with the load history of the bolts, the recorded residual...... strength, the observed fracture modes and the force displacements curves. A total of 11 bolts were pulled out between undamaged bolts. The mean strength was found to be 362 kN with a standard deviation of 37 kN. This residual strength is 95% of previously recorded data. At fracture, a displacement between...... 0.4 mm and 1.0 mm was observed. In the majority of failures the bolts were pulled out like a cork from a bottle. A FEM-analysis confirms the higher load bearing capacity of the special hollowed tapered bolts compared to solid bolts....

1. TENSILE STRESS RELAXATION OF TURBINE BOLT STEELS AT HIGH TEMPERATURE

G.Q. Jia; H.W. Shen; Y.M. Zhu

2004-01-01

Stress relaxation behavior of two turbine bolt steels was evaluated by the manualcontrolled tensile stress relaxation test (TSRT) at high temperature. First, feasibility and the procedure of the manual-controlled tensile stress relaxation test (TSRT) is discussed and carried out on a general creep testing machine. And then, the experimental results from such type of test were compared to the existing data provided by certain Laboratory U.K. Overall good agreement between the results of manualcontrolled TSRT method and the existing data provides confidence in the use of the proposed method in practice. Finally, the experimental results of turbine bolt steels from TSRT were compared with that of bending test. It is observed that great difference exists between the results from two different type stress relaxation tests. It is therefore suggested that the results from TSRT method be adopted in turbine bolt design in engineering.

2. Development of plastic media blasting device for stud bolt

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)

3. The effect of oxidation on the integrity of bolted structures

Oxide growing on mild and low alloy steel components in the high pressure CO2 based coolant of the UK gas cooled nuclear power stations can become porous and continue to grow at the interfaces of structural components even when any interfacial gap has filled with oxide. Because such growth gives rise to a net volume expansion, the adjacent components can be forced apart. Any fastening, such as a weld or bolt, holding them together can then become stressed due to growth of oxide alone, and may sustain mechanical damage. The phenomenon is now well understood and methods of predicting behaviour have been developed and refined over the years to ensure safe and continued plant operation. The basis of such methods is presented for bolted joints, and the way in which joint geometry, environment and mechanical properties of component material influence bolt strain is outlined, with examples. (author)

4. Analysis Of Comparative Strength Model Connection Bolts And Weld To The Plate Materials ST. 42

Saripuddin. M; Hammada Abbas

2015-01-01

The research objective to be achieved is determine the ratio of tensile strength connections of weld combination (longitudinal and transversal) with a tensile strength of connection models with 2 bolts, 3 bolts and 4 bolts. The method used is to form specimens of weld connections (longitudinal and transverse) and the model of connections (2, 3 and 4) bolts, and testing of tensile strength using a tensile test machine to produce maximum load value, the maximum tension and strain. T...

5. Stress Evolution in Roadway Rock Bolts During Mining in a Fully Mechanized Longwall Face, and an Evaluation of Rock Bolt Support Design

Zhang, Kai; Zhang, Guimin; Hou, Rongbin; Wu, Yu; Zhou, Hongqi

2015-01-01

Rock bolts are widely used in coal mines throughout China. Approximately 8,000 km of roadways are excavated in coal mines every year in China, 80 % of which are supported by rock bolts. At present, the design of rock bolt support schemes is mainly based on analogies and experience from previous projects. In the present study, in order to evaluate the design of rock bolt support in roadways, several cross sections of a roadway were monitored for rock bolt stress during the roadway excavation and mining. The study results show that the stress in the rock bolts varied in the areas 20 m behind the excavating face and 30 m ahead of the mining face. For the rock bolts observed in this study, the max axial force was within the design limit of the bolts, thus the support design was shown to be acceptable. Then, numerical simulation was performed using FLAC3D to investigate the stress evolution in the rock bolts during the mining of the fully mechanized longwall face. The simulation results show an overall agreement with the in situ measurements. Finally, parametric study pertaining to length, anchorage length, and rock bolt spacing was carried out with the numerical model, and several suggestions for the support design were proposed.

6. Influence of anchor behaviour on the earthquake response of liquid storage tanks

The dynamic response of thin liquid storage tanks to earthquakes is a very complicated phenomenon, because it can be highly non linear. Among others, one can meet material and geometric non linearities of the tank shell leading eventually to static or dynamic buckling non linear behavior of anchor bolts, contact non-linearities due to the uplift of the tank base and to the unilateral character of the fluid pressure on the shell and high amplitude fluid oscillations. Moreover, linear or non linear soil structure interaction affects considerably the response of the fluid structure system under consideration. In this paper we focus attention on problems related only to the base uplift and anchors plastification. We study a tank similar to the Hualien project tank, but we neglect the soil structure interaction. The studied tank is representative of medium height to radius ratio ratio tanks with relatively thick bottom plate. The contact is simulated via a simple discrete penalty method in order to facilitate the calculation of the impact forces. Modal coordinates calculated for various Fourier harmonics are used for the dynamic analysis and the coupled modal equations of motion are solved with an explicit time integration algorithm. Obviously, this approach is less precise than a direct finite element analysis on the nodal basis but is less expensive. The scope of this paper is to discuss the efficiency of the proposed method to deal with problems like those aforementioned and to give some qualitative results concerning the influence of anchor bolts behaviour on the earthquake response of tanks. (author). 2 refs., 7 figs., 1 tab

7. Cable bolt bearing capacity - an in situ parametric study

Souček, Kamil; Waclawik, Petr; Koníček, Petr; Ptáček, Jiří; Hastíková, Alice; Kukutsch, Radovan

Montreal, Quebec: ISRM, 2015. ISBN 978-1-926872-25-4. [International Symposium on Rock Mechanics /13./. Montreal, Quebec (CA), 10.05.2015-13.05.2015] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406; GA MV VG20102014034 Institutional support: RVO:68145535 Keywords : cable bolt * Cable-Resin-Rock system (CRR system) * bolt borehole ratio * system stiffness * bearing capacity Subject RIV: JQ - Machines ; Tools http://www.isrm2015.com/

8. STRESS-STRAIN FINITE ELEMENT ANALYSIS AND FATIGUE LIFE PREDICTION FOR BOLTED CONNECTIONS

2002-01-01

A cyclic plasticity model is used into finite element (FE) method to obtain the details of elastic-plastic stress-strain in the bolts under cyclic axial loading. Two criteria in multiaxial fatigue are employed to predict fatigue lives of bolts. The predicted fatigue lives are in favorable agreement with the experimental results for machined bolts.

9. NUMERICAL SIMULATION ANALYSES ON REINFORCEMENT FUNCTION OF THE TENSIONED AND GROUTED BOLTS

邹喜正; 李华祥

1998-01-01

The purpose of the paper is to calculate the equivalent mechanics parameters of reinforced surroundings, which is based on the assume that the reinforcement of bolts is equivalent to the improvement of mechanics parameters of surroundings and combines with site engineering practice. Use numerical simulation analysis to study the reinforcement mechanism of full length bolts, thus to provide theoretical bases for bolting design.

10. Characterization of an Unusual Cytoplasmic Chimera Detected in Bolting Garlic (Allium sativum L.) Clones

Production of a visible flower stalk or bolting has been used as a major trait to categorize garlic clones. Analysis of mitochondrial genome variation with PCR revealed differences between bolting and non-bolting clones of garlic. Screening 333 garlic accessions from diverse geographic origins rev...

11. Anchoring in numeric judgments of visual stimuli

Linda eLangeborg

2016-02-01

Full Text Available This article investigates effects of anchoring in age estimation and estimation of quantities, two tasks which to different extents are based on visual stimuli. The results are compared to anchoring in answers to classic general knowledge questions that rely on semantic knowledge. Cognitive load was manipulated to explore possible differences between domains. Effects of source credibility, manipulated by differing instructions regarding the selection of anchor values (no information regarding anchor selection, information that the anchors are randomly generated or information that the anchors are answers from an expert on anchoring were also investigated. Effects of anchoring were large for all types of judgments but were not affected by cognitive load or by source credibility in either one of the researched domains. A main effect of cognitive load on quantity estimations and main effects of source credibility in the two visually based domains indicate that the manipulations were efficient. Implications for theoretical explanations of anchoring are discussed. In particular, because anchoring did not interact with source credibility or cognitive load, the results imply that the process behind anchoring in visual tasks is predominantly automatic and unconscious.

12. Inconspicuous anchoring effects generated by false information

Chen Qu; Jun Wang; Yuejia Luo

2008-01-01

The impact of false information on numerical judgments was examined on young normal subjects by an event-related potential (ERP) experiment. To imitate the judgments in real world, we ensured the subjects acknowledged of the target task. The behavioral results found that both uncertain information and false information assimilated the final estimates: higher after higher anchors and lower after lower anchors; and false information caused a weaker anchoring bias than uncertain information. ERP results provided further electrophysiological evidence for the mechanism of anchoring. In the early phrase, it was an accessibility-dominated process in which two kinds of anchors elicited an N300 component related to the accessibility of anchors propositions. The knowledge relevant to targets joined the process in the late phrase, which caused a larger amplitude of late positive component (LPC) for implausible lower anchors than that for plausible higher anchors. Source analysis showed that medial frontal gyrus, whose activity was suggested to signal the need of adjustment, was more reliable to explain the LPC elicited by implausible lower anchors. Therefore, we suggest that accessibility is facilitated when the external anchor is consistent with the world knowledge, and adjustment is initiated when the external anchor is inconsistent.

13. Anchoring in Numeric Judgments of Visual Stimuli.

Langeborg, Linda; Eriksson, Mårten

2016-01-01

This article investigates effects of anchoring in age estimation and estimation of quantities, two tasks which to different extents are based on visual stimuli. The results are compared to anchoring in answers to classic general knowledge questions that rely on semantic knowledge. Cognitive load was manipulated to explore possible differences between domains. Effects of source credibility, manipulated by differing instructions regarding the selection of anchor values (no information regarding anchor selection, information that the anchors are randomly generated or information that the anchors are answers from an expert) on anchoring were also investigated. Effects of anchoring were large for all types of judgments but were not affected by cognitive load or by source credibility in either one of the researched domains. A main effect of cognitive load on quantity estimations and main effects of source credibility in the two visually based domains indicate that the manipulations were efficient. Implications for theoretical explanations of anchoring are discussed. In particular, because anchoring did not interact with cognitive load, the results imply that the process behind anchoring in visual tasks is predominantly automatic and unconscious. PMID:26941684

14. Apparatus For Eddy-Current Inspection Of Bolts

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.

15. To model bolted parts for tolerance analysis using variational model

Wilma Polini

2015-01-01

Full Text Available Mechanical products are usually made by assembling many parts. Among the different type of links, bolts are widely used to join the components of an assembly. In a bolting a clearance exists among the bolt and the holes of the parts to join. This clearance has to be modeled in order to define the possible movements agreed to the joined parts. The model of the clearance takes part to the global model that builds the stack-up functions by accumulating the tolerances applied to the assembly components. Then, the stack-up functions are solved to evaluate the influence of the tolerances assigned to the assembly components on the functional requirements of the assembly product. The aim of this work is to model the joining between two parts by a planar contact surface and two bolts inside the model that builds and solves the stack-up functions of the tolerance analysis. It adopts the variational solid model. The proposed model uses the simplified hypothesis that each surface maintains its nominal shape, i.e. the effects of the form errors are neglected. The proposed model has been applied to a case study where the holes have dimensional and positional tolerances in order to demonstrate its effectiveness.

16. Modal Experiments and Finite Element Analysis of the Bolted Structure Considering Interface Stiffness and Prtension

WEI Li-dui; DUAN Shu-lin; WU Ji; WU Qi-li; XING Hui

2012-01-01

It is particularly important to evaluate natural frequencies and natural modes of the structure of bolted joints to avoid the failures of the structure due to the resonance. The vibration characteristics of bolted structures are closely connected to surface roughness of contact interfaces, the magnitude of pretension of the bolts and the number of clamping bolts. In this paper, the effect of the factors above on the natural frequencies of bolted structures is sys- tematically investigated by experiments. Then, the finite element method is applied to analyze the effect. Finally, the numerical method is validated by experimental measurements of the natural frequencies.

17. Controllable theory and applications for the wall bolting reinforcement in the roadway of seam

TAN Yun-liang; ZHANG Li-jun; XIAO Ya-xun

2007-01-01

By using the Radar penetrating technology and numerical simulations, the fractured zone could be easily determined. Both wall fractured zone and mining action of coal seam roadway were considered, and the bolt reinforcing criteria for wall including low limit condition and up limit condition were put up, which supply a basis for the bolt reinforcement design. For a particular engineering, there existed a bolt reinforcing controllable range which can be determined by the method put up in this paper. For the out of controllable range of bolt reinforcement in engineering, it is necessary to seek for other kind reinforcing technology, because the bolt reinforcing technology is not omnipotent.

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

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

19. Device Design and Test of Fatigue Behaviour of Expansion Anchor Subjected to Tensile Loads

Zhang Jinfeng

2016-01-01

Full Text Available In order to study on the fatigue behaviour of expansion anchor (M16, grade 8.8 for overhead contact system in electrification railways, a set of safe, practical loading device is designed and a fatigue test campaign was carried out at structural laboratory of China Academy of Building Research on expansion anchor embedded in concrete block. The mobile frame of the loading device was designed well by finite-element simulation. According to some fatigue performance test of expansion anchor with different size and form, the device have been assessed experimentally its dependability. The results were found that no fatigue damage phenomenon occurred in all specimens after 2×106 cycles tensile fatigue test in this specific series. It shows that in the condition of medium level or slightly lower maximum stress limit and nominal stress range, expansion bolt has good fatigue resistance. The biggest relative displacement and the residual relative displacement after test (Δδ = δ2-δ1 was also strongly lower than the symbol of the fatigue test failure index of this specific series (0.5mm in the high cycle fatigue regime. The ultimate tension failures mode after fatigue tests in all tested samples take place in the concrete anchorage zone. The reduction range of the ultimate tensile strength properties of the anchorage system was not obvious, and the concrete was seen to be the weakest link of the system.

20. Anchors and their use in offshore petroleum operations

1984-01-01

Holding a ship or vessel in a fixed position over specific spots is essential in drilling subsea wells. Conventional anchors and holding systems have thus been transformed into permanent mooring points capable of withstanding enormous stresses. This book specifies the parameters directly governing behavior of these new anchors, studies the mechanisms involved in anchor/seabed interaction and interprets these in the context of soil mechanics, and draws practical conclusions in the form of methods for predicting holding capacity in different types of subsea soils. Contents are: history of anchors; high-capacity anchoring systems; kinetics of anchors; holding power of anchors; anchoring site survey; choice of an anchor; and anchoring tests.

1. Shifting Nominal Anchors: The Experience of Mexico

Leonardo Leiderman; Nissan Liviatan; Alfredo Thorne

1995-01-01

In the mid-1980’s Mexico successfully brought down its high rate of inflation by using the exchange rate as nominal anchor in combination with strict fiscal discipline, tight monetary policy, and incomes policy. This paper discusses the role of exchange rate policy as nominal anchor in Mexico and develops the inflation target as the monetary framework for anchoring prices. It also describes how Mexico is applying this frame work while shifting to a more flexible exchange regime and discusses ...

2. Capital Asset Pricing Model Adjusted for Anchoring

2015-01-01

I show that adjusting CAPM for anchoring provides a unified explanation for the size, value, and momentum effects. Anchoring adjusted CAPM (ACAPM) predicts that stock splits are associated with positive abnormal returns and an increase in return volatility, whereas the reverse stock-splits are associated with negative abnormal returns and a fall in return volatility. Existing empirical evidence strongly supports these predictions. Anchoring has the effect of pushing up the equity premium, a ...

3. Study on the Axial force and Assembly Torque value of Bolted Joint

Kim, Dong Il; Kim, Nak Jeom; Choi, Sang Hoon; Kim, Kyung Sub [Korea Plant Service and Enginccring Co., Seongnam (Korea, Republic of)

2009-10-15

When jointing high tension bolt, in order the nut rotary timely operates force we as the torque (Torque moment). The size of the torque is proportionate in axial force of bolt and diameter of bolt. This time the relationship with proportional torque coefficient in afterwards is expressed. T = k {center_dot} d {center_dot} N/1000 (1) Where, T : Jointed torque (Nm) (Nut rotate moment) k : Torque coefficient (Friction coefficient) d : Bolt diameter (mm) N : Bolt axial force (kN) When jointing a bolt with torque formula, design target axial force value according to it calculates a torque value. This time there is not a possibility of knowing the friction coefficient (Torque coefficient k) which is accurate. This coefficient to decide experimentally and influence bolt diameter, bolt material, tightening speed etc. According to type of lubricant which but, is used mostly it changes. It differs the lubricant of Wolsung 4 unit steam generator manway stud bolt jointing at the time of bolt from the present paper axial force it is a result which researches the result which it examines.

4. A Novel RFID-Based Sensing Method for Low-Cost Bolt Loosening Monitoring.

Wu, Jian; Cui, Xingmei; Xu, Yunpeng

2016-01-01

In coal mines, bolt loosening in the cage guide is affected by the harsh environmental factors and cage hoist vibration, leading to significant threats to work safety. It is crucial, to this effect, to successfully detect the status of multipoint bolts of guide structures. This paper proposes a system to monitor bolt status in harsh environments established based on the RFID technique. A proof-of-concept model was demonstrated consisting of a bolt gearing system, passive UHF RFID tags, a reader, and monitoring software. A tinfoil metal film is fixed on the retaining plate and an RFID tag bonded to a large gear, with the bolt to be detected fixed in the center of a smaller gear. The radio-frequency signal cannot be received by the reader if the tag is completely obscured by the tinfoil, and if the bolt is loose, the tag's antenna is exposed when the gear revolves. A radio-frequency signal that carries corresponding bolt's information is transmitted by the RFID tag to the RFID reader due to coil coupling, identifying loose bolt location and reporting them in the software. Confirmatory test results revealed that the system indeed successfully detects bolt loosening and comparative test results (based on a reed switch multipoint bolt loosening monitor system) provided valuable information regarding the strengths and weaknesses of the proposed system. PMID:26828498

5. Finite Element Modeling and Modal Analysis of Complicated Structure with Bolted Joints

PU Da-yu; LIAO Ri-dong; ZUO Zheng-xing; FENG Hui-hua

2009-01-01

A contact bolt model is proposed as a new modeling technique to investigate the complex structure with bolted joints for modal analysis and compared with the coupled bolt model, and the test results are given. Among these models, the coupled bolt model provides the best accurate responses compared with the experimental results. The contact bolt model shows the best effectiveness and usefulness in view of operational time. The bolt models proposed in this study are adopted for a dynamic characteristic analysis of a large diesel engine consisting of several parts which are connected by many bolts. The dynamic behavior of the entire engine structure was investigated by experiment. The coupled bolt model and the contact bolt model were applied to model the assembly of engine with high preload. The experimental results are in good agreement with the finite element method (FEM) results. Compared with the other models, the contact bolt model presented in this paper is more effective and useful in view of operational time and experience of analysts.

6. Ballistics Analysis of Orion Crew Module Separation Bolt Cover

Howard, Samuel A.; Konno, Kevin E.; Carney, Kelly S.; Pereira, J. Michael

2013-01-01

NASA is currently developing a new crew module to replace capabilities of the retired Space Shuttles and to provide a crewed vehicle for exploring beyond low earth orbit. The crew module is a capsule-type design, which is designed to separate from the launch vehicle during launch ascent once the launch vehicle fuel is expended. The separation is achieved using pyrotechnic separation bolts, wherein a section of the bolt is propelled clear of the joint at high velocity by an explosive charge. The resulting projectile must be contained within the fairing structure by a containment plate. This paper describes an analytical effort completed to augment testing of various containment plate materials and thicknesses. The results help guide the design and have potential benefit for future similar applications.

7. PLASMA NITRIDING FOR IMPROVING WEAR RESISTANCE OF CABLE BOLT

SHAOQING NIU; SHUANGSUO YANG; YI LI

2013-01-01

In order to improve the wear resistance of the cable bolt and increase its life-time during operation, plasma nitriding was employed to obtain a protective nitriding layer on its surface. The microstructure, phase constitution, microhardness and wear resistance of the nitriding layer were investigated. It was shown that continuous and dense nitriding layers were formed on the surface of the samples. The microhardness of the nitrided sample was enhanced by the formation of nitriding layer, whi...

8. Experimental study of friction in aluminium bolted joints

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.

9. AN EXPERIMENTAL STUDY ON THE RELAXATION OF BOLTS

2015-05-01

10. Bearing Stresses in Bolted Composite Joints with Different Contact Interactions.

2016-04-01

Full Text Available In a bolted joint, it has been shown to be better to model the real contact between bolt and hole than to fix the boundary of the hole edge, a practice used by most previous researchers. Master-slave interaction was implemented in ABAQUS to simulate full contact conditions. Stress distributions were plotted along net-tension plane and hole boundary. Due to geometric non-linearity, the clearance and friction coefficients used substantially effected the maximum stress on hole boundary as shown using the benchmarking work of Eriksson. A physically-based constitutive model used is based on state-of-the art fracture mechanics was used for bolted joint strength prediction. Idealized models from Hollmann were remodelled both by fixing the hole boundary (following the original author and by implementing full contact condition using CZM and XFEM. The physically-based constitutive law used independently measured of unnotched strength and fracture energy parameter for crack opening, which is calibrated from available literatures (known as apparent fracture energy. Good correlation with experimental results was found when using the real contact condition.

11. Experimental study of friction in aluminium bolted joints

Vincenzi N.

2010-06-01

Full Text Available 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.

12. Experimental Study on Methane Explosion Ignited by Sparks of Cable Bolt Breakage

MA Wen-ding; XU Jia-lin; ZHANG Shao-hua

2004-01-01

An experimental device was designed for studying methane explosion ignited by sparks of cable bolt breakage. With the methane concentration being in explosion range, a series of experiments were conducted to study the law of spark generation during cable bolt breakage and the probability of methane explosion caused by the spark. The results show that the probability of generating sparks during cable bolt breakage is 50%. The spark generated by the breakage of steel cable bolt strand can't ignite a methane explosion. A detection was carried out using infrared-ray imaging apparatus (IRIA) to measure temperature of the spark generated by cable bolt breakage. It is indicated that the maximum temperature of the spark generated by cable bolt breakage is far less than the required ignition temperature for a methane explosion.

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

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

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

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...... with an optimum at low concentrations. It was observed that overexpression of either GLB1 or GLB2 shifts the optimum for NO growth stimulation to a higher concentration. In conclusion, we have found that expression of NO scavenging plant hemoglobin is involved in the control of bolting in Arabidopsis....

15. Introducing aggregate into grouting material and its influence on load transfer of the rock bolting system

Cao Chen; Ren Ting; Chris Cook

2014-01-01

A fully grouted bolt provides greater shear load capacity for transmitting the load from the rock to the bolt, and vice versa. When grout fills irregularities between the bolt and the rock, a keying effect is cre-ated to transfer the load to the bolt via shear resistance at the interface and within the grout. Previous research has revealed that the mechanical properties of the grout had a great impact on the load transfer capacity of the rock bolting system. This paper presents a method to enhance the rock bolting strength by introducing metal granules into the grouting material. Experimental results suggest that both the average peak load of pullout tests and the total energy absorption of the system will increase if some metal gran-ules are mixed into the resin.

16. Method of fabrication of anchored nanostructure materials

Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

2013-11-26

Methods for fabricating anchored nanostructure materials are described. The methods include heating a nano-catalyst under a protective atmosphere to a temperature ranging from about 450.degree. C. to about 1500.degree. C. and contacting the heated nano-catalysts with an organic vapor to affix carbon nanostructures to the nano-catalysts and form the anchored nanostructure material.

17. Suction anchors for floating production systems

Tjelta, T.I.; Rusas, P. [Statoil a.s. (Norway); Edvardsen, G. [HEX a.s. (Norway)

1996-12-31

Since the suction anchor is a recent development in its current use, this work provides a brief historical background. It is shown that the suction anchor throughout evolution today is a competitive foundation solution for many applications. Examples from these categories are included in this paper. Also several installation methods are discussed. 3 refs., 7 figs., 2 tabs.

18. Determination of rational support parameters of bolting and shotcreting with wire mesh in soft roadway

LIU She-yu; MA Nian-jie; LIU Shao-wei

2005-01-01

Based on a great number of measured data, the author put forward zonal compressive and tensile deformation mechanism of soft rock around roadway. By using self-supporting capacity of compressive zone and controlling rock deformation of tensile zone, the long bolt or short bolt group supporting form was given for different size of rock compressive zone and tensile zone. Finally, studied on the determining method of rational support parameters of bolting and shotcreting with wire mesh in different support technology.

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

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.

20. Bolted connections of cold-formed stainless steel at elevated temperatures and post-fire condition

Cai, Yancheng; 蔡炎城

2013-01-01

The structural behaviour of single shear bolted connections and double shear bolted connections of cold-formed stainless steel at elevated temperatures and post-fire condition has been investigated in this study. The current design rules on bolted connections of cold-formed stainless steel are mainly based on those of carbon steel, and are applicable for room (ambient) temperature condition only. These design rules may not be applicable for elevated temperatures. Therefore, design guidelines ...

1. The face bending behaviour of blind-bolted connections to concrete-filled hollow sections

Elamin, Ahmed Mohamed Elamin Ahmed

2014-01-01

Structural Hollow Sections have superior structural performance over open sections and are currently available as circular, elliptical or rectangular sections. However, the practical use of these sections is limited due to complexities involved in their connections. The lack of access to the interior of the section makes it almost impossible to use standard bolted connections. The so-called Blind Bolts are therefore used as fasteners to alleviate these complexities by allowing for bolted rath...

2. Effects of Rock Bolting on Stress Distribution around Tunnel Using the Elastoplastic Model

2006-01-01

To ensure the stability of a tunnel during construction, rock bolts are usually installed, which affects the stress distribution around the tunnel.Therefore, it is necessary to study the effects of rock bolting on the stress distribution around the tunnel.In this article, the effects of rock bolting on the stress distribution around the tunnel, including the position and orientation of bolts, the overburden depths, and the bolt lengths, are simulated using the ANSYS software with an elastoplastic model.The effect of multiple bolts of 2 m and 1 m lengths on the stress distribution in the roof and on the lateral sides of a tunnel and at different overburden depths is considered.An important finding is that the tensile stress region that is very dangerous for rock in the bottom of the tunnel grows rapidly with increasing overburden depths when rock bolts are installed only in the roof or on the lateral sides of a tunnel.The determination of the length of the rock bolt used around a tunnel is dependent on the loads and the integrity of the rock mass around the tunnel.In addition, rock bolting around the tunnel can obviously reduce the coefficients and the size of the region of stress concentration, especially when installed in high-stress areas.This fact is very important and essential for the design of tunnels and ensures engineering safety in tunnel engineering.

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

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

4. Numerical Studies on Time-Varying Stiffness of Disk-Drum Type Rotor with Bolt Loosening

Qin, Zhaoye; Chu, Fulei

2015-07-01

Disk-drum type rotors are widely used in industry for their high stiffness and low weight properties. In disk-drum type rotors, the adjacent disks and drums are commonly connected by bolted joints. Those rotating joint interfaces are subjected to numerous combinations of loads during normal operation, where loosening of the connecting bolts might occur. The bolt loosening will change the local stiffness of the rotor, which in turn affect the rotor dynamics and even result in structural failures. In this paper, the local stiffness of a disk- drum rotor with bolt loosening is investigated numerically. A three-dimensional (3D) finite element (FE) model for the bolted disk-drum joint is established in ANSYS, where the bolt loosening is simulated by reducing the preloads of certain bolts, and removing those bolts as the limiting case. Simulations are performed on the FE model to evaluate the joint behaviour under static loads. Periodic variations of the joint deflections with respect to the rotation angle of the shaft are obtained, which implies the appearance of the time-varying local stiffness in the rotor system. The studies in this paper help accurate prediction of the rotor dynamics and early detection of bolt loosening.

5. A Novel RFID-Based Sensing Method for Low-Cost Bolt Loosening Monitoring

Wu, Jian; Cui, Xingmei; Xu, Yunpeng

2016-01-01

In coal mines, bolt loosening in the cage guide is affected by the harsh environmental factors and cage hoist vibration, leading to significant threats to work safety. It is crucial, to this effect, to successfully detect the status of multipoint bolts of guide structures. This paper proposes a system to monitor bolt status in harsh environments established based on the RFID technique. A proof-of-concept model was demonstrated consisting of a bolt gearing system, passive UHF RFID tags, a reader, and monitoring software. A tinfoil metal film is fixed on the retaining plate and an RFID tag bonded to a large gear, with the bolt to be detected fixed in the center of a smaller gear. The radio-frequency signal cannot be received by the reader if the tag is completely obscured by the tinfoil, and if the bolt is loose, the tag’s antenna is exposed when the gear revolves. A radio-frequency signal that carries corresponding bolt’s information is transmitted by the RFID tag to the RFID reader due to coil coupling, identifying loose bolt location and reporting them in the software. Confirmatory test results revealed that the system indeed successfully detects bolt loosening and comparative test results (based on a reed switch multipoint bolt loosening monitor system) provided valuable information regarding the strengths and weaknesses of the proposed system. PMID:26828498

6. THE PRESENT SITUATION AND DEVELOPMENT OF THE BOLTING AND SHOTCRETING TECHNIQUE IN ROCK TUNNELING

DUANZhenxi

1995-01-01

Application of bolting and shotcreting used in Chinese coal mine underground engineering has been more than 40 years. By the end of 1993. total roadway length adopted bolting and shotcreting was over 21000km. Now, This paper describes developing and achievement of bolting and shotcreting briefly in the recent years. Meanwhile the paper puts forward solving and improving method for problems which exists in present design and construction. Final, combined with feature of coal mine, the paper puts forward some proposals about developing of bolting and shotcreting,dynamic management of both designs and construction, engineering measure and stability judgement as well.

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

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.

8. A Novel RFID-Based Sensing Method for Low-Cost Bolt Loosening Monitoring

Jian Wu

2016-01-01

Full Text Available In coal mines, bolt loosening in the cage guide is affected by the harsh environmental factors and cage hoist vibration, leading to significant threats to work safety. It is crucial, to this effect, to successfully detect the status of multipoint bolts of guide structures. This paper proposes a system to monitor bolt status in harsh environments established based on the RFID technique. A proof-of-concept model was demonstrated consisting of a bolt gearing system, passive UHF RFID tags, a reader, and monitoring software. A tinfoil metal film is fixed on the retaining plate and an RFID tag bonded to a large gear, with the bolt to be detected fixed in the center of a smaller gear. The radio-frequency signal cannot be received by the reader if the tag is completely obscured by the tinfoil, and if the bolt is loose, the tag’s antenna is exposed when the gear revolves. A radio-frequency signal that carries corresponding bolt’s information is transmitted by the RFID tag to the RFID reader due to coil coupling, identifying loose bolt location and reporting them in the software. Confirmatory test results revealed that the system indeed successfully detects bolt loosening and comparative test results (based on a reed switch multipoint bolt loosening monitor system provided valuable information regarding the strengths and weaknesses of the proposed system.

9. Strength evaluation of aluminium alloy bolt by nano-indentation hardness test

A high strength aluminium alloy bolt (A7050, T7 temper treatment) has been developed by the authors. The bolt has a small grain size in the whole area of the bolt because of the large equivalent strain followed by thermo-mechanical treatment. As the bolt made of A7050 has a risk of stress corrosion cracking, to improve the stress corrosion cracking resistance, each grain should be strengthened inside. It has been confirmed that the nano-indentation at each grain inside increased with the increase of the equivalent strain by thermo-mechanical treatment processing (Authors)

10. Theoretical and experimental research on characteristics of lateral vibration for a pre-stress bolt supporting system

LI Qing-feng; ZHU Chuan-qu; DUAN Yu

2009-01-01

According to the structure and stress trait of bearing bolts,a lateral-vibration mechanics model was established for them,and the relation between lateral-vibration fre-quency and axial load was analyzed; then,lateral-vibration trait of bearing bolts was stud-ied through laboratory simulation test.The results indicate that vibration frequency of bolt support system increases as well as axial force,the detection on axial load of bolts can be made by generating lateral vibration of bearing bolts.Theoretical and experimental re-search results show that frequency method is effective for detecting the axial force of bolt support system.

11. 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

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)

12. Isolation and identification of an anti-bolting compound, hexadecatrienoic acid monoglyceride, responsible for inhibition of bolting and maintenance of the leaf rosette in radish plants.

Yoshida, Yuko; Takada, Noboru; Koda, Yasunori

2010-08-01

Generally, the bolting (stem elongation from rosette plants) of winter annuals is believed to be induced by an increase in the levels of gibberellin that occurs after a certain period of chilling (vernalization), and a deficiency of gibberellin allows the plant to maintain a rosette style. Lack of direct evidence proving the above assumption in radish plants (Raphanus sativus L.) encouraged us to assume the presence of an anti-bolting compound actively maintaining the rosette habit through inhibition of bolting. Anti-bolting activity was detected in an extract of rosette shoots of radish plants by an assay using seedlings cultured in vitro. The causal compound that strongly inhibited bolting was isolated and identified as alpha-(7Z,10Z,13Z)-hexadecatrienoic acid monoglyceride (16:3 monoglyceride). This compound did not inhibit leaf production at the apical meristem, indicating that it merely inhibits growth at the internode. The compound disappeared completely after vernalization, and bolting occurred thereafter. The results suggest that the release from inhibition by 16:3 monoglyceride induces the initiation of bolting. The possible mechanism by which the compound exerts the activity is discussed. PMID:20601431

13. Anchored nanostructure materials and method of fabrication

Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

2012-11-27

Anchored nanostructure materials and methods for their fabrication are described. The anchored nanostructure materials may utilize nano-catalysts that include powder-based or solid-based support materials. The support material may comprise metal, such as NiAl, ceramic, a cermet, or silicon or other metalloid. Typically, nanoparticles are disposed adjacent a surface of the support material. Nanostructures may be formed as anchored to nanoparticles that are adjacent the surface of the support material by heating the nano-catalysts and then exposing the nano-catalysts to an organic vapor. The nanostructures are typically single wall or multi-wall carbon nanotubes.

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

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

15. Improvement activities for the maintenance of Baffle Former Bolts

Baffle Former Bolts (BFBs) in PWR nuclear plant have the possibility to be cracked due to Irradiation Assisted Stress Corrosion Cracking (IASCC). The maintenance guideline for BFBs had been established from Thermal and Nuclear Power Engineering Society in 2000, and BFBs have been maintained in accordance with this maintenance rules. Recently, the new edition of this guideline has been published in order to reflect latest IASCC data and more precise stress evaluation of BFB into maintenance rules. The summary of the revised contents and these improvement activities are introduced in this paper. (author)

16. Lightning Bolt: an ecology of imagens, noises and extremes sounds

Fabrício Lopes da Silveira

2011-12-01

Full Text Available The article is focused exclusively on the music video “Dracula Mountain”, by north American noise-rock band Lightning Bolt. The aim is, in fact, sufficiently restricted: to describe the video and call it in question, considering it as a counterpoint to the band sonority and musical performance. At the end, we state that the video is both a symptom and a product of a very particular and contemporary media ecology, in which musical and audiovisual products and genres, as well as musical and audiovisual consumption habits are rebuilt and (repotentialized, sometimes inverted.

17. Hydraulic nuts (HydraNuts) for critical bolted joints

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)

18. Device for distance welding of bolts with a remote controlled gun

The welding gun includes two grounded contacts, on each side of the bolt to weld. They are mounted on springs for a better electric contact with the surface to be welded to the bolts. Remote control of the welding unit is provided for working where there is a radiation risk

19. Effects of curing time and frequency on ultrasonic wave velocity in grouted rock bolts

Madenga, V.; Zou, D. H.; Zhang, C.

2006-05-01

Grouted rock bolts are widely used to reinforce excavated ground in mining and civil engineering structures. To date, opportunities for testing the quality of the grout in grouted rock bolts have been limited to the pull-out tests and the over-coring methods. Both these methods are destructive, time-consuming and costly. These deficiencies have fueled research into the use of ultrasonic methods for testing the quality of the grout in rock bolts. However, only partial success has been achieved in these efforts chiefly due to inadequate knowledge of the ultrasonic wave characteristics such as wave velocity in grouted rock bolts. This paper presents results of an experimental study into the effects of curing time and testing frequency on the velocity of ultrasonic waves propagating along rock bolts grouted in concrete. A substantial wave velocity decrease, as much as 47.7% at certain frequencies, was recorded in rock bolts grouted in fully cured concrete in comparison to non-grouted bolts. The results demonstrate the importance of optimizing the selection of test frequencies as well as suggesting the possibility of a new approach based on wave velocity decrease for testing the grout quality of rock bolts.

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

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)

1. Monitoring bolt torque levels through signal processing of full-field ultrasonic data

Haynes, Colin; Yeager, Michael; Todd, Michael; Lee, Jung-Ryul

2014-03-01

Using full-field ultrasonic guided wave data can provide a wealth of information on the state of a structure through a detailed characterization of its wave propagation properties. However, the need for appropriate feature selection and quantified metrics for making rigorous assessments of the structural state is in no way lessened by the density of information. In this study, a simple steel bolted connection with two bolts is monitored for bolt loosening. The full-field data were acquired using a scanning-laser-generated ultrasound system with a single surface-mounted sensor. Such laser systems have many advantages that make them attractive for nondestructive evaluation, including their high-speed, high spatial resolution, and the ability to scan large areas of in-service structures. In order to characterize the relationship between bolt torque and the resulting wavefield in this specimen, the bolt torque in each of the bolts is independently varied from fully tightened to fully loosened in several steps. First, qualitative observations about the changes in the wavefield are presented. Next, an approach to quantifying the wave transmission through the bolted joint is discussed. Finally, a method of monitoring the bolt torque using the ultrasonic data is demonstrated.

2. The modelling of bolted flange joints used with disc springs and tube spacers to reduce relaxation

Bolted flange joints are prone to leakage when exposed to high temperature. In several cases, the root cause is relaxation that takes place as a result of material creep of the gasket, the bolt and the flange. One way to overcome this problem is to make the joint less stiff by introducing disc springs or the use of longer bolts with spacers. Although widely used, these two methods have no reliable analytical model that could be used to evaluate the exact number of washers or length of the bolts required to reduce relaxation to a minimum acceptable level. This paper describes an analytical model based on the flexibility and deflection interactions of the joint different elements including the axial stiffness of the flange and bolts, used to evaluate relaxation. The developed analytical flange model can accommodate either disc springs or longer bolts with spacer tubes to reduce the bolt load loss to a maximum acceptable value. This model is validated by comparison with the more accurate FEA findings. Calculation examples on a bolted flanged joint are presented to illustrate the suggested analytical calculation procedure.

3. THE MECHANICAL MODEL OF THE FOREPOLING BOLT STRUCTURE FOR STUDYING THE PRE-SUPPORT MECHANISM

陶龙光; 侯公羽; 乔河

1995-01-01

Based on references ,the mechanical models have been developed to study the presupport mechanism of forepoling bolt structure in this paper. The following problems are discussed：(1) the pre-support mechanism of forepoling bolt structure and stress distribution on its upper broken rock! (2) loading state of forepoling bolt； (3) solution of arching in the cross section of excavation。

4. Failure Analysis of Bolts%螺钉失效分析

吴伟

2001-01-01

对断裂螺钉的断口观察，分析了螺钉的装配情况，找出了断裂原因。%On the basis of observation of the ruptured section of a bolt, the author analyzes the assembled condition of the bolt. As a result, the rupture reason is found out.

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

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)

6. The Nuts and Bolts of Michaelis-Menten Enzyme Kinetics: Suggestions and Clarifications

Silverstein, Todd

2011-01-01

Matthew Junker's recent article describes a useful and effective enzyme kinetics application and analogy in which students simulate enzyme activity by unscrewing nut-bolt "substrate molecules", thus, converting them into separate nuts and bolts "products". A number of suggestions and corrections are presented that improve the clarity and accuracy…

7. Fasteners 1 dimensional standards for bolts, screws and studs national standards

2011-01-01

This 7th edition of DIN Handbook 10 contains 90 currently valid German national standards (DIN Standards) dealing with the dimensions of bolts, screws and studs. In this updated compilation four standards are new: DIN 787 T-head bolts; DIN 1445 Clevis pins with head and threaded portion; DIN 5903-1 Fish bolts - Part 1: With round head and oval neck; DIN 5903-2 Fish bolts - Part 2: With square head. 27 standards have been revised for this edition. DIN Handbook 10 is the companion volume to DIN Handbook 362 "Fasteners 6 - Dimensional standards for bolts and screws - European Standards", which reflects the state of the art in Europe. Together, DIN Handbooks 10 and 362 provide the user with a comprehensive overview of standards in the fasteners sector.

8. Effects of sowing time on bolting and returning green in welsh onion

JI Jiaojiao; LIU Jing; XING Xiaoxue; JIANG Xinmei

2007-01-01

Qiyechangbai and Hadacongl were used to study the relationship of the leaf age of overwinter to bolting and returning green by the difference of sowing time. The results showed that the earlier the seeds were sown, the older leaf age of overwinter was, the higher the rates of returning green and bolting rate were, the earlier the bolting time was. The leaf age of overwinter of Qiyechangbai sown August 31 to September 14 was 2.1-3.1 leaves and the rate of returning green was 86.5%-92.1%, while the leaf age of overwinter of Hadacongl sown September 7 to September 14 was 2.3-2.7 leaves and the rate of returning green was 88.5%-93.8%, both varieties didn't bolt. In addition, in the same sowing time, the bolting rate of Hadacong1 was higher than that of Qiyechangbai slightly.

9. Development of signal processing technique for inspection of defects in stud bolts of nuclear reactor vessel

Bolt failure is a hazard factor for the safety of reactor vessels in nuclear power plants. However, in the practical application of ultrasonic technique for crack detection in stud bolt, the classification of crack signal from the signals reflected from threads in stud bolt is very difficult. In this study, shadow effect technique combined with new signal processing method has been investigated to enhance the detectability of small crack initiated from root of thread in stud bolt. The key idea of new signal processing concept 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 from the reference signals. It has shown that the small flaws can be effectively detected by novel ultrasonic technique combined with this new signal processing concept.

10. Detection of cracks in stud bolts of nuclear reactor by novel ultrasonic technique

The stud bolt is one of the most critical parts for the safety of reactor vessels in nuclear power plants. However, in the practical application of ultrasonic technique for crack detection in stud bolt, the classification of crack signal from the signals reflected from threads in stud bolt is very difficult. In this study, shadow effect technique combined with new signal processing method has been investigated to enhance the detectability of small crack initiated from root of thread in stud bolt. The key idea of new signal processing concept 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 from the reference signals. It has shown that the small flaws can be effectively detected by novel ultrasonic technique combined with this new signal processing concept. (orig.)

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

'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)

12. EVALUATION OF TROQUE VS CLOSURE BOLT PRELOAD FOR A TYPICAL CONTAINMENT VESSEL UNDER SERVICE CONDITIONS

Smith, A.

2010-02-16

Radioactive material package containment vessels typically employ bolted closures of various configurations. Closure bolts must retain the lid of a package and must maintain required seal loads, while subjected to internal pressure, impact loads and vibration. The need for insuring that the specified preload is achieved in closure bolts for radioactive materials packagings has been a continual subject of concern for both designers and regulatory reviewers. The extensive literature on threaded fasteners provides sound guidance on design and torque specification for closure bolts. The literature also shows the uncertainty associated with use of torque to establish preload is typically between 10 and 35%. These studies have been performed under controlled, laboratory conditions. The ability to insure required preload in normal service is, consequently, an important question. The study described here investigated the relationship between indicated torque and resulting bolt load for a typical radioactive materials package closure using methods available under normal service conditions.

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

Lee, J.H.; Oh, W.D.; Choi, S.W.; Park, M.H. [Busan National Univ., Busan (Korea, Republic of)

2004-07-01

'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)

14. Development of signal processing technique for inspection of defects in stud bolts of nuclear reactor vessel

Oh, Hyun Deok; Lee, Joon Hyun; Choi, Sang Woo; Cho, Youn Ho [Pusan National University, Pusan (Korea, Republic of); Park, Moon Ho [Korea Plant Service and Engineering Co.,Ltd, Sungnam (Korea, Republic of)

2004-05-15

Bolt failure is a hazard factor for the safety of reactor vessels in nuclear power plants. However, in the practical application of ultrasonic technique for crack detection in stud bolt, the classification of crack signal from the signals reflected from threads in stud bolt is very difficult. In this study, shadow effect technique combined with new signal processing method has been investigated to enhance the detectability of small crack initiated from root of thread in stud bolt. The key idea of new signal processing concept 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 from the reference signals. It has shown that the small flaws can be effectively detected by novel ultrasonic technique combined with this new signal processing concept.

15. A critical flaw size approach for predicting the strength of bolted glass connections

Watson, James; Nielsen, Jens Henrik; Overend, Mauro

2013-01-01

The use of bolted connections in glass installations is common place in contemporary architecture. However, it is difficult to predict the load bearing capacity of these connections accurately due to the several factors that influence the strength of glass in the region of the bolt hole, namely......: the complex stress state, the inherent strength of glass and the magnitude of residual thermal stresses. This paper proposes a critical flaw size approach for bolted connections. The approach uses a numerical tempering model and nonlinear finite element analysis to determine the sizes of the critical...... flaws around the bolt hole, from destructive tests on bolted glass components subjected to in-plane loading. The critical flaw sizes determined by this approach agree with the flaw sizes obtained from optical microscopy. These flaw sizes are subsequently used to plot lifetime prediction curves for the...

16. Experimental and Numerical Investigation of an End Plate Connection with Using Long Shank SMA Bolts

Hongwei Ma; Yongbing Zhu; Michael CH Yam; Yang Wang

2015-01-01

Superelastic shape memory alloys ( SMAs ) have the ability to recover their original shape after experiencing large strains. End⁃plate connection with using superelastic long shank SMA bolts is proposed in this paper. By using strong beam⁃weak bolt cluster design methodology and special configurations to strength beam ends, a superelastic hinge is expected to form in column flange. To validate the mechanical behavior of the proposed beam⁃to⁃column connection, both quasi⁃static tests and numerical analysis are conducted with cyclic transverse loads applied on the beam ends. The results indicate the connection deformations concentrate on the long shank SMA bolts upon loading and the bolt cluster rotates around the axis near beam flange. By using the super elastic effect, the SMA bolts recover most elongations and the connection recovers to its original shape after experiencing 0�02 rad interstorey drift angle. The connection shows obvious self⁃centering properties.

17. Mooring Anchors for Marine Renewable Energy Foundations

Stevens, Robert F.; Rahim, Amir

2014-01-01

With the increasing use of offshore wind turbines, it has become necessary to explore deep-water sites for locating wind farms. Floating turbines are an ideal choice for these locations. Such turbines are anchored with mooring chains to the sea floor using suction anchors, driven piles or gravity foundations. This paper presents design methods for these types of foundations. Moored gravity foundations have been used for the much larger floating oil and gas installations. These concrete founda...

18. Anchoring Adjusted Capital Asset Pricing Model

2015-01-01

An anchoring adjusted Capital Asset Pricing Model (ACAPM) is developed in which the payoff volatilities of well-established stocks are used as starting points that are adjusted to form volatility judgments about other stocks. Anchoring heuristic implies that such adjustments are typically insufficient. ACAPM converges to CAPM with correct adjustment, so CAPM is a special case of ACAPM. The model provides a unified explanation for the size, value, and momentum effects in the stock market. A ke...

19. FRP-to-concrete joint assemblies anchored with multiple FRP anchors: experimental investigation

Zhang, H.; Smith, ST

2010-01-01

Higher strains can be developed in fibre-reinforced polymer (FRP) composites which are bonded to the surfaces of concrete members if the FRP is anchored. Anchors made from FRP (also known as FRP spike anchors but herein referred to as FRP anchors) are a promising type of anchorage as they can be applied to a variety of different shaped structural elements and they have been shown to be effective in en-hancing the strain capacity of externally bonded FRP. Limited research, however, has been co...

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

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.)

1. Performance of bolted closure joint elastomers under cask aging conditions

Verst, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Sindelar, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Skidmore, E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Daugherty, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-07-23

2. Modeling and simulation of Polymer Composite laminate bolted Joint

B. Sutharson

2013-10-01

Full Text Available Environmental awareness today motivates the researchers, worldwide on the studies of natural fiber reinforced polymer composite and cost effective option to synthetic fiber reinforced composites. This work is concerned with the modeling and simulation of bearing properties of hybrid fiber polymer composite mechanical joint using Artificial Neural Network (ANN. In general it was found that increase in bearing capacity was always with increasing the e/d and w/d ratio. However, the extent of increase/decrease depends on the type of stacking sequence. There was increase in strength with rise in natural fiber loading. In this study, an artificial neural network is developed to predict the response of bolt-loaded fiber reinforced polymer composite plates. To predict the behavior of the laminate failure, a multilayered feed-forward neural network trained with the back-propagation algorithm is constructed. The ANN was trained and verified using experimental data. Comparisons of ANN results with desired values showed that there is a good agreement between input and output variables of the experimental data. The results indicate that ANN was illustrated to be a valid useful and powerful tool for the prediction of bearing properties predictions of bolted joints in composite laminates.

3. Twofold hidden conformal symmetry of Kerr Bolt black holes

Previously we have shown that a four-dimensional Kerr—Bolt black hole in non-extremal and also in extremal cases could be described by a holographic two-dimensional (2D) conformal field theory (CFT) [Ghezelbash A M, Kamali V and Setare M R 2010 Phys. Rev. D 82 124051; Setare M R and Kamali V 2010 JHEP 10 074]. Motivated by recent work [Chen C M, Huang Y M, Sun J R, Wu M F and Zou S J 2010 Phys. Rev. D 82 066004], we show that there is another holographic description for these black holes. The first description is called the J-picture, whose construction is based on the black hole angular momentum. The new description is called the Q-picture, whose constructions originate from the nut charge of the black hole. Similar to the previous cases [Ghezelbash A M, Kamali V and Setare M R 2010 Phys. Rev. D 82 124051; Setare M R and Kamali V 2010 JHEP 10 074], we show that this new picture for a low frequency limit of the wave equation of a massless charged scalar field in the background of a Kerr—Bolt black hole can be written as the Casimir of SL(2, R) symmetry. Our result shows that the entropy of the black hole is reproduced by the Cardy formula. In addition, the absorption cross section is consistent with the finite temperature absorption cross section for a two-dimensional CFT. (general)

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

5. Babcock ampersand Wilcox experience with alloy A-286 reactor vessel internal bolting

Multiple reactor vessel internal bolt failures were discovered during the 1981 and 1982 in service inspections performed at three PWR nuclear power plants. All the failures were limited to bolts that fastened the lower portion of the reactor vessel internal thermal shield to the lower grid assembly. Subsequent examinations during 1982, 1983 and 1984 revealed bolt failures at four additional plants. These failures included bolts that fastened the core barrel to the core support shield and lower grid assembly. Additional failures were also discovered in the bolts used to join the surveillance specimen holder tube to the thermal shield. All the affected fasteners were fabricated from Alloy A-286 (ASTM A453 Grade 660) material. Alloy A-286 is a high strength precipitation hardened austenitic stainless steel containing a nominal Cr and Ni content of 15% and 25%, respectively. As a result of these bolt failures, the Babcock ampersand Wilcox Co., under the direction of the B ampersand W Owners Group, performed extensive evaluations of Alloy A-286 reactor vessel internal fasteners. The principal conclusions obtained from this investigation are given below. 1. Internals bolting failures have been observed at nominal peak calculated stress levels of greater than or equal to 690 MPa (100 ksi). The number of failures generally increases with increasing stress. Variations in this correlation are postulated to be the result of scatter in the calculated peak stress data. 2. A variety of material conditions including the use of highly cold worked barstock in the fabrication of some of the bolts, degree of annealing and hot forging may have contributed to the bolt failures. 3. No specific upset environmental conditions were found that could be judged to be a leading cause of the bolt failures. 4 refs., 2 tabs

6. Rock reinforcement by integrated system of bolting and grouting

Šňupárek, Richard; Paloncy, L.

Rotterdam : A. A. Balkema, 1995 - (Widmann, R.), s. 125-130 - (90-5410-577-1). [International Symposium on Anchors in Theory and Practice. Salzburg (AT), 09.10.1995-10.10.1995] R&D Projects: GA ČR GA103/94/0777

7. Anchors as Semantic Primes in Value Construction: An EEG Study of the Anchoring Effect.

Qingguo Ma

Full Text Available Previous research regarding anchoring effects has demonstrated that human judgments are often assimilated to irrelevant information. Studies have demonstrated that anchors influence the economic valuation of various products and experiences; however, the cognitive explanations of this effect remain controversial, and its neural mechanisms have rarely been explored. In the current study, we conducted an electroencephalography (EEG experiment to investigate the anchoring effect on willingness to accept (WTA for an aversive hedonic experience and the role of anchors in this judgment heuristic. The behavioral results demonstrated that random numbers affect participants' WTA for listening to pieces of noise. The participants asked for higher pay after comparing their WTA with higher numbers. The EEG results indicated that anchors also influenced the neural underpinnings of the valuation process. Specifically, when a higher anchor number was drawn, larger P2 and late positive potential amplitudes were elicited, reflecting the anticipation of more intensive pain from the subsequent noise. Moreover, higher anchors induced a stronger theta band power increase compared with lower anchors when subjects listened to the noises, indicating that the participants felt more unpleasant during the actual experience of the noise. The levels of unpleasantness during both anticipation and experience were consistent with the semantic information implied by the anchors. Therefore, these data suggest that a semantic priming process underlies the anchoring effect in WTA. This study provides proof for the robustness of the anchoring effect and neural evidence of the semantic priming model. Our findings indicate that activated contextual information, even seemingly irrelevant, can be embedded in the construction of economic value in the brain.

8. Numerical simulation of attenuation and group velocity of guided ultrasonic wave in grouted rock bolts

Cui, Y.; Zou, D. H.

2006-08-01

In this paper, the guided ultrasonic wave propagating in grouted rock bolts was simulated with finite element method. An 800 mm partially grouted cylindrical rock bolt model was created. Dynamic input signals with frequency from 25 to 100 kHz were used to excite ultrasonic wave. The simulated waveform, group velocity and amplitude ratio matched well with the experimental results. This model made it possible to study the behaviour of the guided waves in the grouted bolt along its central axis. Analysis of the simulated results showed that the group velocity in grouted rock bolts is constant along the grouted length, and the boundary effect on the group velocity is negligible. This paper also presents methods to determine the attenuation coefficient from simulation and to determine the boundary effect on attenuation at the bolt ends. The analysis showed that the attenuation of the guided wave propagating inside the grouted bolts is similar to the theoretical solution in steel bar with infinite length. After correction for the boundary effects the grout length of a grouted rock bolt can be determined using the measured attenuation, with sufficient accuracy.

9. Corrosion and stress corrosion cracking of bolting materials in light water reactors

The primary coolant of a pressurized water reactor contains dissolved boric acid added as a soluble neutron absorber. Corrosion and stress corrosion cracking of bolts on pumps and on primary system manways have occurred where gaskets leak this boric acid onto the low alloy steel bolting material. Laboratory experiments have shown that the concentration of the 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. Frequently molybdenum disulfide is used as a lubricant for tightening bolts on massive flanges. Laboratory experience has shown that when the primary coolant leaks through a gasket the molybdenum disulfide can react with the leaking steam to produce hydrogen sulfide and subsequent stress corrosion cracking of the bolts. Additionally, contaminants concentrating over significant time periods have caused stress corrosion cracking failures of reactor coolant pump internals. Failure analysis of cracked bolts from service and the results of laboratory tests that demonstrate these mechanisms of bolt cracking are presented

10. Health monitoring of bolted joints using the time reversal method and piezoelectric transducers

Tao, Wang; Shaopeng, Liu; Junhua, Shao; Yourong, Li

2016-02-01

In this paper, the time reversal method based on piezoelectric active sensing is investigated for health monitoring of bolted joints. Experiments are conducted on bolted joints to study the relationship between the time reversal focused signal peak amplitudes and the bolt preload. Two piezoelectric patches are bonded on two different sides of a bolted joint. Any one of the piezoelectric patches can be used as an actuator to generate an ultrasonic wave, and the other one can be used as a sensor to detect the propagated wave. With the time reversal method, the received response signal is reversed in the time domain and then is re-emitted as an excitation signal to acquire the time reversal focused signals. The experimental results show that the time reversal focused signal peak amplitudes increase with the increasing bolt preload until reaching saturation, and when the bolt preload increases to a certain value, the focused signal peak amplitudes will remain unchanged. Experiments show that the surface roughness of the bolted joint impacts the saturation value. A higher surface roughness value corresponds to a higher saturation value. In addition, the proposed method has a high signal to noise ratio benefiting from the time reversal method time and space focusing ability.

11. 连杆螺栓的强度分析%Strength Analysis for Connecting Rod Bolt

李笑岩; 付冰洋; 张建云; 张士永

2016-01-01

对连杆螺栓受力进行了研究，利用ANSYS对螺栓进行静力学分析，得出螺栓的应力分布状况。对连杆螺栓断裂事故进行了分析，得出可能造成螺栓断裂的原因；利用Miner疲劳损伤理论和ANSYS软件，分别对连杆螺栓进行疲劳寿命计算，预估螺栓的使用寿命。%The force of the connecting rod bolts is researched in the paper. Using ANSYS software, static analysis of connecting rod bolts is calculated. And the stress distribution of connecting rod bolts is got from ANSYS. The accident that the connecting rod bolts broken is analyzed and the reason for the bolt fracture is obtained. Using Miner Fatigue Damage Theory and ANSYS software, the fa-tigue life of connecting rod bolt is calculated and the using life of bolt is estimated.

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

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.

13. Monitoring ground anchor using non-destructive ground anchor integrity test (NDT-GRANIT)

Monitoring at ground anchor commonly uses a pull out test method, therefor we developing a non-destructive ground anchor integrity testing (NDT-GRANIT). NDT-GRANIT using the principle of seismic waves that have been modified into form of sweep signal, the signal will be demodulated, filtered, and Fourier transformation (inverse discrete Fourier transform) so the data can be interpreted reflected wave from the ground anchor. The method was applied to determine whether the ground anchor still gripped in the subsurface by looking the attenuation of the wave generated sources. From the result we can see that ground anchor does not grip. To validate the results of the comparison method of measurement used pile integrity test

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

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

15. Application of shape memory alloys in bolted flanged connections

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)

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

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.

17. Stress state and caving danger of the roof in bolt supporting roadway

LIU Shao-wei; XU Li-li

2006-01-01

The start point of this text is the bottleneck problem of bolt supporting coal entry that is security problem of bolt supporting roof,we divide one entry into some sections with different stress, simulate stress field of wall rock and rockbolt solidified at different sections used umbrella disperse soft UDEC(universal distinct element code), we educe that the stress level of wallrock and bolt solidified is higher in roof fall risk section, and roof rockbolt load can reflect this rule clearly, that offer an important guideline in monitoring entry roof fall risk.

18. Prying Force Calculation and Design Method for T-shaped Tensile Connector with High Strength Bolt

Zhaoxin Hou; Guohong Huang; Chao Gong

2015-01-01

In order to establish the design method for T⁃shaped tensile connector with high strength bolt, the theoretical analysis is carried out. Firstly, it analyzes the performance of the connector and establishes prying force calculation model. Based on the model, prying force equation and function between bolt prying force and flange thickness is derived, and the min and max thickness requirement of flange plate under a certain tension load is then obtained. Finally, two simplified design methods of the connector are proposed, which are bolt pulling capacity method and flange plate bending capacity method.

19. Research on coal roadway truss and numerical simulation of bolting support effect

NING Jian-guo; ZHANG Xin-guo; GAO Ming-tao

2007-01-01

According to the research results in world, the paper comprehensively analyzed and gave a demonstration of mechanism of single-truss and its stressing advantage. Comparison and analysis effect were given to single-truss and bolting supporting. By the way of element simulation. The paper shows that single truss supporting have better effect to bolting supporting to improving the stress condition of surrounding rocks, controlling the surrounding rocks plastic failure development zone and deformation effect of surrounding rocks, which provided the elementary theory basis to the research, experiment and expanding the single-truss bolting technology in colliery.

20. Bolted flanged connections with longitudinal bending moments: Experimental results

Flanges in piping systems and on tall vertical pressure vessels such as columns or fractionators, are often subjected to external, longitudinal bending moments of considerable magnitude. In piping systems, such bending moments are usually caused by thermal expansion. On pressure vessel flanges, external bending moments are often the result of wind or seismic loadings. In the ASME Code, only Section III, the Nuclear Power Plant Code, Subsections NB, NC, and ND, contain design rules for external bending moments on flanges. In Subsections NB, NC, and ND, 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. Other sections of the ASME Code, in particular Section VIII, Divisions 1 and 2, also the ASME-ANSI Piping Codes, do not contain rules for such external, longitudinal bending moments. In previous papers by the same authors, it was shown that a single empirical expression to convert external bending moments to intemal pressure, cannot include the differences between the geometries of flanges of various sizes. An attempt was also made to analyse the stresses in the flange-bolt assembly due to extemal bending moments and to compare flange thicknesses thus obtained with thicknesses required using the equivalent design pressure, specified in Subsections NB, NC, and ND. The present paper reports the findings of a series of experiments on a pair of 100 mm, Class 10 (4 inch, Class 150) pipe flanges which were subjected to various combinations of intemal pressure and extemal longitudinal bending. Measured values are compared with a proposed analytic design method and with results using the empirical formula of the ASME Code, Section III

1. Twofold hidden conformal symmetry of Kerr-Bolt black holes

M.R. Setare; V. Kamali

2012-01-01

Previously we have shown that a four-dimensional Kerr-Bolt black hole in non-extremal and also in extremal cases could be described by a holographic two-dimensional (2D) conformal field theory (CFT) [Ghezelbash A M,Kamali V and Setare M R 2010 Phys.Rev.D 82 124051; Setare M R and Kamali V 2010 JHEP 10 074].Motivated by recent work [Chen C M,Huang Y M,Sun J R,Wu M F and Zou S J 2010 Phys.Rev.D 82 066004],we show that there is another holographic description for these black holes.The first description is called the J-picture,whose construction is based on the black hole angular momentum.The new description is called the Q-picture,whose constructions originate from the nut charge of the black hole.Similar to the previous cases [Ghezelbash A M,Kamali V and Setare M R 2010 Phys.Rev.D 82 124051; Setare M R and Kamali V 2010 JHEP 10 074],we show that this new picture for a low frequency limit of the wave equation of a massless charged scalar field in the background of a Kerr-Bolt black hole can be written as the Casimir of SL(2,R) symmetry.Our result shows that the entropy of the black hole is reproduced by the Cardy formula.In addition,the absorption cross section is consistent with the finite temperature absorption cross section for a two-dimensional CFT.

2. Pipe-anchor discontinuity analysis utilizing power series solutions, Bessel functions, and Fourier series

One of the paradigmatic classes of problems that frequently arise in piping stress analysis discipline is the effect of local stresses created by supports and restraints attachments. Over the past 20 years, concerns have been identified by both regulatory agencies in the nuclear power industry and others in the process and chemicals industries concerning the effect of various stiff clamping arrangements on the expected life of the pipe and its various piping components. In many of the commonly utilized geometries and arrangements of pipe clamps, the elasticity problem becomes the axisymmetric stress and deformation determination in a hollow cylinder (pipe) subjected to the appropriate boundary conditions and respective loads per se. One of the geometries that serve as a pipe anchor is comprised of two pipe clamps that are bolted tightly to the pipe and affixed to a modified shoe-type arrangement. The shoe is employed for the purpose of providing an immovable base that can be easily attached either by bolting or welding to a structural steel pipe rack. Over the past 50 years, the computational tools available to the piping analyst have changed dramatically and thereby have caused the implementation of solutions to the basic problems of elasticity to change likewise. The need to obtain closed form elasticity solutions, however, has always been a driving force in engineering. The employment of symbolic calculus that is currently available through numerous software packages makes closed form solutions very economical. This paper briefly traces the solutions over the past 50 years to a variety of axisymmetric stress problems involving hollow circular cylinders employing a Fourier series representation. In the present example, a properly chosen Fourier series represent the mathematical simulation of the imposed axial displacements on the outside diametrical surface. A general solution technique is introduced for the axisymmetric discontinuity stresses resulting from an

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

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.

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

Jensen, Torben Slott; Carlsen, Jakob Gram; Sørensen, Jens Christian;

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) and...... %), 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 to...

5. Analysis profile of the fully grouted rock bolt in jointed rock using analytical and numerical methods

Ghadimi Mostafa; Shahriar Kourosh; Jalalifar Hossein

2014-01-01

The purpose of this study was to investigate the effect of bolt profile on load transfer mechanism of fully grouted bolts in jointed rocks using analytical and numerical methods. Based on the analytical method with development of methods, a new model is presented. To validate the analytical model, five different profiles modeled by ANSYS software. The profile of rock bolts T3 and T4 with load transfer capacity, respectively 180 and 195 kN in the jointed rocks was selected as the optimum profiles. Finally, the selected profiles were examined in Tabas Coal Mine. FLAC analysis indicates that patterns 6+7 with 2NO flexi bolt 4 m better than other patterns within the faulted zone.

6. The research of the stud bolt bore checking equipment of the nuclear reactor pressure vessel

This article introduces a kind of new equipment that can work under the environment of high radiation and can-automaticly check the main stud bolt bore. The technical parameters and key techniques of the checking equipment are presented. (authors)

7. Monogenean anchor morphometry: systematic value, phylogenetic signal, and evolution.

Khang, Tsung Fei; Soo, Oi Yoon Michelle; Tan, Wooi Boon; Lim, Lee Hong Susan

2016-01-01

Background. Anchors are one of the important attachment appendages for monogenean parasites. Common descent and evolutionary processes have left their mark on anchor morphometry, in the form of patterns of shape and size variation useful for systematic and evolutionary studies. When combined with morphological and molecular data, analysis of anchor morphometry can potentially answer a wide range of biological questions. Materials and Methods. We used data from anchor morphometry, body size and morphology of 13 Ligophorus (Monogenea: Ancyrocephalidae) species infecting two marine mugilid (Teleostei: Mugilidae) fish hosts: Moolgarda buchanani (Bleeker) and Liza subviridis (Valenciennes) from Malaysia. Anchor shape and size data (n = 530) were generated using methods of geometric morphometrics. We used 28S rRNA, 18S rRNA, and ITS1 sequence data to infer a maximum likelihood phylogeny. We discriminated species using principal component and cluster analysis of shape data. Adams's K mult was used to detect phylogenetic signal in anchor shape. Phylogeny-correlated size and shape changes were investigated using continuous character mapping and directional statistics, respectively. We assessed morphological constraints in anchor morphometry using phylogenetic regression of anchor shape against body size and anchor size. Anchor morphological integration was studied using partial least squares method. The association between copulatory organ morphology and anchor shape and size in phylomorphospace was used to test the Rohde-Hobbs hypothesis. We created monogeneaGM, a new R package that integrates analyses of monogenean anchor geometric morphometric data with morphological and phylogenetic data. Results. We discriminated 12 of the 13 Ligophorus species using anchor shape data. Significant phylogenetic signal was detected in anchor shape. Thus, we discovered new morphological characters based on anchor shaft shape, the length between the inner root point and the outer root

8. Analysis of alternatives for using cable bolts as primary support at two low-seam coal mines

Esterhuizen Gabriel S; Tulu Ihsan B

2016-01-01

Cable bolts are sometimes used in low-seam coal mines to provide support in difficult ground conditions. This paper describes cable bolting solutions at two low-seam coal mines in similar ground conditions. Both mines used support systems incorporating cable bolts as part of the primary support system. Two original cable bolt based support systems as well as two modified systems are evaluated to estimate their ability to prevent large roof falls. One of the support systems incorporated passive cable bolts, while the other used pre-tensioned cable bolts. The results and experience at the mines showed that the mod-ified systems provided improved stability over the original support systems. The presence of the cable bolts is the most important contribution to stability against large roof falls, rather than the details of the support pattern. It was also found that a heavy steel channel can improve the safety of the system because of the‘sling’ action it provides. Additionally, the analysis showed that fully-grouted rebar bolts load much earlier than the cable bolts, and pre-tensioning of the cable bolts can result in a more uniform distribution of loading in the roof.

9. Review Paper on Performance Evaluation of Nut and Bolt Recognition System Using Artificial Neural Network

Shruti Paunikar; Sandeep Shrivastava

2013-01-01

There is constant research going on in the field of recognition by means of artificial intelligence to enhance the productivity. The automotive industry requires an automated system to sort different sizes and shapes nut and bolt which are the mainly used component in the industry, to improve the overall productivity. This review paper deals with some feature extraction techniques and its performance impact on the artificial neural network efficiency for the recognition of nut and bolt. The m...

10. On the performance of Usain Bolt in the 100 metre sprint

Gómez, J J Hernández; Gómez, R W

2013-01-01

A theoretical model of the performance of the 100 m world record sprint of Usain Bolt during the 2009 World Championships at Berlin is developed, assuming a drag force proportional to \$v\$ and to \$v^2\$. The resulting equation of motion is solved and fitted to the experimental data obtained from the International Amateur of Athletics Federations that recorded Bolt's position with a LAVEG (laser velocity guard) device. It is worth to note that our model works only for short sprints.

11. Experimental analysis of thread movement in bolted connections due to vibrations

Ramsey, G. ED; Jenkins, Robert C.

1995-01-01

This is the final report of research project NAS8-39131 #33 sponsored by NASA's George C. Marshall Space Flight Center (MSFC) and carried out by the Civil Engineering Department of Auburn University (Auburn, Alabama) and personnel of MSFC. The objective of this study was to identify the main design parameters contributing to the loosening of bolts due to vibration and to identify their relative importance and degree of contribution to bolt loosening. Vibration testing was conducted on a shaketable with a controlled-random input in the dynamic testing laboratory of the Structural Test Division of MSFC. Test specimens which contained one test bolt were vibrated for a fixed amount of time and a percentage of pre-load loss was measured. Each specimen tested implemented some combination of eleven design parameters as dictated by the design of experiment methodology employed. The eleven design parameters were: bolt size (diameter), lubrication on bolt, hole tolerance, initial pre-load, nut locking device, grip length, thread pitch, lubrication between mating materials, class of fit, joint configuration, and mass of configuration. These parameters were chosen for this experiment because they are believed to be the design parameters having the greatest impact on bolt loosening. Two values of each design parameter were used and each combination of parameters tested was subjected to two different directions of vibration and two different g-levels of vibration. One replication was made for each test to gain some indication of experimental error and repeatability and to give some degree of statistical credibility to the data, resulting in a total of 96 tests being performed. The results of the investigation indicated that nut locking devices, joint configuration, fastener size, and mass of configuration were significant in bolt loosening due to vibration. The results of this test can be utilized to further research the complex problem of bolt loosening due to vibration.

12. Asymptotic Analysis of the Load Transfer on Double-Lap Bolted Joints

KRATOCHVIL, Jan

2012-01-01

In this thesis, the complex potential method along with the method of compound asymptotic expansions is applied to the analysis of selected problems of plane elasticity related to double-lap bolted joints. The contribution to the thesis lies in the construction of several closed-form approximations of solutions to the considered problems. After a brief introduction of the basic theoretical concepts in Chapter 2, a mathematical model of a double-lap bolted joint is presented in Chapter 3....

13. Bolting sequence for attaching the container to the strong-back for 241SY101

This bolting sequence is for attaching the container to the strong-back for Tank 241-SY-101. This supporting document includes information for the proper bolting sequence for attaching the container to the strong-back is found in supporting document WHC-SD-WM-DA-165 (WHC 1994a) and is in accordance with Standard Arch-Civil Design Criteria, Design Loads for Facilities (SDC 4.1) Safety Class 3

14. Anchor Stress Checking of Security Injection Tank

2011-01-01

The intention of the calculating is to check the anchor stresses of the security injection tank to know whether the stress is satisfied the code requirements on the basis of all the reaction forces gained in the static, seismic and thermal stress results.

15. Stone anchors from Minicoy Island, Lakshadweep, India

Tripati, S.

at Androth, Kadmat, Kavaratti and Minicoy. In addition to these finds, in recent past an Indo-Arabian type of stone anchor has come to lime light at the Jama Mosque of Funhilol of Minicoy. In this paper an attempt has been made to describe the Indo...

16. Predicting Anchor Links between Heterogeneous Social Networks

2016-01-01

People usually get involved in multiple social networks to enjoy new services or to fulfill their needs. Many new social networks try to attract users of other existing networks to increase the number of their users. Once a user (called source user) of a social network (called source network) joins a new social network (called target network), a new inter-network link (called anchor link) is formed between the source and target networks. In this paper, we concentrated on predicting the formation of such anchor links between heterogeneous social networks. Unlike conventional link prediction problems in which the formation of a link between two existing users within a single network is predicted, in anchor link prediction, the target user is missing and will be added to the target network once the anchor link is created. To solve this problem, we use meta-paths as a powerful tool for utilizing heterogeneous information in both the source and target networks. To this end, we propose an effective general meta-pat...

17. A new approach for field instrumentation in grouted rock bolt monitoring using guided ultrasonic waves

Zou, D. H.; Cui, Y.

2011-11-01

A rock bolt installed in the field for ground support has only one short exposed end on the rock surface. This condition has posed challenges in field instrumentation. In this paper, a new approach for field monitoring of grouted rock bolts using guided ultrasonic waves is proposed with the receiving transducer on the grout surface near the exposed end of the bolt. The effects of the receiver location are studied with numerical modeling. A location correction factor is introduced to correlate the amplitude ratio along the bolt and that on the grout surface. Experiments are conducted to verify the modeling results. This research indicates that it is practically possible to receive meaningful signals with the receiver on the grout surface and that with the recorded data the attenuation and wave velocity of guided waves in grouted rock bolts can be determined with reasonable accuracy. The proper receiver location is found to be 27 to 32 mm from the bolt center for the test condition.

18. Ultimate strength of single shear bolted connections with cold-formed ferritic stainless steel

Jin-seong LIM; Tae-soo KIM; Seung-hun KIM

2013-01-01

This paper is focused on the structural behavior of the single shear bolted connections with thin-walled ferritic stainless steel.The purpose of this study is to investigate the ultimate behaviors,such as ultimate strength and fracture mode of the single shear bolted connections of thin-walled ferritic stainless steel (low cost steel) rather than austenitic stainless steel (high cost steel).Bolt arrangement and end distance parallel to the direction of applied load are considered as main variables of the test specimens for bolted connections.Specimens have a constant dimension of edge distance perpendicular to the loading direction,bolt diameter,pitch,and gauge.A monotonic tensile test for specimens has been carried out and some bolted connections with long end distance showed curling (out of plane deformation) occurrence which led to strength reduction.The ultimate behaviors such as fracture mode,ultimate strength are compared with those predicted by current design codes.Further,conditions of curling occurrence and the strength reduction due to curling are investigated and modified strength equations are suggested considering the curling effect.

19. Safety evaluation for bolting design of a transportable storage canister of spent nuclear fuels

This paper is to perform safety evaluation for bolting design of a transportable storage canister of spent nuclear fuels in a nuclear power plant. To develop the related techniques for inter unit transfer of the spent nuclear fuels, a seamless metal canister design with reopening function is adopted. The canister with bolting flange needs to maintain its seamless and structural integrity under normal operation and postulated accident conditions. For bolting design, the requirements on material and structural strength are completely examined by following ASME Boiler and Pressure Vessel Codes. All calculations in this work are performed by using the commercial finite element analysis software, ANSYS. With different sensitivity analysis results of numerical finite element models, the maximum and minimum operation value of bolting preload torque can be thus obtained. Moreover, during the inter unit transfer and operation of spent nuclear fuels, fatigue of the bolt is addressed and no leakage occurs as the canister keeps closure with lids subject to the accident condition is also verified. The structural functions and safety of a transportable storage canister with new bolting design can be shown.

20. Nonlinear Bending Stiffness of Plates Clamped by Bolted Joints under Bending Moment

Naruse, Tomohiro; Shibutani, Yoji

Equivalent stiffness of plates clamped by bolted joints for designing should be evaluated according to not only the strength of bolted joints but also the deformation and vibration characteristics of the structures. When the applied external axial load or the bending moment is sufficiently small, the contact surfaces of the bolted joint are stuck together, and thus both the bolt and the clamped plates deform linearly. Although the sophisticated VDI 2230 code gives the appropriate stiffness of clamped plates for the infinitesimal deformation, the stiffness may vary nonlinearly with increasing the loading because of changing the contact state. Therefore, the present paper focuses on the nonlinear behaviour of the bending stiffness of clamped plates by using Finite Element (FE) analyses, taking the contact condition on bearing surfaces and between the plates into account. The FE models of the plates with thicknesses of 3.2, 4.5, 6.0 and 9.0 mm tightened with M8, 10, 12 and 16 bolts were constructed. The relation between bending moment and bending compliance of clamped plates is found to be categorized into three regions, namely, (i) constant compliance with fully stuck contact surfaces, (ii) transition showing the nonlinear compliance, and (iii) constant compliance with one-side contact surfaces. The mechanical models for these three regions are proposed and compared with FEM solutions. The prediction on the bounds of three regions is in a fairly good agreement except the case with smaller bolts and thicker plates.

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

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)

2. Influence of Anchoring on Burial Depth of Submarine Pipelines

Zhuang, Yuan; Li, Yang; Su, Wei

2016-01-01

Since the beginning of the twenty-first century, there has been widespread construction of submarine oil-gas transmission pipelines due to an increase in offshore oil exploration. Vessel anchoring operations are causing more damage to submarine pipelines due to shipping transportation also increasing. Therefore, it is essential that the influence of anchoring on the required burial depth of submarine pipelines is determined. In this paper, mathematical models for ordinary anchoring and emergency anchoring have been established to derive an anchor impact energy equation for each condition. The required effective burial depth for submarine pipelines has then been calculated via an energy absorption equation for the protection layer covering the submarine pipelines. Finally, the results of the model calculation have been verified by accident case analysis, and the impact of the anchoring height, anchoring water depth and the anchor weight on the required burial depth of submarine pipelines has been further analyzed. PMID:27166952

3. Influence of Anchoring on Burial Depth of Submarine Pipelines.

Zhuang, Yuan; Li, Yang; Su, Wei

2016-01-01

Since the beginning of the twenty-first century, there has been widespread construction of submarine oil-gas transmission pipelines due to an increase in offshore oil exploration. Vessel anchoring operations are causing more damage to submarine pipelines due to shipping transportation also increasing. Therefore, it is essential that the influence of anchoring on the required burial depth of submarine pipelines is determined. In this paper, mathematical models for ordinary anchoring and emergency anchoring have been established to derive an anchor impact energy equation for each condition. The required effective burial depth for submarine pipelines has then been calculated via an energy absorption equation for the protection layer covering the submarine pipelines. Finally, the results of the model calculation have been verified by accident case analysis, and the impact of the anchoring height, anchoring water depth and the anchor weight on the required burial depth of submarine pipelines has been further analyzed. PMID:27166952

4. Stone anchors of India: Findings, classification and significance.

Tripati, S.

Honolulu, Hawaii, May 12-16, 2014, Vol. 2: 973-986 973 Stone anchors of India: Findings, Classification and Significance Sila Tripati CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004, India Email: sila@nio.org Abstract Various.... The making of anchors from the hero stones indicates their alternative use (Sila Tripati and Patnaik, 2008). Classification Stone anchors are classified according to character, shape and region. In general stone anchors have been classified...

5. Susceptibility to anchoring effects: How openness-to-experience influences responses to anchoring cues

Todd McElroy; Keith Dowd

2007-01-01

Previous research on anchoring has shown this heuristic to be a very robust psychological phenomenon ubiquitous across many domains of human judgment and decision-making. Despite the prevalence of anchoring effects, researchers have only recently begun to investigate the underlying factors responsible for how and in what ways a person is susceptible to them. This paper examines how one such factor, the Big-Five personality trait of openness-to-experience, influences the effect of previously p...

6. How curved membranes recruit amphipathic helices and protein anchoring motifs

Hatzakis, Nikos; Bhatia, Vikram Kjøller; Larsen, Jannik;

2009-01-01

: membrane-anchored proteins. The fact that unrelated structural motifs such as alpha-helices and alkyl chains sense MC led us to propose that MC sensing is a generic property of curved membranes rather than a property of the anchoring molecules. We therefore anticipate that MC will promote the...... redistribution of proteins that are anchored in membranes through other types of hydrophobic moieties....

7. 33 CFR 401.14 - Anchor marking buoys.

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Anchor marking buoys. 401.14 Section 401.14 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Condition of Vessels § 401.14 Anchor marking buoys. A highly visible anchor marking...

8. Students' Anchoring Predisposition: An Illustration from Spring Training Baseball

Mohrweis, Lawrence C.

2014-01-01

The anchoring tendency results when decision makers anchor on initial values and then make final assessments that are adjusted insufficiently away from the initial values. The professional literature recognizes that auditors often risk falling into the judgment trap of anchoring and adjusting (Ranzilla et al., 2011). Students may also be unaware…

9. Lubrication properties of silver-palladium alloy prepared by ion plating method for high temperature stud bolt

Jung-Dae KWON; Sunghun LEE; Koo-Hyun LEE; Jong-Joo RHA; Kee-Seok NAN; Se-Hun KWON

2011-01-01

As a solid lubricant, silver-palladium (Ag-Pd) alloy coating was investigated for the application to high temperature studbolt. A glue layer nickel (Ni) film was deposited on the surface of the hex bolt sample and then Ag-Pd alloy coating was performed on it using ion plating method. The friction coefficient of Ag-Pd alloy film coated bolt was lower than that of N-5000 oil coated bolt by the result of axial force measurement. The cyclic test of heat treatment was conducted to evaluate the durability of Ag-Pd alloy film coated bolt. In a cycle, sample was assembled into the block using torque wrench, followed by heating and disassembling. It was not successful to disassemble the N-5000 oil coated bolt from the block after only one cycle. However, the Ag-Pd alloy film coated bolt was able to be disassembled softly till 12 cycles.

10. Assessing the effects of insufficient rebar and missing grout in grouted rock bolts using guided ultrasonic waves

Cui, Y.; Zou, D. H.

2012-04-01

One of the challenges in field monitoring of grouted rock bolts, which normally have a short exposed end, is to detect the defects of the bolt or grout. In this paper, grouted rock bolts are studied using guided ultrasonic waves. Numerical modeling for grouted rock bolts is performed to assess the effects of insufficient rebar and missing grout. The numerical results are verified with laboratory tests on rock bolt samples. With introduction of correction factors at the reflection end, the results indicate that it is practically possible to identify insufficient rebar and grout defects with guided ultrasonic signals received at the exposed end. It also indicates that with the attenuation and wave velocity of guided waves, defective rock bolts with insufficient rebar length or missing grout in the ground can be detected with reasonable accuracy.