WorldWideScience

Sample records for bolting

  1. Bolting applications

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  3. Piezoelectric Bolt Breakers and Bolt Fatigue Testers

    Science.gov (United States)

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

    2008-01-01

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

  4. Overall bolt stress optimization

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The state of stress in bolts and nuts with International Organization for Standardization metric thread design is examined and optimized. The assumed failure mode is fatigue, so the applied preload and the load amplitude together with the stress concentrations define the connection strength....... Maximum stress in the bolt is found at the fillet under the head, at the thread start, or at the thread root. To minimize the stress concentration, shape optimization is applied. Nut shape optimization also has a positive effect on the maximum stress. The optimization results show that designing a nut...... of up to 34% is found, still with the standard International Organization for Standardization thread. The design changes suggested in this article also have the positive advantage of reducing the joint stiffness factor. The reduction in the bolt shank directly reduces the bolt stiffness but the design...

  5. Optimization of Bolt Stress

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

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

  6. Bolting Multicenter Solutions

    CERN Document Server

    Bena, Iosif; Katmadas, Stefanos; Turton, David

    2016-01-01

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

  7. Bolting multicenter solutions

    Science.gov (United States)

    Bena, Iosif; Bossard, Guillaume; Katmadas, Stefanos; Turton, David

    2017-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

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

  9. Bolt Thread Stress Optimization

    DEFF Research Database (Denmark)

    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...

  10. Bolt load simulation and its practical application

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, P.G.; Hume, B.G.; Hume, R.G. [Barrett Fuller and Partners, Melbourne, Vic. (Australia)

    1996-12-31

    The large range of rock bolting options now available makes choosing the best system for any given environment increasingly difficult. Bolt performance is highly dependent on the type of bolt used, the properties of the resin or grout, the plate type and the rock condition. The use of pre-tensioning or the presence of unbounded zones along the bolt provides further complications. The program BoltCalc has been developed to model the loads generated within bolts by rock mass displacements. The operation of the program is outlined and a series of examples illustrating the effects of various factors on bolt performance is presented. 1 ref., 11 figs.

  11. Inhibition of spinach bolting by growth regulators

    Directory of Open Access Journals (Sweden)

    Jan Borkowski

    2015-06-01

    Full Text Available Spinach (Spinacia oleracea L. plants must be harvested during a short period of time because they bolt just after producing some edible leaves. Maleic hydrazide (MH and its commercial preparation "Antyrost" were found to inhibit bolting very strongly. The preparation Off-shoot-O showed very weak activity in suppressing bolting but diminished markedly the resistance of spinach plants to fungus diseases. Triiodobenzoic acid stimulated bolting, and the retardant succinic acid-2-2-dimethylhydrazide (SADH did not affect bolting. Application of MH to inhibit spinach bolting cannot be recommended in practice before investigating the residues of this compound in leaves.

  12. A study of rock bolting failure modes

    Institute of Scientific and Technical Information of China (English)

    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.

  13. Removable Type Expansion Bolt Innovative Design

    Science.gov (United States)

    Wang, Feng-Lan; Zhang, Bo; Gao, Bo; Liu, Yan-Xin; Gao, Bo

    2016-05-01

    Expansion bolt is a kind of the most common things in our daily life. Currently, there are many kinds of expansion bolts in the market. However, they have some shortcomings that mainly contain underuse and unremovement but our innovation of design makes up for these shortcomings very well. Principle of working follows this: expansion tube is fixed outside of bolt, steel balls and expansion covers are fixed inside. Meanwhile, the steel balls have 120° with each other. When using it ,expansion cover is moved in the direction of its internal part. So the front part of expansion bolt cover is increasingly becoming big and steel halls is moved outside. Only in this way can it be fixed that steel balls make expansion tube expand. When removing them, expansion bolt is moved outside. So the front part of expansion bolt cover is gradually becoming small and steel balls moves inside, after expansion tube shrinks, we can detach them.

  14. A microprocessor based portable bolt tension monitor

    Science.gov (United States)

    Perey, D. F.

    1991-01-01

    A bolt tension monitor (BTM) which uses ultrasonics and a pulsed phase locked loop circuit to measure load-induced acoustic phase shifts which are independent of friction is described. The BTM makes it possible to measure the load in a bolt that was tightened at some time in the past. This capability to recertify a load after-the-fact will help to insure the integrity of a bolted joint.

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

    Directory of Open Access Journals (Sweden)

    b Osman Mohamad Hairi

    2017-01-01

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

  16. The new structure of fibre glass reinforced plastics bolt

    Institute of Scientific and Technical Information of China (English)

    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.

  17. Spacer lock of roof bolting

    Energy Technology Data Exchange (ETDEWEB)

    Shirokov, A.P.; Boronov, N.N.; Isachenko, V.M.; Kuntsevich, V.I.

    1980-04-05

    The object of the invention is a spacer joint of anchor bolting, which includes a wedge-shaped head and half-coupling, which are beveled on the inner side of the walls, and have ribs on the outer sides of the walls. It is characterized in that in order to reduce cost of the joint by reducing the amount of steel and manufacturing costs, the walls of the half-couplings hae identical thickness lengthwise, and the ribs are of varying height with corresponding projections on the inner side of the half-couplings.

  18. Self drilling rock bolt technology - development of self drilling rock bolt

    Energy Technology Data Exchange (ETDEWEB)

    Peter Gray [Ground Support Services (Australia)

    2007-06-15

    A new Self Drilling Rock Bolt (SDRB) system has been developed which uses a pumpable resin system for full column resin encapsulation for immediate roof and rib support. A new drilling and injection system has also been developed to enable fast and efficient bolt installation. This new SDRB provides higher tensile strength than conventional solid bolts, and also provides a load transfer capacity that is almost double that of conventional bolts. This new SDRB uses low viscosity pumpable resin to ensure full encapsulation right down to the collar.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  1. Bolt Cutter Blade's Imprint in Toolmarks Examination.

    Science.gov (United States)

    Volkov, Nikolai; Finkelstein, Nir; Novoselsky, Yehuda; Tsach, Tsadok

    2015-11-01

    Bolt cutters are known as cutting tools which are used for cutting hard objects and materials, such as padlocks and bars. Bolt cutter blades leave their imprint on the cut objects. When receiving a cut object from a crime scene, forensic toolmarks examiners can determine whether the suspected cutting tool was used in a specific crime or not based on class characteristic marks and individual marks that the bolt cutter blades leave on the cut object. The paper presents preliminary results of a study on ten bolt cutters and suggests a quick preliminary examination-the comparison between the blade thickness and the width of the imprint left by the tool on the cut object. Based on the comparison result, if there is not a match, the examiner can eliminate the feasibility of the use of the suspected cutting tool in a specific crime. This examination simplifies and accelerates the comparison procedure.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  4. Decision Fusion System for Bolted Joint Monitoring

    Directory of Open Access Journals (Sweden)

    Dong Liang

    2015-01-01

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

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

    Science.gov (United States)

    Lechner, Joseph H.

    2011-01-01

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

  6. Design of Bolted L-Flanged Connections

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2016-01-01

    on the tower and the tensile force in the bolt. In the literature and also in design standards different models are presented for this important non-linear response. The present work presents a simplified expression for the non-linear force response based on finite element calculations using contact analysis......In wind turbine towers the preferred design is circular tubes that are connected to each other by a bolted flange joint. The design is typically that of an L-flange resulting in an eccentrically loaded bolted connection. The eccentricity results in a non-linear relationship between external load....... Secondly, focus is on simple modifications of the flange design that considerably improves the strength of the connection....

  7. Retained crossbow bolt after penetrating facial trauma.

    Science.gov (United States)

    Shah, Manan U; Sridhara, Shankar K; Wolf, Jeffrey S; Ambro, Bryan T

    2016-01-01

    We present an unusual case of a retained crossbow bolt in the maxillofacial area of a 31-year-old man. While crossbow injuries are rare, this case is of interest because otolaryngologists are often faced with treating retained foreign objects after penetrating facial trauma. These cases are difficult to manage because of the complexity and variety of injuries that can occur during both the initial trauma and the removal. We focus on the management of the bolt's removal and provide a brief discussion of the relevant literature on crossbow injuries to the head and neck.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  9. 30 CFR 75.204 - Roof bolting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Roof bolting. 75.204 Section 75.204 Mineral... or the equivalent may be used. (3) Bearing plates used with wood or metal materials shall be at least... against wood; or (ii) Have exceeded the maximum specified torque or tension by 50 percent. (6) The...

  10. Inedible Nuts and Non-Lightning Bolts

    Science.gov (United States)

    Rynone, William

    2010-01-01

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

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

    Science.gov (United States)

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

    2017-04-05

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

  12. Parameters determination and bolting control of gateway floor

    Institute of Scientific and Technical Information of China (English)

    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.

  13. Bolting Cabin Assistance System Using a Sensor Network

    Directory of Open Access Journals (Sweden)

    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.

  14. Infrastructure anchor bolt inspection program with NDE applications

    Science.gov (United States)

    Fish, Philip E.

    1996-11-01

    In 1990, Wisconsin Department of Transportation found a high mast light pole with two of six anchor bolts failed. This failure along with published reports from Michigan DOT about anchor bolt failures on cantilever sign structures, raised concern about the quality and condition of anchor bolts on the Wisconsin DOT system. Wisconsin Department of Transportation implemented an Anchor Bolt Inspection Program in 1990 for cantilever sign structures, high mast light towers, interstate light towers, and signal masts. The program requires an experienced inspection team and a practical inspection approach. Inspection preparation includes review of all background information such as design plans, design computations, construction plans, shop plans, and maintenance history. An inspection plan is developed. Special emphasis is placed on determining material type, cut or rolled threads, and type of coating for anchor bolts. Inspection emphasis are on "hands on" and Nondestructive evaluation. Special emphasis is placed on visual conditions of anchor bolts (cut or rolled threads, straightness, corrosion, nut tension etc.) along with ultrasonic inspection. This program places a strong emphasis on Non Destructive Testing (NDT), especially ultrasonic. Procedures and inspection calibrations are developed from similar anchor bolt geometry and material type. Cut notches are placed in the anchor bolts at locations of possible failure. NDT inspection calibrations are performed from these bolts. Report documentation includes all design plans, pictorial documentation of structural deficiencies, sketches, nondestructive evaluation reports, conclusions, and recommendations. This program has been successful in locating failed anchor bolts and critical cracks before failure of an entire structure.

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

    Science.gov (United States)

    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.

  16. Finite element analysis of bolted flange connections

    Science.gov (United States)

    Hwang, D. Y.; Stallings, J. M.

    1994-06-01

    A 2-D axisymmetric finite element model and a 3-D solid finite element model of a high pressure bolted flange joint were generated to investigate the stress behaviors. This investigation includes comparisons for axisymmetric loading of both the 2-D and 3-D models, the effects of non-axisymmetric bolt pretensions in the 3-D models, and the differences between 2-D and 3-D models subjected to non-axisymmetric loading. Comparisons indicated differences in von Mises stress up to 12% at various points due to the non-axisymmetric bolt pretensions. Applied bending moments were converted to equivalent axial forces for use in the 2-D model. It was found that the largest von Mises stresses in 3-D model did not occur on the side of the connection where the bending stresses and applied axial stresses were additive. Hence, in the 2-D model where the equivalent axial force (for bending moment) and applied axial forces were added, the 2-D model under estimated the maximum von Mises stress obtained from the 3-D model by 30%.

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

    DEFF Research Database (Denmark)

    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 the stiffness...

  18. Characteristic Evaluation on Bolt Stress by Ultrasonic Nondestructive Methods

    Directory of Open Access Journals (Sweden)

    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.

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

    DEFF Research Database (Denmark)

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

    1999-01-01

    In 1993 after 9 years of use one of the blades of a windmill with wooden blades was struck by lightning. After demounting the damaged blade was handed over to the Technical University of Denmark for the investigation of potential fatigue damage. The paper presents an experimental determination...... of the residual strength of the glued-in bolts that served as the blade to rotor hub connection in the windmill. The load history of the bolts, the test method, the observed fracture modes and the force displacement curves are presented along with the recorded residual strength of the bolts. The bolts...

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

    Institute of Scientific and Technical Information of China (English)

    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.

  1. Evaluation of bolted connections in wood-plastic composites

    Science.gov (United States)

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

    2017-03-01

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

  2. Factors Influencing the Quality of Encapsulation in Rock Bolting

    Science.gov (United States)

    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.

  3. Mechanics of Re-Torquing in Bolted Flange Connections

    Science.gov (United States)

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

    2010-01-01

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

  4. Preloading of bolted connections in nuclear reactor component supports

    Energy Technology Data Exchange (ETDEWEB)

    Yahr, G T

    1984-10-01

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

  5. Study on Rock Bolt Reinforcement for a Gravity Dam Foundation

    Science.gov (United States)

    Chen, S. H.; Yang, Z. M.; Wang, W. M.; Shahrour, I.

    2012-01-01

    In this article, the rock bolt reinforcement mechanism is discussed, and the gravity method as well as the finite element method for the bolted rock is presented. These methods are applied to study the gravity dam foundation of the Xiaoxi Hydropower Project, which is influenced by the presence of a large fault with a cracked zone over 180 m wide. Rock bolt reinforcement was used to improve the stability of the dam foundation, and the reinforcement parameters were determined from a semi-empirical equation controlled by in situ test. The stability analysis was conducted using the above methods, and the improvement in terms of deformation and stress as well as stability of the dam foundation due to the reinforcement is assessed. Rock bolt reinforcement was completed successfully, and the dam started normal operations in January 2008.

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

    Science.gov (United States)

    2012-01-01

    P., Pascoe , K., Polak, C., & Stroud, D. (1986). The Behaviour of Single-Lap Bolted Joints in CFRP Laminates. Composite Structures, 41-55...Interferometry. J Nondestruct Eval, 135-142. Smith, P., Pascoe , K., Polak, C., & Stroud, D. (1986). The Behaviour of Single-Lap Bolted Joints in...in [Kretsis & Matthews, 1985], [Smith, Pascoe , Polak, & Stroud, 1986],[Godwin & Matthews, 1980] UNCLASSIFIED UNCLASSIFIED implies that under

  7. What Makes Usain Bolt Unique as a Sprinter?

    Science.gov (United States)

    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…

  8. Effect of bolting on roadway support in extremely weak rock.

    Science.gov (United States)

    Li, Qinghai; Shi, Weiping; Qin, Zhongcheng

    2016-01-01

    In mine roadway support operations, floor bolting not only played a role in floor heave control, but also in reinforcing roof and its two sides. Correspondingly, bolting of roof and two sides also played a part in floor heave control. To quantify the effect of such bolting, based on roadway support in extremely weak rock, three physical models were produced and tested in laboratory. Through comparison of their displacements in three physical simulation experiments, the reinforcing effect of bolting in extremely weak rock roadways was quantified. Reinforcing coefficients was defined as displacement ratio between original support and new support regime. Results indicated that the reinforcing coefficients, for bolting of roof and its two sides, on floor, two sides, and roof reached 2.18, 3.56, and 1.81 respectively. The reinforcing coefficients for floor bolting on floor, two sides, and roof reached 3.06, 2.34, and 1.39 respectively. So in this extremely weak rock, the surrounding rock should be considered as an integral structure in any support operation: this allows for better local strength improvement, and provided future design guidance.

  9. Response surface reconciliation method of bolted joints structure

    Directory of Open Access Journals (Sweden)

    Yunus Mohd Azmi

    2017-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Mechanical Behavior of CFRP Lattice Core Sandwich Bolted Corner Joints

    Science.gov (United States)

    Zhu, Xiaolei; Liu, Yang; Wang, Yana; Lu, Xiaofeng; Zhu, Lingxue

    2017-02-01

    The lattice core sandwich structures have drawn more attention for the integration of load capacity and multifunctional applications. However, the connection of carbon fibers reinforced polymer composite (CFRP) lattice core sandwich structure hinders its application. In this paper, a typical connection of two lattice core sandwich panels, named as corner joint or L-joint, was investigated by experiment and finite element method (FEM). The mechanical behavior and failure mode of the corner joints were discussed. The results showed that the main deformation pattern and failure mode of the lattice core sandwich bolted corner joints structure were the deformation of metal connector and indentation of the face sheet in the bolt holes. The metal connectors played an important role in bolted corner joints structure. In order to save the calculation resource, a continuum model of pyramid lattice core was used to replace the exact structure. The computation results were consistent with experiment, and the maximum error was 19%. The FEM demonstrated the deflection process of the bolted corner joints structure visually. So the simplified FEM can be used for further analysis of the bolted corner joints structure in engineering.

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

    DEFF Research Database (Denmark)

    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......, but with finite element (FE) and contact analysis, it is possible to find the stiffness of the member. In the case of many connections and for practical applications, it is not suitable to make a full FE analysis. The purpose of the present paper is to find simplified expressions for the stiffness of the member......, including the case when the width of the member is limited. The calculation of the stiffness is based on the FE, including the solution to the contact problem, and we express the stiffness as a function of the elastic energy in the structure, whereby the definition of the displacements related...

  14. Probabilistic Evaluation of Bolted Joints in Polymer Matrix Composites

    Science.gov (United States)

    Chamis, C. C.; Minnetyan, L.

    1997-01-01

    Computational methods are described to probabilistically simulate fracture in bolted composite structures. Progressive fracture is simulated via an innovative approach independent of stress intensity factors and fracture toughness. The effect on structure damage of design variable uncertainties is quantified. The Fast Probability Integrator is used to assess the scatter in the composite structure response before and after damage. Sensitivity of the response to design variables is evaluated. The methods are demonstrated for bolted joint polymer matrix composite panels under end loads. The effects of fabrication process are included in the simulation of damage in the bolted panel. The results show that the most effective way to reduce the end displacement at fracture is to control the load and ply thickness.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Science.gov (United States)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    DEFF Research Database (Denmark)

    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...

  19. NASA's Radio Frequency Bolt Monitor: A Lifetime of Spinoffs

    Science.gov (United States)

    2005-01-01

    This story begins in the 1970s, when Dr. Joseph Heyman, a young scientist at NASA s Langley Research Center, was asked to support the investigation of a wind tunnel accident at a sister center. Although the work was outside of his physics background, it sparked a research focus that guided his lengthy NASA career and would earn him a slew of accolades, including NASA s highest award medals for Exceptional Leadership, Exceptional Achievement, and Exceptional Service; the coveted Silver Snoopy Astronaut Award for Space Shuttle Return to Flight; and the Arthur Fleming Award for being one of the Top Ten Federal Scientists in Government Service. He won 30 additional NASA awards, including the Agency s Invention of the Year and the Agency s highest award for technology transfer, and was the only person to ever win 4 R&D 100 Awards. Back in 1973, though, Heyman was a young civil servant with a background in physics who was asked to sit on an accident review panel. The panel met at Ames Research Center, in Moffet Field, California, and after considerable investigation, concluded that a high-pressure pebble heater used for heating gas had failed, due to improperly tightened bolts in a 1,000-pound gate valve control section. The accident showered the facility with incendiary ceramic spheres and nearly a ton of metal, but, luckily, caused no injuries. Heyman returned to Langley and began work on a solution. He developed an ultrasonic device that would measure bolt elongation, as opposed to torque, the factor typically measured in testing bolt preload or tension. Torque measurement can lead to load errors, with miscalculations as high as 80 percent that can be passed over during installation. Bolt stretch, however, is nearly always accurate to 1 percent or better. Within 1 month, he had an acoustic resonance solution that accurately determined bolt elongation. He assumed his work on this project had ended, but it was actually the start of nearly 15 years of work perfecting

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

    Energy Technology Data Exchange (ETDEWEB)

    Syd S. Peng

    2005-10-01

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

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

    Institute of Scientific and Technical Information of China (English)

    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.

  2. A novel ultrasonic method to quantify pressure in bolted joints

    Science.gov (United States)

    Sisman, A.; Martinez, J.; Guldiken, R.

    2012-12-01

    In structures most of fasteners are not critical for rigidity, however significant damage can occur if majority of uncritical fasteners fail. Furthermore, the maintenance is not feasible due to their vast quantity. In this study, we explored a new method to significantly improve the maintenance capability for these fasteners. The method distantly detects the preload between the bolt and the surface. We use a linear transducer array that generates acoustic beam using surface acoustic waves (SAWs) transmitted by array elements. The bolt boundary reflects SAW and array elements receive the echo signals. The signals are processed in the beamformer to generate the boundary's image which quantifies the preload to enable a strong estimation about the health of the bolted joint. We experimentally investigated the proposed method by using used a 5-MHz, 50-elements synthetic array. We measured the preload for five different tightening levels. As expected, two saturation regions (for too tightening and too loosening cases) and a linear region are observed (between them). The electronically steering of the array enables to make simultaneous preload measurements of many bolted joints in the same surface. The distant pressure measurement sensor could be integrated to a data acquisition system to track the health of the joints over time.

  3. Hollo-Bolt®: Blind Connector for Structural Steelwork

    OpenAIRE

    ECT Team, Purdue

    2008-01-01

    Structural steel connections for connecting to square, rectangular or circular structural tube or to conventional steel where access is available from one side only poses problems. A technology was needed which could provide a quicker and tidier installation than traditional methods such as welding, unsightly strapping or drilling and tapping holes. The invention of the Hollo-Bolt® provided such a solution.

  4. Design of floating type bolted flange connections with grp flanges

    Energy Technology Data Exchange (ETDEWEB)

    Kurz, H., E-mail: hariolf.kurz@mpa.uni-stuttgart.de [Materialpruefungsanstalt (MPA), University of Stuttgart, Pfaffenwaldring 32, D-70569 Stuttgart (Germany); Roos, E. [Materialpruefungsanstalt (MPA), University of Stuttgart, Pfaffenwaldring 32, D-70569 Stuttgart (Germany)

    2012-01-15

    The goal of the presented work is to enable plant operators in the chemical industry to design and to operate glass-reinforced-plastics (specified in the following as grp) piping with grp flanges at temperatures up to 80 Degree-Sign C, using polytetraflourethylene (PTFE) gaskets that shall replace the mandatory rubber gaskets. Various gaskets on the basis of rubber (EPDM) and PTFE were investigated in view of the boundary conditions in bolted flange connections with glass-fiber reinforced plastic flanges in compliance with DIN EN 13555. The rubber gasket and the PTFE based gasket with a PTFE-diffusion barrier meet the leakage rate criterion of TA Luft under the conditions of bolted flange connections with grp flanges. The mechanical behavior of bolted flange connections DN50 with grp flanges was investigated and is taken into consideration in a new calculation procedure, that accounts for the specific material properties of grp and thus allows higher bolt forces, what leads to increased tightness and operational reliability of the plants. This draft procedure with experimental pre-tests (already demanded in DIN 16966) is now available to design bolted flange connections with grp flanges. - Highlights: Black-Right-Pointing-Pointer In this study we identify a PTFE-gasket with an acceptable performance in grp flanges. Black-Right-Pointing-Pointer The mechanical behavior of grp flanges is examined via experiment and FEM. Black-Right-Pointing-Pointer The derivation of a design concept for grp-loose flanges is presented. Black-Right-Pointing-Pointer The design concept shows good agreement with the FE simulation and experiment. Black-Right-Pointing-Pointer Applying the design concept leads to an increase in service reliability.

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

    Institute of Scientific and Technical Information of China (English)

    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. Pyroshock Prediction of Ridge-Cut Explosive Bolts Using Hydrocodes

    Directory of Open Access Journals (Sweden)

    Juho Lee

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Hilton Ahmad

    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.

  8. Experimental study of friction in aluminium bolted joints

    Science.gov (United States)

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

    2010-06-01

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

  9. AN EXPERIMENTAL STUDY ON THE RELAXATION OF BOLTS

    Directory of Open Access Journals (Sweden)

    Muhammad Abid

    2015-05-01

    Full Text Available Loss of pre-load with time, commonly known as ‘Relaxation’ is an established phenomena. Behaviour of a bolted joint depends upon the pre-load in the bolts in use, not the pre-load introduced by the mechanic. Loss of pre-load is expected due to the many factors such as embedment relaxation, gasket creep, elastic interactions, and vibration loosening or stress relaxation. In a gasketed joint, due to the gasket flexibility, relaxation is always substantial during preliminary passes, as 80 to 100% loss is not uncommon in almost all the bolts, resulting in a dynamic behaviour. Pre-load in a gasketed joint is stabilized and retained to certain extent in the final passes only. In a non-gasketed joint, due to no gasket and no rotation its static behaviour is concluded. This paper highlights the factors affecting the amount of relaxation with time and presents important considerations that can reduce this. Both the short and long term relaxations are recorded and a ‘best fit’ model for relaxation behaviour is derived.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  11. A failure analysis study on the fractured connecting bolts of a filter press

    Directory of Open Access Journals (Sweden)

    Sh. Molaei

    2015-10-01

    Full Text Available The purpose of this study was to investigate the main causes of the co-fracture of sixteen connecting bolts of a filter press cylinder–piston system. Stress state of the bolts during the service conditions has been analyzed and the failure reasons were determined from the fractography analysis and gathered information. According to the obtained results, it was concluded that the bolts had failed by the fatigue mechanism. It seems that insufficient torque was used during assembly.

  12. Improved wire stiffness with modified connection bolts in Ilizarov external frames: a biomechanical study.

    Science.gov (United States)

    Gessmann, Jan; Jettkant, Birger; Königshausen, Matthias; Schildhauer, Thomas Armin; Seybold, Dominik

    2012-01-01

    Frame stability in Ilizarov external fixators is mainly dependent on the tension of the transosseous wires, which are clamped to the ring by connection bolts. It was the purpose of this biomechanical study to investigate the holding capacity of a modified bolt design featuring a ruffled wire-bolt interface (TrueLok™) and its influence on wire stiffness in comparison with that of classic bolts featuring a smooth, unruffled wire-bolt interface. Six different ring and bolt configurations were tested using a simplified model consisting of a single ring and wire. The holding capacity at two different tightening torques (10 and 14 Nm) of classic cannulated bolts (CB) and slotted bolts (SB) was determined on Ilizarov and Taylor Spatial Frame (TSF™) rings, whereas the modified TrueLok™ CBs and SBs were used with the TrueLok™ rings. The wire stiffness was calculated via a regression analysis of the load-displacement graphs. The modified TrueLok™ bolts demonstrated significantly better slippage resistance than the classic bolts in all configurations and wire stiffness was significantly higher in the TrueLok™ frame set-ups. After maximum loading, all of the wires showed plastic deformation, including constant wire deflection and dent marks at the clamped wire ends. In conclusion, the decrease in wire stiffness can be explained mainly as a result of wire slippage, but plastic deformation and material yielding also contribute. The relatively simple modification made by roughening the wire-bolt interface results in improved holding capacity and wire stiffness. A frame that contains these modified TrueLok™ bolts should provide improved mechanical stiffness.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-04-30

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

  16. Preliminary Reactor Head Bolt Design of Prototype Sodium-cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Han, Insu; Koo, Gyeonghoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    As structural requirements, the reactor head is designed to withstand all of the pressure, temperatures and forces which are likely to be imposed on it. The bolts that fasten the head to the vessel flange. Design of the reactor head bolts so as to withstand the loads applied should be designed. Currently, preliminary design of the PGSFR reactor bolts is progressed. So far, we have designed and evaluated example. The number and cross-sectional areas of bolts were determined using the procedure given in ASME BPVC Section III, Division 1, Appendix E. The purpose of this study is to conduct design the number and cross-sectional area of bolts attaching the PGSFR reactor head to the reactor vessel, using the ASME procedure. In this paper, preliminary bolt design for PGSFR was carried out according to the ASME procedure. Detailed calculations were carried out for bolt root diameter = 80 mm and number of bolts Nb = 45. It should be noted that the seating pressure recommended in the ASME code is only a suggested value, not mandatory appendix E. It does not guarantee a leak-tight joint. So these quantities are needed to carry out fatigue analysis of the bolts and to assure leak tightness of the joint during operation. For the future work, the fatigue and seismic analysis will be performed.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    OpenAIRE

    Schnupp, Keith Otto

    2003-01-01

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

  19. Degradation and failure of bolting in nuclear power plants: Volume 2: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Nickell, R.E.

    1988-04-01

    A four-year program to resolve the generic safety issue of bolting degradation and failure in nuclear power plants has developed guidelines for material selection, bolting preload control, and plant operation, as well as a realistic method for evaluating the structural integrity of bolted joints. These measures can help improve plant availability while reducing radiation exposure and costs of maintenance and inspection. This report provides the technical basis for resolution of the generic issue of bolting degradation and failure in nuclear power plants.

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

    Directory of Open Access Journals (Sweden)

    Rasim Guldiken

    2012-09-01

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

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Bayesian probabilistic modeling for damage assessment in a bolted frame

    Science.gov (United States)

    Haynes, Colin; Todd, Michael

    2012-04-01

    This paper presents the development of a Bayesian framework for optimizing the design of a structural health monitoring (SHM) system. Statistical damage detection techniques are applied to a geometrically-complex, three-story structure with bolted joints. A sparse network of PZT sensor-actuators is bonded to the structure, using ultrasonic guided waves in both pulse-echo and pitch-catch modes to inspect the structure. Receiver operating characteristics are used to quantify the performance of multiple features (or detectors). The detection rate of the system is compared across different types and levels of damage. A Bayesian cost model is implemented to determine the best performing network.

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

    Science.gov (United States)

    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…

  4. Mechanical properties and supporting effect of CRLD bolts under static pull test conditions

    Science.gov (United States)

    Sun, Xiao-ming; Zhang, Yong; Wang, Dong; Yang, Jun; Xu, Hui-chen; He, Man-chao

    2017-01-01

    A device for supporting soft rock masses combined with a constant resistance structure characterized by constant resistance and large deformation at the end of a steel bar, known as the constant resistance and large deformation (CRLD) bolt, has recently been developed to counteract soft rock swelling that often occurs during deep mining. In order to further study the mechanical properties of the CRLD bolt, we investigated its mechanical properties by comparison with the conventional strength bolt (rebar) using static pull tests on many aspects, including supporting capacity, elongation, radial deformation, and energy absorption. The tests verified that the mechanical defects of the rebar, which include the decrease of bolt diameter, reduction of supporting capacity, and emergence and evolution of fracture until failure during the whole pull process, were caused by the Poisson's ratio effect. Due to the special structure set on the CRLD bolt, the bolt presents a seemingly unusual phenomenon of the negative Poisson's ratio effect, i.e., the diameter of the constant resistance structure increases while under-pulling. It is the very effect that ensures the extraordinary mechanical properties, including high resistance, large elongation, and strong energy absorption. According to the comparison and analysis of numerical simulation and field test, we can conclude that the CRLD bolt works better than the rebar bolt.

  5. MADS-Box Genes and Gibberellins Regulate Bolting in Lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Han, Yingyan; Chen, Zijing; Lv, Shanshan; Ning, Kang; Ji, Xueliang; Liu, Xueying; Wang, Qian; Liu, Renyi; Fan, Shuangxi; Zhang, Xiaolan

    2016-01-01

    Bolting in lettuce is promoted by high temperature and bolting resistance is of great economic importance for lettuce production. But how bolting is regulated at the molecular level remains elusive. Here, a bolting resistant line S24 and a bolting sensitive line S39 were selected for morphological, physiological, transcriptomic and proteomic comparisons. A total of 12204 genes were differentially expressed in S39 vs. S24. Line S39 was featured with larger leaves, higher levels of chlorophyll, soluble sugar, anthocyanin and auxin, consistent with its up-regulation of genes implicated in photosynthesis, oxidation-reduction and auxin actions. Proteomic analysis identified 30 differentially accumulated proteins in lines S39 and S24 upon heat treatment, and 19 out of the 30 genes showed differential expression in the RNA-Seq data. Exogenous gibberellins (GA) treatment promoted bolting in both S39 and S24, while 12 flowering promoting MADS-box genes were specifically induced in line S39, suggesting that although GA regulates bolting in lettuce, it may be the MADS-box genes, not GA, that plays a major role in differing the bolting resistance between these two lettuce lines.

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

    Science.gov (United States)

    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.

  7. Mapping of quantitative trait loci for the bolting trait in Brassica rapa under vernalizing conditions.

    Science.gov (United States)

    Wang, Y G; Zhang, L; Ji, X H; Yan, J F; Liu, Y T; Lv, X X; Feng, H

    2014-05-23

    Premature bolting can occur occasionally during spring cultivation of heading Chinese cabbage in East Asia when the plants encounter low temperatures (vernalization), leading to economic loss. Breeding bolting-resistant cultivars is the best choice for solving this problem. We looked for QTLs responsible for varietal differences in the bolting trait in Brassica rapa under environmental conditions that promote vernalization. To achieve this goal, we constructed a linkage map with 107 simple sequence repeats and 54 insertion/deletion markers based on a segregating population of 186 F2 individuals. The resulting map consisted of 10 linkage groups and covered a total length of 947.1 cM, with an average genetic distance of 5.84 cM between adjacent markers. QTL analysis of the bolting trait was performed by two phenotypic evaluations (bolting index and flowering time) based on the scores in an F2 population in the spring of 2010, and scores in F2:3 families in autumn 2010 and spring 2011, respectively. Twenty-six QTLs that controlled bolting were detected, accounting for 2.6 to 31.2% of the phenotypic variance. The detected QTLs with large effects co-localized mainly on linkage groups A02, A06, and A07. These QTLs may provide useful information for marker-assisted selection in a breeding program for late bolting or bolting-resistant cultivars in B. rapa crops.

  8. MADS-Box Genes and Gibberellins Regulate Bolting in Lettuce (Lactuca sativa L.)

    Science.gov (United States)

    Han, Yingyan; Chen, Zijing; Lv, Shanshan; Ning, Kang; Ji, Xueliang; Liu, Xueying; Wang, Qian; Liu, Renyi; Fan, Shuangxi; Zhang, Xiaolan

    2016-01-01

    Bolting in lettuce is promoted by high temperature and bolting resistance is of great economic importance for lettuce production. But how bolting is regulated at the molecular level remains elusive. Here, a bolting resistant line S24 and a bolting sensitive line S39 were selected for morphological, physiological, transcriptomic and proteomic comparisons. A total of 12204 genes were differentially expressed in S39 vs. S24. Line S39 was featured with larger leaves, higher levels of chlorophyll, soluble sugar, anthocyanin and auxin, consistent with its up-regulation of genes implicated in photosynthesis, oxidation-reduction and auxin actions. Proteomic analysis identified 30 differentially accumulated proteins in lines S39 and S24 upon heat treatment, and 19 out of the 30 genes showed differential expression in the RNA-Seq data. Exogenous gibberellins (GA) treatment promoted bolting in both S39 and S24, while 12 flowering promoting MADS-box genes were specifically induced in line S39, suggesting that although GA regulates bolting in lettuce, it may be the MADS-box genes, not GA, that plays a major role in differing the bolting resistance between these two lettuce lines. PMID:28018414

  9. MADS-box genes and gibberellins regulate bolting in lettuce (Lactuca sativa L.

    Directory of Open Access Journals (Sweden)

    Yingyan Han

    2016-12-01

    Full Text Available Bolting in lettuce is promoted by high temperature and bolting resistance is of great economic importance for lettuce production. But how bolting is regulated at the molecular level remains elusive. Here, a bolting resistant line S24 and a bolting sensitive line S39 were selected for morphological, physiological, transcriptomic and proteomic comparisons. A total of 12204 genes were differentially expressed in S39 vs S24. Line S39 was featured with larger leaves, higher levels of chlorophyll, soluble sugar, anthocyanin and auxin, consistent with its up-regulation of genes implicated in photosynthesis, oxidation-reduction and auxin actions. Proteomic analysis identified 30 differentially accumulated proteins in lines S39 and S24 upon heat treatment, and 19 out of the 30 genes showed differential expression in the RNA-Seq data. Exogenous gibberellins (GA treatment promoted bolting in both S39 and S24, while 12 flowering promoting MADS-box genes were specifically induced in line S39, suggesting that although GA regulates bolting in lettuce, it may be the MADS-box genes, not GA, that plays a major role in differing the bolting resistance between these two lettuce lines.

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

    DEFF Research Database (Denmark)

    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: ...

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    CERN Document Server

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  15. Degradation and failure of bolting in nuclear power plants: Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Nickell, R.E.

    1988-04-01

    These two volumes provide the documentation for industry resolution of the US Nuclear Regulatory Commission (NRC) generic issue B-29, Degradation and Failure of Bolting in Nuclear Power Plants. The issue was identified as a consequence of concerns about the structural integrity of component supports circa 1980. When bolting integrity became a separate issue in 1982, the utility industry responded by forming a Task Group on Bolting under the aegis of the Atomic Industrial Forum (AIF) and the Materials Properties Council (MPC). The AIF/MPC Task Group on Bolting formulated a comprehensive nineteen-task action plan aimed at resolution of the issue, with implementation of the plan, the responsibility of EPRI and the affected Owner's Groups. EPRI organized a matrix-managed Generic Bolted Joint Integrity Program to carry out the research, with the results reported herein.

  16. Smart washer—a piezoceramic-based transducer to monitor looseness of bolted connection

    Science.gov (United States)

    Huo, Linsheng; Chen, Dongdong; Kong, Qingzhao; Li, Hongnan; Song, Gangbing

    2017-02-01

    The safety of a bolted connection, as one of the most common ways of making two or more parts/components work together in engineering structures, is very important in order to ensure the health of the whole structure. However, bolt loosening or pre-load degradation may induce the failure of the bolt connection, threatening the normal operation of the system’s structure. As a result, it would be beneficial if the health condition of the bolt connection could be monitored in real time. In this paper, a ‘smart washer’, fabricated by embedding a piezoceramic patch into two pre-machined flat metal rings, was invented and then introduced as a transducer to detect the looseness of a bolted connection. A simple specimen, which consists of two steel plates connected by a nut, a bolt and two smart washers, was fabricated as the test object to study the performance of the ‘smart washers’ (SWs). For the specimen, a smart washer was used as an actuator to generate a stress wave, and the other one was used as a sensor to detect the propagated wave that traveled through the interface of the bolted connection. A time reversal method was employed to quantify the energy of the stress wave propagating between the two washers, and thus it was possible to build a relationship between the extent of any pre-loaded degradation of the bolt connection and the response signal of the stress wave traveling between the two washers. In addition, a normalized bolt looseness index was proposed for evaluating the looseness of a bolt connection based on wavelet energy analysis.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wieser, G.; Qiao Linan; Eberle, A.; Voelzke, H. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2004-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    The bolted closure joint of a bare spent fuel cask is susceptible to age-related degradation and potential loss of confinement function under long-term storage conditions. Elastomeric seals, a component of the joint typically used to facilitate leak testing of the primary seal that includes the metallic seal and bolting, is susceptible to degradation over time by several mechanisms, principally via thermo-oxidation, stress-relaxation, and radiolytic degradation under time and temperature condition. Irradiation and thermal exposure testing and evaluation of an ethylene-propylene diene monomer (EPDM) elastomeric seal material similar to that used in the CASTOR® V/21 cask for a matrix of temperature and radiation exposure conditions relevant to the cask extended storage conditions, and development of semiempirical predictive models for loss of sealing force is in progress. A special insert was developed to allow Compressive Stress Relaxation (CSR) measurements before and after the irradiation and/or thermal exposure without unloading the elastomer. A condition of the loss of sealing force for the onset of leakage was suggested. The experimentation and modeling being performed could enable acquisition of extensive coupled aging data as well as an estimation of the timeframe when loss of sealing function under aging (temperature/radiation) conditions may occur.

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

    Directory of Open Access Journals (Sweden)

    Wen Jinglin

    2015-01-01

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

  20. Comparative Modal Analysis of Gasketed and Nongasketed Bolted Flanged Pipe Joints: FEA Approach

    Directory of Open Access Journals (Sweden)

    Muhammad Abid

    2012-01-01

    Full Text Available It is widely known that resonance can quickly lead to failure in vibrating bolted flanged pipe joints. Condition monitoring is performed time to time in some industries for smooth operation of a system, whereas mostly trial-and-error tests are performed to control vibration. During all this process, the inherent design problems are not considered. A bolted flange joint in piping system is not a simple problem, being the combination of flange, gasket, bolts, and washers. The success of a bolted flanged pipe joint is defined by the “static mode of load” in the joint. However, it has been recognized that a “dynamic mode of load” governs in a gasketed bolted flanged pipe joint, which leads to its failure due to flange rotation, providing flange yielding, fatigue of bolts, and gasket crushing. This paper presents results of detailed 3D finite element and mathematical modal analysis under bolt up to determine natural frequencies and mode shapes of gasketed flanged joints with and without raised face in comparison to the nongasketed flange joint.

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

    DEFF Research Database (Denmark)

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

    1996-01-01

    deviation of 37 kN. Comparing this mean residual strength with previously recorded test data reveals a 5% strength reduction. The force displacement curves shows no plastic capacity in the connections. 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. This localised failure mode explains the surprisingly high mean residual strength of 304 kN of bolts pulled out between failed bolts....

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Directory of Open Access Journals (Sweden)

    Debasis Deb

    2010-01-01

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

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

    DEFF Research Database (Denmark)

    Hebelstrup, Kim Henrik; Jensen, Erik Østergaard

    2008-01-01

    -symbiotic hemoglobin gene, GLB2, in Arabidopsis thaliana. Lines with GLB1 silencing had a significant delay of bolting and after bolting, shoots reverted to the rosette vegetative phase by formation of aerial rosettes at lateral meristems. Lines with overexpression of GLB1 or GLB2 bolted earlier than wild type plants...... molecule, NO. So far, NO scavenging has only been demonstrated for class 1 non-symbiotic hemoglobins. A direct assay in Arabidopsis leaf cells shows that GLB1 as well as the class 2 non-symbiotic hemoglobin, GLB2, scavenge NO in vivo. NO has also been demonstrated to be a growth stimulating signal...

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  7. Study of the dynamic behavior of a bolted joint under heavy loadings

    Science.gov (United States)

    Daouk, Sami; Louf, François; Cluzel, Christophe; Dorival, Olivier; Champaney, Laurent; Audebert, Sylvie

    2017-03-01

    In structural dynamics, the quantification of the quality and reliability of numerical models remains a relevant issue. While the behavior of structures such as beams and plates is generally understood, a large number of industrial structures are bolted assemblies of many components with connections that are not well understood. The main reason for this lack of understanding is that the dynamical behavior of the whole assembly depends critically upon joint conditions, especially under heavy loadings. For the purpose of improving our understanding and the development of pertinent models, a dynamic test bed, based on a bolted structure, is designed and modal testing is performed. The configuration of the bolted joint and the level of the loading are the relevant parameters, related to joint conditions, that are considered in this study. The results of the experimental campaign show the variation of the dissipation in a bolted joint and its apparent stiffness as a function of joint conditions.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-01

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

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

    CERN Document Server

    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.

  10. Stabilization of ground movement with yield rock bolts using spatial effect

    Energy Technology Data Exchange (ETDEWEB)

    Naprasnikov, S.V.; Alexandrov, S.N.; Sazhnev, V.P.; Nazimko, V.V. [Donetsk State Technical University, Donetsk (Ukraine)

    1999-07-01

    New rock bolting technology has been developed for stabilization of roofs and floor closures in underground openings. Yield rock bolts should be inclined 5-40{degree} to the relative direction of expected roof deflection and oriented in the plane under an angle of 5-90{degree} relative to the orthogonal cross-section of the roadway. Such an orientation increases the pullout force by 2% and enhances stability of a roadway. 3 refs., 2 figs., 1 tab.

  11. NDE applications in an anchor bolt and sign bridge inspection program

    Science.gov (United States)

    Fish, Philip E.

    1998-03-01

    Wisconsin Department of Transportation implemented an Anchor Bolt Inspection Program and Sign Bridge Inspection Program in 1990 for cantilever & overhead sign structures, high mast light towers, interstate light towers, and signal masts. All cantilever & overhead sign structures and high mast light towers have been inspected in-depth 'hands on' during this time period while implementation of inspection continues for interstate light towers and signal masts. The program requires an experienced inspection team and a practical inspection approach. Inspection preparation includes review of all background information such as design plans, design computations, construction plans, shop plans, and maintenance history. An inspection plan is developed. Special emphasis is placed on determining type of structure, type of material, welding details. For anchor bolts, type of material, cut or rolled threads, type of coating, and method of placement are important issues. Inspection emphasis are on 'hands on' and Nondestructive evaluation. Special emphasis is placed visual conditions of sign structures and anchor bolts (cut or rolled threads, straightness, corrosion, nut tension, etc.) along with ultrasonic inspection. This program places a strong emphasis on Non Destructive Testing (NDT), especially ultrasonic. Procedures and inspection calibrations for anchor bolts, are developed from similar anchor bolt geometry and material type. Cut notches are placed in the anchor bolts at locations of possible failure. NDT inspection calibrations are performed from these bolts. Report documentation includes all design plans, pictorial documentation of structural deficiencies, sketches, nondestructive evaluation reports, conclusions, and recommendations. This program has been successful in locating critical cracks and failed members on existing sign structures and new sign structures less than six months old. Also, failed anchor bolts and critical cracks have been located on high mast light

  12. Oil-to-coal cavern conversion pins its success on rock bolts

    Energy Technology Data Exchange (ETDEWEB)

    Hamrin, H. (Atlas Copco MCT AB (Sweden))

    1989-07-01

    A new pressurized fluidized bed combustion power plant is being built in Stockholm. Coal will be stored underground, in old oil storage chambers. The roof had to be bolted and shotcreted and swellex bolts were used. These act as roof support with immediate action for the protection of the workers, and as a safety pin to reinforce the bond between shotcrete and the rock surface. 4 figs.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Science.gov (United States)

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

    2016-01-01

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

  15. Matching nuts and bolts in O(n log n) time

    Energy Technology Data Exchange (ETDEWEB)

    Komlos, J. [Rutgers Univ., Piscataway, NJ (United States); Ma, Yuan [Stanford Univ., CA (United States); Szemeredi, E. [Rutgers Univ., Piscataway, NJ (United States)

    1996-12-31

    Given a set of n nuts of distinct widths and a set of n bolts such that each nut corresponds to a unique bolt of the same width, how should we match every nut with its corresponding bolt by comparing nuts with bolts (no comparison is allowed between two nuts or between two bolts)? The problem can be naturally viewed as a variant of the classic sorting problem as follows. Given two lists of n numbers each such that one list is a permutation of the other, how should we sort the lists by comparisons only between numbers in different lists? We give an O(n log n)-time deterministic algorithm for the problem. This is optimal up to a constant factor and answers an open question posed by Alon, Blum, Fiat, Kannan, Naor, and Ostrovsky. Moreover, when copies of nuts and bolts are allowed, our algorithm runs in optimal O(log n) time on n processors in Valiant`s parallel comparison tree model. Our algorithm is based on the AKS sorting algorithm with substantial modifications.

  16. Failure Characteristics of Joint Bolts in Shield Tunnels Subjected to Impact Loads from a Derailed Train

    Directory of Open Access Journals (Sweden)

    Qixiang Yan

    2017-01-01

    Full Text Available Impact loads generated by derailed trains can be extremely high, especially in the case of heavy trains running at high speeds, which usually cause significant safety issues to the rail infrastructures. In shield tunnels, such impact loads may not only cause the damage and deformation of concrete segments, but also lead to the failure of segmental joint bolts. This paper presents a numerical study on the failure behavior of segmental joint bolts in the shield tunnel under impact loading resulting from train derailments. A three-dimensional (3D numerical model of a shield tunnel based on the finite element (FE modelling strategy was established, in which the structural behavior of the segmental joint surfaces and the mechanical behavior of the segmental joint bolts were determined. The numerical results show that the occurrence of bolt failure starts at the joints near the impacted segment and develops along the travel direction of train. An extensive parametric study was subsequently performed and the influences of the bolt failure on the dynamic response of the segment were investigated. In particular, the proposed FE model and the analytical results will be used for optimizing the design method of the shield tunnel in preventing the failure of the joint bolts due to the impact load from a derailed HST.

  17. Improving boiler foundation bolt installation technology%提高锅炉地脚螺栓安装工艺

    Institute of Scientific and Technical Information of China (English)

    李晓峰

    2014-01-01

    阐述了锅炉地脚螺栓安装前的准备工作,通过对螺栓安装施工工艺流程的介绍,分析了提高螺栓与螺栓支架安装精度的方法,并对检验螺栓安装质量的技术要点作了研究,以确保锅炉地脚螺栓安装的正确无误。%The paper illustrates boiler foundation bolt installation preparations. Through introducing bolt installation technology procedures, it analyzes methods of improving bolt and bolt support installation accuracy, and studies technological points of examining bolt installation quality, with a view to guarantee boiler foundation bolt installation correct.

  18. Analysis of Yielding Steel Arch Support with Rock Bolts in Mine Roadways Stability Aspect

    Science.gov (United States)

    Majcherczyk, Tadeusz; Niedbalski, Zbigniew; Małkowski, Piotr; Bednarek, łukasz

    2014-10-01

    The result of the search for new technological solutions in the field of support for roadways in coal mines has in recent years been the widespread use of steel arch with rockbolt support systems. The efficiency of these systems is affected among other things by the option of installing rock bolts after the actual driving the mine roadway, the increased load capacity that these systems can support, and their resistance to dynamic weight. Large variation in the way that these steel arch support can be connected using different types of rock bolts necessitates mining research revealing the effectiveness of such solutions. Although the steel arch with rockbolt support system is used in the majority of European coal mines, it is still not possible to apply templates of schemes due to the diversity of geological and mining conditions. Therefore, throughout a period of several years, the authors of this article conducted research in situ under conditions of different schemes related to connecting arched support frames with rock bolts, with only selected results being presented in the article. The measurements of convergence, load supported by the system frame, load supported by the rock bolts, and the stratification of roof rocks were analyzed, carried out in two roadways with yielding steel arch support in which strand bolts were applied. The article also proposes the index for working maintenance nuw, used in preliminarily assessing the stability of a given working with a limited number of data concerning geomechanical conditions. Additionally considered are empirical methods used in Poland for designing steel arch with rock bolt support systems. The results of mine research indicate that strengthening yielding steel support with strand bolts through steel beams maintains the stability of a roadway, even when exposed to the exploitation stress. Aside from the impact of exploitation, deformations of the support system are negligible, despite the fact that the tensile

  19. Forces in bolted joints: analysis methods and test results utilized for nuclear core applications (LWBR Development Program)

    Energy Technology Data Exchange (ETDEWEB)

    Crescimanno, P.J.; Keller, K.L.

    1981-03-01

    Analytical methods and test data employed in the core design of bolted joints for the LWBR core are presented. The effects of external working loads, thermal expansion, and material stress relaxation are considered in the formulation developed to analyze joint performance. Extensions of these methods are also provided for bolted joints having both axial and bending flexibilities, and for the effect of plastic deformation on internal forces developed in a bolted joint. Design applications are illustrated by examples.

  20. European development Rock bolting. Desarrollo Europeo del Bulonaje

    Energy Technology Data Exchange (ETDEWEB)

    1999-01-01

    The project European Development Rockbolting which was developed during the period 1994-1997 and carried out within the OCICARBON Action Program (OCICARBON-ITGE agreement dated September 1, 1994, Code C-13-438) as well as within the framework of the Coal Technical research Program of the D. G. XVII of the EEC, n 7220/AB/143. The project has had the following external partners: DMT (Germany), BCC (UK) and CDF (France), and the collaboration of INERIS (France), RMT (UK) and GEOCONTROL S. A. (Spain). The objective of the investigation was to improve the techniques and design currently used in the application of rockbolts for supporting of both infrastructure and beds in the European coal mining. The most important result, besides that derived from the sharing of experiences and knowledge, was the technological design of a supporting system, which was carried out by each partner for the various proposed exploitations. The Spanish part carried out the works of designing and estimation of the bolting system corresponding to the exploitations of: -Carbones de Pedraforca SA. Saldes mine. -U. E. Provence. Pit Y. Morandat.

  1. European development Rock bolting; Desarrollo Europeo del Bulonaje

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-01

    The project European Development Rockbolting which was developed during the period 1994-1997 and carried out within the OCICARBON Action Program (OCICARBON-ITGE agreement dated September 1, 1994, Code C-13-438) as well as within the framework of the Coal Technical research Program of the D. G. XVII of the EEC, n 7220/AB/143. The project has had the following external partners: DMT (Germany), BCC (UK) and CDF (France), and the collaboration of INERIS (France), RMT (UK) and GEOCONTROL S. A. (Spain). The objective of the investigation was to improve the techniques and design currently used in the application of rockbolts for supporting of both infrastructure and beds in the European coal mining. The most important result, besides that derived from the sharing of experiences and knowledge, was the technological design of a supporting system, which was carried out by each partner for the various proposed exploitations. The Spanish part carried out the works of designing and estimation of the bolting system corresponding to the exploitations of: -Carbones de Pedraforca SA. Saldes mine. -U. E. Provence. Pit Y. Morandat.

  2. FE-MODELLING OF A CONTACT LAYER BETWEEN ELEMENTS JOINED IN PRELOADED BOLTED CONNECTIONS FOR THE OPERATIONAL CONDITION

    Directory of Open Access Journals (Sweden)

    Rafał Grzejda

    2014-11-01

    Full Text Available Modelling and calculations of a contact layer between elements joined in a preloaded bolted connection for the operational condition are presented. The physical model of the bolted connection is based on a flexible flange element that is joined with a rigid support by means of the no-bolt model (at the assembly stage or the rigid body bolt model (at the operational stage. The contact layer between joined elements is described as the nonlinear Winkler model. The contact joint model considering an experimental normal elastic characteristic is presented. Examples of normal contact pressure and normal contact deformations distributions are contained.

  3. Strengths of composite-to-metal double-lap bolted joints

    Science.gov (United States)

    Sun, Hsien-Tang

    1998-12-01

    A three-dimensional analysis was proposed to study the through-the-thickness clamping effect on the bearing failure of double-lap bolted laminated composite joints. Experiments were first performed to characterize the material response due to bearing failure in composite bolted joints with and without lateral clamp-up supports. Composite plates made of T800H/3900-2 graphite/epoxy were selected in the tests, and various washer sizes and clamping forces were used in the study. The clamping force in the bolt was found to vary with the applied load, and may increase significantly due to a sudden through-the-thickness expansion of the laminate under the washers where bearing failure occurred. Experiments showed that the joint strength and response can be significantly affected by the bolt clamp-up, and the bolt bearing failure is a 3-D phenomenon. In order to facilitate the use of the proposed model with the ABAQUS code, an interface module 3DBOLT was developed. In order to reinforce the incompressibility condition in calculations for bearing-damaged material predicted by the model, the condition was imposed through a penalty method in the frame work of finite element analyses. The module provides a user-friendly input deck, generates automatically a joint mesh, and produces outputs and graphics for displaying the stresses, strains, and deformations of the joints and for simulating the failure progression in joints during loading. Extensive comparisons were made between the test data and model predictions. Overall, the model predicts both the failure load and response of bolted composite joints very well for various clamping forces and washer sizes. The model also predicted very well for joints failed in net-tension and shear-out modes. The predicted bolt clamp-up load as a function of the applied load agreed also very well with the data, which validates that the proposed incompressibility assumption for bearing-damaged material. Based on the model, a parametric study

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

    Institute of Scientific and Technical Information of China (English)

    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°.

  5. Corrosion monitoring of rock bolt by using a low coherent fiber-optic interferometry

    Science.gov (United States)

    Wei, Heming; Zhao, Xuefeng; Li, Dongsheng; Zhang, Pinglei; Sun, Changsen

    2015-04-01

    Corrosion of rock bolts is a major cause for deterioration of the anchor-reinforced concrete slopes structures. In order to evaluate this corrosion-based deterioration in an early stage, a nondestructive technique was required. However, until now, there are no commercialized solutions that are straightforwardly available. Here, a low-coherent fiber-optic sensing technique was developed. This method can carry out the monitoring of the corrosion-caused expansion at the accuracy of sub-microstrains by circled the sensing optical fiber in two ways. One was wound the fiber on the surface of steel rock bolt directly, and thereby generated a nonuniformity in the interface of cement with rock bolt. The other was circled the fiber on a cement mortar cushion without destroying the interface any way. The sensing fiber was configured as one arm of the fiber-optic Michelson interferometer. The acceleration corrosion experiments demonstrated that a uniform interface between cement and rock bolt determined the progress of corrosion development. An early stage evaluation of the corrosion development in rock bolts was monitored.

  6. Submillimeter bolt location in car bodywork for production line quality inspection

    Science.gov (United States)

    Altamirano-Robles, Leopoldo; Arias-Estrada, Miguel; Alviso-Quibrera, Samuel; Lopez-Lopez, Aurelio

    2000-03-01

    In the automotive industry, a vehicle begins with the construction of the vehicle floor. Later on, several robots weld a series of bolts to this floor which are used to fix other parts. Due to several problems, like welding tools wearing, robot miscalibration or momentary low power supply, among others, some bolts are incorrectly positioned or are not present at all, bringing problems and delays in the next work cells. Therefore, it is of importance to verify the quality of welded parts before the following assembly steps. A computer vision system is proposed in order to locate autonomously the presence and quality of the bolts. The system should carry on the inspection in real time at the car assembly line under the following conditions: without touching the bodywork, with a precision in the submillimeter range and in few seconds. In this paper we present a basic computer vision system for bolt location in the submillimeter range. We analyze three arrangements of the system components (camera and illumination sources) that produce different results in the localization. Results are presented and compared for the three approaches obtained under laboratory conditions. The algorithms were tested in the assembling line. Variations up to one millimeter in the welded position of the bolts were observed.

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

    Directory of Open Access Journals (Sweden)

    Yongpeng Chu

    2016-01-01

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

  8. Numerical Computation of Stress Intensity Factors for Bolt-hole Corner Crack in Mechanical Joints

    Institute of Scientific and Technical Information of China (English)

    Wang Liqing; Gai Bingzheng

    2008-01-01

    The three-dimensional finite element method is used to solve the problem of the quarter-elliptical comer crack of the bolt-hole in mechanical joints being subjected to remote tension. The square-root stress singularity around the corner crack front is simulated using the collapsed 20-node quarter point singular elements. The contact interaction between the bolt and the hole boundary is considered in the finite element analysis. The stress intensity factors (SIFs) along the crack front are evaluated by using the displacement correlation technique. The effects of the amount of clearance between the hole and the bolt on the SIFs are investigated. The numerical results indicate that the SIF for mode I decrease with the decreases in clearance, and in the cases of clearance being present, the corner crack is in a mix-mode, even if mode I loading is dominant.

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

    Directory of Open Access Journals (Sweden)

    Shruti Paunikar

    2013-09-01

    Full Text Available 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 main feature extraction techniques analysed for this review paper are stationary wavelet transform, principle component analysis and radius analysis. The aforementioned techniques are already tested and simulation is done on MATLAB.The results obtained varies depending on pre-processing techniques used for the nut and bolt recognition.

  10. Simulation and experiment for the inspection of stainless steel bolts in servicing using an ultrasonic phased array

    Science.gov (United States)

    Chen, Jinzhong; He, Renyang; Kang, Xiaowei; Yang, Xuyun

    2015-10-01

    The non-destructive testing of small-sized (M12-M20) stainless steel bolts in servicing is always a technical problem. This article focuses on the simulation and experimental research of stainless steel bolts with an artificial defect reflector using ultrasonic phased array inspection. Based on the observation of the sound field distribution of stainless steel bolts in ultrasonic phased array as well as simulation modelling and analysis of the phased array probes' detection effects with various defect sizes, different artificial defect reflectors of M16 stainless steel bolts are machined in reference to the simulation results. Next, those bolts are tested using a 10-wafer phased array probe with 5 MHz. The test results finally prove that ultrasonic phased array can detect 1-mm cracks in diameter with different depths of M16 stainless steel bolts and a metal loss of Φ1 mm of through-hole bolts, which provides technical support for future non-destructive testing of stainless steel bolts in servicing.

  11. The Effect of Temperature on Bearing Strength of CFRP Bolted Joint with Washer Constraining

    OpenAIRE

    Hirano, Noriyoshi; Wang, Wen-Xue; Takao, Yoshihiro

    2012-01-01

    Effects of temperature on the bearing strength of a CF/Epoxy quasi-isotropic laminate bolted joint are investigated experimentally. The material system is CF/Epoxy T800H/#3631 with stacking sequence of [0/45/-45/90]_. In this study, a semi-circular notched specimen is chosen and loaded in compression instead of a well-known double lap joint. This method has advantages in material cost and simplicity of its damage mode. A bolted joint with the washer constraint is loaded at 25, 150 and —100℃. ...

  12. Thermal conductance measurements of bolted copper joints for SuperCDMS

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, R.; Tatkowski, Greg; Ruschman, M.; Golwala, S. R.; Kellaris, N.; Daal, M.; Hall, Jeter C.; Hoppe, Eric W.

    2015-09-01

    Joint thermal conductance testing has been undertaken for bolted copper to copper connections from 60 mK to 26 K. This testing was performed to validate an initial design basis for the SuperCDMS experiment, where a dilution refrigerator will be coupled to a cryostat via multiple bolted connections. Copper used during testing was either gold plated or passivated with citric acid to prevent surface oxidation. Results obtained are well fit by a power law regression of joint thermal conductance to temperature and match well with data collected during a literature review.

  13. Loosening and Sliding Behaviour of Bolt-Nut Fastener under Transverse Loading

    Directory of Open Access Journals (Sweden)

    Naruse T.

    2010-06-01

    Full Text Available The thread joint has been frequently used for the efficient productivity and maintainability as a machine element. However, many troubles such as loosening of bolted joints or fatigue failure of bolt were often experienced. Many attentions must be paid on the improvement of the strength and the reliability of the thread joints [1, 2]. It is generally said that the fastening axial force rapidly decreases by the rotation loosening of nuts if the relative slippage on the interfaces between nuts and fastened body goes beyond a certain critical limit [3]. This critical relative slippage (Scr that prescribes the upper limit for preventing the loosening behaviour has been estimated according to the theoretically obtained equation considering the bending deformation of bolt and the geometrical constraint condition. In this paper, firstly we present the equation for estimating the Scr based on the fundamental cantilever deformation model. Then we present the investigated results of the deformation behaviour of bolt-nut joint under transverse loading condition considering the reaction moment by nut (Mn. Finaly we can confirmed that these estimated results of critical relative slippage coincided well with the experimental results [4, 5].

  14. Secondary skull fractures in head wounds inflicted by captive bolt guns: autopsy findings and experimental simulation.

    Science.gov (United States)

    Perdekamp, Markus Grosse; Kneubuehl, Beat P; Ishikawa, Takaki; Nadjem, Hadi; Kromeier, Jan; Pollak, Stefan; Thierauf, Annette

    2010-11-01

    Apart from one article published by Rabl and Sigrist in 1992 (Rechtsmedizin 2:156-158), there are no further reports on secondary skull fractures in shots from captive bolt guns. Up to now, the pertinent literature places particular emphasis on the absence of indirect lesions away from the impact point, when dealing with the wounding capacity of slaughterer's guns. The recent observation of two suicidal head injuries accompanied by skull fractures far away from the bolt's path gave occasion to experimental studies using simulants (glycerin soap, balls from gelatin) and skull–brain models. As far as ballistic soap was concerned, the dimensions of the bolt's channel were assessed by multi-slice computed tomography before cutting the blocks open. The test shots to gelatin balls and to skull-brain models were documented by means of a high-speed motion camera. As expected, the typical temporary cavity effect of bullets fired from conventional guns could not be observed when captive bolt stunners were discharged. Nevertheless, the visualized transfer of kinetic energy justifies the assumption that the secondary fractures seen in thin parts of the skull were caused by a hydraulic burst effect.

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

    DEFF Research Database (Denmark)

    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...

  16. Velocity dispersions in a cluster of stars: How fast could Usain Bolt have run?

    CERN Document Server

    Eriksen, H K; Langangen, O; Wehus, I K

    2008-01-01

    Since that very memorable day at the Beijing 2008 Olympics, a big question on every sports commentator's mind has been "What would the 100 meter dash world record have been, had Usain Bolt not celebrated at the end of his race?" Glen Mills, Bolt's coach suggested at a recent press conference that the time could have been 9.52 seconds or better. We revisit this question by measuring Bolt's position as a function of time using footage of the run, and then extrapolate into the last two seconds based on two different assumptions. First, we conservatively assume that Bolt could have maintained Richard Thompson's, the runner-up, acceleration during the end of the race. Second, based on the race development prior to the celebration, we assume that he could also have kept an acceleration of 0.5 m/s^2 higher than Thompson. In these two cases, we find that the new world record would have been 9.61 +/- 0.04 and 9.55 +/- 0.04 seconds, respectively, where the uncertainties denote 95% statistical errors.

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

    Directory of Open Access Journals (Sweden)

    Heyue Yin

    2016-10-01

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

  18. Linkage Map Construction and Quantitative Trait Loci Analysis for Bolting Based on a Double Haploid Population of Brassica rapa

    Institute of Scientific and Technical Information of China (English)

    Xu Yang; Yang-Jun Yu; Feng-Lan Zhang; Zhi-Rong Zou; Xiu-Yun Zhao; De-Shuang Zhang; Jia-Bing Xu

    2007-01-01

    Early bolting of Chinese cabbage (Brassica rapa L.) during spring cultivation often has detrimental effects on the yield and quality of the harvested products. Breeding late bolting varieties is a major objective of Chinese cabbage breeding programs. in order to analyze the genetic basis of bolting traits, a genetic map of B. rapa was constructed based on amplified fragment-length polymorphism (AFLP), sequence-related amplified polymorphism (SRAP), simple sequence repeat (SSR), random amplification of polymorphic DNA (RAPD), and isozyme markers. Marker analysis was carried out on 81 double haploid (DH) lines obtained by mlcrospore culture from F1 progeny of two homozygous parents: B. rapa L. ssp. pekinensis (BY) (an extra-early bolting Chinese cabbage line) and B. rapa L. ssp. rapifera (MM) (an extra-late bolting European turnip line). A total of 326 markers including 130 AFLPs, 123 SRAPs, 16 SSRs, 43RAPDs and 14 isozymes were used to construct a linkage map with 10 linkage groups covering 882 cM with an average distance of 2.71 cM between loci. The bolting trait of each DH line was evaluated by the bolting index under controlled conditions. Quantitative trait loci (QTL) analysis was conducted using multiple QTL model mapping with MapQTL5.0 software. Eight QTLs controlling bolting resistance were identified. These QTLs, accounting for 14.1% to 25.2% of the phenotyplc variation with positive additive effects, were distributed into three linkage groups. These results provide useful information for molecular marker-assisted selection of late bolting traits in Chinese cabbage breeding programs.

  19. Failure of intramedullary femoral nail with segmental breakage of distal locking bolts: a case report and review of the literature

    Institute of Scientific and Technical Information of China (English)

    Sameer Aggerwal; Nitesh Gahlot; Uttam C. Saini; Kamal Bali

    2011-01-01

    Breakage of locking bolts is an important cause of interlocking nail failure in femoral fractures. It usually occurs in the form of single breakage in one of the distal bolts of the nail or nail breakage around the distal locking hole. Here we report an unusual case of intramedullary femoral nail failure with segmental breakage of both the distal locking bolts. Such a scenario usually complicates further management. We successfully managed this case with exchange nailing without bone grafting. Here we briefly reviewed the literature regarding such an unusual presentation and discussed in detail the possible etiology of such a presentation and the management options when facing such a complex situation.

  20. Experimental characterization of damage at countersunk bolted joints tested under quasi-static bearing loads

    Science.gov (United States)

    Popescu, Alexandru Paul

    The use of composite materials in aerospace vehicles has allowed for creation of lighter structures that provide excellent stiffness. Although they allow for easy disassembly and inspection of critical assemblies, bolted joints are common damage initiation sites in composite structures. In order for aging aircraft to be considered for life extension programs, the damage at these locations must be characterized and well-understood. Failure studies require that data be provided through experimental tests. The drawback of the present test standard for bolted composite joints is that it was initially designed for testing polymers. This thesis discusses deficiencies in the measurement of bearing strength as a result of this shortcoming, although the battery of bearing tests is modeled after this established test standard. The goal of the present work is to characterize the bearing load induced damage in laminates with pin bearing and countersunk fasteners through a series of bearing tests on laminated composites using a new modified ASTM D5961 fixture designed for testing countersunk bolted joints. This thesis examines variations in measurement of bearing strength that comes with using different test fixtures. The reliability of each test fixture to represent real conditions is evaluated using test fixtures that represent real joint configurations. Results for damage conditions and joint responses are compared. This thesis presents a study of the damage initiation and accumulation in composite specimens loaded in bearing using three different test fixtures: Procedure A, Procedure C, and Procedure A Modified. Procedure A, which is used to load the test specimen in double-shear via a straight pin, is a well known test fixture that comes from ASTM D5961. Procedure C has a countersunk fastener that loads the test specimen in single-shear. These types of fasteners are preferred in the aerospace industry over traditional bolts in order to maintain a smooth aerodynamic profile

  1. 栓焊结合钢桥高强度螺栓施工质量控制%Construction Quality Control of High-Strength Bolts for a Bolted and Welded Steel Bridge

    Institute of Scientific and Technical Information of China (English)

    张志伟; 文世军; 高琳琳

    2012-01-01

    To ensure the construction quality of the big hexagonal head high-strength bolts, the construction quality of the bolted steel truss girder members (used with the frictional type big hexagonal head bolt sets) of Fenfangwan Changjiang River Bridge is cited as an example. The construction quality of the bolts is discussed from the following aspects of the principal'parame-ters, checking, acceptance and storage of the bolts delivered to the construction site; the site torque moment test, selection and utilization of the tightening spanners, handling of the frictional surfaces; the construction technology of the bolts, construction sequences of the welded and bolted connection and also the checking, acceptance and corrosion protection of the bolts. The construction practice of the bridge-proves that in the process of the construction, the construction strictly following the formulated quality control requirements for the high-strength bolts can well control the various procedures related to the construction quality of the bolts and control the qualification ratios of the bolts in all aspects of the construction methods, construction requirements and construction technology.%为了保证大六角高强度螺栓施工质量,以重庆粉房湾长江大桥钢桁梁杆件栓接(摩擦型高强度大六角头螺栓连接副)施工及质量控制为背景,从高强度螺栓的主要参数、高强度螺栓进场验收及保管、工地扭矩系数试验、扭力扳手的选择及使用、摩擦面的处理、大六角头高强度螺栓施工工艺、栓焊结合型高强度螺栓施工顺序、高强度螺栓的验收及防腐等方面进行讨论.实践表明,在高强度螺栓施工过程中,严格按照制定的质量控制要求进行施工,从施工方法、施工要求、施工工艺上,对涉及高强度螺栓质量的各个环节进行把关,可以较好地控制高强度螺栓的终拧合格率.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  3. 压水堆反应堆压力容器密封主螺栓预紧过程模拟%Simulation of Bolt-up Process for Seal Main Bolts of PWR Pressure Vessel

    Institute of Scientific and Technical Information of China (English)

    陈宝

    2015-01-01

    建立了我国自主压水堆反应堆压力容器分析模型,采用通用结构分析软件ABAQUS对密封主螺栓的预紧过程进行了模拟分析。通过计算,可以得到螺栓载荷的变化、上下法兰的变形过程,从而判断螺栓加载荷顺序和大小是否合理。对于一回路压力容器的密封预紧操作具有很好的参考价值。%The reactor pressure vessel of self-owned pressure water reactor (PWR) is built, and the bolt-up process for main bolts is analyzed in this paper. According to the calculation, the change of the pre-load on the bolts and the deformation of the main flange can be checked, and a lot of useful conclusions can be got, such as whether the bolt-load of every step is good or not, whether the bolt groups are good or not. The simulation results of this paper are very meaningful for the bolt-up process operation of the first loop pressure vessel.

  4. The Nuts and Bolts of Zinc-Nickel: OEM Zinc Nickel Implementation on Fasteners - Getting It Into Production

    Science.gov (United States)

    2014-11-01

    Blake Simpson Louie Tran The Nuts and Bolts of Zinc- Nickel OEM Zinc Nickel Implementation on Fasteners – Getting It Into Production Report...REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE The Nuts and Bolts of Zinc- Nickel : OEM Zinc Nickel Implementation on...currently in production 2. Problem at Hand – Hexavalent Chromates 3. Transition to Zinc- Nickel 4. Preliminary Testing 5. Plan moving forward for

  5. Effect of pre-tensioned rock bolts on stress redistribution around a roadway insight from numerical modeling

    Institute of Scientific and Technical Information of China (English)

    GAO Fu-qiang; KANG Hong-pu

    2008-01-01

    The importance of the pre-tensioned force of rock bolts has been recognized by more and more researchers. To investigate the effect of pre-tensioned rock bolts on stress redistribution around roadways, a numerical analysis was carded out using FLAC3D and a special post-process methodology, using surfer, is proposed to process the numerical simulation results. The results indicate that pre-tensioned rock bolts have a significant effect on stress redistribution around a roadway. In the roof, pre-tensioned rock bolts greatly increase vertical stress; as a result, the strength of the rock mass increased significantly which results in a greater capacity of bearing a large horizontal stress. The horizontal stress decreases in the upper section of the roof, indicating that pre-tensioned rock bolts significantly reduce the coefficient and the size of the region concentration of horizontal stress. At the lateral side, pre-tensioned rock bolts greatly increase the horizontal stress; therefore, the rock mass strength significantly increases which results also in a greater capacity of bearing a large vertical stress. The greater the size of pre-tensioned force, the larger the region of stress redistribution around a roadway is affected and the higher the size of the stress on the roadway surface the more the rock mass strength increases.

  6. Effect of pre-tensioned rock bolts on stress redistribution around a roadway - insight from numerical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Fu-qiang Gao; Hong-pu Kang [Central Coal Research Institute, Beijing (China). Mining and Designing Branch

    2008-12-15

    The importance of the pre-tensioned force of rock bolts has been recognized by more and more researchers. To investigate the effect of pre-tensioned rock bolts on stress redistribution around roadways, a numerical analysis was carried out on a level drift at Chengzhuang coal mine using FLAC3D and a special post-process methodology, using surfer, is proposed to process the numerical simulation results. The results indicate that pre-tensioned rock bolts have a significant effect on stress redistribution around a roadway. In the roof, pre-tensioned rock bolts greatly increase vertical stress; as a result, the strength of the rock mass increased significantly which results in a greater capacity of bearing a large horizontal stress. The horizontal stress decreases in the upper section of the roof, indicating that pre-tensioned rock bolts significantly reduce the coefficient and the size of the region concentration of horizontal stress. At the lateral side, pre-tensioned rock bolts greatly increase the horizontal stress; therefore, the rock mass strength significantly increases which results also in a greater capacity of bearing a large vertical stress. The greater the size of pre-tensioned force, the larger the region of stress redistribution around a roadway is affected and the higher the size of the stress on the roadway surface the more the rock mass strength increases. 10 refs., 6 figs., 1 tab.

  7. Variables Affecting Probability of Detection in Bolt Hole Eddy Current Inspection

    Science.gov (United States)

    Lemire, H.; Krause, T. W.; Bunn, M.; Butcher, D. J.

    2009-03-01

    Physical variables affecting probability of detection (POD) in a bolt-hole eddy current inspection were examined. The POD study involved simulated bolt holes in 7075-T6 aluminum coupons representative of wing areas on CC-130 and CP-140 aircraft. The data were obtained from 24 inspectors who inspected 468 coupons, containing a subset of coupons with 45 electric discharge machined notches and 72 laboratory grown fatigue cracks located at the inner surface corner of the bi-layer structures. A comparison of physical features of cracks and notches in light of skin depth effects and probe geometry was used to identify length rather than depth as the significant variable producing signal variation. Probability of detection based on length produced similar results for the two discontinuity types, except at lengths less than 0.4 mm, where POD for cracks was found to be higher than that of notches.

  8. Rock mass movements around development workings in various density of standing-and-roof-bolting support

    Institute of Scientific and Technical Information of China (English)

    MAJCHERCZYK Tadeusz; MALKOWSKLI Piotr; NIEDBALSKI Zbighiew

    2008-01-01

    Presented measurement results of roof rocks and wall rock movements of un-derground development workings after their drifting. The research was carried out in thecoal mine workings with standing-and-roof bolting support. There were various density ofthe support, so the aim of the special monitoring programme was to determine movementintensity of rock mass in the premises of the heading area. There were four types of re-search did by the authors. They measured convergence, roof layers separation using tell-tales and sonic probes and load bearing of the headings' roofs by hydraulic dynamometers.Evaluation of fracture zone around the heading and investigation the load zone caused byfailed roof rocks may become a basement for the determination of support parameters ofthe workings. The combined system of standing support and roof bolting seems to be anessential for underground headings protection.

  9. Mathematical Model of Load Pass and Prediction of Fatigue Life on Bolt Threads with Reduced Lead

    Science.gov (United States)

    Asayama, Yukiteru

    A mathematical model is proposed in order to elucidate the mechanism that the fatigue strength of external threads increases by reducing the lead on a thread system such as a bolt and nut. The model is constructed from the concept that a local strain proportional to the reducing degree of the lead, although the local strain is at first produced in the bolt thread farthest from the bearing surface of the nut, is induced in each thread root with an increase of applied load. The fatigue life predicted from the mathematical model shows good agreement with the experimental fatigue life of cadmium-plated external threads with the reduced lead on the material having strength as high as 1270MPa. The model can provide useful suggestions for the design of fasteners for aerospace, which are required to satisfy severe requirements of fatigue strengths and dimensions.

  10. Thermal Performance Evaluation of Friction Stir Welded and Bolted Cold Plates with Al/Cu Interface

    Science.gov (United States)

    Lakshminarayanan, A. K.; Suresh, M.; Sibi Varshan, M.

    2015-05-01

    An attempt is made to design and fabricate a cold plate with aluminum-copper dissimilar interface joined by friction stir welding. Optimum welding conditions for obtaining sound-quality corner and T joints with an aluminum-copper interface were established. Welded cross sections of the friction stir welded cold plate were analyzed to understand the bonding characteristics. Computational fluid dynamics (CFD) was used to evaluate the fluid-flow characteristics and thermal resistance of friction stir welded cold plate and the resulted are compared with the conventional bolted cold plate configuration. For CFD modeling of a cold plate with a dissimilar interface, a new methodology is proposed. From the CFD analysis and experimental results, it is observed that friction stir welded cold plate offered better thermal performance compared to the bolted cold plate and it is due to the metallurgical bonding at the aluminum-copper interface with the dispersion of copper particles.

  11. Contact Stress Analysis around Elliptical Bolt-loaded Hole in Orthotropic Plates

    Directory of Open Access Journals (Sweden)

    O. Aluko

    2012-12-01

    Full Text Available The practicality of changing the bolt shape from circular to elliptical under friction effects in order to reduce the contact stress distributions was analytically investigated. The analysis utilized the complex stress functions obtained from the assumed displacement expressions that satisfy the boundary conditions around the hole to determine the contact stresses. In the method of solution coulomb friction was used to determine the prescribed displacements at the boundary. The material properties of graphite/epoxy and carbon fiber reinforced plastics laminates were used in this investigation and the results compared with available literature. It was revealed that the stress distributions followed the same pattern in both geometries but with lower magnitude in elliptical shape and the reduction in stress distributions caused by changing the bolt shape from circular to elliptic depend on friction coefficient.

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

    Science.gov (United States)

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

    2013-09-01

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

  13. Bolted Joints in Composite Structures: Design, Analysis and Verification. Task II. Test Results--Multifastener Joints

    Science.gov (United States)

    1985-08-01

    Aeronautical Labs., Attn: FIBRA , Wright- Patterson AFB, OH 45433. WRDC/ASD ltr dtd 17 Oct 1990 FTrtf Kf( cry AFWAL-TR-85-3065 BOLTED JOINTS IN...removed from our mailing list, or if the addressee is no longer employed by your organization please noti fy list". AFWAL/ FIBRA , W-PAFB, OH 45433 to...test and evaluation; Aug 1985; other requests must be referred to AFWAL/ FIBRA . WPAFB. OH 45433 4. PERFORMING ORGANIZATION REPORT NUMBER(S

  14. Experimental Study on Mechanical Characteristics of Cracked Rock Mass Reinforced by Bolting and Grouting

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The stress hardening characteristics of the reinforced rock mass in uniaxial compression tests were revealed by means of the experimental study on mechanical characteristics of cracked rock mass reinforced by bolting and grouting. And the load-bearing mechanism of the reinforced rock mass was perfectly reflected by the experiment. The results can offer some useful advice for support design and stability analysis of deep drifts in unstable strata.

  15. FFTF report: drilled-in expansion bolts under static and alternating load

    Energy Technology Data Exchange (ETDEWEB)

    Tsang, H.S.

    1976-10-01

    The objective of this investigation was to establish the allowable design loads (tension, shear, and combined load) for expansion bolts to be installed in regular 4000 psi mix concrete, Magnetite 5000 psi mix concrete, and Steel Shot 5000 psi mix concrete at the Fast Flux Test Facility. The test loads included Static Loads and Alternating Loads which simulate the dynamic loads of vibratory equipment and dynamic earthquake loads.

  16. Bolt-grouting combined support technology in deep soft rock roadway

    Institute of Scientific and Technical Information of China (English)

    Chen Yanlong; Meng Qingbin; Xu Guang; Wu Haoshuai; Zhang Guimin

    2016-01-01

    Analyzing the mineral composition, mechanical properties and ground stress testing in surrounding rock, the study investigated the failure mechanism of deep soft rock roadway with high stress. The bolt-grouting combined support system was proposed to prevent such failures. By means of FLAC3D numer-ical simulation and similar material simulation, the feasibility of the support design and the effectiveness of support parameters were discussed. According to the monitoring the surface and deep displacement in surrounding rock as well as bolt axial load, this paper analyzed the deformation of surrounding rock and the stress condition of the support structure. The monitor results were used to optimize the proposed support scheme. The results of field monitors demonstrate that the bolt-grouting combined support tech-nology could improve the surround rock strength and bearing capacity of support structure, which con-trolled the great deformation failure and rheological property effectively in deep soft rock roadway with high stress. As a result, the long term stability and safety are guaranteed.

  17. Preload Analysis of Screw Bolt Joints on the First Wall Graphite Tiles in EAST

    Institute of Scientific and Technical Information of China (English)

    曹磊; 宋云涛

    2012-01-01

    The first wall in the Experimental Advanced Superconducting Tokamak (EAST) used graphite tiles to withstand high thermal energy. The graphite tiles are mounted on the heat sink using screw bolts which have been preloaded to produce a clamp force. The clamp force is very important to keep the graphite tiles tightly on the surface of the heat sink so that the heat flux crosses this contacting surface in a small thermal resistor. Without the clamp force, the small gap between the graphite tiles and the heat sink will make it impossible for thermal power to be carried away by cooling water. Some bolts may even fall off with the loss of clamp force. From the mathematical models, the loss process of the clamp force has been studied. Research results explain how the different thermal expansions of three members of the screw joint makes the clamp force decrease to zero under temperature rise and external force, and how the stiffness affects the relation between the clamp force and temperature. The research also gives the critical temperature at which the clamp force can remain above zero. Analysis results indicate that the current screw joints are almost destined to lose their clamp force during the running time of EAST, so the bolt joints should be redesigned in order to improve its reliability.

  18. Roof strata horizontal movement assessed by instrumented bolts monitoring and FEM modelling

    Energy Technology Data Exchange (ETDEWEB)

    Pytel, W. [CBPM ' ' Cuprum' ' OBR (Poland)

    2004-07-01

    Results of investigation concerning in-situ assessment of roof strata 3-d movement in the vicinity of a selected hard rock yielding pillar are presented in the paper. Based on laboratory calibration tests it was possible to establish the analytical relationships between the load (or stress) increment within the bolt rod, and the extensometer read-out box increment for all pairs of extensometers, glued-in at five measurement horizons. These relationships were a base for the assessment of rod axial forces and bending moments in time domain. The finite difference method technique was used for bolt rod deflection (lateral) assessment based on the elastic beam (rod) deflection differential equation solution involving the values of in-situ measurement based bending moments. In-situ obtained measurement data were supplemented with numerical experiments performed in a large geometric scale. The numerical models based on the 3-d finite element method, represented the roof bolting-pillar-floor systems in the in-situ measurement sites conditions.

  19. Characterization of tensile and shear loading on indented PC-strand cable bolts

    Institute of Scientific and Technical Information of China (English)

    Tadolini Stephen C.; ⇑; Derycke Steven; Bhagwat Anand

    2016-01-01

    The tensile and shear strength of intrinsic bolting support systems has always been a major concern of designers. A comprehensive laboratory testing program was designed to evaluate the tensile and shear strength of individual wires and completely wound PC-strand cables. PC-strand cables with smooth wires and the recent anchorage enhancement innovation of indentation were evaluated and compared. The testing protocol detailed in ISO Standard 15630 utilizes a mandrel system that was investigated at 3 different diameters which alters the wire to mandrel ratio from 2:1 to 9:1. The results demonstrate that the difference between smooth and indented wires is statistically insignificant when larger diameter mandrels are used, and that indentation does not adversely affect strand properties and performance. Insight into the shearing mechanism and evaluation techniques are discussed with the introduction of triaxial loading to describe the PC-strand tensile and shearing mechanisms. Another important result indicates that the shear strength of PC-strand cable bolting systems has a greater shear strength value than traditional steel bar bolting systems.

  20. Developing a highly reliable cae analysis model of the mechanisms that cause bolt loosening in automobiles

    Directory of Open Access Journals (Sweden)

    Ken Hashimoto

    2014-10-01

    Full Text Available In this study, we developed a highly reliable CAE analysis model of the mechanisms that cause loosening of bolt fasteners, which has been a bottleneck in automobile development and design, using a technical element model for highly accurate CAE that we had previously developed, and verified its validity. Specifically, drawing on knowledge gained from our clarification of the mechanisms that cause loosening of bolt fasteners using actual machine tests, we conducted an accelerated bench test consisting of a threedimensional vibration load test of the loosening of bolt fasteners used in mounts and rear suspension arms, where interviews with personnel at an automaker indicated loosening was most pronounced, and reproduced actual machine tests with CAE analysis based on a technical element model for highly accurate CAE analysis. Based on these results, we were able to reproduce dynamic behavior in which larger screw pitches (lead angles lead to greater non-uniformity of surface pressure, particularly around the nut seating surface, causing loosening to occur in areas with the lowest surface pressure. Furthermore, we implemented highly accurate CAE analysis with no error (gap compared to actual machine tests.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    -up was 21.4±14.6 (mean±SDM) months, 64% of patients suffered from diabetes with a preoperative Hba1c of 8.5±2.4. The mean number of revisions per foot was 3.6±4.1. Bolt dislocation was seen in 57% of the patients following 11.3±8.5 months; in 75% of these patients bony healing occurred before dislocation......In Charcot's osteoarthropathy stabilization of the medial column of the foot was introduced in order to establish a stable foot and reduce the risk for amputation. This study was performed to analyze postoperative complications, define risk factors for those and develop strategies for prevention....... Since bolt dislocation takes place frequently, it was aimed to predict an appropriate time point for bolt removal under the condition that osseous healing has occurred. Fourteen consecutive patients with neuroosteoarthropathy of the foot and arch collapse were treated with open reduction...

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

    Science.gov (United States)

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

    2017-01-27

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

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

    Directory of Open Access Journals (Sweden)

    Yong Cao

    2017-01-01

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

  5. Identification of Flowering-Related Genes Responsible for Differences in Bolting Time between Two Radish Inbred Lines

    Science.gov (United States)

    Jung, Won Yong; Park, Hyun Ji; Lee, Areum; Lee, Sang Sook; Kim, Youn-Sung; Cho, Hye Sun

    2016-01-01

    Late bolting after cold exposure is an economically important characteristic of radish (Raphanus sativus L.), an important Brassicaceae root vegetable crop. However, little information is available regarding the genes and pathways that govern flowering time in this species. We performed high-throughput RNA sequencing analysis to elucidate the molecular mechanisms that determine the differences in flowering times between two radish lines, NH-JS1 (late bolting) and NH-JS2 (early bolting). In total, 71,188 unigenes were identified by reference-guided assembly, of which 309, 788, and 980 genes were differentially expressed between the two inbred lines after 0, 15, and 35 days of vernalization, respectively. Among these genes, 218 homologs of Arabidopsis flowering-time (Ft) genes were identified in the radish, and 49 of these genes were differentially expressed between the two radish lines in the presence or absence of vernalization treatment. Most of the Ft genes up-regulated in NH-JS1 vs. NH-JS2 were repressors of flowering, such as RsFLC, consistent with the late-bolting phenotype of NH-JS1. Although, the functions of genes down-regulated in NH-JS1 were less consistent with late-bolting characteristics than the up-regulated Ft genes, several Ft enhancer genes, including RsSOC1, a key floral integrator, showed an appropriate expression to the late-bolting phenotype. In addition, the patterns of gene expression related to the vernalization pathway closely corresponded with the different bolting times of the two inbred lines. These results suggest that the vernalization pathway is conserved between radish and Arabidopsis. PMID:28018383

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

    Directory of Open Access Journals (Sweden)

    Hye Sun Cho

    2016-12-01

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

  7. Planned complex suicide by penetrating captive-bolt gunshot and hanging: case study and review of the literature.

    Science.gov (United States)

    Viel, Guido; Schröder, Ann Sophie; Püschel, Klaus; Braun, Christian

    2009-05-30

    Captive-bolt guns or slaughterer's guns are devices widely used in meat industry and private farmer households for slaughtering animal stocks. They consist of a simple cylindrical metal tube (barrel) with a metal bolt placed in their centre (around 9-15cm long and 1-1.5cm wide). The bolt is actuated by a trigger pull and is propelled forward by compressed air or by the discharge of a blank powder gun cartridge. Violent deaths inflicted by captive-bolt guns are rarely encountered in forensic practice and are predominantly suicidal events. We report an unusual complex suicide by hanging and self-shooting with a slaughterer's gun in a 21-year-old boy. The victim after putting a ceiling fixed rope around his neck shot himself in the head (occipital region) with a Kerner captive-bolt gun. He used two mirrors (a cosmetic mirror and a man-sized one) in order to properly visualize his back and to target the occipital region of his head. Radiological data (computed tomography with three dimensional reconstruction) and autopsy findings are discussed according to the clinical and forensic literature. A brief review on planned complex suicides is also given.

  8. The nuts and bolts of proofs an introduction to mathematical proofs

    CERN Document Server

    Cupillari, Antonella

    2005-01-01

    The Nuts and Bolts of Proof instructs students on the basic logic of mathematical proofs, showing how and why proofs of mathematical statements work. It provides them with techniques they can use to gain an inside view of the subject, reach other results, remember results more easily, or rederive them if the results are forgotten.A flow chart graphically demonstrates the basic steps in the construction of any proof and numerous examples illustrate the method and detail necessary to prove various kinds of theorems.* The "List of Symbols" has been extended.* Set Theory section has been strengthened with more examples and exercises.* Addition of "A Collection of Proofs"

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

    Institute of Scientific and Technical Information of China (English)

    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 ...

  10. Numerical and experimental analysis on load sharing & optimization of the joint parameters of polymer composite multi bolted joints

    Science.gov (United States)

    Latha Shankar, B.; Sudeep Kumar, T.; Shiva Shankar, G. S.

    2016-09-01

    In the present work, the bearing failure of composite bolted connections of composite laminates was analysed both experimentally and numerically. The glass fiber woven mat 600GSM/ epoxy composite laminates were prepared using wet-layup technique. The process parameters were taken care during preparation of laminates. Examination is done for various estimations of edge-to-hole diameter and width-to-hole diameter proportion. Stress is evaluated in laminates by utilizing Hart-Smith criteria. Ideal estimation of e/d proportion, d/w proportion is recommended for most extreme effectiveness. A numerical technique is utilized for the rough determination of a load shared by bolts in a numerous "bolted" joints loaded in tension were investigated experimentally and numerically. The effect of un-evenness in load shearing is suggested.

  11. Failure Mode Analysis of Aluminium Alloy 2024-T3 in Double-Lap Bolted Joints with Single and Double Fasteners; A Numerical and Experimental Study

    Directory of Open Access Journals (Sweden)

    Khosro Fallahnezhad

    2015-06-01

    Full Text Available This paper aims to study the mechanical behaviour and failure mode of Al 2024-T3 in double-lap bolted joints. To accomplish this, the effect of geometric parameters was investigated in both configurations of single and double fasteners. Using ABAQUS/Standard, a three-dimensional finite element model was developed and verified against the experimental results of the joints loaded in tension. In general, double bolt joints were found to have greater load carrying capacities than single bolt joints (by 40%–49%. In single bolt joints, the plate width had insignificant effect on the behaviour of the joint under tensile loading; whereas, increasing the distance of the hole from the edge, considerably enhanced the strength of the joint. In double bolt joints, changing the edge distance had almost no effect on the behaviour of the joint. However, increasing the plate width from 25.4 to 30 mm increased the load carrying capacity by 28%. This study showed that in single bolt connections, with increasing the edge distance, the failure mode can favourably shift from shear-out to bearing. Also, double bolt joints with wider plates (increased width can beneficially shift the failure mode from net-tension to bearing. The geometric parameters were found to play an important role in controlling the failure mode so that catastrophic failure modes of net-tension and shear-out can be prevented in bolted joint.

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

    Science.gov (United States)

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

    2017-02-23

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

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

    Science.gov (United States)

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

    2017-01-01

    Rock bolts, as a type of reinforcing element, are widely adopted in underground excavations and civil engineering structures. Given the importance of rock bolts, the research outlined in this paper attempts to develop a portable non-destructive evaluation method for assessing the length of installed rock bolts for inspection purposes. Traditionally, piezoelectric elements or hammer impacts were used to perform non-destructive evaluation of rock bolts. However, such methods suffered from many major issues, such as the weak energy generated and the requirement for permanent installation for piezoelectric elements, and the inconsistency of wave generation for hammer impact. In this paper, we proposed a portable device for the non-destructive evaluation of rock bolt conditions based on a giant magnetostrictive (GMS) actuator. The GMS actuator generates enough energy to ensure multiple reflections of the stress waves along the rock bolt and a lead zirconate titantate (PZT) sensor is used to detect the reflected waves. A new integrated procedure that involves correlation analysis, wavelet denoising, and Hilbert transform was proposed to process the multiple reflection signals to determine the length of an installed rock bolt. The experimental results from a lab test and field tests showed that, by analyzing the instant phase of the periodic reflections of the stress wave generated by the GMS transducer, the length of an embedded rock bolt can be accurately determined. PMID:28241503

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

    Directory of Open Access Journals (Sweden)

    Moyseychik Evgeniy Alekseevich

    2014-12-01

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

  15. Mechanism and technology study of collaborative support with long and short bolts in large-deformation roadways

    Institute of Scientific and Technical Information of China (English)

    Yu Hui⇑; Niu Zhiyong; Kong Linggen; Hao Caicheng; Cao Peng

    2015-01-01

    Common short bolts of equal length are widely used to support the roofs of roadways in coal mines. However, they are insufficient to keep the roof stable against large deformations, so docking long bolts with high levels of elongation that can adapt to large deformations of the surrounding rock have been adopted. This paper proposes a collaborative support method that uses long and short bolts. In this study, the mechanism of docking long bolts and collaborative support was studied. Numerical simulation, sim-ilarity simulation, and field testing were used to analyze the distribution law of the displacement, stress, and plastic failure in the surrounding rock under different support schemes. Compared with the equal-length short bolt support, the collaborative support changed the maximum principal stress of the shallow roof from tensile stress to compressive stress, and the minimum principal stress of the roof significantly increased. The stress concentration degree of the anchorage zone clearly increased. The deformation of the roof and the two sides was greatly reduced, and the subsidence shape of the shallow roof changed from serrated to a smooth curve. The roof integrity was enhanced, and the roof moved down as a whole. Plastic failure significantly decreased, and the plastic zone of the roof was within the anchorage range. The similarity simulation results showed that, under the maximum mining stress, the roof collapsed with the equal-length short bolt support but remained stable with the collaborative support. The collaborative support method was successfully applied in the field and clearly improved the stability of the surrounding rock for a large deformation roadway.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  17. STATISTICAL ENTROPIES OF THE TAUB-NUT/BOLT AdS SPACES FROM THE HORIZON CONFORMAL FIELD THEORY

    Institute of Scientific and Technical Information of China (English)

    JING JI-LIANG; ZHOU SAN-QING; HUANG YI-BIN

    2001-01-01

    The covariant phase technique is used to compute the constraint algebra of the four-dimensional space-times which are asymptotic to anti-de Sitter (AdS), such as the planar Taub-NUT AdS and Taub-bolt AdS spaces, and the hyperbolic Taub-bolt AdS space. The standard Virasoro subalgebrae with corresponding central charges for these objects are constructed and the resulting densities of states yield the expected Bekenstein-Hawking entropies.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Hun; Hwang, Sun Kwang [National Research Laboratory for Computer Aided Materials Processing, Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Im, Yong-Taek, E-mail: ytim@kaist.ac.kr [National Research Laboratory for Computer Aided Materials Processing, Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Son, Il-Heon; Bae, Chul Min [Wire Rod Research Group, Technical Research Laboratories, POSCO, 1 Goedong-dong, Nam-gu, Pohang, Gyeongbuk 790-785 (Korea, Republic of)

    2012-08-30

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

  19. A Detailed Analysis of the BR1 Locus Suggests a New Mechanism for Bolting after Winter in Sugar Beet (Beta vulgaris L.).

    Science.gov (United States)

    Tränkner, Conny; Lemnian, Ioana M; Emrani, Nazgol; Pfeiffer, Nina; Tiwari, Surya P; Kopisch-Obuch, Friedrich J; Vogt, Sebastian H; Müller, Andreas E; Schilhabel, Markus; Jung, Christian; Grosse, Ivo

    2016-01-01

    Sugar beet (Beta vulgaris ssp. vulgaris) is a biennial, sucrose-storing plant, which is mainly cultivated as a spring crop and harvested in the vegetative stage before winter. For increasing beet yield, over-winter cultivation would be advantageous. However, bolting is induced after winter and drastically reduces yield. Thus, post-winter bolting control is essential for winter beet cultivation. To identify genetic factors controlling bolting after winter, a F2 population was previously developed by crossing the sugar beet accessions BETA 1773 with reduced bolting tendency and 93161P with complete bolting after winter. For a mapping-by-sequencing analysis, pools of 26 bolting-resistant and 297 bolting F2 plants were used. Thereby, a single continuous homozygous region of 103 kb was co-localized to the previously published BR1 QTL for post-winter bolting resistance (Pfeiffer et al., 2014). The BR1 locus was narrowed down to 11 candidate genes from which a homolog of the Arabidopsis CLEAVAGE AND POLYADENYLATION SPECIFICITY FACTOR 73-I (CPSF73-I) was identified as the most promising candidate. A 2 bp deletion within the BETA 1773 allele of BvCPSF73-Ia results in a truncated protein. However, the null allele of BvCPSF73-Ia might partially be compensated by a second BvCPSF73-Ib gene. This gene is located 954 bp upstream of BvCPSF73-Ia and could be responsible for the incomplete penetrance of the post-winter bolting resistance allele of BETA 1773. This result is an important milestone for breeding winter beets with complete bolting resistance after winter.

  20. The Extended Thermodynamic Properties of a topological Taub-NUT/Bolt-AdS spaces

    CERN Document Server

    Lee, Chong Oh

    2015-01-01

    We consider the extended thermodynamic quantities of higher dimensional topological Taub-NUT/Bolt-AdS black holes with a cosmological constant treated as a pressure and find their general form for arbitrary dimensions and the thermodynamics of these configurations is argued to some extent. In particular by introducing Gibbs free energy, it is found out to be a new thermodynamically stable region of these black holes. At an equilibrium condition we find an entropy of a NUT solution, volume, and latent heat are negative where the Clapeyron equation is satisfied for these thermodynamic quantities. These negative volume and entropy may be interpreted as that the environment applies work to the system in the process of the Taub-NUT-AdS black hole formation, and such negative latent heat may indicate a net release of latent energy back into the environment because of evaporating of the system. Intriguingly, we also find that like the AdS black hole case, Taub-Bolt-AdS black hole with two phases (phase of small and ...

  1. Entry roof truss-bolt system test under the gob of contiguous seams

    Institute of Scientific and Technical Information of China (English)

    LIAN Chuan-jie; XU Wei-ya; WANG Ya-jie

    2007-01-01

    Roof bolt support system has been widely applied in the No.7.9 seam in Caozhuang coal mine.However,it has not been able to be applied in the NO.10-2 seam since the small interburden(2m)between NO.9 and NO.10-2 seam.The NO.9 and NO.10-2 seams are contiguous seams.The NO.9 seam has been mined out and the NO.10-2 seam will be mined under the gob of the NO.9 seam.The roof strata of the NO.10-2 seam may have been weakened and fractured due to the shear failure caused by the NO.9 seam mining activities.The steel beam sets spaced at 0.8 m have been used to support the entry of the NO.10-2 seam.In order to speed up the advance rate and cut entry development cost,a test area,using roof bolt in conjunction with truss-system,was successfully conducted.This paper presents the support system design,application of designed system,and the test results.Test results provide a cheaper,quicker,and safer way to support entry for the No.10-2 seam.

  2. Professor Usain Bolt Welcomes You to the Schoolyard: Physics for Champions

    Science.gov (United States)

    Vourlias, Kostas; Seroglou, Fanny

    2016-01-01

    Could Usain Bolt achieve what teachers often fail to do? Could this famous Olympic winner challenge and motivate students to study mechanics and introduce them to the principles of physics in a fun way, outside of the classroom? In order to answer these questions, we "invited" for one semester the world record holder to visit our Greek high school in Thessaloniki as a guest teacher. For 13 weeks, 27 fifteen-year-olds run (or at least try to run) side by side with this great athlete, intending to learn his secrets. Within 9.58 s or 100 m, students have the chance to study a "phenomenon" of their daily lives and be introduced to a variety of concepts of physics in a pleasant and effective way. Students use simple athletic and innovative biomechanical equipment for their experiments, but mostly their own bodies, as experimental tools in order to study and to "feel" physics. Students have the chance to compare their athletic abilities to Bolt's and confront some of their ideas concerning concepts of physics.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

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

  4. Effect of parameters on local stress field in single-lap bolted joints with the interference fit

    Directory of Open Access Journals (Sweden)

    Jiefeng Jiang

    2016-05-01

    Full Text Available From the interference fit bolt installation to tensile loading stage in single-lap joint with a hi-lock bolt, the stress and strain fields were studied experimentally and numerically. A three-dimensional finite element model was generated to simulate the experimental setup, which was validated using the experimental data. The fatigue behavior of the bolted joint is influenced by the local stress fields on the faying surface near the holes in single-lap joints. Therefore, with the aim to improve design awareness, the effects of the parameters on the local stress fields were investigated by means of finite element simulation. With an increase in the interference fit size, the occurred position of the maximum stress values on the upper plate faying surface moves away from the hole edge gradually. As the clamping force or friction coefficient increases, the position of larger stress area is changed to the side of bearing load from the transverse direction. The lap geometry of the bolted joint as well as the amplitude of tensile load has apparent impact on the maximum stress value.

  5. Large Scale Finite Element Thermal Analysis of the Bolts of a French PWR Core Internal Baffle Structure

    Energy Technology Data Exchange (ETDEWEB)

    Rupp, Isabelle; Christophe, Peniguel [EDF R and D, Paris (France); Tommy, Martin Michel [1 av du General de Gaulle, Paris (France)

    2009-11-15

    The internal core baffle structure of a French Pressurized Water Reactor (PWR) consists of a collection of baffles and formers that are attached to the barrel. The connections are done thanks to a large number of bolts (about 1500). After inspection, some of the bolts have been found cracked. This has been attributed to the Irradiation Assisted Stress Corrosion Cracking (IASCC). The Electricite De France (EDF) has set up a research program to gain better knowledge of the temperature distribution, which may affect the bolts and the whole structure. The temperature distribution in the structure was calculated thanks to the thermal code SYRTHES that used a finite element approach. The heat transfer between the by-pass flow inside the cavities of the core baffle and the structure was accounted for thanks to a strong thermal coupling between the thermal code SYRTHES and the CFD code named Code{sub S}aturne. The results for the CP0 plant design show that both the high temperature and strong temperature gradients could potentially induce mechanical stresses. The CPY design, where each bolt is individually cooled, had led to a reduction of temperatures inside the structures. A new parallel version of SYRTHES, for calculations on very large meshes and based on MPI, has been developed. A demonstration test on the complete structure that has led to about 1.1 billion linear tetraedra has been calculated on 2048 processors of the EDF Blue Gene computer

  6. Inflatable rock bolt bond strength versus rock mass rating (RMR):A comparative analysis of pull-out testing data from underground mines in Nevada

    Institute of Scientific and Technical Information of China (English)

    Barnard Chase; Kallu Raj R.; Warren Sean; Thareja Rahul

    2016-01-01

    The purpose of this paper is to establish confidence in anticipated minimum bond strength for inflatable rock bolts by comparing the bond strength to variable geotechnical conditions using the rock mass rating (RMR) system. To investigate a correlation between these parameters, the minimum bond strength of pull-out tested inflatable rock bolts was compared to the RMR of the rock in which these bolts were placed. Bond strength vs. RMR plots indicate that expected minimum bond strength is positively corre-lated with RMR;however, the correlation is not strong. Cumulative percent graphs indicate that 97%of pull-out tests result in a minimum bond strength of 3.3 and 1.7 ton/m in RMR P 45 and<45, respectively. Although lower bond strengths are more commonly encountered in low RMR ground, high bond strengths are possible as well, yielding higher variability in bond strengths in low RMR ground. Bond strength of friction bolts relies on contact between the rock bolt and drill hole. Experience in Nevada indicates that RMR is known to affect both the quality and consistency of drill holes which likely affects bond strength. Drilling and bolting in low RMR ground is more sensitive to drilling and bolting practices, and strategies for maximizing bond strength in these conditions are discussed.

  7. BOLTS: a BiOphysical Larval Tracking System for Measuring Dispersal Characteristics and Marine Population Connectivity

    Science.gov (United States)

    Paris, C. B.; Srinivasan, A.; Kourafalou, V.; Sponaugle, S.; Cowen, R. K.

    2008-12-01

    While metapopulation research with hypothetical dispersal matrices has shown how the scales of larval dispersal, transport processes, local recruitment, and temporal and spatial variability in dispersal influence population persistence, the pattern of demographic connectivity produced by larval dispersal is still a key uncertainty. To address this problem, a coupled bio-physical model has been developed that quantifies the degree of connectivity between populations. Such spatially explicit models, forced by dynamic currents coupled to a realistic seascape and life history traits, produce dispersal kernels for a range of scales over which dispersal is practically unquantifiable by current empirical methods. The BiOphysical Larval Tracking System (BOLTS) presented here allows a Lagrangian stochastic individual-based model (IBM) to be coupled via OPENDAP framework to any 3-dimensional fields of circulation models including to domains of various resolutions through 'Lagrangian nesting'. We demonstrate the capabilities of the software in measuring the characteristics of dispersal and evaluating the variability of larval connectivity through two examples at different scales: 1) Caribbean-scale simulations of BOLTS using the large scale (resolution ~7 km) Hybrid Coordinate Ocean Model (HYCOM) from the Global Data Assimilative Experiment (GODAE) provide us with expected connectivity patterns of a reef building coral. By seeding the model with a large number of active particles, it is possible to assemble dispersal kernels and migration matrices from the start (spawning) and the end point (settlement) of individual particle trajectories. Any single run is a stochastic realization of a probabilistic process, thus the full probability density function (pdf) of the kernel requires averaging over many dispersal events. The model output is further corroborated with empirical measures of gene flow among coral colonies around the Caribbean. 2) Coastal-scale simulations of BOLTS

  8. Fracture failure analysis of driving bolts%驱动螺栓断裂失效分析

    Institute of Scientific and Technical Information of China (English)

    邓德伟; 张翠萍; 鲁俊

    2013-01-01

    Driving bolts made of 3Cr13 stainless steel was fractured during the service .Chemical composition , mechanical properties and microstructure of the failed bolt were analysed .The results show that the inappropriate heat treatment leads anormal microstructure to unquenched and untempered which result to the bolt failure .The microstructure is tempered martensites and undissolved carbides that lead to high microhardness .Additionally , globular nonmetallic inclusions and multidirectional cracks are also observed in the bolt and accelerated the failure when the bolt is suffered from a shock or a torsional load .%3 Cr13不锈钢驱动螺栓在服役一段时间后在螺纹处发生断裂,对其化学成分、力学性能、断口及显微组织进行观察和分析。结果表明,螺栓断裂主要是由于热处理工艺不当,导致螺栓最终服役状态并非调质态,显微组织为回火马氏体及未溶碳化物颗粒,螺栓整体硬度过高;另外,组织中存在链状及球状非金属夹杂物,螺纹部位也有多种取向的裂纹,因而螺栓在受到冲击或扭转载荷时,裂纹和非金属夹杂可能成为裂纹源,以致发生脆性断裂。

  9. Numerical study of rock bolting parameter variation effect on stability of stratified, composite roof structure of drift in a coal mine

    Institute of Scientific and Technical Information of China (English)

    LU Ting-kan; LIU Yu-zhou

    2005-01-01

    Described the outcomes of a comprehensive numerical modeling on the rock bolting performance for preventing the deformation of stratified, composite roof structure of drift in a coal mine. The investigation was undertaken in the adverse geological conditions, with variation of belt parameters, including length, density, distribution, pretension,as well as the geometry of opening, so as to determine the effect of bolting parameter variation on roof deformation and stability. The outcomes clearly demonstrated that a significant improvement of roof stability can be achieved associating with bolting parameters optimization, and indicated the importance of flexible geotechnical designation of rock mbolting reinforcement in mining practice.

  10. INFORMATION FOR USERS OF NUTS, BOLTS, SCREWS, NAILS AND RIVETS (SCEM GROUP 47)

    CERN Multimedia

    Logistics Group

    2002-01-01

    We should like to remind users that, since the closure of the self-service stores, nuts, bolts, screws, nails and rivets (Group 47 of the Stores Catalogue) can be obtained, in smaller packages than via EDH, from the 'Emergency Counter' in the Central Stores (Building 73, R-002) upon presentation of a duly completed hard-copy Materials Request form. The 'Emergency Counter' is open Mondays to Fridays from 7.30 a.m. to 11.50 a.m. and from 1.00 p.m. to 4.20 p.m. Information concerning the available packages can be found under the appropriate SCEM reference number in the Stores Catalogue. Logistics Group SPL Division

  11. 1300 MPa High Strength Steel for Bolt with Superior Delayed Fracture Resistance

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By the increase in Mo content, the addition of microalloying elements V and Nb and by reducing the contents of Mn, P and S based on the composition of steel 42CrMo, we have developed a 1300 MPa-grade high strength steel (ADF1) for bolts. The sustained load bending test, sustained load tensile test and stress corrosion cracking test have been carried out to evaluate the delayed fracture resistance of steel ADF1 and commercial steel 42CrMo. The results showed that steel ADF1 has superior delayed fracture resistance to that of 42CrMo steel. It's concluded that the superior delayed fracture resistance of ADF1 is mainly due to the increase of tempering temperature, fine homogeneously distributed MC carbide and fine prior austenite grain size.

  12. Thermal Shock Effects Modeling On A Globe Valve Body-Bonnet Bolted Flange Joint

    CERN Document Server

    Mathieu, Jean-Philippe; Ferrari, Jerome; Hersant, David

    2012-01-01

    This paper attends to show efforts made at EDF R&D to improve comprehension of valve parts loadings during operation. Thermal shock in a globe valve is represented and modeled using EDF R&D Finite Element Analysis code (Code_Aster). Choices of modeling are discussed and balanced on the basis of "what an engineer can obtain without becoming a researcher". First simulation results are presented. Attention is focused on the evolution of Body-Bonnet Bolted Flange Joint (BBBFJ) tightening forces which are simulated during the thermal shock. An experimental setup is also presented for the studied valve, which implies thermocouple implementation for comparison of the simulated thermal field and strain measurement on each threaded rod to validate the mechanical modeling.

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

    Directory of Open Access Journals (Sweden)

    Marian Blaško

    2014-12-01

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

  14. Crystalline capsules: metal-organic frameworks locked by size-matching ligand bolts.

    Science.gov (United States)

    Wang, Hao; Xu, Jian; Zhang, Da-Shuai; Chen, Qiang; Wen, Rong-Mei; Chang, Ze; Bu, Xian-He

    2015-05-11

    Metal-organic frameworks (MOFs) are shown to be good examples of a new class of crystalline porous materials for guest encapsulation. Since the encapsulation/release of guest molecules in MOF hosts is a reversible process in nature, how to prevent the leaching of guests from the open pores with minimal and nondestructive modifications of the structure is a critical issue. To address this issue, we herein propose a novel strategy of encapsulating guests by introducing size-matching organic ligands as bolts to lock the pores of the MOFs through deliberately anchoring onto the open metal sites in the pores. Our proposed strategy provides a mechanical way to prevent the leaching of guests and thereby has less dependence on the specific chemical environment of the hosts, thus making it applicable for a wide variety of existing MOFs once the size-matching ligands are employed.

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    This study represents an effort to predict the bearing strength, failure modes, and failure load of bolted joints in foam-core sandwich composites. The studied joints have been used in a light full composite airplane. By using solid laminates, a new design for the joint zone is developed....... These solid laminates include a number of glass plies with total thickness equal to core thickness. The effect of solid laminate size and interface angle of foam -solid laminate in the bonding zone on the bearing strength, failure loads and type of modes are investigated. The numerical study is performed...... using 3D FEM in ANSYS commercial code. Tsai-Wu failure criterion is used in the failure analysis. The results indicate that the most important parameter in the proposed joint zone design is the foam -solid laminate interface angle which plays an important role on the value of failure criterion (damage...

  16. Failure behavior for composite single-bolted joints in double shear tension

    Science.gov (United States)

    Tang, Zhanwen; Liu, Hanyang; Yang, Zhiyong; Shi, Hanqiao; Sun, Baogang

    2016-05-01

    In order to improve the reliability and load carrying capacity of composite laminates structures which were lap jointed by bolt, in this paper, the failure strength and failure mode of laminated composite pinned-joints is investigated. To determine the effects of joint geometry and stacking sequence on the bearing strength and damage mode, the multi-scale numerical model combining with the Generalized Method of Cells (GMC) and considering the failure and the damage of constituent materials was created based on the ABAQUS and its user subroutine (USDFLD). A three-dimensional finite element technique was used for the stress analysis. Based on the three-dimensional state of stress of each element, different failure modes were detected by the failure theories of constituent materials, all of which are applied at the fiber, matrix and fiber-matrix interface constituent level. Numerical simulations have been carried out by which edge distance-to-hole diameter ratio, and plate width-to-hole diameter ratio are varied, The composite laminated plates are stacked with the following four different orientations: [+45/-45]2s, [90/+45/-45]s, and [0/90/0]s, the results show that failure mode and bearing strength are closely related to by stacking sequence of plates and geometrical parameters. Finally, the ultimate strength and failure modes of composite bolted joints in static tension double-shear loading conditions are predicted by using the progressive damage method established and the effects of layup and dimension of laminates on the properties of the connection structure were researched in this paper. An excellent agreement is found between data obtained from this study and the experiment.

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

    Science.gov (United States)

    Chou, Ying-Chao; Yeh, Wen-Lin; Chao, Chien-Lin; Hsu, Yung-Heng; Yu, Yi-Hsun; Chen, Jan-Kan; Liu, Shih-Jung

    2016-01-01

    A composite biodegradable polymeric model was developed to enhance tendon graft healing. This model included a biodegradable polylactide (PLA) bolt as the bone anchor and a poly(D,L-lactide-co-glycolide) (PLGA) nanofibrous membrane embedded with collagen as a biomimic patch to promote tendon–bone interface integration. Degradation rate and compressive strength of the PLA bolt were measured after immersion in a buffer solution for 3 months. In vitro biochemical characteristics and the nanofibrous matrix were assessed using a water contact angle analyzer, pH meter, and tetrazolium reduction assay. In vivo efficacies of PLGA/collagen nanofibers and PLA bolts for tendon–bone healing were investigated on a rabbit bone tunnel model with histological and tendon pullout tests. The PLGA/collagen-blended nanofibrous membrane was a hydrophilic, stable, and biocompatible scaffold. The PLA bolt was durable for tendon–bone anchoring. Histology showed adequate biocompatibility of the PLA bolt on a medial cortex with progressive bone ingrowth and without tissue overreaction. PLGA nanofibers within the bone tunnel also decreased the tunnel enlargement phenomenon and enhanced tendon–bone integration. Composite polymers of the PLA bolt and PLGA/collagen nanofibrous membrane can effectively promote outcomes of tendon reconstruction in a rabbit model. The composite biodegradable polymeric system may be useful in humans for tendon reconstruction. PMID:27601901

  18. Identification of bolting-related microRNAs and their targets reveals complex miRNA-mediated flowering-time regulatory networks in radish (Raphanus sativus L.).

    Science.gov (United States)

    Nie, Shanshan; Xu, Liang; Wang, Yan; Huang, Danqiong; Muleke, Everlyne M; Sun, Xiaochuan; Wang, Ronghua; Xie, Yang; Gong, Yiqin; Liu, Liwang

    2015-09-15

    MicroRNAs (miRNAs) play vital regulatory roles in plant growth and development. The phase transition from vegetative growth to flowering is crucial in the life cycle of plants. To date, miRNA-mediated flowering regulatory networks remain largely unexplored in radish. In this study, two small RNA libraries from radish leaves at vegetative and reproductive stages were constructed and sequenced by Solexa sequencing. A total of 94 known miRNAs representing 21 conserved and 13 non-conserved miRNA families, and 44 potential novel miRNAs, were identified from the two libraries. In addition, 42 known and 17 novel miRNAs were significantly differentially expressed and identified as bolting-related miRNAs. RT-qPCR analysis revealed that some miRNAs exhibited tissue- or developmental stage-specific expression patterns. Moreover, 154 target transcripts were identified for 50 bolting-related miRNAs, which were predominately involved in plant development, signal transduction and transcriptional regulation. Based on the characterization of bolting-related miRNAs and their target genes, a putative schematic model of miRNA-mediated bolting and flowering regulatory network was proposed. These results could provide insights into bolting and flowering regulatory networks in radish, and facilitate dissecting the molecular mechanisms underlying bolting and flowering time regulation in vegetable crops.

  19. Fatigue Property of Open-Hole Steel Plates Influenced by Bolted Clamp-up and Hole Fabrication Methods

    Directory of Open Access Journals (Sweden)

    Zhi-Yu Wang

    2016-08-01

    Full Text Available Steel plates with open holes are commonly used in structural assemblies. The fatigue properties of such details are influenced by bolted clamp-up and hole fabrication methods. The fracture surface, stiffness degradation and fatigue life of test specimens are investigated in detail and compared with the contemporary test data. The analysis results show that the presence of draglines greatly influences the fatigue crack initiation at the open-hole cut by laser. The bolted clamp-up condition greatly enhances the stiffness and the fatigue life of the open-hole details. A discussion is also made from a comparison with the referred fatigue life of hole fabrication details, such as the influence of plate thickness and plasma cutting, drilling and oxy-fuel gas cutting, with the details studied herein. This work could enhance the understanding of the fatigue property and design of such details.

  20. History of rock bolts and the sprayed concrete lining method. Part II. Milestones up to the 1960s

    Energy Technology Data Exchange (ETDEWEB)

    Kovari, K. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    2004-07-01

    In this part, first the origin and development of rock anchors are described. Their history began with a patent application in 1913 in Germany. The breakthrough in application came, however, only in the 1940s from the American mining industry. The first application of systematic rock bolting in a tunnel was the diversion tunnel for the Keyhole Dam in the USA in 1950. The paper describes numerous examples of civil engineering work world-wide with early application of rock bolting. It is shown how the combined application of the new support elements - steel arch, sprayed concrete and anchors has lead to the sprayed concrete lining method in the 1950s. In concluding, it is demonstrated that the so called ''New Austrian Tunnelling Method'' (NATM), which has been propagated since 1963, is in many respects borrowed and has created much confusion amongst professional engineers by dint of its pseudo-scientific basis.

  1. What would be Usain Bolt's 100-meter sprint world record without Tyson Gay? Unintentional interpersonal synchronization between the two sprinters.

    Science.gov (United States)

    Varlet, Manuel; Richardson, Michael J

    2015-02-01

    Despite the desire of athletes to separate themselves from their competitors, to be faster or better, their performance is often influenced by those they are competing with. Here we show that the unintentional or spontaneous interpersonal synchronization of athletes' movements may partially account for such performance modifications. We examined the 100-m final of Usain Bolt in the 12th IAAF World Championship in Athletics (Berlin, 2009) in which he broke the world record, and demonstrate that Usain Bolt and Tyson Gay who ran side-by-side throughout the race spontaneously and intermittently synchronized their steps. This finding demonstrates that even the most optimized individual motor skills can be modulated by the simple presence of another individual via interpersonal coordination processes. It extends previous research by showing that the hard constraints of individual motor performance do not overwhelm the occurrence of spontaneous interpersonal synchronization and open promising new research directions for better understanding and improving athletic performance.

  2. 飞轮连接螺栓可靠性提升研究%Reliability Improvement Of Flywheel Connecting Bolt

    Institute of Scientific and Technical Information of China (English)

    栗明; 胡伟; 李广; 赵建永

    2016-01-01

    The flywheel and crankshaft is connected with the bolt of the flywheel,As flywheel connecting boltsis an important part of the transmission torque.If there is a problem of the flywheel connecting bolt fracture,is a great harm,it will cause the crank and the connecting parts to be declared worthless,cause serious economic losses. In order to ensure the reliability of the bolt connection,the following file will through the working condition、the influence of the EVB、driver’s driving habits、clutch matching specification、the bolts design to put forward corrective and preventive measures.%飞轮与曲轴采用飞轮连接螺栓进行联接,由于飞轮连接螺栓是传递力矩的重要部件,如果出现飞轮连接螺栓断裂的问题,危害性极大,会导致曲轴和曲轴连接件报废,造成严重的经济损失;为了确保螺栓联接的可靠性,文章从使用的工况、 EVB排气制动使用对发动机影响情况、用户驾驶习惯、离合器匹配规范、曲轴飞轮连接螺栓设计等方面提出整改预防措施。

  3. Richard H. Bolt introduced me to acoustics, and I am still engaged

    Science.gov (United States)

    Dyer, Ira

    2003-04-01

    I arrived at the MIT Acoustics Laboratory in 1948, and quickly learned from Dick Bolt that U.S. submarines needed coatings to reduce vulnerability via active sonar detection. All who remember Dick will be familiar with his next step: He brought me to Robert Blizzard and A. Wilson Nolle, both then at the Lab, from whom I learned in detail how to measure and then how to understand the dynamic moduli of rubber-like materials. My path, of course, widened to include medical acoustics (under the leadership of Theodore Hueter) and scattering (Phillip Morse and Uno Ingard). Fast-forward to the present. Rubber-like materials are not only in use as submarine coatings to avoid detection by active sonars, but also to reduce noise radiated by submarines. Further, such materials cover submarine acoustic arrays to reduce flow-noise interference with signals received by such arrays. The problem that most engages me today is the stochastic nature of sound propagation in the ocean, a problem that has the practical consequence of degraded sonar performance. In the spirit of Dick, I will present snippets of my current work, with the hope of painting the big picture that he always did so well.

  4. CFD Simulations of the IHF Arc-Jet Flow: Compression-Pad/Separation Bolt Wedge Tests

    Science.gov (United States)

    Gokcen, Tahir; Skokova, Kristina A.

    2017-01-01

    This paper reports computational analyses in support of two wedge tests in a high enthalpy arc-jet facility at NASA Ames Research Center. These tests were conducted using two different wedge models, each placed in a free jet downstream of a corresponding different conical nozzle in the Ames 60-MW Interaction Heating Facility. Panel test articles included a metallic separation bolt imbedded in the compression-pad and heat shield materials, resulting in a circular protuberance over a flat plate. As part of the test calibration runs, surface pressure and heat flux measurements on water-cooled calibration plates integrated with the wedge models were also obtained. Surface heating distributions on the test articles as well as arc-jet test environment parameters for each test configuration are obtained through computational fluid dynamics simulations, consistent with the facility and calibration measurements. The present analysis comprises simulations of the non-equilibrium flow field in the facility nozzle, test box, and flow field over test articles, and comparisons with the measured calibration data.

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

    Roettgen, Daniel R.; Allen, Matthew S.

    2017-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Chou YC

    2016-08-01

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

  8. Failure Analysis on Fracture of Worm-gear Connecting Bolts%蜗轮连接螺栓断裂失效分析

    Institute of Scientific and Technical Information of China (English)

    王荣; 李玲

    2012-01-01

    装卸料机上的蜗轮连接螺栓材料为35钢,强度等级为10.9级,在设备运行大约10a后发生断裂。对断裂螺栓进行宏观、化学成分、硬度、金相、能谱和断口分析后得出,该螺栓的断裂性质为双向弯曲疲劳断裂,螺栓表面的脱碳和螺纹颈部的应力集中降低了该部位的疲劳性能。通过综合分析和螺栓受力估算后得出,螺栓断裂的主要原因是螺栓和内齿轮螺栓孔之间存在较大的间隙,使螺栓的受力状态和受力大小过早地发生了变化,造成连接螺栓疲劳断裂。%The worm-gear connecting bolts of refueling machines of a nuclear power plant,with material of 35 steel and strength grade of 10.9,fractured after the device running for about a decade,and means such as macro examination,chemical compositions analysis,hardness test,metallographic examination,fracture SEM analysis and so on,were used to analyze the fractured bolts.The results show that the fracture property of the bolts is two-way bending fatigue fracture.Surface decarburization of the bolts and stress concentration at the bolt thread neck decreased the fatigue strength,which resulted fatigue cracks formed here.By comprehensive analysis and force estimating,it was concluded that the main reason for the fracture is that there is a big gap between the bolt shank parts and their matching internal gear bolt holes,which made the force state and force size of the bolts changed early and finally resulted in fatigue fracture of the worm-gear connecting bolts.

  9. Design on the Transporting and Bolting Machine with Hopper and Two Arms%料斗式两臂运锚机的研制

    Institute of Scientific and Technical Information of China (English)

    马昭

    2014-01-01

    The transporting and bolting machine with hopper and two arms is a kind of equipment which is researched according to parallel working of the excavating and bolting integration on fully mechanized winning faces. It has the function of bolt supporting, materials transporting and self-driving. Its main structure, operation principle and service condition are introduced. It realizes reasonably connect of excavating, bolting and transporting work. The excavating and bolting efficiency is improved.%料斗式两臂运锚机是基于井下综掘工作面掘锚平行作业而研制的一种可进行锚杆支护和物料转运的具有自行走功能的运锚装备,本文详细介绍了该机的主要结构组成、工作原理以及使用情况,可实现掘锚运作业的合理衔接,提高了成巷效率。

  10. Calculation of bolted flange connections of metal to metal contact type. Results of MPA/VGB-project SA ''AT'' 19/08

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, G. [EnBW Kernkraftwerk GmbH, Neckarwestheim (Germany); Bieselt, R. [RWE Power AG, Essen (Germany); Klucke, D. [E.ON Kernkraft GmbH, Hannover (Germany); Schuemann, D. [Vattenfall Europe, Nuclear Energy GmbH, Hamburg (Germany); Kurz, H.; Kockelmann, H. [Stuttgart Univ. (Germany). MPA

    2010-07-01

    Subject of a research project carried out at Material Testing Institute (MPA) University of Stuttgart was the investigation of bolted flange connections (DN100 PN100 and PN160) of metal-to-metal contact type. In a special test rig external loadings (axial forces, bending and torsional moments as well as shearing forces) can be applied in addition to the internal pressure. Further on an analytical approach was developed for the determination of the loading in different cross sections of the flanges and for the tightness proof by means of the gap between the flanges at the position of the gasket. On the basis of a comparison of the experimental results and those of numerical calculations with results according to the new developed analytical approach the latter can be regarded as validated as far as investigated. In the nuclear code KTA 3211.2 (draft 2003) [1] the flange rotation at metal-to-metal contact (MMC) is restricted globally to 0.1 . This limitation does not comply with a lot of bolted flange connections in service although the strength and tightness criteria are met. This problem is now resolved with the new developed analytical approach which takes also into consideration the non-negligible influence of the assembly bolt load exceeding the minimum required bolt load for metal-to-metal contact. In a following project for defined boundary conditions the basis for the strength and tightness proof for bolted flange connections (MMC type) without explicit calculation shall be created. (orig.)

  11. Quantitative evaluation of residual torque of a loose bolt based on wave energy dissipation and vibro-acoustic modulation: A comparative study

    Science.gov (United States)

    Zhang, Zhen; Liu, Menglong; Su, Zhongqing; Xiao, Yi

    2016-11-01

    A wave energy dissipation (WED)-based linear acoustic approach and a vibro-acoustic modulation (VM)-based nonlinear method were developed comparatively, for detecting bolt loosening in bolted joints and subsequently evaluating the residual torque of the loose bolt. For WED-based, an analytical model residing on the Hertzian contact theory was established, whereby WED was linked to the residual torque of a loose bolt, contributing to a linear index. For VM-based, contact acoustic nonlinearity (CAN) engendered at the joining interface, when a pumping vibration perturbs a probing wave, was interrogated, and the nonlinear contact stiffness was described in terms of a Taylor series, on which basis a nonlinear index was constructed to associate spectral features with the residual torque. Based respectively on a linear and a nonlinear premise, the two indices were validated experimentally, and the results well coincided with theoretical predication. Quantitative comparison of the two indices surmises that the VM-based nonlinear method outperforms the WED-based linear approach in terms of sensitivity and accuracy, and particularly when the bolt loosening is in its embryo stage. In addition, the detectability of the nonlinear index is not restricted by the type of the joint, against a high dependence of its linear counterpart on the joint type.

  12. 深水法兰连接机具螺栓预紧方法及装置研究%Research on Method of Bolt Tightening and Bolt Tightening Equipment of the Deep Water Flange Connection Tool

    Institute of Scientific and Technical Information of China (English)

    李伟; 王芳; 田玉江; 王上原; 王亚伟

    2012-01-01

    随着陆地和浅水油气资源的日益枯竭,急须开发深水油气资源以满足国民经济发展对能源的需求.法兰螺栓连接是深水管道连接的常用方法,也是深水管道回接必须攻克的难点.深水法兰连接机具是应用于深水管道法兰连接的一种专用设备,确定深水法兰连接机具的螺栓预紧方法对开发设计深水法兰连接机具具有重要意义,通过对比几种常用的螺栓预紧方法,确定了适用于深水的螺栓预紧方法,并设计了一种深水工作的螺栓预紧装置.该研究成果对机具的进一步开发,促进我国深水作业设备发展和提高我国深水管道连接技术具有一定意义.%Along with the wearing out of petroleum resource, petroleum resource of deep water must be exploited to improve nation economy development. The one of the methods of the deep water pipeline connection is the flange connection, but it is a difficult problem must be conquered. The deep water pipeline flange connection tool is a kind of special equipment to connect the deep water pipeline, to determine the method of the bolt tightening is important for developing the deep water pipeline flange connection tool. Through comparing the some methods of the bolt tightening, a method of the deep water bolt tightening is determined, and a set of the bolt tightening equipment is designed. The method and the equipment could promote the development of the deep sea technology and improve deep sea pipe flange connecting technology.

  13. An Application of Bolt Connect Process in Foundation Embedded Bolts and Its Repair%螺套连接工艺在预埋基础螺栓及其修复上的应用

    Institute of Scientific and Technical Information of China (English)

    周四林; 王东升

    2014-01-01

    对港口散杂货码头中锈蚀腐烂的基础预埋螺栓常规更换工艺进行了分析,揭示了其中存在的问题,通过创新更换工艺,较好地解决了上述问题。%The conventional replacement process for the seriously rusted foundation embedded bolts in bulk and general cargo terminal in the port is analyzed and so the existing problem is found out. Then the problem is solved better by innovating the replacement process.

  14. Development of an FPGA-based multipoint laser pyroshock measurement system for explosive bolts

    Science.gov (United States)

    Abbas, Syed Haider; Jang, Jae-Kyeong; Lee, Jung-Ryul; Kim, Zaeill

    2016-07-01

    Pyroshock can cause failure to the objective of an aerospace structure by damaging its sensitive electronic equipment, which is responsible for performing decisive operations. A pyroshock is the high intensity shock wave that is generated when a pyrotechnic device is explosively triggered to separate, release, or activate structural subsystems of an aerospace architecture. Pyroshock measurement plays an important role in experimental simulations to understand the characteristics of pyroshock on the host structure. This paper presents a technology to measure a pyroshock wave at multiple points using laser Doppler vibrometers (LDVs). These LDVs detect the pyroshock wave generated due to an explosive-based pyrotechnical event. Field programmable gate array (FPGA) based data acquisition is used in the study to acquire pyroshock signals simultaneously from multiple channels. This paper describes the complete system design for multipoint pyroshock measurement. The firmware architecture for the implementation of multichannel data acquisition on an FPGA-based development board is also discussed. An experiment using explosive bolts was configured to test the reliability of the system. Pyroshock was generated using explosive excitation on a 22-mm-thick steel plate. Three LDVs were deployed to capture the pyroshock wave at different points. The pyroshocks captured were displayed as acceleration plots. The results showed that our system effectively captured the pyroshock wave with a peak-to-peak magnitude of 303 741 g. The contribution of this paper is a specialized architecture of firmware design programmed in FPGA for data acquisition of large amount of multichannel pyroshock data. The advantages of the developed system are the near-field, multipoint, non-contact, and remote measurement of a pyroshock wave, which is dangerous and expensive to produce in aerospace pyrotechnic tests.

  15. Development of an FPGA-based multipoint laser pyroshock measurement system for explosive bolts.

    Science.gov (United States)

    Abbas, Syed Haider; Jang, Jae-Kyeong; Lee, Jung-Ryul; Kim, Zaeill

    2016-07-01

    Pyroshock can cause failure to the objective of an aerospace structure by damaging its sensitive electronic equipment, which is responsible for performing decisive operations. A pyroshock is the high intensity shock wave that is generated when a pyrotechnic device is explosively triggered to separate, release, or activate structural subsystems of an aerospace architecture. Pyroshock measurement plays an important role in experimental simulations to understand the characteristics of pyroshock on the host structure. This paper presents a technology to measure a pyroshock wave at multiple points using laser Doppler vibrometers (LDVs). These LDVs detect the pyroshock wave generated due to an explosive-based pyrotechnical event. Field programmable gate array (FPGA) based data acquisition is used in the study to acquire pyroshock signals simultaneously from multiple channels. This paper describes the complete system design for multipoint pyroshock measurement. The firmware architecture for the implementation of multichannel data acquisition on an FPGA-based development board is also discussed. An experiment using explosive bolts was configured to test the reliability of the system. Pyroshock was generated using explosive excitation on a 22-mm-thick steel plate. Three LDVs were deployed to capture the pyroshock wave at different points. The pyroshocks captured were displayed as acceleration plots. The results showed that our system effectively captured the pyroshock wave with a peak-to-peak magnitude of 303 741 g. The contribution of this paper is a specialized architecture of firmware design programmed in FPGA for data acquisition of large amount of multichannel pyroshock data. The advantages of the developed system are the near-field, multipoint, non-contact, and remote measurement of a pyroshock wave, which is dangerous and expensive to produce in aerospace pyrotechnic tests.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Gui-xiao LA; Ping FANG; Yi-bo TENG; Ya-juan LI; Xian-yong LIN

    2009-01-01

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

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

    Science.gov (United States)

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

    2009-06-01

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

  19. Higher performance in rockbolting technology by use of immediate-bearing grouted bolts; Leistungssteigerung in der Ankertechnik durch Einsatz sofort tragender Injektionsanker

    Energy Technology Data Exchange (ETDEWEB)

    Richter, Archibald; Eigemann, Ernst A. [Minova CarboTech GmbH, Essen (Germany)

    2009-01-29

    Efficient support technology and in particular rockbolting systems are increasingly important under ever more difficult working conditions. Recognised worldwide as an efficient, innovative and highly automated mining company RAG relies on high-quality, economical support concepts for one of the most demanding coal deposits in the world. Two new methods for setting immediate-bearing bolts with the use of a highly reactive bolt resin and prospects of replacement of wire mesh by a shotsscreting system in roadway supports are described in this contribution. (orig.)

  20. Conventional drivage of gate roads with bolted supports. Indication of performance potential; Konventionelle Auffahrung von Floezstrecken mit Ankerausbau. Aufzeigen von Leistungspotenzialen

    Energy Technology Data Exchange (ETDEWEB)

    Beimdieck, J. [RAG Anthrazit Ibbenbueren GmbH, Ibbenbueren (Germany). Bereich Bergbau; Stoettner, M.T. [RAG Anthrazit Ibbenbueren GmbH, Ibbenbueren (Germany). Bereich Stab

    2008-06-19

    The road drivages at the Ibbenbueren mine are highly standardised. Drivage is carried out exclusively by drilling and shortfiring. A three-layer combined support - bolting, arches and backfilling with concrete - is used. Alternatives were sought in order to achieve a further increase in performance and reduce costs. Meanwhile the mine is driving 2 roadways by blasting and with only bolted supports. The equipment and process optimisations of the old standard were utilised with considerable increases in performance. The article describes the initial experience required. (orig.)

  1. Structural health monitoring for bolt loosening via a non-invasive vibro-haptics human-machine cooperative interface

    Science.gov (United States)

    Pekedis, Mahmut; Mascerañas, David; Turan, Gursoy; Ercan, Emre; Farrar, Charles R.; Yildiz, Hasan

    2015-08-01

    For the last two decades, developments in damage detection algorithms have greatly increased the potential for autonomous decisions about structural health. However, we are still struggling to build autonomous tools that can match the ability of a human to detect and localize the quantity of damage in structures. Therefore, there is a growing interest in merging the computational and cognitive concepts to improve the solution of structural health monitoring (SHM). The main object of this research is to apply the human-machine cooperative approach on a tower structure to detect damage. The cooperation approach includes haptic tools to create an appropriate collaboration between SHM sensor networks, statistical compression techniques and humans. Damage simulation in the structure is conducted by releasing some of the bolt loads. Accelerometers are bonded to various locations of the tower members to acquire the dynamic response of the structure. The obtained accelerometer results are encoded in three different ways to represent them as a haptic stimulus for the human subjects. Then, the participants are subjected to each of these stimuli to detect the bolt loosened damage in the tower. Results obtained from the human-machine cooperation demonstrate that the human subjects were able to recognize the damage with an accuracy of 88 ± 20.21% and response time of 5.87 ± 2.33 s. As a result, it is concluded that the currently developed human-machine cooperation SHM may provide a useful framework to interact with abstract entities such as data from a sensor network.

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

    Directory of Open Access Journals (Sweden)

    Yazhou Xu

    2016-01-01

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

  3. 基于ADAMS的枪机碰撞力研究%Bolt's Impact Simulation Based on ADAMS

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    In this paper ,the simple model of the barrel and automation was established by ADAMS ,the counter-recoil velocity and the mass of bolt and bolt box were defined by Impact function in ADAMS ,and the accurate control of step size and interpolation algorithm was realized ,then the counter-recoil collision force was obtained .%  建立由枪管和自动机构件组成的简易模型,通过在ADAMS中进行动力学仿真,赋予枪机和枪机框实际的复进到位速度和质量,利用ADAMS中的Impact函数对参数进行设置,并对求解步长和插值算法等进行精确控制,对结果进行测量,得到了枪机复进到位的碰撞力。

  4. AVSA. Parallelised bolting and cutting in roadways with arch supports; AVSA. Parallelisiertes Ankern und Schneiden in Bogenstrecken

    Energy Technology Data Exchange (ETDEWEB)

    Matusche, T. [Bergwerk West, Kamp-Lintfort (Germany); Stratmann, T. [Deutsche Steinkohle AG (DSK), Herne (Germany). Abt. TB

    2002-09-05

    In the middle of the 90's a research project was initiated to improve the drivage rates of roadway headings in the German hard coal industry. The target of the project was to get a significant increase in performance by parallelisation of cutting and bolting in mechanical headings, also in very hard rock conditions. In the first operation the prototype of the developed heading machine achieved not the expected performance. Although the aim of parallel cutting and bolting was gained, the drivage performance was especially hampered due to a high amount of hunks during the cutting process. Additionally geological difficulties occurred. Steps were made to optimize this system getting a clear increase in performance for the second operation to achieve the initial target. (orig.) [German] Vor dem Hintergrund stagnierender Vortriebsgeschwindigkeiten im Floezstreckenvortrieb des deutschen Steinkohlenbergbaus wurde Mitte der 90er Jahre des letzten Jahrhunderts ein Forschungsvorhaben initiiert. Ziel war es, durch Parallelisierung von Schneid- und Ankerarbeit bei maschinellen Vortrieben eine signifikante Leistungserhoehung auch in schwer schneidbarem Gestein zu erzielen. Der entwickelte Prototyp erreichte in einem ersten Einsatz die erwartete Leistung nicht. Obwohl die angestrebte Parallelisierung der Vorgaenge Schneiden und Ankern erreicht wurde, behinderte insbesondere ein hoher Brockenanfall die Vortriebsleistung. Zusaetzlich traten geologische Probleme auf. Optimierungsmassnahmen sollen in einem zweiten Einsatz deutliche Leistungssteigerungen bewirken, um die urspruengliche Zielsetzung zu erreichen. (orig.)

  5. Synthetical deformation analysis of anchor bolt in jointed rock mass%节理岩体锚杆的综合变形分析

    Institute of Scientific and Technical Information of China (English)

    张伟; 刘泉声

    2012-01-01

    在总结国内外对节理岩体中锚杆加固机制的试验研究和理论探讨基础上,综合考虑锚杆的切向和轴向变形能力,建立节理锚固锚杆在剪切荷载作用下的变形模型,将节理锚固锚杆的变形区划分为弹性变形段和挤压破坏段,引入表征挤压破坏段长度的变量,对锚杆与岩体的相互作用机制进行理论分析,推导了剪切荷载与剪切位移和轴向荷载与轴向位移的关系.通过分析锚杆的屈服破坏形式,得到了确定挤压破坏段长度的方法.最后,通过算例分析了挤压破坏段长度与锚杆直径、岩体强度、锚固角度等参数的关系,得到了以下结论:(1)节理锚固锚杆抗剪作用的实质是锚杆调动岩体的抗压强度抵抗节理切向荷载.在抗压强度较高的硬岩中,挤压破坏段局限于节理面附近,锚杆影响范围小;而在抗压强度较低的软岩中,挤压破坏段较大,而且会产生较大的剪切变形,锚杆影响范围较大.(2)锚杆屈服破坏形式与岩质和锚杆直径有关.硬质岩体发生剪切屈服,而较软岩体中容易发生弯曲屈服;小直径锚杆一般直接剪切屈服,而大直径锚杆可能发生弯曲屈服.锚杆屈服破坏后出现塑性铰,挤压破坏段范围在节理一侧约为直径的1~2倍,继续增加剪切荷载,挤压破坏段长度不再增大.(3)随岩质的不同,锚杆锚固节理的最优锚固角变化较大.岩质较硬时,最优锚固角度较小,反之则较大.%Based on the former experimental and theoretical researches on the reinforcement mechanisms of anchor bolt in jointed rock mass at home and abroad, and comprehensive considering of the tangential and axial deformability of anchor bolt, a deformation model of joint bolts under shear load is proposed. The deformation of joint bolts is divided into two parts: elastic deformation zone and crushing failure zone. A variable is introduced to express the length of crushing failure zone. Mechanism

  6. 用于风电机组的新型螺栓连接形式探究%Analysis of New Bolt Connection Forms for Wind Turbines

    Institute of Scientific and Technical Information of China (English)

    关雪松; 万保库; 张芹

    2013-01-01

    In order to increase the reliability and load capacity of bolted connection and decrease the connection size, two methods of bolted connection used in wind turbine are proposed in this paper, one is to use friction shims to increase the friction coefcient between the interface, the other is to use the bolt enveloped with a hollow pin to increase the load capacity of connection. These two methods all can increase the load capacity of bolted connection that can provide the safe and reliable connection methods for wind turbine.%为了提高风电机组中螺栓连接的可靠性,提高螺栓连接的承载能力,并减小相应零部件的连接尺寸,本文提出了两种新型的风电机组螺栓连接形式:一种是采用摩擦片增加接触面摩擦系数;一种是采用销套螺栓的形式提高螺栓连接的抗剪切能力。这两种方法都可以有效地提高螺栓连接的承载能力,为风电机组提供安全可靠的连接方式。

  7. Torque ultra difference fault analysis of flywheel bolt tightening machine%飞轮螺栓拧紧机力矩超差问题分析

    Institute of Scientific and Technical Information of China (English)

    李绍红

    2013-01-01

    对轿车发动机主装配线飞轮螺栓拧紧机力矩超差原因进行分析并排除故障.%In this paper, the main assembly line for car engine flywheel bolt tightening machine torque error cause is analyzed, and the troubleshooting process is described.

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  9. 一种螺栓拉伸器校准方法研究%A Calibration Method Research for Bolt Tensioners

    Institute of Scientific and Technical Information of China (English)

    赵兴亮; 杨思凡; 李玮; 陈宝有

    2015-01-01

    A calibration method for bolt tensioners is presented. According to the theory of Newton's Third Law, the calibration device is researched and designed to calibrate the bolt tensioners. The meas-urement error and repeatability analysis and uncertainty evaluation show the linearity is good. Considering the measurement error is within ±1%, which meets the calibration requirements for bolt tensioners, the designed calibration device is capable to carry out the calibration work for bolt tensioners.%介绍了螺栓拉伸器的一种校准方法,运用牛顿第三定律的基本原理,研究并设计了一种拉伸器校准装置对螺栓拉伸器进行校准,通过对实验结果的误差和重复性分析,以及不确定度评定,表明该拉伸器校准装置具有良好的线性度,测量误差在±1%以内,符合螺栓拉伸器校准要求,达到了校准螺栓拉伸器的目的,可以开展螺栓拉伸器校准工作。

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-11-15

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

  11. COMPOSITE MATERIAL BOLT THREADED NUT CONTACT FINITE ELEMENT ANALYSIS%复合材料锚杆螺纹螺帽接触有限元分析

    Institute of Scientific and Technical Information of China (English)

    温敏; 崔小朝; 王红霞

    2008-01-01

    利用ANSYS大型分析软件,建立属于表面非线性和材料非线性相耦合问题的复合材料锚杆螺纹螺帽联接的弹塑性轴对称接触有限元模型.对复合材料锚杆螺纹螺帽在间隙配合时轴向载荷作用下的应力应变场进行了数值计算.计算结果表明,复合材料锚杆螺纹螺帽联接能够满足煤矿安全生产的强度和刚度要求,为复合材料螺纹螺帽联接的设计提供了理论依据,对复合材料锚杆螺纹螺帽联接在工程实际中的推广使用有着重要的意义.%By means of large-scale analysis software ANSYS, a finite element model of elastic plastic axial symmetry contact problem is established which remained with the nonlinear surface and the nonlinear materials for the connecting of composite material bolt threaded nut. Stress-strain field has been calculated under the axial load with gap coordination of the composite material bolt threaded nut. The results indicate that, the joint of the composite material bolt threaded nut can satisfy the intensity and the rigidity request for the coal mine safety production. The researches in the paper have provided theoretical basis for the design of connecting the composite material bolt thread nut, and have important significance for widely using of the composite material bolt thread nut in project.

  12. 参数化建模的螺栓法兰连接刚度分析%Stiffness analysis of bolted flange joint based on parameterized modeling

    Institute of Scientific and Technical Information of China (English)

    蒋国庆; 李家文; 唐国金

    2014-01-01

    为分析几何参数对螺栓法兰连接刚度的影响,用 MSC.Patran 软件的二次开发工具 PCL(Patran Command Language)建立了螺栓法兰连接的参数化模型。研究了螺栓法兰连接刚度随连接结构几何参数的变化规律并进行了灵敏度分析。经分析可知,连接结构刚度对开孔位置比例参数最敏感,其次是上法兰厚度。当上部段长度大于某一数值时,连接结构刚度对上部段长度参数不敏感,这一结论能为连接结构动力学简化建模提供一定理论参考。%In order to analyze the effects of geometric parameters on the stiffness of bolted flange joint,a parameterized model of bolted flange joint was constructed by using PCL (Patran Command Language)on the platform of software MSC.Patran.The law of the stiffness of bolted flange joint with the change of geometric parameters was studied,and the sensitivity of geometric parameters was analyzed based on the parameterized model.The results show that the ratio of the location of hole is the most sensitive factor to the stiffness of bolted flange joint,and the next one is thickness of upper flange.When the length of upper body is up to a const,the stiffness of bolted flange joint is insensitive to the length of upper body,and this conclusion can provide a reference to simplify the dynamic model of joint.

  13. Statistical time series methods for damage diagnosis in a scale aircraft skeleton structure: loosened bolts damage scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Kopsaftopoulos, Fotis P; Fassois, Spilios D, E-mail: fkopsaf@mech.upatras.gr, E-mail: fassois@mech.upatras.gr [Stochastic Mechanical Systems and Automation (SMSA) Laboratory Department of Mechanical and Aeronautical Engineering University of Patras, GR 265 00 Patras (Greece)

    2011-07-19

    A comparative assessment of several vibration based statistical time series methods for Structural Health Monitoring (SHM) is presented via their application to a scale aircraft skeleton laboratory structure. A brief overview of the methods, which are either scalar or vector type, non-parametric or parametric, and pertain to either the response-only or excitation-response cases, is provided. Damage diagnosis, including both the detection and identification subproblems, is tackled via scalar or vector vibration signals. The methods' effectiveness is assessed via repeated experiments under various damage scenarios, with each scenario corresponding to the loosening of one or more selected bolts. The results of the study confirm the 'global' damage detection capability and effectiveness of statistical time series methods for SHM.

  14. Tightness and Material Aspects of Bolted Flange Connections With Gaskets of Nonlinear Properties Exposed to Variable Loads

    Directory of Open Access Journals (Sweden)

    Walczak R.

    2016-09-01

    Full Text Available The paper presents the problems regarding bolted flange connections with gaskets used in chemical, petrochemical and energy industry. The aim of the research is to present state of knowledge regarding pipelines and apparatus in industrial installations and rules and regulations regarding flange connections tightness. Additionally a calculation example regarding flange connection according to ASME VIII DIV 1 requirement and then detailed Finite Element Analysis presented; impact of nonlinear material properties (gasket loading unloading curves on the connection tightness for complex loading programme is shown. It is finally concluded that in addition to usual design calculations more precise calculation is needed to fully verify behaviour of sealed connection at complex extreme variable loadings. Material aspect is very important at designing, testing, service and maintenance; taking it into consideration may avoid many problems related to safe exploitation.

  15. Ultraprecision XY stage using a hybrid bolt-clamped Langevin-type ultrasonic linear motor for continuous motion

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong-Jin; Lee, Sun-Kyu, E-mail: skyee@gist.ac.kr [School of Mechatronics, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 500-712 (Korea, Republic of)

    2015-01-15

    This paper presents a design and control system for an XY stage driven by an ultrasonic linear motor. In this study, a hybrid bolt-clamped Langevin-type ultrasonic linear motor was manufactured and then operated at the resonance frequency of the third longitudinal and the sixth lateral modes. These two modes were matched through the preload adjustment and precisely tuned by the frequency matching method based on the impedance matching method with consideration of the different moving weights. The XY stage was evaluated in terms of position and circular motion. To achieve both fine and stable motion, the controller consisted of a nominal characteristics trajectory following (NCTF) control for continuous motion, dead zone compensation, and a switching controller based on the different NCTFs for the macro- and micro-dynamics regimes. The experimental results showed that the developed stage enables positioning and continuous motion with nanometer-level accuracy.

  16. Tests and analysis of mechanical behaviours of rock bolt components for China’s coal mine roadways

    Institute of Scientific and Technical Information of China (English)

    Hongpu Kang; Jinghe Yang; Xianzhi Meng

    2015-01-01

    A series of laboratory tests were performed to study the mechanical behaviours of newly developed high strength rock bolt components, including rebar, thread, plate, and domed washer. The characteristics of deformation and damage of each component were presented. The stress distribution of plate and domed washer was investigated through finite element modelling. The numerical results show that the yield and tensile strengths of the developed high strength rebar are 33.6%e58.3% and 17.2%e28.7% greater than those of the conventional rebar, respectively. The increase in yield strength was higher than that in tensile strength, suggesting an increase in yield to tensile strength ratio and a decrease in elongation. It is well-known that the thread processing may not be of high precision and accuracy as expected, which is characterised as rough thread surface, non-identical tooth height, toe stripping, and cracks in the surface. Hardening during thread processing tends to increase the thread yield and tensile strengths. In this paper, the typical deformation process of arch-shaped plate is classified into five stages. The tested plates exhibited distinct deformation characteristics and bearing capacities due to variations in shape, size, material and presence of washer. It was observed that uneven bottom surface, low bearing arch and large radius of the transitional arc connecting bearing arch and bottom surface were the major reasons ac-counting for low load-bearing capacity of plates. The performance of domed washer has a close relation with the shape, size, strength, and deformation compatibility with plate. Stress concentration was observed on the periphery of the contact surface between domed washer and plate, which is significantly influenced by the strength of domed washer and is considered to be 20%e30%higher than that of plate. Finally, a case study in the Datong coal mining district was presented, and the support pattern and effect of the developed rock bolt

  17. 锚杆尾部断裂机制和防破断方法应用%Fracture Mechanism of the Bolt Tail and Applications of Anti-breaking Methods

    Institute of Scientific and Technical Information of China (English)

    李夕兵; 马少维; 马春德; 李金跃; 郭阳

    2013-01-01

    基于岩体弹性能释放对锚杆的冲击作用,采用冲击动力学中刚性块对杆轴向碰撞的应力解,推导出了锚杆断裂的4种围岩应力条件.在此基础上分析了岩石弹性模量、锚杆弹性模量、锚杆直径与岩石泊松比等因素对锚杆断裂的影响.分析结果显示:在这4种围岩应力条件中,杆头被一次冲断基本上是不可能的,由于其他几种锚杆断裂时的围岩应力条件很接近,所以在实际中锚杆尾部被一次冲断的可能性最高,这也印证了锚杆尾部容易断裂的观点;另外,锚杆断裂的围岩应力条件受岩石弹性模量、岩石泊松比、岩石密度、锚杆弹性模量、锚杆密度、锚杆直径等因素的影响,其中影响较大的是岩石弹性模量与锚杆弹性模量的比值、锚杆直径和岩石泊松比;锚杆尾部断裂的围岩应力条件对于改进锚杆形式、优化锚杆力学性质有理论指导意义.最后,以马路坪矿的巷道工程为例,说明了锚杆防破断方法的具体应用,收到了良好的效果,可以在实际工程中推广应用.%Based on the bolt impacted by the elastic energy of rock mass and the stress solution that a rigid block collides with rod along axially in impact dynamics is adopted; four stress conditions of rock mass are derived before the bolt is fractured. And on the basis, several factors, including elastic modulus of rock, elastic modulus of bolt, diameter of bolt, and Poisson's ratio of rock, are discussed. The analytical results show as follows: In four stress conditions of rock mass, it is impossible that bolt head is directly fractured, but the rest parts have high possibility. In addition, the rest bolts have the similar stress conditions of rock mass, therefore it has a high possibility that the bolt tail is directly fractured, it also confirms with the view that bolt tail is easily broken; Besides, before the bolt is fractured, the stress condition of rock mass is affected by

  18. DRAFT One Year Extension of the Short-Term National Product Waiver for Stainless Steel Nuts and Bolts used in Pipe Couplings, Restraints, Joints, Flanges and Saddles for State Revolving Fund Projects

    Science.gov (United States)

    DRAFT one year extension of the short-term national product waiver for stainless steel nuts and bolts used in pipe couplings, restraints, joints, flanges and saddles for State Revolving Fund projects.

  19. Physical and underway data collected aboard the MELVILLE during cruise BOLT02MV in the North Pacific Ocean from 2008-11-09 to 2008-11-20 (NCEI Accession 0155596)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0155596 includes physical and underway data collected aboard the MELVILLE during cruise BOLT02MV in the North Pacific Ocean from 2008-11-09 to...

  20. Physiological Changes before and after Leaf Color Transition in the Bolting Process of Chinese Cabbage%大白菜抽薹过程叶色转变前后的生理变化

    Institute of Scientific and Technical Information of China (English)

    韩丹萍; 李春刚; 张耀伟

    2011-01-01

    Chinese cabbage [ Brassica campestris L. Ssp. Pekinensis ( Lour.) Olsson ] shows leaf color transition during the period from vernalization to bolting. After the change it will bud and then bolting, flowering. This phenomenon is particularly prominent in early-bolting species. In present study, Chinese cabbage cultivars of late-bolting and early-bolting were used to investigate the physiological changes during leaf color transition in the bolting process. The results revealed that there were some correlations between leaf color transition and the hormones, pigment content and protein composition. The content of chlorophyll (a/b), IAA and GA3 reached their peak in bolting process, the stem initiates elongation growth after leaf color is changed. The changes of leaf color are physiological signal in Chinese cabbage bolting.%大白菜通过春化后至抽薹,叶色由绿变灰,这一叶色转变过程在弱冬性品系上的表现尤为突出.本试验以不同冬性的大白菜品系为材料,从激素、色素含量变化和蛋白质组分变化等方面研究大白菜抽薹过程叶色转变前后的生理变化.结果表明:激素、色素含量和蛋白质的变化均与叶色转变有一定关系,叶绿素a/b、IAA和GA3含量均在叶色转变期出现峰值.

  1. 螺栓组拧紧顺序对结构体接触刚度的影响研究%Research on Influence of Contact Stiffness of Bolted Assembly Structure from Bolt-up Sequence

    Institute of Scientific and Technical Information of China (English)

    李培林; 王庆力; 王崴; 刘晓卫

    2014-01-01

    针对螺栓连接结构体接触刚度受拧紧顺序影响机理研究存在的不足,首先建立了单螺栓拧紧扭矩T与结合面刚度K的关联模型;然后在ANSYS中仿真分析了不同拧紧顺序下结合面模态频率特征,根据频率f与结合面刚度K之间的映射关系,进而得出最佳拧紧顺序;最后利用实验进行验证。结果表明,不同拧紧顺序结合面等效刚度K不同,结构的一阶固有频率也随之改变,同时拧紧最优、对角拧紧次之、顺序拧紧最差,说明拧紧顺序与固有频率之间存在着非线性关系。仿真分析与测试得到的一阶模态频率间的误差较小,证明了该建模方法能够有效分析拧紧顺序对结合面动力学性能的影响。%According to the existence problems of study on the mechanism of contact stiffness of bolted as-sembly structure formed by tightening sequence ( TS ) , a TK model of single bolt structure is established;then the frequency characteristics of combined surface under different TS was analyzed by using ANSYS;the optimal TS is obtained based on the frequency and the interface stiffness mapping. At last, a group of experiments was done to verify the above conclusions. The results show that the interface stiffness is verify under different TS, and so does the first rank natural frequency of the structure;the nonlinear response of the structure is significantly affected by TS that tighten at the same time is the optimal method compared with other TS. A small error of modal frequency between simulating and testing proves that the modeling method can effectively analyze impacts of the TS on the dynamic properties of the interface.

  2. Projecting of a roadway with support by bolts and steel fibre reinforced shotcrete; Projektierung eines Sprengvortriebes mit armiertem Anker-Spritzbeton-Ausbau

    Energy Technology Data Exchange (ETDEWEB)

    Beimdieck, J.; Israel, C.; Michelis, U. [DSK Anthrazit Ibbenbueren GmbH (Germany)

    2004-07-01

    The annual performance of headings at the Ibbenbueren Colliery is about 9,000 m, completely driven by shotfiring. In principle, the combined support, ''System Ibbenbueren'', with systematic bolting right in the face is standard. This system reaches its limits at about 8,5 m/d. Analyses of the single steps led to the idea, to substitute rolled wire mesh, which is necessary in the ''System Ibbenbueren'', by a 15 cm layer of steel fibre reinforced shotcrete. The project ''Support by bolts and steel fibre reinforced shotcrete'' raised out of this idea. In the following report, all of the considerations for the new supporting system will be explained and the equipment for the new method up to the first application underground will be introduced to the audience.

  3. Further development of remote testing of submerged bolts and screws in reactors; Weiterentwicklung der ferngesteuerten Schrauben- und Stiftpruefung unter Wasser in Reaktoren

    Energy Technology Data Exchange (ETDEWEB)

    Mohr, F.; Schirner, G.; Meier, R.; Wiesinger, W. [intelligeNDT Systems und Services, Erlangen (Germany)

    2007-07-01

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

  4. 大型风机连接螺栓的疲劳特性分析%Fatigue Characteristics Analysis of Bolted Connection of Large Wind Turbine

    Institute of Scientific and Technical Information of China (English)

    刘胜祥; 宋晓萍; 向际超

    2013-01-01

    Through analysis of the mechanical properties of the large-scale wind turbine bolt,a safety life estimation method of high strength bolt is established based on the Palmgren Miner linear damage rule and the average stress is corrected by considering the construction of engineering uncertainty.Simultaneously,a method to determinate the relative stiffness coefficient between different bolt size and flange thickness is given.And then,a fatigue calculation program is compiled in Matlab platform.So,the most dangerous load case and fatigue damage is calculated.Finally,the bolt's location of the maximum fatigue damage is not consistent with the dangerous location of limit state.%通过分析大型风机螺栓力学特性,建立了基于Palmgren Miner线性累积损伤法则的高强度螺栓安全寿命估计方法,考虑到施工时的不确定性,进行了平均应力的修正,给出了不同螺栓规格和法兰厚度的相对弹性系数确定方法,采用Matlab编制了螺栓疲劳计算程序,计算出最危险疲劳工况及其疲劳损伤值,并发现疲劳损伤最大的螺栓与极限状态下的危险螺栓的位置并不重合.

  5. Dynamic and Stability of Harmonic Driving Flexible Cartesian Robotic Arm with Bolted Joints Based on the Sensitivity and Multiple Scales Method

    Directory of Open Access Journals (Sweden)

    Yufei Liu

    2015-01-01

    Full Text Available Flexible Cartesian robotic arms (CRAs are typical multicoupling systems. Considering the elastic effects of bolted joints and the motion disturbances, this paper investigates the dynamic and stability of the flexible CRA. With the kinetic energy and potential energy of the comprising components, Hamilton’s variational principle and Duhamel integral are utilized to derive the dynamic equation and vibration differential equation. Based on the proposed elastic restraint model of the bolted joints, boundary conditions and mode equations of the flexible CRA are determined with using the principle of virtual work. According to the mode frequencies and sensitivities analysis, it reveals that the connecting stiffness of the bolted joints has significant influences, and the mode frequencies are more sensitive to the tensional stiffness. Moreover, describing the motion displacement of the driving base as combination of an average motion displacement and a harmonic disturbance, the vibration responses of the system are studied. The result indicates that the motion disturbance has obvious influence on the vibration responses, and the influence enhances under larger accelerating operations. The multiple scales method is introduced to analyze the parametric stability of the system, as well as the influences of the tensional stiffness and the end-effector on the stability.

  6. Assessment and evaluation of noise controls on roof bolting equipment and a method for predicting sound pressure levels in underground coal mining

    Science.gov (United States)

    Matetic, Rudy J.

    Over-exposure to noise remains a widespread and serious health hazard in the U.S. mining industries despite 25 years of regulation. Every day, 80% of the nation's miners go to work in an environment where the time weighted average (TWA) noise level exceeds 85 dBA and more than 25% of the miners are exposed to a TWA noise level that exceeds 90 dBA, the permissible exposure limit (PEL). Additionally, MSHA coal noise sample data collected from 2000 to 2002 show that 65% of the equipment whose operators exceeded 100% noise dosage comprise only seven different types of machines; auger miners, bulldozers, continuous miners, front end loaders, roof bolters, shuttle cars (electric), and trucks. In addition, the MSHA data indicate that the roof bolter is third among all the equipment and second among equipment in underground coal whose operators exceed 100% dosage. A research program was implemented to: (1) determine, characterize and to measure sound power levels radiated by a roof bolting machine during differing drilling configurations (thrust, rotational speed, penetration rate, etc.) and utilizing differing types of drilling methods in high compressive strength rock media (>20,000 psi). The research approach characterized the sound power level results from laboratory testing and provided the mining industry with empirical data relative to utilizing differing noise control technologies (drilling configurations and types of drilling methods) in reducing sound power level emissions on a roof bolting machine; (2) distinguish and correlate the empirical data into one, statistically valid, equation, in which, provided the mining industry with a tool to predict overall sound power levels of a roof bolting machine given any type of drilling configuration and drilling method utilized in industry; (3) provided the mining industry with several approaches to predict or determine sound pressure levels in an underground coal mine utilizing laboratory test results from a roof bolting

  7. Prediction of moment-rotation characteristic of top- and seat-angle bolted connection incorporating prying action

    Science.gov (United States)

    Ahmed, Ali

    2017-02-01

    Finite element (FE) analyses were performed to explore the prying influence on moment-rotation behaviour and to locate yielding zones of top- and seat-angle connections in author's past research studies. The results of those FE analyses with experimental failure strategies of the connections were used to develop failure mechanisms of top- and seat-angle connections in the present study. Then a formulation was developed based on three simple failure mechanisms considering bending and shear deformations, effects of prying action on the top angle and stiffness of the tension bolts to estimate rationally the ultimate moment M u of the connection, which is a vital parameter of the proposed four-parameter power model. Applicability of the proposed formulation is assessed by comparing moment-rotation (M-θ r ) curves and ultimate moment capacities with those measured by experiments and estimated by FE analyses and three-parameter power model. This study shows that proposed formulation and Kishi-Chen's method both achieved close approximation driving M-θ r curves of all given connections except a few cases of Kishi-Chen model, and M u estimated by the proposed formulation is more rational than that predicted by Kishi-Chen's method.

  8. Bolted Joints in Three Axially Braided Carbon Fibre/Epoxy Textile Composites with Moulded-in and Drilled Fastener Holes

    Science.gov (United States)

    Ataş, Akın; Gautam, Mayank; Soutis, Constantinos; Potluri, Prasad

    2016-10-01

    Experimental behaviour of bolted joints in triaxial braided (0°/±45°) carbon fibre/epoxy composite laminates with drilled and moulded-in fastener holes has been investigated in this paper. Braided laminates were manufactured by vacuum infusion process using 12 K T700S carbon fibres (for bias and axial tows) and Araldite LY-564 epoxy resin. Moulded-in fastener holes were formed using guide pins which were inserted in the braided structure prior to the vacuum infusion process. The damage mechanism of the specimens was investigated using ultrasonic C-Scan technique. The specimens were dimensioned to obtain a bearing mode of failure. The bearing strength of the specimens with moulded-in hole was reduced in comparison to the specimens with drilled hole, due to the increased fibre misalignment angle following the pin insertion procedure. An improvement on the bearing strength of moulded-in hole specimens might be developed if the specimen dimensions would be prepared for a net-tension mode of failure where the fibre misalignment would not have an effect as significant as in the case of bearing failure mode, but this mode should be avoided since it leads to sudden catastrophic failures.

  9. The Use of the Direct Optimized Probabilistic Calculation Method in Design of Bolt Reinforcement for Underground and Mining Workings

    Directory of Open Access Journals (Sweden)

    Martin Krejsa

    2013-01-01

    Full Text Available The load-carrying system of each construction should fulfill several conditions which represent reliable criteria in the assessment procedure. It is the theory of structural reliability which determines probability of keeping required properties of constructions. Using this theory, it is possible to apply probabilistic computations based on the probability theory and mathematic statistics. Development of those methods has become more and more popular; it is used, in particular, in designs of load-carrying structures with the required level or reliability when at least some input variables in the design are random. The objective of this paper is to indicate the current scope which might be covered by the new method—Direct Optimized Probabilistic Calculation (DOProC in assessments of reliability of load-carrying structures. DOProC uses a purely numerical approach without any simulation techniques. This provides more accurate solutions to probabilistic tasks, and, in some cases, such approach results in considerably faster completion of computations. DOProC can be used to solve efficiently a number of probabilistic computations. A very good sphere of application for DOProC is the assessment of the bolt reinforcement in the underground and mining workings. For the purposes above, a special software application—“Anchor”—has been developed.

  10. 多层预拼装钢结构系统特殊连接螺栓抗剪性能试验研究%Experimental Study on a New Bolt Connnection Used in Mutti-story Fabricated Steel Structure

    Institute of Scientific and Technical Information of China (English)

    张齐; 张其林; 丁娟

    2014-01-01

    A new kind of bolt connection consisted of self-tapping steel plate and high strength bolt will be used in a multistory fabricated steel structure system .But there are no regulations on such kind of bolted con-nection .Therefore ,extensive experimental research on bolted connection was taken .The objective of the re-search was to determine the ductility and resistance of such connection .The failure mode of bolted connections could be observed in the test .The ultimate bearing capacities of friction type high-strength bolt and bearing type high-strength bolt are different due to different design provisions and both bearing capacities were dotained in this experiment .The ultimate bearing capacities were compared with that predicted by the current connec-tion provisions specified in china steel design standards .%某新型多层预拼装钢结构系统采用了钢板自攻螺纹螺栓连接形式,超出现行规范中连接类型,需进行相关试验进行论证,针对工程常用6种规格高强螺栓自攻螺纹连接进行了单个螺栓抗剪试验,研究了此种连接的抗剪破坏模式,并依据摩擦型高强螺栓及承压型高强螺栓不同的设计假定确定两种情况下的极限承载力,与规范要求承载力设计值进行比对,为该种新型螺栓连接提供设计依据。

  11. 实心铆钉铆接与螺栓连接强度对比试验研究%Experimental research on joint strength of solid rivet and bolt

    Institute of Scientific and Technical Information of China (English)

    黄志超; 夏令君; 刘伟燕; 刘晓坤

    2012-01-01

    Steel sheets were joined by bolts and solid rivets. The best rivet height for solid rivet was obtained by simulating the riveting process in Deform software. The joint strength under lap shear load and coach peel load for solid riveting and bolt connection were analyzed. The tensile tests of solid riveting and bolt connection were done. The results show that the shear strength of bolt connection is a litter higher than those of solid riveting, and the strip strength of bolt connection is significantly higher than those of solid riveting.%采用螺栓连接、实心铆钉铆接两种连接方式对钢板进行连接试验.对实心铆钉铆接进行了有限元数值模拟,得出合理的铆钉高度.对螺栓连接件与实心铆钉铆接件进行板料搭接及对接结构拉伸强度测试,结果表明:螺栓连接件的抗剪强度略大于实心铆钉铆接件的抗剪强度,螺栓连接件的抗剥离强度明显大于实心铆钉铆接件的抗剥离强度.

  12. Discussion on the Installation Position of the Locknut of the Puller Bolt%顶紧螺栓的防松螺母安装位置探讨

    Institute of Scientific and Technical Information of China (English)

    李文鹏

    2016-01-01

    顶紧螺栓配合防松螺母的结构在工程实际中得到广泛应用,防松螺母安装在顶紧螺栓的工作面侧和非工作面侧都比较常见,本文分析了这两种安装方式的螺旋副受力情况,认为两种方式各有优劣。安装在非工作面侧时,螺母预紧力的操作方向和螺栓的顶紧操作方向一致,拆卸方向也一致,操作方便,但是需要的预紧力要大于受到的外力;安装在工作面侧时,螺母预紧力的操作方向和螺栓的顶紧操作方向相反,拆卸方向也相反,防松效果较好,但是需要从工艺上保证防松效果。%In the engineering practice, the structure of the puller bolt and locknut is widely used. It is common in the working face and non working side of the bolt. This paper analyzes the two kinds of screw pair force condition, and thinks that the two methods have their own advantages and disadvantages. Installed in the non working side, nuts pretightening force operating direction and bolt top tight operating in the same direction, disassembly direction, easy to operate, but need to preload to greater than by force; installed in the side of the working face, nuts pretightening force operating direction and bolt the top tight operating in the opposite direction, disassembly direction is opposite, anti loosening effect is good, but need to from process ensure locking effect.

  13. 我国蒜薹产业2010年回顾和2011年展望%2011 Review and 2010 Outlook of Garlic Bolt Industry in China

    Institute of Scientific and Technical Information of China (English)

    马岩松; 孙广智; 宋茂树; 杜孟学

    2011-01-01

    The article reviewed acquisition price,storage and sales status of garlic bolts in main producing areas of China in 2010,analysed the main factors and problems which affect operating conditions of our garlic bolt industry such as climate, the vegetable market and garlic planting, and looked forward to the development prospects of garlic bolt industry in 2011.%从2010年全国各主产区蒜薹收购价格比较及收贮与销售蒜薹情况的回顾,分析了气候、蔬菜市场、大蒜种植等影响我国蒜薹产业经营状况的主要因素及存在的问题,展望了2011年蒜薹产业的发展前景.

  14. Rock anchoring mechanism of bolt connecting chain under complicated geological conditions%复杂地质条件下锚杆联系链的围岩锚固机理探讨

    Institute of Scientific and Technical Information of China (English)

    甘仕伟; 许梦国; 王平; 王明旭; 陈顺满

    2014-01-01

    介绍一种与锚杆联合使用的锚杆联系链及其组合支护方式,重点研究其围岩锚固机理,采用数值模拟和现场试验的方法对锚杆联系链组合支护效果进行分析。结果表明,锚杆联系链、锚杆和混凝土喷层三者之间的有机结合提高了围岩的自支撑能力;锚杆联系链组合支护具有作业时间短、安装方便、结构简单、成本低等优点;在兼具喷锚网支护优点的同时,锚杆联系链组合支护也弥补了喷锚网支护的不足,是对矿山现行支护方式的补充和改进。%This paper introduces bolt connecting chain which is used together with bolts and its com-bined supporting method ,with the discussion focused on its rock anchoring mechanism .It analyzes the effect of combined anchor supporting of the bolt connecting chain .The results show that the com-bined use of the bolt connecting chain ,anchors and sprayed concrete layer can improve the self-sup-porting ability of rock .The bolt connecting chain has many advantages ,such as shorter operation time ,easy installation ,simple structure and low cost .While boasting the advantages of shotcrete rock bolt wire mesh supporting ,it makes up for the disadvantages of the wire mesh supporting ,pro-ving to be a supplement for and improvement on the existing supporting methods in mines .

  15. Model Test Study of the Anchor Bolt Arrangement in a Loess Subway Tunnel%黄土地铁隧道锚杆布置方式的模型试验研究

    Institute of Scientific and Technical Information of China (English)

    郑甲佳; 撒蕾; 郭永建

    2014-01-01

    文章利用平面应变三向加载装置进行室内模型试验,对无锚杆、全环锚杆和边墙锚杆三种锚杆布置方式进行了对比试验,并参考工程现场测试结果,对系统锚杆在黄土地铁隧道中的作用进行了研究;通过模型试验获得了适合黄土地铁隧道的锚杆相似材料,实现了“先加载,后挖洞”以及锚杆和衬砌联为一体的试验方法。通过对比发现:系统锚杆能较好地控制掌子面周围的塑性区发展;边墙锚杆在隧道洞室开挖支护后能加快围岩应力调整,且能有效改善衬砌的受力情况;综合考虑经济因素,认为边墙锚杆支护系统在浅埋暗挖黄土地铁围岩中加固效果较好,实际施工中应予以保留。%In this paper, a three-axial loading device of plane strain is used for a laboratory model test. Contrast tests are carried out for three kinds of anchor bolt arrangements, i.e., an arrangement with no anchor bolts, a whole-section arrangement of anchor bolts, and an arrangement of anchor bolts on the sidewall. The role of the anchor bolt system in a loess subway tunnel is studied in reference to field test results. Data regarding anchor bolts applied to a loess subway tunnel are obtained by model testing, and "loading-before-excavation" and anchor-lining integration are realized. By contrast, the development of a plastic zone around the working face is well controlled by the anchor bolt system; after excavation and support of the tunnel cavern, the sidewall anchor bolt can comply quickly with surrounding rock stress and effectively improve the stress distribution of the lining. Considering the economic factors, the sidewall anchor support system is a good method for reinforcing surrounding rock in shallow-bored loess subway tunnels and should be adopted in actual construction.

  16. Research on Influences of Construction Time of Anchor Bolts on Mechanical Response of Carbonaceous Phyllite Tunnel%锚杆施作时机对炭质千枚岩隧道力学响应影响研究

    Institute of Scientific and Technical Information of China (English)

    罗敖; 熊竹

    2013-01-01

    针对炭质千枚岩隧道施作锚杆时容易剥落掉块并导致局部失稳的问题,对先喷后锚法与传统先锚后喷法进行比较研究.为了分析2种施工方法对围岩与支护体系力学响应的影响,借助三维数值分析手段对洞周位移变化、初期支护结构受力、锚杆受力及围岩的塑性发展进行分析.结果表明,先喷后锚法引起的围岩变形与支护体系应力略大,先锚后喷法对控制围岩变形效果显著,二者均可满足一般工程需要;当对围岩变形控制要求严格时应选用先锚后喷法.%In allusion to the problems of easy peeling and chipping as well as loss of stability caused during construction of anchor bolts in grey phyllite tunnels,this paper studies the construction method for tunnels,namely erection of steel frames followed by spraying concrete and then construction of anchor bolts,i.e.the method of spray of concrete before construction of anchor bolts and the traditional method of construction of anchor bolts before spray of concrete.In order to analyze the influences of two construction methods on mechanical responses of wall rocks and supporting systems,the paper analyzes changes of peripheral displacement,initial stress on supporting structures and anchor bolts as well as plastic development of wall rocks by means of 3 D numerical analysis means.The results show that the method of spray of concrete before construction of anchor bolts leads to slightly larger deformation of wall rocks and stress on supporting systems,while the method of construction of anchor bolts before spray of concrete exhibits significant effect on control for deformation of wall rocks,and both methods can satisfy the needs of general projects; when control for deformation of wall rocks is strictly required,the method of construction of anchor bolts before spray of concrete should be selected.

  17. A review on condition monitoring and identification for bolt-joints in wind turbine tower%风力机塔架螺栓连接状态监测与辨识研究进展

    Institute of Scientific and Technical Information of China (English)

    董晓慧; 马如宏; 詹月林

    2013-01-01

    The bolt-jointed structure is the only way of connection in wind turbine tower between two short conical towers, as well as foundation. If the bolt-jointed structure is failure, wind turbine will take the catastrophic damage. In order to prevent the looseness of bolts, or even fracture, the wind turbine tower bolt-jointed condition monitoring and identification is crucial. Bolt-jointed structure dynamic analysis methods and bolt-jointed condition monitoring and identification methods were summarized, and these methods of based on dynamic model and based on signal analysis that can be used with the wind turbine tower bolt-jointed condition monitoring and identification were reviewed. Lastly, dynamic development for the wind turbine tower bolt-jointed condition monitoring and identification was pointed out.%螺栓连接是大型风力机塔架各段塔筒及塔架与塔基之间的唯一连接方式,若其连接状态失效,将会造成灾难性的破坏.为了预防螺栓松动,甚至断裂,对风力机塔架螺栓连接状态进行监测与辨识至关重要.综述了螺栓连接结构动特性分析方法和螺栓连接状态监测与辨识方法,并对基于动力学模型和基于信号分析的无模型状态监测与辨识方法能否应用于风力机塔架螺栓连接状态的监测与辨识进行了述评,重点论述了波传播非线性动力学模型和应用非线性动力学理论进行信号分析的无模型状态监测与辨识方法,综述了风力机塔架螺栓连接状态监测与辨识的发展动态.

  18. Failure Anaylsis of Bolt Cracking in Pressure Gauge of Liquid Chlorine Tank%液氯储罐压力表用螺栓断裂失效分析

    Institute of Scientific and Technical Information of China (English)

    端震

    2011-01-01

    对液氯储罐压力表用螺栓的断裂进行了失效分析.通过对化学成分分析、断口分析和金相检验,探讨了压力表用螺栓断裂的主要原因,并提出了相应的预防措施.%Failure analysis of cracking bolts was carried out. Through the analysis of macroscopic and microscopic fracture, chemical composition and microstructure, the main reasons for the bolt cracking in pressure gauge were discussed, and the preventing way was proposed.

  19. Arts-inspired students sync their assets to a nuts and bolts world: A career mentoring pilot progam

    Science.gov (United States)

    Hudson, Lynn

    This research examined how students who are arts-inspired feel about their futures in a STEM-based work climate. Science, Technology, Engineering, and Math are the nuts and bolts, and in education today, the only avenue touted for our country and our students' success in this 21st century economy. This can be disconcerting to those interested in other fields, like the arts. This study was guided by the following questions in an effort to understand if our artists and arts-inspired students realize their options and importance in this 21st century climate. The pilot study was designed to help improve the students' perception of their abilities or self-efficacy in the STEM areas by introducing STEM professionals as mentors who designed hands-on activities that simulate work in the STEM fields. Research Questions: 1. Do arts-inspired students have an interest in a STEM career area prior to participating in the career mentoring program? 2. Does participation in a STEM career mentoring program improve student's self-efficacy in STEM fields? 3. Does participation in STEM career mentoring program increase student's interest in pursuing STEM-related careers? Lent, Brown and Hackett's Social Cognitive Career Theory and Daniel Pink's, "A Whole New Mind: Why Left-Brainers Will Rule the Future" were used as the theoretical framework for this study. Seventeen African-American girls who were enrolled in the "I AM COMPLETE" summer program participated in the pilot study. Data was collected from the College Foundation of North Carolina Career Interest Explorer and the STEM Career Interest Survey, which served as a pre and post-test. This pilot offered limited support for the hypothesis, however, career mentoring and opportunities for young people to experience careers, especially in the STEM areas must continue to grow. The role that the arts play in this process is pivotal in galvanizing females and minorities to join these professions. It is the hope of this researcher that the

  20. 某丙烯球罐底部人孔螺栓失效分析%Failure Analysis of a Spherical Tank Manhole Bolt

    Institute of Scientific and Technical Information of China (English)

    袁军; 程欣; 史进

    2015-01-01

    某石化企业一台容积400m3球罐,操作介质为液态丙烯,该球罐下人孔螺栓发生断裂失效。丙烯属甲类可燃液化气体,人孔螺栓失效极易造成罐内液体泄漏,引起人员中毒、火灾事故,并造成环境污染。为了尽可能的预防此类风险发生,本文对人孔螺栓开展失效分析工作。%There is a volume of 400m3 spherical tank using liquid propylene as its working medium. One of manhole bolt under the spherical tank occurred fracture failure. Propylene is a kind of combustible liquefied gas. Manhole bolt failure is easily to cause tank liquid leakage, poisoning, fire accidents, and environmental pollution. This paper analyzed the reason of the manhole bolt’s failure to prevent this risk happen again.

  1. 复合材料小尺寸螺栓的成型工艺方法探讨%Discussion on Molding Process of Smallsize Composite Bolts

    Institute of Scientific and Technical Information of China (English)

    孙博

    2014-01-01

    复合材料螺栓已经广泛应用到汽车、航天、航空等各个领域,其中小尺寸螺栓的热塑性注塑工艺成型方法也比较成熟,但热固性模压工艺成型的方法还处于研究阶段,本文通过对热塑性注塑成型的工艺方法和热固性模压成型的工艺方法的对比,阐明热固性模压成型的工艺方法的优、劣势,并对热固性模压成型的工艺方法进行分析和探讨。%Composite bolts are widely used in the fields of automobiles ,aerospace ,aviation and so on .Thermoplastic in-fusion process for smallsize bolts is mature ,but thermosetting mould pressing is still in research .In this paper ,by the com-parison of the two processes ,the advantages and disadvantages of the thermosetting mould pressing are illustrated ; mean-while,the thermosetting mould pressing is also analyzed and discussed .

  2. Effect Mechanism of SVP Gene Regulation on Bolting and Flowering%抽薹开花调控基因SVP的作用机制

    Institute of Scientific and Technical Information of China (English)

    杨修勤; 王志敏; 汤青林; 宋明

    2013-01-01

    SHORT VEGETATIVE PHASE(SVP)基因属于MADS盒基因,它编码的蛋白转录因子对开花具有抑制作用.SVP主要在营养生长阶段表达,受自主途径等多个开花路径调控,并可以调节开花途径整合子FLOWERING LOCUS T(FT),SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC 1)的表达,从而调控抽薹开花时间.本文综述了SVP基因调控抽薹开花的作用机制,并结合SVP基因的研究现状展望了未来的研究方向.%SHORT VEGETATIVE PHASE ( SVP) encoded MADS-box protein is a represser of bolting and flowering in Cruciferous plants. SVP is mainly expressed in vegetative growth stage, which is regulated by some flowering pathways, such as autonomous pathway. It can control flowering time by regulating several floral signal integrators, such as FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 ( SOC1 ). This paper summarizes the effect mechanism of SVP gene regulation on bolting and flowering. It also discusses about the prospects of future research activities, according to present research status on SVP gene.

  3. Development of rock bolt grout and shotcrete for rock support and corrosion of steel in low-pH cementitious materials

    Energy Technology Data Exchange (ETDEWEB)

    Boden, Anders (Vattenfall Power Consultant AB, Vaellingby (Sweden)); Pettersson, Stig (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden))

    2011-04-15

    It is foreseen that cementitious products will be utilized in the construction of the final repository. The use of conventional cementitious material creates pulses in the magnitude of pH 12.13 in the leachates and release alkalis. Such a high pH is detrimental mainly to impairment of bentonite functioning, but also to possibly enhanced dissolution of spent fuel and alteration of fracture filling materials. It also complicates the safety analysis of the repository, as the effect of a high pH-plume should be considered in the evaluation. As no reliable pH-plume models exist, the use of products giving a pH below 11 in the leachates facilitates the safety analysis, although limiting the amount of low-pH cement is recommended. In earlier studies it was found that shotcreting, standard casting and rock bolting with low-pH cement (pH . 11 in the leachate) should be possible without any major development work. This report summarizes the results of development work done during 2008 and 2009 in the fields of low-pH rock bolt grout, low-pH shotcrete and steel corrosion in low-pH concrete. Development of low-pH rock bolt grout mixes and laboratory testing of the selected grout was followed by installation of twenty rock bolts for rock support at Aspo HRL using the chosen low-pH grout. The operation was successful and the bolts and grout are subject to follow up the next ten years. Low-pH shotcrete for rock support was initially developed within the ESDRED project, which was an Integrated Project within the European Commission sixth framework for research and technological development. ESDRED is an abbreviation for Engineering Studies and Demonstrations of Repository Designs. ESDRED was executed from 1st February 2004 to 31st January 2009. The development of the mix design described in this report was based on the results from ESDRED. After laboratory testing of the chosen mix, it was field tested in niche NASA 0408A at Aspo HRL. Further, some areas in the TASS-tunnel were

  4. Bolt Shear Force Sensor

    Science.gov (United States)

    2015-03-12

    to connect to a signal conditioner 200 (See FIG. 6). The deformable ring 102 may be constructed from conventional materials (metal, composite...plastic etc.) or with piezoelectric ceramics. If the ring 102 is constructed with piezoelectric ceramics, the ring itself is the sensor; therefore...elements used (i.e., resistance strain gages, fiber optic Bragg grating or piezoelectric material ), an output is generated (i.e., resistance

  5. 基于图像识别技术的螺栓裂缝识别系统研究%The Research of Bolt Cracks Discern System based on Image Recognition Technology

    Institute of Scientific and Technical Information of China (English)

    李亚琳; 王玉增; 李柏震; 刘双源

    2013-01-01

    提出了一种基于图像识别技术的螺栓裂缝非接触识别技术.利用高精度工业相机对待检螺栓进行拍摄,然后采用细化、提高曝光度、图像分割等技术对拍摄到的图片进行处理,获取图像特征,最终达到识别裂缝的目的.实验表明,将图像识别技术应用于螺栓裂缝识别领域,可以大大简化识别步骤,提高识别精度,为螺栓裂缝检测提供了新的发展方向.%Propose a non-contact identification of bolt crack based on image recognition technology. Take photo of every bolt waiting for the detection with high-precision industrial cameras, then process the photos with image thinning, improve exposure, edge detection technology, so we can get the image feature, and finally achieve the purpose of crack identification. The experiment shows that the use of image recognition technology in bolt cracks identification can greatly simplify the identification step, improving recognition accuracy, and provides a new direction of development for the bolt cracks detection.

  6. Drivage of roof-bolted roadways with rectangular cross-section as gate roads in zones with a high rock pressure; Auffahrung von Rechteckankerstrecken als Abbaubegleitstrecken in Zonen hohen Gebirgsdrucks

    Energy Technology Data Exchange (ETDEWEB)

    Vierhaus, R.; Arentz, A. [Bergwerk Auguste Victoria/Blumenthal, Marl (Germany)

    2001-11-08

    In DKS's Auguste Victoria colliery the utilization of rectangular bolted roadways has for several years proved successful. On the basis of this, a roadway under highly stressed conditions (up to 45 MPa) was developed in the year 2000. During the planning phase, bolting patterns for the various stress areas were designed, including the use of cable bolts up to a length of 8 m. In the development process an accompanying monitoring programm assisted in correctly adjusting the support dimensioning to the requirements. After the development, early results showed that the bolting technique used reflected previous expectations. (orig.) [German] Bereits seit mehreren Jahren liegen auf dem Bergwerk Auguste Victoria der DSK gute Erfahrungen bei der Nutzung von Rechteckankerstrecken vor. Auf der Grundlage dieser Erfahrungen ist im Jahr 2000 eine einfache genutzte Abbaubegleitstrecke unter hohem Gebirgsdruck aufgefahren worden. In der Planungsphase wurden Ankerschemata fuer die unterschiedlichen Druckzonen erarbeitet und der Einsatz von Seilankern bis 8 m Laenge vorgesehen. Im Zug der Auffahrung konnte mit dem begleitenden Messprogramm die Ausbaudimensionierung optimal den Erfordernissen angepasst werden. Nach der Fertigstellung zeigen die ersten Ergebnisse, dass die angewandte Ankertechnik den bisherigen Erwartungen entspricht. (orig.)

  7. 基于压电主动传感方式的螺栓松动检测实验研究*%Bolt Loosening Detection Based on Piezoelectric Active Sensing Technology*

    Institute of Scientific and Technical Information of China (English)

    王涛; 罗毅; 刘绍鹏; 肖涵; 王志刚; 李友荣

    2013-01-01

    For the measurement of bolt axial force and detection of bolt loosening,the ultrasonic method is studied using the piezoelectric active sensing technique. When the ultrasonic wave generated by a piezoelectric patch propagates across the interface of the components jointed by the bolt,only part of the ultrasonic wave energy passes through it. The transmitted wave energy depends on the true contact area which is decided by the bolt pretension ac-cording to the Classical Hertz contact theory. By measuring the received energy with another piezoelectric patch on the other side of the connected components, the bolt pretension or bolt connection status can be detected. The experiment device is set up and serials experiments were carried out. The experiment results show that the wave energy propagated across the interface has good correlation with the torque level. This method has potential application for the monitoring of bolt loosening in-site.%针对螺栓联接结构中螺栓易松动而引发事故的情况,进行了压电主动传感方式的螺栓松动检测研究。采用压电材料激发超声波,根据透射波通过螺栓联接界面时,透射波携带的能量与界面间实际接触面积相关,而界面实际接触面积与界面压力(即螺栓作用力)成一定关系,通过测量透射波的能量确定螺栓的松紧程度。建立了实验装置,进行了实验研究。实验结果显示,作为传感器的压电材料所接收到的超声波能量与螺栓紧固力具有较好相关性,该方法可作为螺栓联接结构健康监测的一种新方法。

  8. 锚杆预应力支护效应的数值模拟研究%Study on the Numerical Simulation of Anchor Bolt ’s Pre-stressed Supporting Effect

    Institute of Scientific and Technical Information of China (English)

    张金鑫

    2015-01-01

    通过ANSYS软件对巷道中锚杆在预应力取值分别为0 MPa (无支护)、0.02 MPa、0.1 MPa时的无人支护效果进行了研究,根据研究结果,认为在II类围岩巷道中,锚杆预应力为0.02 MPa~0.1 MPa时形成的承压带的强度和厚度都明显增加,支护效果较好,预应力在0.1 MPa以上时,支护效果的改善不明显,在III类围岩巷道中,锚杆预应力比普通围岩的值略大,在0.05 MPa~0.15 MPa表现得比较明显。%ABSTRACT:This paper studies the unmanned supporting effects of anchor bolts in roadway selecting the prestress values of 0 MPa, 0,02 MPa and 0.1 MPa respectively through software ANSYS, and According to the study results, holds that in the class II surrounding rock roadway, the strength and thickness f the pressure-bearing belt formed at the anchor bolt prestress of 0.02 MPa~0.1 MPa were significantly increase, its supporting effect was good;the improvement of its supporting effect was not obvious at when the anchor bolt prestress was more than 0.1 MPa;and in the class III surrounding rock roadway, the anchor bolt prestress was slightly larger than the value of ordinary surrounding rock, and it behaved more apparently at the anchor bolt prestress of 0.05 MPa~0.15 MPa.

  9. Inconel 718十二角头螺栓制造工艺技术研究%Study on Manufacturing Technology for Inconel 718 Twelve-Point Bolt

    Institute of Scientific and Technical Information of China (English)

    王玉凤; 刘风雷; 庄宝潼

    2015-01-01

    The material and structure features of Inconel 718 twelve-point bolt are introduced, and key manufacturing technologies, such as hot heading, heat treatment, warm rolling, etc. are analyzed, and optimal technological parameters are obtained. Dimensional in-spection and qualiifcation tests are carried out. The results show that technology designing is rational..%介绍了Inconel 718十二角头螺栓的材料和结构特点,分析了关键制造加工技术,如热镦锻、热处理、滚压螺纹等,确定了合理的工艺参数,并对研制件的尺寸和性能进行了评估,结果表明工艺技术设计合理。

  10. Bolt-mesh-anchor support design of fully mechanized caving face gateway%综放回采巷道锚网索支护设计

    Institute of Scientific and Technical Information of China (English)

    王建华

    2011-01-01

    针对放回采巷道为全煤巷道,受采动影响巷道围岩变形大,破坏严重的问题,为了解决该类巷道支护问题,通过应用工程类比法、理论计算法,对山河煤矿首采工作面回采巷道变形破坏特点设计出合理的支护方案,确定了锚杆、锚索的长度及间距排距和预紧力四个关键支护参数.巷道矿压观测数据表明该方案有效的控制了巷道变形与破坏,取得良好的经济效益.%Fully mechanized caving face gateway is coal roadway, and its deformation and destruction are serious under mining influence.In order to solve the support problem of such gateway,engineering analogy and theoretical calculation method were used in the paper based on the deformation failure character of gateway of first work face in Shanhe coal mine, then reasonable design was obtained, moreover, pre-stressed bolt's length, spacing between bolts,distance between rows and pretension force were put forward.Finally,the strata control observation dat shows that gateway deformation was under control by this plan, and the better economic benefit was obtained.

  11. Probabilistic Reliability and Sensitivity of System Bolt in Soft Rock Highway Tunnel%软岩公路隧道系统锚杆概率可靠度及灵敏度分析

    Institute of Scientific and Technical Information of China (English)

    巩正玺; 杨建国; 陈明

    2011-01-01

    In order to understand the force in a system of rock bolts in bolt-shotcrete support, judge the stability of the tunnel lining structure and avoid loss resulting from instability of the support structure, the probabilistic reliability of the system of rock bolts is calculated based on the geological conditions of the discussed project with the elastic modulus of surrounding rock and thickness of the lining as the main random variables. Probabilistic sensitivity is analyzed using the Spearman rank correlation coefficient method. Prefabricated bolts were installed in random cross sections in the studied tunnel section, anchoring forces were monitored continually at different points within the surrounding rock, and a large number of data points were obtained. The magnitude, cross distribution and change of bolt axial forces over time are analyzed according to a curve of variation vs. Time and an axial force diagram. Bolt reliability is verified by bearing capacity and field test results are in accordance with the calculation of probabilistic reliability. It is concluded that physical property parameters of the surrounding rock and the thickness of shotcrete are the main factors affecting bolt reliability. The construction quality of system bolts should be guaranteed in order to improve safety and stability of bolt-shotcrete. Moreover, thickness of shotcrete and its construction quality should also be guaranteed.%为了解锚喷支护中系统锚杆受力情况,判断隧道衬砌结构稳定性,确保施工安全,避免支护结构失稳带来的损失,结合工点工程地质条件,选择围岩弹性模量、衬砌厚度等作为主要随机变量,计算得到锚杆概率可靠度.利用Spearman秩相关系数对锚杆概率灵敏度进行分析,认为围岩物性参数和喷混凝土厚度是影响锚杆可靠性的主要因素.要提高锚喷支护的安全和稳定性,除保证系统锚杆施工质量外,应确保喷混凝土厚度及其施工质量.在研究段

  12. SYSTEM RELIABILITY ANALYSIS OF ROCK SLOPES CONSIDERING ROCK BOLT CORROSION%考虑锚杆腐蚀作用的岩质边坡系统可靠度分析

    Institute of Scientific and Technical Information of China (English)

    李典庆; 蒋水华; 张利民; 周创兵

    2013-01-01

    锚杆腐蚀是导致锚固工程事故的重要原因之一,为此,主要研究锚杆腐蚀作用对锚固岩质边坡系统可靠度的影响.首先,在系统分析现有钢筋腐蚀模型及锚杆腐蚀试验数据基础上,确定锚杆腐蚀模型.分析与腐蚀作用相关的锚杆自由段屈服失效模式和锚固段锚杆与注浆体界面黏结失效模式,进而确定相应的锚固边坡失效模式.给出基于蒙特卡洛模拟的边坡时变系统可靠度分析方法,并以锚固岩质边坡为例证明所提方法的有效性.结果表明:K.A.T.Vu和M.G Stewart提出的钢筋腐蚀模型适用于分析处于密闭潮湿和干湿交替环境条件之间的锚杆腐蚀作用.在锚杆服役的前期,自由段锚杆的腐蚀作用对边坡稳定性的影响较大,而在后期锚固段锚杆的腐蚀作用对边坡稳定性的影响开始变得较大,并且锚杆服役后期锚固力和边坡系统失效概率的变化幅度明显大于前期.边坡系统失效概率随锚杆握裹层厚度的增加而减小,随注浆体水灰比的增加而增大,当握裹层厚度和水灰比达到一定值时,边坡系统失效概率随时间增大的程度并不明显.%A large number of engineering accidents have demonstrated that the failures of rock bolts are mainly induced by the corrosion of reinforcing steel bars.This study aims to investigate the effect of rock bolt corrosion on the system reliability of anchored rock slopes.A uniform corrosion model for rock bolts and its applicable environmental conditions are first examined based on systematical analysis of the existing corrosion models for reinforcing steel bars and the experiment data for rock bolt corrosion.Two failure modes related to rock bolt corrosion are determined.They are the yield failure mode of rock bolts at free section and the bond failure mode at the bolt-grout interface,respectively.Then,the failure models of anchored rock slope corresponding to those of rock bolts are established

  13. Mechanism analysis of shear deformation of joint bolt based on elastic-plastic theory%基于弹塑性理论的节理处锚杆剪切变形机理分析

    Institute of Scientific and Technical Information of China (English)

    马超甫; 冯涛; 姚琦; 王平; 廖泽

    2016-01-01

    为了研究节理面处锚杆的剪切变形机制,建立了节理岩体中锚杆的受力模型,对锚杆在节理面处的剪切变形进行了理论分析,利用单位载荷法推导了节理面处锚杆竖向位移与载荷、节理宽度、材料性质间的关系。理论分析表明,节理岩体中锚杆的剪切变形过程为:小挠度变形阶段、弹塑性剪切变形阶段、塑性铰阶段;剪切变形至塑性铰阶段时,节理面处杆体将出现两个塑性铰;节理面处锚杆具有一段结构对称、载荷反对称部分;节理宽度对节理处杆体的弹性区、弹塑性区的分界面位置存在线性影响。%The stressing model of anchor bolt in jointed rock mass is established to study the shear deformation mechanism of jointed rock bolts,and the shear deformation at the joints is analyzed theoretically. Relationships between vertical displacement and load,and joint width and material properties of anchor bolt in the vicinity of the joint plane are deducted.The theoretical analysis shows that the shear deformation process of anchor bolt in jointed rock has the following stages,i.e.small deflection deformation stage,elastic -plastic shear deformation stage,and plastic hinge stage.In plastic hinge stage,two plastic hinges will appear on the anchor bolt near the joint plane.The anchor bolt has a section of body of symmetrical structure and anti -symmetrical load near the joint plane.The joint width has linear effect on Interface position between elastic region and elastic-plastic region near the joint.

  14. Finite element analysis on optimized arrangement of long list bolts group with high strength in steel truss bridges%钢桁桥长列高强螺栓群优选布置的有限元分析

    Institute of Scientific and Technical Information of China (English)

    朱铭; 王荣辉; 黄永辉

    2009-01-01

    针对高强螺栓群在钢桁桥中受力性能复杂、优化布置困难的问题,采用有限元软件ANSYS建立了考虑接触状态的三维有限元实体模型,对4种不同的螺栓布置方式在拉力荷载作用下的板件相对位移、板件应力以及接触面的摩擦应力分布状态等进行了模拟,并对比分析了优选前后螺栓群布置的效果.结果表明:优选布置后的螺栓拼接接头应力状态变化不大;采用优选的布置方案可节省螺栓19%~25%.%In order to solve the problem of complicated structural behavior and difficult optimum arrangement of high-strength bolts group used in steel truss bridges, a 3D solid FEM model with the consideration of contact state was established by using software ANSYS to simulate the displacement between coreplate and buttcover plate, the normal stress on the plate and frictional stress state on the contact surface of four different high-strength bolts arrangements under tension force. The optimized effect was compared to the one before being optimized. The calculation results show that: when the optimized arrangement was used, the stress state of the high-strength bolts connections has a little change, but 19%~25%bolts can be saved. 3 tabs, 10 figs, 11 refs.

  15. 大直径铝合金铆钉以铆代螺可行性试验研究%Experimental Investigation on Feasibility of Substituting Large Diameter Riveting for Bolting

    Institute of Scientific and Technical Information of China (English)

    于海平; 张旭; 章茂云; 孙立强; 李春峰

    2016-01-01

    The EMR experiments were performed on bi-layer aluminum alloy plates withΦ10mm 2A10 aluminum alloy rivets. The microstructure of EMR joints were observed, mechanical properties were tested and compared with those of bolting joint with steel bolt. The results show that an increasing discharge voltage enhances dimensions of rivet head. The rivet head is characterized with adiabatic shear deformation. Maximum shear and pull off load of the rivet joints are respectively 23.3kN and 35.0kN, which are higher than those of bolting joint. And the weight loss of EMR joint is up to 15.8%in contrast to bolting one.%针对双层铝合金板铆接结构,通过电磁铆接工艺试验,分析Φ10mm-2A10铝合金铆钉镦头的微观组织,与钢质螺栓连接接头对比评价了铆接接头的力学性能。研究发现,随放电电压的增加,铆钉镦头直径逐渐增加、高度逐渐降低。铆钉镦头以绝热剪切为主要变形模式。铆接接头的最大剪切和拉脱载荷分别为23.3kN和35.0kN,均高于钢质螺栓连接接头,并且相对于螺接接头可减重15.8%。

  16. Cause Analysis and Improvement of Fracture Bolts on the Pipe Plate of Floating Head Type Heat Exchanger%浮头式热交换器浮头管板螺栓断裂原因分析及改进

    Institute of Scientific and Technical Information of China (English)

    陈彩霞; 赵青

    2014-01-01

    通过扫描电镜观察、硬度测试、化学成分分析及金相检验等方法分析了浮头式热交换器浮头管板连接螺栓的断裂失效原因。结果表明,硫化物应力腐蚀开裂、氢致开裂和螺纹加工产生应力集中、材料硬度不满足湿硫化氢介质中的使用要求是螺栓断裂的主要原因。%Fracture analysis of the bolts on the pipe plate of floating head type heat exchanger was conducted by means of scanning electron microscopy (SEM ) ,energy dispersive spectrometer (EDS) ,hardness test ,chemical analysis and metallographic examination etc .The results showed that the sulfide stress corrosion cracking (SSCC ) and hydrogen induced cracking (HIC ) is the main reason for the bolts fracture .The thread processing stress concentration ,the mismatch be-tween the H2 S medium on the material hardness requirements and the used material finally caused the bolts fracture .

  17. 锚杆初始支护阻力的计算及预测%Calculation and prediction of initial support pressure in bolt support

    Institute of Scientific and Technical Information of China (English)

    王成; 杜泽生; 李志兵

    2012-01-01

    In order to get and predict initial support pressure,mechanical models of bolt’s stress and bolt’s installation were established,based on the hypothesis on surrounding rock of immediate bolt support in elastic-plastic status.The relationship between initial support pressure and tightening torque was analyzed,and theoretical solutions to initial support pressure were obtained for two contacts of pallet and nut.Meanwhile,verification research was carried out by "Bolt Force Transfer and Attenuating Test System".The results show that there is a linear relationship between initial support pressure and tightening torque under the same condition of bolt’s material quality,specification,row line space;when the tightening torque is among 0-300 N.m,the equations of initial support pressure and tightening torque is right;initial support pressure can be quantized and predicted by tightening torque.%为了便于计算和预测锚杆支护的初始支护阻力,基于锚杆及时支护时锚固区围岩处于弹塑性状态的假设,建立锚杆受力和安装力学模型,分析研究初始支护阻力与预紧力矩之间的关系,得出锚杆支护螺母、托盘两种接触类型的初始支护阻力的理论解,同时采用自制的"锚杆锚固传递及衰减规律"模拟试验台对初始支护阻力进行验证。研究结果表明:锚杆支护材质、规格及支护间排距相同时,其初始支护阻力与预紧力矩呈线性关系;预紧力矩在0-300 N.m时,初始支护阻力与预紧力矩间有准确的数学表达式,采用预紧力矩能够量化和预测初始支护阻力。

  18. Fuzzy Comprehensive Evaluation of Bolt Support Effects in Deep-Mining Gateway%回采巷道锚杆支护效果模糊综合评判

    Institute of Scientific and Technical Information of China (English)

    申艳梅; 韦四江

    2011-01-01

    Bolt support has become the main form of surrounding rock control in deep-mining gateway. Good or bad supporting effect, is related not only to the support patterns, but also to the surrounding rock properties and mining conditions. To evaluate the bolt support effect in gateway accurately, taking the gateways in Pingdingshan MiningArea as the research object, 32 deep-mining gateways are selected as samples to study in this paper. Based on seven indexes such as surrounding rock strength, support strength, gateway depth, surrounding rock integrity, mining influence, gateway section and coal pillar width, etc, the bolt support effects in gateway can be divided into four kinds including better, good, common and poor by the fuzzy clustering analysis. Based on the above method, the bolt support effect in new driving gateway is pre-evaluated under given conditions, which provides the basis for bolting parameters, determination.%锚杆支护已成为深井巷道围岩控制的主要形式,支护效果的好坏除与所采用的支护方式有关外,还与围岩性质、开采条件有关,为准确评判回采巷道锚杆支护效果,以平顶山矿区深部回采巷道为研究对象,选取32条回采巷道为样本,依据围岩强度、支护强度、巷道埋深、围岩完整性、采动影响、巷道断面、煤柱宽度等7个指标,采用模糊聚类分析的方法将巷道围岩支护效果分成好、较好、一般、差4类.据此对新掘巷道给定条件下的支护效果进行预判,为锚杆支护参数确定提供依据.

  19. Technical study on bolt support of road driving next goaf in fully mechanized caving workface%综放沿空掘巷锚杆支护技术

    Institute of Scientific and Technical Information of China (English)

    任润厚

    2001-01-01

    Through simulating numerical value to stress distribu tion of sidecoal in mine goaf in fully machanized caving workface and appling li miting equilibrium principle,this paper fix width of narrow pillar of road drivi ng next goaf and have a ratinal location of road.This paper raises control mecha nism of rock and scheme of bolt support in road driving next goaf in fully mecha nized caving workface and apply to engineering pracfice,it makes a good economic benefit of technique.%通过对综放面采空区侧煤体应力分布的数值模拟,运用极限平衡理论确定了沿空巷道窄煤柱的宽度,进行了合理的巷道定位。提出了综放沿空掘巷围岩控制机理和高强锚杆支护方案,并应用于工程实践,取得了良好的技术经济效果。

  20. Analyzing and studying factors for determining neutral point position of fully grouted rock bolt%全长注浆岩石锚杆中性点影响因素分析研究

    Institute of Scientific and Technical Information of China (English)

    朱训国; 杨庆

    2009-01-01

    The neutral point theory is the important theory in underground engineering reinforcement theory. At present, the formula to determine neutral point position has been existed some unreasonable place. The neutral point theory had been further consummated and improved on the foundation of pre-researchers. Base on the developed analytical model and the theory of frictional resistance is zero at the neutral point, the factors have been detailed analyzed for affecting the neutral point position; and the correlations have been gained which affecting neutral point position. Through analyzing, it is revealed that the hydrostatic primary stress, bolt length, bolt spacing having no influence to neutral point position, and the radius of tunnel, Young's moduli of rock and bolt, the bolt diameter having remarkable influence to it. Among them, it is linear relation among the radius of tunnel, the bolt diameter with the neutral point position, but it is exponential function relations among the Young's modulus of rock and bolt with the neutral point position. The relationship of Young's modulus of rock mass and neutral point position presents exponential decreasing; the relationship of -Young's modulus of bolt and neutral point position presents exponential increasing. Through the factors analyzed, it has obtained that the general functional between the neutral point position and the correlation parameter, for further to study the neutral point theory providing the certain reference significance.%中性点理论是地下工程锚固理论中的重要理论,但目前对于中性点位置的确定计算公式存在不合理之处.在前人工作的基础上,对中性点理论进行了完善和改进.在建立的锚杆解析本构模型的基础上,结合中性点理论中锚杆中性点位置处的摩阻力为0的思想,对影响中性点位置的因素进行了较详细的分析,得出了影响锚杆中性点位置的相关因素.通过分析研究得到,

  1. Materials for Advanced Ultrasupercritical Steam Turbines Task 3: Materials for Non-Welded Rotors, Buckets, and BoltingMaterials for Advanced Ultrasupercritical Steam Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Deepak

    2015-09-15

    The primary objective of the task was to characterize the materials suitable for mechanically coupled rotor, buckets and bolting operating with an inlet temperature of 760°C (1400°F). A previous study DOE-FC26-05NT42442, identified alloys such as Haynes®282®, Nimonic 105, Inconel 740, Waspaloy, Nimonic 263, and Inconel 617 as potential alloys that met the requirements for the necessary operating conditions. Of all the identified materials, Waspaloy has been widely utilized in the aviation industry in the form of disk and other smaller forgings, and sufficient material properties and vendor experience exist, for the design and manufacture of large components. The European program characterizing materials for A-USC conditions are evaluating Nimonic 263 and Inconel 617 for large components. Inconel 740 has been studied extensively as a part of the boiler consortium and is code approved. Therefore, the consortium focused efforts in the development of material properties for Haynes®282® and Nimonic 105 to avoid replicative efforts and provide material choices/trade off during the detailed design of large components. Commercially available Nimonic 105 and Haynes®282® were evaluated for microstructural stability by long term thermal exposure studies. Material properties requisite for design such as tensile, creep / rupture, low cycle fatigue, high cycle fatigue, fatigue crack growth rate, hold-time fatigue, fracture toughness, and stress relaxation are documented in this report. A key requisite for the success of the program was a need demonstrate the successful scale up of the down-selected alloys, to large components. All property evaluations in the past were performed on commercially available bar/billet forms. Components in power plant equipment such as rotors and castings are several orders in magnitude larger and there is a real need to resolve the scalability issue. Nimonic 105 contains high volume fraction y’ [>50%], and hence the alloy is best suited

  2. Sugar beet contains a large CONSTANS-LIKE gene family including a CO homologue that is independent of the early-bolting (B) gene locus.

    Science.gov (United States)

    Chia, T Y P; Müller, A; Jung, C; Mutasa-Göttgens, E S

    2008-01-01

    Floral transition in the obligate long-day (LD) plant sugar beet (Beta vulgaris ssp. vulgaris) is tightly linked to the B gene, a dominant early-bolting quantitative trait locus, the expression of which is positively regulated by LD photoperiod. Thus, photoperiod regulators like CONSTANS (CO) and CONSTANS-LIKE (COL) genes identified in many LD and short-day (SD)-responsive plants have long been considered constituents and/or candidates for the B gene. Until now, the photoperiod response pathway of sugar beet (a Caryophyllid), diverged from the Rosids and Asterids has not been identified. Here, evidence supporting the existence of a COL gene family is provided and the presence of Group I, II, and III COL genes in sugar beet, as characterized by different zinc-finger (B-box) and CCT (CO, CO-like, TOC) domains is demonstrated. BvCOL1 is identified as a close-homologue of Group 1a (AtCO, AtCOL1, AtCOL2) COL genes, hence a good candidate for flowering time control and it is shown that it maps to chromosome II but distant from the B gene locus. The late-flowering phenotype of A. thaliana co-2 mutants was rescued by over-expression of BvCOL1 thereby suggesting functional equivalence with AtCO, and it is shown that BvCOL1 interacts appropriately with the endogenous downstream genes, AtFT and AtSOC1 in the transgenic plants. Curiously, BvCOL1 has a dawn-phased diurnal pattern of transcription, mimicking that of AtCOL1 and AtCOL2 while contrasting with AtCO. Taken together, these data suggest that BvCOL1 plays an important role in the photoperiod response of sugar beet.

  3. Linhagens de coentro com pendoamento tardio sob dois sistemas de plantio Coriander lines with later-bolting resistance under two planting systems

    Directory of Open Access Journals (Sweden)

    Gabriel M Maciel

    2012-12-01

    comparados com a cv. Verdão.The agronomic performance was evaluated on coriander lines tolerant to early bolting under two production systems (no-tillage and seedling transplant. The experiment was carried out from June to November 2010. Three coriander lines were evaluated (Guarani#1, Guarani#21 and Guarani#36, and one control (cv. Verdão in a randomized complete block experimental design, with three replications. The number of leaves per plant (NF, green mass (MVM, green mass/m² (REND, supported marketable period in the field (COM, cycle (CIC and percentage of bolting (PP, were evaluated. The PP was evaluated in the two production systems at 20, 40, 60, 80, 100 and 120 days after sowing (DAS. Significant differences were obtained in the production system with seedling transplant for NF, MVM and DP between the lines Guarani#36 and Guarani#21 and 'Verdão'. The coriander line Guarani#36 compared to the cv. Verdão was superior in NF, MVM and REND in 246.05%, 162.90% and 165.38%, respectively. Similar superiority was observed in the coriander line Guarani#21 with 211.95%, 148.10% and 150.00% for parameters NF, MVM and REND, respectively. There were no significant differences for CIC between the lines and 'Verdão'. 'In the system of no-tillage the coriander lines Guarani#36 and Guarani#21 presented significant effect in all the evaluated parameters when compared to cv. Verdão, except for cycle of the coriander lines. In the parameters NF, MVM and REND the Guarani#36 coriander line presented superiority of 251.27%, 148.14% and 150% to the cv. Verdão, respectively. The Guarani#21 coriander line compared to cv. Verdão presented superiority of 218.13%, 136.17% and 137.50% for NF, MVM and REND, respectively. The three lines were superior to cv. Verdão on COM for the two tillage systems. The coriander lines Guarani#21 and Guarani#36 present later-bolting in both the systems of production when compared to the cv. Verdão.

  4. Laboratory Method for Evaluating the Characteristics of Expansion Rock Bolts Subjected to Axial Tension / Laboratoryjna Metoda Badania Charakterystyk Kotew Rozprężnych Poddanych Rozciąganiu Osiowemu

    Science.gov (United States)

    Korzeniowski, Waldemar; Skrzypkowski, Krzysztof; Herezy, Łukasz

    2015-03-01

    Rock bolts have long been used in Poland, above all in the ore mining. Worldwide experience (Australia, Chile, Canada, South Africa, Sweden, and USA) provides evidence of rock bolt supports being used for loads under both static and dynamic conditions. There are new construction designs dedicated to the more extreme operating conditions, particularly in mining but also in tunneling. Appreciating the role and significance of the rock bolt support and its use in Polish conditions amounting to millions of units per year, this article describes a new laboratory test facility which enables rock bolt testing under static load conditions. Measuring equipment used as well as the possibilities of the test facility were characterized. Tests were conducted on expansion rock bolt supports installed inside a block simulating rock mass with compression strength of 80 MPa, which was loaded statically as determined by taking account of the load in order to maintain the desired axial tension, which was statically burdened in accordance with determined program load taking into consideration the maintenance of set axial tension strength at specified time intervals until capacity was exceeded. As an experiment the stress-strain characteristics of the rock bolt support were removed showing detailed dependence between its geometrical parameters as well as actual rock bolt deformation and its percentage share in total displacement and deformation resulting from the deformation of the bolt support elements (washer, thread). Two characteristic exchange parts with varying intensity of deformation /displacement per unit were highlighted with an increase in axial force static rock bolt supports installed in the rock mass. Obudowa kotwowa jest już od dawna stosowana w Polsce, przede wszystkim w górnictwie rudnym. Światowe doświadczenia (Australia, Chile, Kanada, RPA, Szwecja,USA) świadczą o stosowaniu obudowy kotwowej zarówno w warunkach obciążeń o charakterze statycznym jak i

  5. 破碎围岩锚注加固浆液扩散规律研究%Slurry diffusion within cracked wall rock during the bolt-grouting process

    Institute of Scientific and Technical Information of China (English)

    李慎举; 王连国; 陆银龙; 张蓓

    2011-01-01

    基于连续介质力学和渗流力学理论,运用渗透张量法得出浆液在破碎围岩中扩散的基本方程;并通过对实际锚注支护工程进行假设与简化,建立锚注加固系统浆液在包含正交裂隙组的围岩中渗透扩散的数学模型.在此基础上,运用COMSOL软件对锚注支护工程进行实时模拟,研究了不同注浆压力和不同注浆锚杆布置方式对浆液流动扩散规律的影响.结果表明:对于巷道锚注支护工程,合理的注浆压力约为1.0~4.0MPa,合理的钻孔间距约为浆液扩散半径的1.3倍左右.将研究成果用于祁南煤矿新掘大巷锚注支护设计,取得了良好的效果.%Continuum mechanics were used with seepage theory to obtain a basic equation for slurry diffusion within cracked wall rock.The permeability tensor method was used to obtain the diffusion behavior.A mathematical model of slurry diffusion in a bolt grouting system within a wall rock having orthogonal fractures was developed.Certain assumptions and simplifications of field grouting and support methods were used during this derivation.A numerical simulation of the bolt grouting process was conducted using COMSOL.The slurry diffusion at different grouting pressures and for different bolt layouts were studied.The results show that a rational grouting pressure is from 1.0 to 4.0 MPa for roadway bolt supports.The borehole spacing should be nearly 1.3 times the slurry diffusion radius.These results were applied to the design of roadway supports in the Qinan coal of the Huaibei mine to good effect.

  6. 钢梁长圆孔螺栓变形性研究%Research on deformability of bolt with slotted hole for steel girder

    Institute of Scientific and Technical Information of China (English)

    鞠晓臣; 田越

    2015-01-01

    长圆孔高强螺栓连接不同于普通的螺栓连接,它可以有效改善所连接钢梁的纵向变形性能,避免次弯矩的产生,从而降低梁体的应力应变。长圆孔螺栓的工作性能跟钢梁翼缘与垫块之间的摩擦有密切的联系,摩擦越严重,越不利于梁端的纵向移动。除了跟摩擦有关外,外力荷载,温度荷载,车辆冲击荷载等也会影响钢梁的纵向移动。本文首先根据钢梁端长圆孔变形受力机理提出了长圆孔高强螺栓变形的计算公式,然后结合有限元模拟分析对变形性能做了进一步的分析和验证,最后对现役钢桥中的长圆孔螺栓连接进行了试验研究,并对长圆孔螺栓变形工作性能进行了实际评估。%High strength bolt connection with slotted hole ( HSBC-SH) ,different from that for common round holes, can improve the deformation performance along the horizontal direction of steel beam effectively,and avoid secondary bending moment. Thus,it can decrease the stress and strain of the steel beam. The deformation performance of HSBC-SH is closely related to the friction between the bottom flange of the steel beam and heel block. T his friction is detrimental to the longitudinal movement at the beam end. In addition,external force loading, temperature loading and vehicle impact loading etc. can also influence the deformation performance of HSBC-SH. In this paper,the study was carried out considering this effect on the deformation performance of the HSBC-SH. Firstly, based on the mechanism of HSBC-SH,a theoretical equation to calculate the deformation was put forward; and then the finite element analysis was performed to validate the theoretical analysis; finally,a field experimental study on an existed steel bridge for HSBC-SH was done,the deformation performance of HSBC-SH was assessed practically.

  7. 转管炮降低机心组导轨摩擦力研究%Reducing Bolts Rail Friction for Gatling Gun

    Institute of Scientific and Technical Information of China (English)

    徐健; 李强; 杨臻

    2016-01-01

    In order to reduce the minimal driving power ,to reduce the bolts velocity,the main roller relative to whole body,and the right-and-left rail and obliquity is researched. And the result indicates the maximal acceleration of cam ,the main roller relative to whole body is zero. It is well in non-altitude difference with bilateral angle. The optimization results shows that in the case of 9 000 rpm its driving power is 140 kw bellows to 31 kw and it is 22 % of its intrinsic ;its show in the case of 3 300 rpm 1 086.5 N to 10 000 rpm 9 779.3 N. And it shows in the no- transverse and yes-inclination 90.9%that yes- transverse and no- inclination.%为了使转管炮机心组消耗的驱动功率最小,对机心组速度、主滚轮相对机体位置、机心体左右导轨及倾角关系等对驱动功率的影响进行研究。表明最好选用机心组凸轮加速度最小,主滚轮相对机体质心位置等于零,最好用无横向位移以及有夹角的关系最好。优化结果表明:9000 rpm的射速,驱动功率由机心组加速度变化引起140 kw下降到31 kw,降到不足于原设计曲线的22%;射速为3300 rpm的主滚轮压力峰值参数化峰值1086.5 N,升高到10000 rpm的峰值9779.3 N。无横向以及有夹角降低压力有横向以及无夹角90.9%。

  8. 复杂围岩条件下开切眼全锚支护%Full-bolt supporting in open-off cut under complex surrounding rock condition

    Institute of Scientific and Technical Information of China (English)

    刘惠德; 尹根成; 栗兴仁; 李志强

    2001-01-01

    The mine open-off cut should be very safety because it is a wide-spanned place where the mining facilities are located. In the past, the supporting of open-off cut used to be log shed. Since the space is limited, the facilities fixing efficiency and safety are influenced greatly. The rock layer above coal bed of Malan mine 2th coal bed is composed of multiple layers of different rock beds or thin coal beds. So if using log shed to support open-off cut, the deformation of surrounding would be large and the space would be limited, then the facilities fixing efficiency would be low and the log consume would be huge. The method of bolt + stay rope is an effective way. It can improve the facilities fixing environment greatly as well as efficiency and safety reliability. At the same time, the cost and working intensity are lowed geratly.%采煤工作面的开切眼不仅跨度大,而且是采煤设备安装的场所,对于空间的安全有较高的要求。以往开切眼的支护一般为木棚,使开切眼的空间狭小,对于安装设备的效率和安全有很大影响。马兰矿2#煤层的顶板为多层不同性质的岩层和薄煤层组成,属于复杂性顶板,用木棚支护,开切眼围岩变形大,安装空间狭小,使安装效率低下,而且木材消耗量大。用锚杆+锚索支护获得成功,从根本上改善了综采设备安装的环境,提高了安装的效率和安全可靠性,降低了开切眼的支护成本和劳动强度。

  9. 风电机组预应力锚栓基础局部承压分析%Analysis on Local Pressure of Prestressed Anchor Bolts Foundation of Wind Turbine Generator

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The prestressed anchor bolts foundation of the wind turbine generator, under the pre-pressure, results in the higher local pres-sure on the concrete in the anchoring area.In the paper, the local compressive stress, section size of the local compressive area, and the local compressive bearing capacity of the concrete in the anchoring area are calculated and analyzed.This provides the design of the pres-tressed bolts concrete with reference.%风电机组预应力锚栓基础在预压力作用下,锚固区混凝土将承受较大的局部压力。文章对锚固区混凝土的局部压应力、局部受压区的截面尺寸和局部受压承载力进行了验算分析,对预应力锚栓基础的设计具有参考价值。

  10. Discussion and Simulation Analysis for Flywheel Bolt of 6110/125Z Engine%6110/125Z 发动机飞轮螺栓断裂仿真分析和探讨

    Institute of Scientific and Technical Information of China (English)

    唐贵基; 宋彩盟; 陈卓群

    2013-01-01

    Engine is the power source of a power transmission system ,and torsional vibration (TV ) is the main failure form of the engine .The torsional vibration (TV ) analysis of 6110/125Z engine shows the shaft system resonance is the main reason for the breakage of flywheel bolts .After improving the TV damper ,both the additional torque of the shaft and the amplitude of torsional vibration are decreased ,and the breakage of the flywheel bolts is solved .%  发动机是动力传动系统的动力来源,而扭转振动是发动机产生故障的主要形式。通过对6110/125Z发动机进行扭振分析,发现其飞轮螺栓断裂的主要原因是轴系共振引起的,通过对扭转减振器进行改进,减小了飞轮传递的附加扭振力矩,同时也减小了扭振振幅,最终解决了螺栓断裂问题。

  11. 某轻型卡车后桥车轮螺栓松动问题分析及优化%Bridge wheel bolts loose after a problem analysis and optimization of light trucks

    Institute of Scientific and Technical Information of China (English)

    向莎

    2014-01-01

    In this paper, through the bridge after a light truck wheel bolts loosening problem analysis to identify the causes and mechanism of loose produce, and accordingly improved design. Finally, the improved design for the sample kind have proved to be effective for the improvement. Through this failure analysis and design optimization, but also for the wheel bolt design similar structure provides several key controlling factors for solving similar problems provided for reference ideas.%本文主要通过对某轻型卡车后桥车轮螺栓松动问题进行分析,找出了松动产生的原因和机理,并相应进行了改进设计。最后对改进设计的样件进行了实物验证,证明了改进是有效的。通过本次故障分析和优化设计,也为同类结构的车轮螺栓设计提供了几个关键控制因素,为解决同类问题提供可供参考的思路。

  12. Study on Structural Bolt Debonding Monitoring Based on Focused Lamb Waves%采用聚焦Lamb波方法的板结构螺钉松动监测

    Institute of Scientific and Technical Information of China (English)

    王强; 袁慎芳; 田峰; 江兵

    2012-01-01

    针对基于压电元件和主动Lamb波的螺钉松动监测研究中存在的问题,研究采用聚焦Lamb波信号方法改进现有监测技术.介绍和分析了基于时间反转处理的Lamb波信号聚焦原理和过程,以及基于此的螺钉松动监测特征参数提取以及方法的实现技术;通过在铝板盒段试件上的实验,给出了实验验证,证明了该方法具有较好的实用性.%Aiming to the problems in the bolt debonding monitoring based on PZT and active Lamb wave, this paper presented the improved monitoring method based on focused Lamb waves. The principle and procedure of the Lamb waves focalization by time-reversal process. Improved bolt debonding monitoring method and its application technique are analyzed. The effect and practicability of the new method were demonstrated in experiments in which the joints of a test box with aluminum board were monitoring.

  13. 芥蓝菜薹不同节间芥子油苷组分及含量分析%Composition and content of glucosinolates in different sections of bolting stems of Chinese kale

    Institute of Scientific and Technical Information of China (English)

    腊贵晓; 刘国顺; 杨俞娟

    2011-01-01

    The composition and content of glucosinolates ( GSs) in different bolting stem sections ( Bol-ting stem was divided into four sections from the bottom to top) of three Chinese kale ( Brassica albo-glabra L. ) cultivars (CH, CHCT and QNYQ) were analyzed by HPLC and identified by LC-MS. E-leven kinds of GSs were identified including seven aliphatic GSs ( glucoiberin, progoitrin, sinigrin, glucoraphanin, glucoalyssin, gluconapin and glucoerucin) and four indolyl GSs (4-hydroxyglucobrassi-cin, glucobrassicin, 4-methoxyglucobrassicin and neoglucobrassincin) , except for that in QNYQ, there was no glucoerucin in the first section and 4-methoxyglucobrassicin in the first and second section of bolting stems identified. In the three Chinese kale cultivars, total GS content, total aliphatic GS content and total indolyl GS content were all achieved in the top section of bolting stems in Chinese kale, however, the change trend of different GS in bolting stem sections were not consistent.%采用高效液相色谱及液相色谱-质谱联用法,以芥蓝(Brassica alboglabra L.)3个品种‘中花’、‘澄海粗条,和'全年油青’为材料,对菜薹不同节间(菜薹从膨大处到顶端依次平分为4节)芥子油苷组分和含量进行了鉴定和分析.结果表明,除4-甲硫基丁基芥子油苷在全年油青菜薹的第1节中没有检测到、4-羟基-3-吲哚甲基芥子油苷在全年油青菜薹的第1节位和第2节位中没有检测到外,在3个芥蓝品种菜薹的其它节均检测到11种芥子油苷,包括7种脂肪族芥子油苷(3-甲基亚硫酰丙基芥子油苷、2-羟基-3-丁烯基芥子油苷、2-丙烯基芥子油苷、4-甲基亚硫酰丁基芥子油苷、5-甲基亚硫酰戊基芥子油苷、3-丁烯基芥子油苷和4-甲硫基丁基芥子油苷)和4种吲哚族芥子油苷(4-羟基-3-甲基吲哚芥子油苷、3-吲哚甲基芥子油苷、4-甲氧基-3-吲哚甲基芥子油苷和1-甲氧基-3-吲哚甲基芥子油苷).在3个芥蓝品种

  14. 冷弯薄壁型钢钢板-螺栓梁柱节点的力学性能分析%Mechanical properties investigation of cold-formed steel beam-column joints with bolt-plate

    Institute of Scientific and Technical Information of China (English)

    杨娜; 钟延营

    2011-01-01

    The ANSYS software is used to investigate the influential factors of the static behavior of gusset plate-bolted connection. The influential factors of the connections of three kinds of width of beam-column web were studied, including bolt pitch, the thickness of gusset plate, and the thickness of web and the width of flange and so on. It is found that the width of beam-column web the thickness of gusset plate, the thickness of web are highly effective factors for the static behavior,while the bolt pitch and the width of flange do not affect the initial stiffness and the ultimate bearing capacity of the joints. Finally, design proposals of three sections form connections are demonstrated, the dynamic performance of three kinds of recommended connections have been preliminarily studied in this paper.%为了观察不同梁、柱截面尺寸冷弯薄壁型钢钢板-螺栓节点静力性能的影响因素,采用AN-SYS软件对连接进行非线性有限元分析,研究3种梁柱腹板的节点螺栓间距、连接板厚度、腹板厚度和翼缘宽度等因素对其连接性能的影响.结果表明,梁柱腹板宽度、连接板厚度、梁柱腹板厚度是影响该连接节点静力性能的有效因素,而改变螺栓间距、梁柱翼缘宽度对节点的初始刚度和极限承载力的影响都不明显.给出了3种截面形式节点的设计建议,并对节点滞回性能进行了初步探讨,提出了滞回性能指标分析结论.

  15. 渗水泥化巷道锚杆支护围岩稳定性控制研究%Surrounding rock stability control with bolt support in seepage argillaceous roadway

    Institute of Scientific and Technical Information of China (English)

    王成; 韩亚峰; 张念超; 钱德雨

    2014-01-01

    Because of the poor reliability of bolt support in seepage argillaceous roadway, roof fall accidents occur frequently. In this paper, typical rock disintegration and weathering experiments, field tests of roadway deformation rules and bolt anchorage performance in water seepage roadways were studied. The results indicate that once the clay mineral in roadway surrounding rock meet water, the rock will become sliming and weathering embrittlement, which will cause a sharply decrease in the load bearing capability. In addition, the deformation of seepage argillaceous roadway has obvious stage cha-racteristics, which shows whole process of “decelerated deformation-weak argillization-accelerated deformation-strong argillization-instability”. Thus, the key point of stability control in such roadway is to control the argillaceous process effectively. Meanwhile, the surrounding rock control technology in seepage argillaceous roadway was proposed, which is composed of “there-high” bolt enhancement technology and lag grouting strengthening technology. Moreover, the best grouting time which is 10 to 30 days after the roadway drivage was given, engineering practice was then conducted, and good results were obtained.%渗水泥化巷道锚杆支护可靠性差,导致此类巷道冒顶事故频发。通过典型岩样崩解和风化实验、渗水泥质巷道变形规律及锚杆锚固性能实测开展研究。结果表明:煤系地层含有黏土类矿物,使得巷道围岩遇水崩解,发生泥化现象,且风化脆裂,导致自身承载力急剧降低;渗水泥质巷道围岩变形破坏具有明显阶段性,演绎“减速变形-弱泥化-加速变形-强泥化-失稳”全过程,有效控制泥化进程是该类巷道稳定性控制的关键;提出了渗水泥化巷道围岩的控制技术,即新型“三高”锚杆强化控制技术和滞后注浆加固技术,给出巷道掘进后10~30 d最佳注浆时机,开展了典型的工程实践

  16. Produção e resistência ao pendoamento de alfaces tipo lisa cultivadas sob diferentes ambientes Production and resistance to bolting of loose-leaf lettuce grown in different environments

    Directory of Open Access Journals (Sweden)

    Marla Silvia Diamante

    2013-03-01

    Full Text Available Com o objetivo de indicar qual ambiente, telado ou campo aberto, fornece melhores condições para a produção e maior resistência ao pendoamento de diferentes cultivares de alface lisa, para as condições climáticas de Cáceres-MT, desenvolveu-se esse trabalho no período de fevereiro a abril de 2011. Foram avaliados vinte tratamentos, empregando o delineamento experimental em blocos casualizados em esquema fatorial 5 x 4, sendo cinco ambientes de cultivo (telas de sombreamento 30 e 50%, telas termo-refletoras 30 e 50% e campo aberto e quatro cultivares de alface tipo lisa (Elisa, Elizabeth, Regiane e Regina, com quatro repetições. A colheita foi realizada aos 30 dias após o transplante. As cultivares de alface lisa mais produtivas foram Regiane, que obteve maior número de folhas e Regina com menor comprimento de caule. Os ambientes de cultivo que aumentaram a resistência ao pendoamento da alface foram as tela de sombreamento e termorefletora 50%. As cultivares não apresentaram diferenças significativas entre si quanto à resistência ao pendoamento.This work was developed during the period of February to April, 2011, with the objective of indicating which environment, greenhouse or open field, provides better conditions for production, and greater resistance to bolting of different cultivars of loose-leaf lettuce, for the climatic conditions of Cáceres, Mato Grosso, Brazil, Twenty treatments were evaluated, using a randomized block experimental design in a 5 x 4 factorial of five environmental conditions (shading screens of 30 and 50%, heat-reflective screens of 30 and 50%, and open field and four cultivars of loose-leaf lettuce (Elisa, Elizabeth, Regiane and Regina, with four replications. Harvesting was carried out 30 days after transplanting. The most productive lettuce cultivars were Regiane, which obtained the greatest number of leaves, and Regina with the smallest stem length. The environmental conditions that increased

  17. Compound seabuckthorn oil bolt joint poly cresol son in cervical LEEP postoperative suffonylureas solution of application%复方沙棘子油栓联合聚甲酚磺溶液在宫颈LEEP术后的应用

    Institute of Scientific and Technical Information of China (English)

    徐静; 孙建新

    2011-01-01

    目的 探讨复方沙棘子油栓联合聚甲酚黄溶液在宫颈LEEP术后的临床疗效.方法 将120例阴道镜病理回报:宫颈上皮内瘤变1-2级患者随机分成治疗组及对照组,治疗组宫颈LEEP刀治疗后宫颈用聚甲酚黄溶液1:10冲洗,后给复方沙棘子油栓一枚日一次应用,对照组,宫颈LEEP刀术后未曾特殊治疗.结果 宫颈LEEP刀术后,阴道流液多,出血时间长,创面愈合时间长,复方沙棘子油栓联合聚甲酚黄溶液可减少术后阴道排液时间,缩短出血时间,促进创面愈合时间.结论 复方沙棘子油栓联合聚甲酚黄溶液在宫颈LEEP治疗过程中,效果好,疗程短,复发率低.%Objective Explore compound seabuckthom oil bolt joint sons gather cresol yellow solution in cervical LEEP postoperative clinical curative effect. Methods 120 cases of vaginal mirror pathological return:cervical intraepithelial neoplasia of grade 2 variable 1-patients were randomly divided into treatment group and control group,the treatment group cervical LEEP knife after treatment cervical with polycarboxylate cresol yellow solution “flush,empress give compound seabuckthorn oil tethered to a medal,son,controls,cervix once application DaoShu LEEP after not special treatment. Results the cervix DaoShu LEEP after vaginal bleeding time,fluid flow,coagulant long long time,compound seabuckthorn oil bolt joint gather together son solution can reduce postoperative yellow cresol vaginal drainage time,reduce hemorrhage time, promote wound healing time. Conclusion compound seabuckthorn oil bolt joint gather together the son in cervical LEEP yellow cresol solution treatment process,good effect,short course,and the recurrence rate is low.

  18. Projected double use of a rectangular roof-bolted roadway at a depth of 1200 m in seam D2/C; Geplante Doppelnutzung einer Rechteckankerstrecke in 1200 m Teufe im Floez D2/C

    Energy Technology Data Exchange (ETDEWEB)

    Breinig, F. [Bergbau AG Lippe, Gelsenkirchen (Germany); Opolony, K. [DSK-Werksdirektion zentrale Technik, Herne (Germany)

    2004-08-01

    The contribution outlines the projecting of seam D2/C at Lippe mine, which will be characterized by double use of the roof-bolted roadway. The experience with dimensioning based on numeric and physical investigations is presented, and the performance so far is described and analyzed. (orig.) [German] Der Beitrag schildert die Planung des Floezes D2/C auf dem Bergwerk Lippe. Beginnend mit dem Projekt der ersten Rechteckankerstrecke in der BH 328 und dem Teilprojekt 'Offenhalten nach Strebdurchgang' bis zur Entwicklung eines Ausbauschemas fuer die Doppelnutzung der Kohlenabfuhrstrecke in der BH 330 des Floezes D2/C. Die Entwicklungen der Ausbau- und Verschalungseinheit fuer die neue Dammtechnik wird eroertert und die Erfahrung mit den Dimensionierungsmethoden, basierend auf numerischen und physikalischen Untersuchungen, dargestellt. Abschliessend werden die Betriebserfahrungen der ersten Nutzung dargelegt und analysiert. (orig.)

  19. Numerical and experimental assessment of stainless and carbon bolted tensioned members with staggered bolts Avaliação numérica e experimental de membros tracionados em aço carbono e aço inoxidável com parafusos defasados

    Directory of Open Access Journals (Sweden)

    João de Jesus dos Santos

    2013-06-01

    Full Text Available Current stainless steel design codes, like the Eurocode 3, part 1.4, (2006, are still largely based on analogies with carbon steel structural behavior. The net section rupture represents one of the ultimate limit states usually verified for structural elements submitted to normal tension stress. An investigation aiming to evaluate the tension capacity of carbon and stainless steel bolted structural elements was performed and in this article, the results are discussed and compared in terms of stress distribution, and force-displacement curves, among others. The result assessment was done by comparisons to the Eurocode 3 (2003 provisions for carbon and stainless steels. The investigation indicated that when stainless steel is used in certain structural engineering applications like joints under tension forces, the current design criteria based on deformation limits need to be re-evaluated, especially due to the differences in the yields for ultimate deformation and stress ratios.As normas atuais de projeto de estruturas em aço inoxidável, como o Eurocódigo 3, parte 1.4 (2006, são, em grande parte, baseadas em analogias assumidas com o comportamento de estruturas desenvolvidas com aço carbono. A ruptura da seção transversal representa um dos estados-limites últimos usualmente verificados para elementos estruturais submetidos a tensões normais de tração. Esse artigo apresenta uma investigação para se avaliar a resistência à tração de elementos aparafusados em aço carbono e aço inoxidável. Os resultados são discutidos e comparados em termos de distribuição de tensões, curvas carga-deslocamento, entre outros. Esses resultados foram comparados com as recomendações de projeto do Eurocódigo 3, para aço carbono e aço inoxidável, respectivamente. Essa investigação indicou que, quando o aço inoxidável é utilizado em certas aplicações da engenharia estrutural, como ligações submetidas a esforços de tração, o crit

  20. The Encapsulation Performance Analysis of Series Enhanced Electromagnetic Railgun with Bolt Pre-tightening%串联增强型电磁轨道炮螺栓预紧封装性能分析

    Institute of Scientific and Technical Information of China (English)

    石江波; 栗保明

    2016-01-01

    For the purpose of studying the encapsulation performance of series enhanced electromag-netic railgun with bolt pre-tightening,calculated was the electromagnetic force of the rails from the per-spective of electromagnetic field with the stress,strain and displacement of the gun barrel achieved. Then a three dimensional series enhanced railgun tube model was built,and a ramp current was loaded to calculate the changing law of rail stress,strain and displacement. And these parametrical varying patterns of the barrel units were also obtained. As the calculation results show,under the condition of the blot pre-tightening,the rails and the barrel units are under the impact of certain initial displace-ment,stress and strain. With the gradual increase of the current and duration,the parameters of rail and barrel units were increased gradually with an obvious fluctuation pattern. The rail displacement in the bolt position shows obvious drop trend. And the displacement of barrel units was smaller than that of the rail,so the rail and the barrel unit can have good contact condition. This phenomenon demon-strates that the use of discrete seal barrel with bolt pre-tightening can control the maximum displace-ment of the rail to a certain extent,which works well for the barrel encapsulation performance.%为了研究螺栓连接预紧方式的串联增强型轨道炮的身管封装性能,从电磁场的角度出发,计算了电磁轨道炮发射时导轨中的电磁力,进而得到了身管应力、应变和位移量。建立三维串联增强型电磁轨道炮离散预紧身管模型,计算了在一种斜坡电流激励条件下导轨的应力、应变和位移量的变化规律,以及身管封装部件应力、应变及位移的变化规律。从计算结果看出,在螺栓预紧条件下,导轨及身管处于一定初始位移及应力、应变下,随着电流的逐渐增大和作用时间增大,各参量也逐渐增大,且呈现明显的波动状,导轨

  1. 导波在端锚锚杆锚固段上界面的反射研究%Research on the guided wave reflecting from the upper interface of partially grouted rock bolt

    Institute of Scientific and Technical Information of China (English)

    何文; 王成; 宁建国; 唐永刚

    2009-01-01

    Finite element method was used to simulate longitudinal guided wave reflecting from the upper interface of partially grouted bolt, with the excitation wave frequencies 5 ~ 60 kHz. Reflection coefficient was used to evaluate the upper interface reflection wave which can be seen clearly while reflection coefficient was large. The effect of thickness of the grout layer, wedge angle between the upper interface and the bolt axial direction and grout materials on the upper interface reflection wave was studied. The results show that the factors above have little effect on reflection coefficient with the same excitation wave frequency, and reflection coefficient is larger when the excitation wave frequency is lower than 20 kHz, and reflection coefficient reaches its minimun when the frequency is 40 kHz. The results of numerical simulation agree well with the experimental results.%利用有限元数值模拟研究了5~60 kHz纵向导波在端锚锚杆锚固段上界面的反射情况.使用反射系数衡量导波在锚固段上界面反射能量的大小,反射系数越大,即导波在锚固段上界面的反射越明显.通过改变锚固层厚度、锚固段上界面与锚杆轴向间的楔角和锚固层的材料,研究了反射系数的变化.結果表明,以上因素对同频率导波的反射系数影响不大;当激发波频率低于20 kHz,反射系数较大;而频率为40 kHz时,反射系数最小.数值模拟导波在锚固段上界面反射系数与现场测试所得结果吻合较好.

  2. Studies of Kernel Function in the Nonlocal Friction Model and Its Application on Bolt%非局部摩擦模型的核函数研究及其在锚杆中应用

    Institute of Scientific and Technical Information of China (English)

    刘伟平; 扶名福; 罗小艳

    2011-01-01

    为研究非局部摩擦理论中核函数的性质及其选取原则,在Oden等提出的非局部摩擦模型的基础上,分别采用指数型、三角函数型、负指数型和幂函数型等4种函数作为非局部摩擦模型中的核函数,并利用Mindlin问题的位移解导出的全长黏结式锚杆沿杆体表面所受剪应力的弹性解,对全长黏结式锚杆进行非局部摩擦分析.研究表明,基于这几种核函数的非局部摩擦模型以及局部摩擦模型所得到的剪应力分布大致相似.通过与实验数据对比可知,采用负指数函数的核函数形式计算所得锚杆侧剪应力分布比其他形式更接近于实验值.%To investigate the characteristics together with optimum selection of kernel functions in the nonlocal friction model, the nonlocal friction model proposed by Oden et al is modified. The kernel function in model is replaced by exponential function, trigonometric function, negative exponential function and power function. Based on the elastic solution of shear stress on bolt surface of the wholly grouted anchor derived with Mindlin's solution of displacement, wholly grouted anchor is analyzed by the modified nonlocal friction models which have four different kernel functions. The shear stress distributions on bolt surface given by the modified nonlocal friction models and the local friction models are similar. The nonlocal friction effect is also discussed. The results obtained by the modified nonlocal friction model with different kernel functions and local friction model are compared with experimental results. It is found that the calculating results obtained by modified nonlocal friction model with the negative exponential kernel functions agree better with experimental results.

  3. 自钻式锚杆在深基坑支护中的应用%Technical Study on Application of Self-drilling Bolts in Deep Foundation Excavation Support

    Institute of Scientific and Technical Information of China (English)

    戚瑞安

    2014-01-01

    桩锚支护是近年来新兴的深基坑支护方式,但常规锚杆在饱和软土地区施工中效果不佳。结合胜利油田中心医院综合病房楼基坑支护工程,提出一种适合特殊地质特点的自钻式锚杆施工技术,研究了其施工工艺、操作要点,探讨了监测方式,该工艺实施效果显著,技术先进可行,在多项工程中获得推广应用。%Pile-anchor support is a rising deep excavation support pattern in recent years, but the conventional pile-anchor does not work well in the areas of saturated soft soil. Illustrated by foundation excavation supports of comprehensive inpatient building of Central Hospital of Shengli Oilfield, this paper puts forward a new construction technique of applying self-drilling bolts in special geologic condition with a study on its technology and operating instructions and a further discussion on testing method. This technique is advance, effective and practical and has been applied and promoted in many projects.

  4. Development of Long Shank Repair Tool for Defect of Pressure Vessel Bolt Hole in Pressure Vessel of Nuclear Power Plant%核电站压力容器螺孔长杆梳刀装置研制

    Institute of Scientific and Technical Information of China (English)

    黄新东; 黄辉; 洪龙; 李鑫

    2013-01-01

    In the reactor operation and operations with open lid,various defects may emerge on thread section of the main bolt hole pressure vessel.These defects must be dealt with before the closing of the lid.In view of the above conditions,this paper developed a pressure vessel screw rod cutter device,and expounds the long shank repair tool,a detailed description of the design scheme of the tool as well as the concrete structure.%在反应堆运行和开盖操作过程中,压力容器的主螺栓孔的螺纹段可能会产生各种缺陷,这些缺陷在再次扣盖前必须经过处理.针对上述工况,研制了一种压力容器螺孔长杆梳刀装置,本文阐述了该长杆梳刀装置的设计要求,详细描述该装置的设计方案以及具体结构形式.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

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

  6. 蜜腺发达Ogura晚抽薹不结球白菜雄性不育系的鉴定%Evaluation of Late - bolting Ogura Chinese Cabbage Male Sterile Lines with Developed Nectar Gland

    Institute of Scientific and Technical Information of China (English)

    孙艳; 刘维信

    2011-01-01

    By comparing of bumble bee visiting and staying time on flowers of Ogura non - heading Chinese cabbage male sterile lines, two plants were identified and selected as they attracted more bumble bee visiting. Nectar gland size, flowering, and pod set of these two plants were further determined. The results showed that the two selected plants all had developed nectar glands, flowered and set pod normally. This finding set a well foundation for breeding out elite late -bolting Ogura male sterile lines in non -heading Chinese cabbage.%本试验以Ogura晚抽薹不结球白菜薹ms等为材料,通过观察和比较熊蜂对不同白菜品种访花次数和访花滞留时间的差异,选择出能吸引熊蜂访花且访花滞留时间长的Ogura薹ms植株.对选择出植株的蜜腺大小和开花结实特性进行了进一步鉴定,结果表明选出的薹ms株蜜腺发达,开花结实正常,为选育优良晚抽薹胞质不结球白菜雄性不育系奠定了基础.

  7. Experimental study on using expansion bolt anchoring half pipe to reinforce beam negative moment area%膨胀螺栓外锚半钢管加固梁负弯矩区的试验研究

    Institute of Scientific and Technical Information of China (English)

    王智巍; 张鸿梅; 周静雅

    2013-01-01

    The test used the implant expansion bolt anchor half pipe technology to achieve carbon fiber reinforced frame beam negative moment area of purpose. Providing a new reinforcement technology that uses half pipe to anchor CFRP at the negative moment of the beam position for node reinforcement. To verify the efficiency of the strengthening methods, five frame joints have been tested under static loading test and analyzed with the ANSYS non-linear finite element analysis software. The test and analysis results show that by the strengthening way of this paper the ultimate load of the five specimens are increased.%试验采用内植膨胀螺栓外锚半钢管技术来达到碳纤维布加固框架节点梁负弯矩区的目的.提出利用半钢管对负弯矩区加固的碳纤维布进行锚固的一种新技术.通过对5个框架节点的静力加载试验,以及用非线性软件ANSYS进行模拟分析,验证了本文采用的加固方法可行.试验及分析结果表明,本文采用的加固方法加固效果明显,能有效提高试件的承载力.

  8. Macro-micro mechanical on joint -grout-bolt interaction in rockmass subjected to shear loading%剪切荷载下岩体结构面-浆体-锚杆相互作用机理宏细观研究

    Institute of Scientific and Technical Information of China (English)

    王刚; 袁康; 蒋宇静; 吴学震

    2015-01-01

    The mechanical behavior of bolted rock joints was researched by using bilinear constitutive model of bolt in virtue of the inner-embed FISH language of PFC based on DEM. Through a variation of the bolt’s elastic modulus and the strength of grout, their influence on macroscopic mechanical response and microscopic mechanical response of anchoring system were studied under the bolt−grout−rock interaction. The results show that there is a clear relationship between the mechanical response of bolted rock joint and the mechanical property of anchoring structures. Macroscopic aspect: the stiffer the bolt the more shear strength of bolted rock joint has. Microscopic aspect: the quantity of cracks in grout and rock increase with the increase of bolt’s stiffness so as to result in more damage to anchoring system. Cracks will appear in the joint and the intersection of bolt and joint initially. With the increase of shear displacement, the cracks in joint will be generated at the place whose compressive contact force is very concentrated while the cracks around the bolt will propagate from the intersection of bolt and joint to the two ends of bolt. Besides, the cracks are mainly concentrated on the compression side. Most of the cracks are tension cracks which are induced by compression among particles. The number of cracks in rock and grout will increase when the strength of grout is much larger or smaller. The cracks are mainly tension cracks which are result from the compression among the particles. When the strength of grout is much smaller, the cracks are mainly concentrated on the rock otherwise the cracks will be mainly distributed in grout. Therefore, the shearing strength of bolted rock joint in macroscopic aspect and the damage of anchoring system resulting from anchoring structure in microscopic aspect should be considered comprehensively while reinforcing jointed rock mass so as to realize the macroscopic-microscopic coupling support. It has a certain

  9. GRADIENT DEPENDENT NONLOCAL FRICTION MODEL AND ITS APPLICATION IN MECHANICAL ANALYSIS OF BOLT%梯度依赖的非局部摩擦模型及其在锚杆受力分析中的应用

    Institute of Scientific and Technical Information of China (English)

    刘伟平; 扶名福

    2014-01-01

    Based on the gradient theory , a gradient dependent nonlocal friction model was established and used to analyze bolt .By using Mindlin's solution of displacement , a solution of shear stress in the anchorage was derived . The nonlocal effect on the contact surface was revealed and the solution of shear stress of the anchorage section was given.The results were compared with those obtained by the gradient dependent nonlocal friction model and local frication model .Factors affecting the nonlocal friction were discussed .Taking account of the nonlocal friction effects , the shear stress peak value in the anchorage zone was smaller than the one without the consideration .%基于梯度理论,建立了梯度依赖的非局部摩擦模型,并应用其对锚杆受拉时锚固段的剪应力进行理论分析。根据Mindlin问题的位移解,导出锚杆锚固段的剪应力,得到在非局部摩擦模型下的锚杆锚固段的剪应力解,并对梯度依赖的非局部摩擦模型和局部摩擦模型(库仑模型)下的剪应力结果进行比较,进一步对影响剪应力非局部效应的相关因素进行分析。计算结果表明,考虑非局部摩擦效应时,沿锚固体的剪应力峰值比不考虑的要小。

  10. REINFORCING MECHANISM AND SIMULATING METHOD FOR REINFORCING EFFECTS OF SYSTEMICALLY GROUTED BOLTS IN DEEP-BURIED HARD ROCK TUNNELS%深埋硬岩隧洞系统砂浆锚杆的加固机制与加固效果模拟方法

    Institute of Scientific and Technical Information of China (English)

    吴文平; 冯夏庭; 张传庆; 邱士利; 李占海

    2012-01-01

    Systematically grouted bolts, as the main support structure of deep-buried hard rock tunnels, compose the bolt-rock composite structure with surrounding rocks. which reinforces the mechanical property of surrounding rocks. Based on the Mohr-Coulomb(M-C) criterion, the stress condition and the strength of the composite structure meeting the M-C criterion were derived under high-stress conditions. Combining with the rock mass deterioration model(RDM) of brittle rock, an approach to determine the mechanical parameters of the composite structure was presented. The difference of mechanical parameters between two different composite structures of bolt-elastic surrounding rock and bolt-yielding surrounding rock was taken into account. In this approach, the mechanical parameters of the bolt-yielding surrounding rock composite structure were associated with present equivalent plastic strain of surrounding rocks. A numerical method, which could model the reinforcing effect of normally grouted bolts laid out systematically during excavating and supporting stages, was proposed. It is identified that this method has an advantage over other methods in modeling the effect of supporting time on surrounding rock stability. Finally, the method was applied to evaluate the stability of surrounding rocks, and related references were provided for design and construction of the diversion tunnel #2 of Jinping Ⅱ hydropower station.%系统布置的砂浆锚杆是深埋硬岩隧洞主要支护结构,锚杆与围岩组成锚杆-围岩复合结构体,使围岩的力学特性得到改善.基于岩体的莫尔-库仑(M-C)屈服准则,推导锚杆-围岩复合结构体满足M-C准则的应力条件.结合岩体劣化本构模型,提出确定锚杆-围岩复合结构体力学参数的方法.锚杆与弹性围岩和屈服围岩组成的锚杆-围岩复合结构体的力学参数确定方法不同,锚杆与屈服围岩组成的锚杆-围岩复合结构体的力学参数与围岩当前状态的等

  11. Nuts and Bolts: Poetry That Really Works

    Science.gov (United States)

    Olson, Barbara

    1972-01-01

    Eighth-grade students normally turned off by poetry became enthusiastic and skilled writers of the cinquain, haiku, tanka and Korean sijo forms after teacher explained their structure and showed films for inspiration. (PD)

  12. Bolt elongation of variable message signs

    Science.gov (United States)

    Scancella, Robert J.; Skalla, Robert

    1998-03-01

    The purpose of this paper is to describe existing problem areas in the manufacturing and erecting of variable message signs (VMS) on cantilever truss units. VMS are electronic message boards that are rectangular in shape and weigh between 3,000 and 5,000 pounds. The structures that were inspected for this paper are part of the Route 80 Magic Project and the Traffic Signal Contract #25 (Route 37).

  13. Wind farm construction : the nuts and bolts

    Energy Technology Data Exchange (ETDEWEB)

    Hall, T.A. [Northwind Solutions, Whitby, ON (Canada)

    2007-07-01

    This presentation discussed wind farm construction techniques and strategies. Issues related to permits and bonds were discussed, and an outline of pre-planning issues related to erosion and sediment plans, site layouts, and transportation requirements were presented. Work related to foundations, roads, collection systems, and sub-stations was discussed with particular reference to procedures for digging, levelling, and preparing roads. Photographs of builders constructing a wind turbine foundation were included along with planning details for the construction of collection systems. Issues related to ground grids and dead ends were also reviewed. The presentation also discussed topics related to rotors; offloading; electrical completion; and turbine erection. Issues related to the construction of meteorological towers were also reviewed. Rotor assembly procedures were outlined, and details of mechanical completion plans were presented. tabs., figs.

  14. Optimization of bolt thread stress concentrations

    DEFF Research Database (Denmark)

    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 concentrati...... are found in the optimized designs leading to the proposal of a new standard. The reductions in the stress are achieved by rather simple changes made to the cutting tool....

  15. Brazil Lightning Bolts Set Shocking World Record

    Institute of Scientific and Technical Information of China (English)

    卞小翩

    2002-01-01

    巴西是世界上最大的地处热带地区的国家,因此,它就成了世界“雷电之国”。让我们吃惊的是,10%of all lightning-rylated deaths in the world竟然发生在巴西!文章出现一个名词词组 power blackouts,而擅长使用词汇connotation的英语也常常“活用”此词。 He had had a blackout after the accident./事故发生后,他晕过去一阵子。

  16. Nuts and Bolts for Creating Space

    CERN Document Server

    Czech, Bartlomiej

    2014-01-01

    We discuss the way in which field theory quantities assemble the spatial geometry of three-dimensional anti-de Sitter space (AdS3). The field theory ingredients are the entanglement entropies of boundary intervals. A point in AdS3 corresponds to a collection of boundary intervals, which is selected by a variational principle we discuss. Coordinates in AdS3 are integration constants of the resulting equation of motion. We propose a distance function for this collection of points, which obeys the triangle inequality as a consequence of the strong subadditivity of entropy. Our construction correctly reproduces the static slice of AdS3 and the Ryu-Takayanagi relation between geodesics and entanglement entropies. We discuss how these results extend to quotients of AdS3 -- the conical defect and the BTZ geometries. In these cases, the set of entanglement entropies must be supplemented by other field theory quantities, which can carry the information about lengths of non-minimal geodesics.

  17. Effect of Cracking on Lag Bolt Performance

    OpenAIRE

    Ramskill, Thomas Edward

    2002-01-01

    This dissertation presents the results of testing to determine the load-slip characteristics of single-shear single lag screw connections subjected to monotonic lateral loading parallel to grain. Of particular importance was the comparison of experimental capacity and 5% offset yield load resistances to load resistances as predicted by the American Forest & Paper Association's (AF&PA) publication General Dowel Equations for Calculating Lateral Connection Values, Technical Report 12 (TR-12)...

  18. The Nuts and Bolts of USMC Fasteners

    Science.gov (United States)

    2012-08-28

    Dry Film Thickness – Torque-Tension – Porosity • Develop better process to procure fasteners in the USMC ...despite the fact that they were of the recommended “brand.” • The investigation and subsequent reworking of these vehicles was expensive

  19. Nuts and bolts of conducting feasibility studies.

    Science.gov (United States)

    Tickle-Degnen, Linda

    2013-01-01

    Many factors can affect the successful implementation and validity of intervention studies. A primary purpose of feasibility and pilot studies is to assess the potential for successful implementation of the proposed main intervention studies and to reduce threats to the validity of these studies. This article describes a typology to guide the aims of feasibility and pilot studies designed to support the development of randomized controlled trials and provides an example of the studies underlying the development of one rehabilitation trial. The purpose of most feasibility and pilot studies should be to describe information and evidence related to the successful implementation and validity of a planned main trial. Null hypothesis significance testing is not appropriate for these studies unless the sample size is properly powered. The primary tests of the intervention effectiveness hypotheses should occur in the main study, not in the studies that are serving as feasibility or pilot studies.

  20. The NUTs and Bolts of squashed holography

    Science.gov (United States)

    Bobev, Nikolay; Hertog, Thomas; Vreys, Yannick

    2016-11-01

    We evaluate the partition function of the free O( N ) model on a two-parameter family of squashed three spheres. We also find new solutions of general relativity with negative cosmological constant and the same double squashed boundary geometry and analyse their thermodynamic properties. Remarkably, both systems exhibit a qualitatively similar behaviour over the entire configuration space of boundary geometries. Recent formulations of dS/CFT enable one to interpret the field theory partition function as a function of the two squashing parameters as the Hartle-Hawking wave function in a minisuperspace model of anisotropic deformations of de Sitter space. The resulting probability distribution is normalisable and globally peaked at the round three sphere, with a low amplitude of boundary geometries with negative scalar curvature.

  1. The NUTs and Bolts of Squashed Holography

    CERN Document Server

    Bobev, Nikolay; Vreys, Yannick

    2016-01-01

    We evaluate the partition function of the free O(N) model on a two-parameter family of squashed three spheres. We also find new solutions of general relativity with negative cosmological constant and the same double squashed boundary geometry and analyse their thermodynamic properties. Remarkably, both systems exhibit a qualitatively similar behaviour over the entire configuration space of boundary geometries. Recent formulations of dS/CFT enable one to interpret the field theory partition function as a function of the two squashing parameters as the Hartle-Hawking wave function in a minisuperspace model of anisotropic deformations of de Sitter space. The resulting probability distribution is normalisable and globally peaked at the round three sphere, with a low amplitude of boundary geometries with negative scalar curvature.

  2. 钢板箍螺栓连接高强复合螺旋箍装配整体式柱抗震性能试验%SEISMIC BEHAVIOR RESEARCH OF STEEL PLATE HOOP-BOLT PREFABRICATED COLUMN CONFINED BY HIGH-STRENGTH COMPOSITE SPIRAL STIRRUPS

    Institute of Scientific and Technical Information of China (English)

    李进; 陈鹏; 魏威; 李青宁

    2014-01-01

    通过低周反复拟静力试验方法,研究钢板箍螺栓连接装配整体式柱的抗震性能。试验共设计4根长柱试件,观察各试件开裂、屈服、破坏全过程和破坏状态,得出各试件荷载-位移滞回曲线和骨架线,对比研究各试件承载力、延性和耗能能力,研究钢板箍螺栓连接方式的可行性。试验证明:钢板箍螺栓连接高强复合螺旋箍筋装配整体式柱和现浇整体柱具有相当的承载力和抗震能力,在连接可靠的情况下可以在工程中代替现浇柱。%In order to study the seismic behavior of steel plate hoop-bolt prefabricated column by high-strength composite spiral stirrups , the low cyclic loading tests were carried out .Four long column specimens were designed . Cracking, yield, destroyed process and destroyed state of specimens were observed in the tests , and the load-displacement hysteretic curves and skeleton curves of each specimen were also obtained .Comparative study on carrying capacity , ductility and energy dissipation capacity of each specimen was conducted , and analysis of the reliability of steel plate hoop-bolt connection was done .The test proves that steel plate hoop-bolt prefabricated column confined by high-strength composite spiral stirrups has about the same bearing capacity and seismic capacity as compared with cast-in-place column, and the prefabricated column can be used to replace the cast-in-place column in project in case of secure connections .

  3. Differences of hectometer technique between Su Bingtian,Zhang Peimeng and Bolt%苏炳添、张培萌与博尔特百米技术差异分析

    Institute of Scientific and Technical Information of China (English)

    易文娟; 詹晓梅; 王双; 朱小桢

    2015-01-01

    This research adopted information technology approach to study Su Bingtian and Zhang Peimeng's sprint technique in the men's 1 00 m final of 1 7 th Inchon Asian Games and compared their technique with that of Bolt.The results show that the step size ability is the main technique shortness and they should increase the step size as a breakthrough to improve athletic performance on the perquisite of keeping the step frequency not sharply reduced.The high frequency index reveals the unbalanced characteristics of their step length and step frequency.Therefore,they should combine with their own characteristics to improve the step index so that the step length and step frequency can develop collaboratively.To perfect the stride length and the stride frequency,they need not only increase the angle of the support leg cushion and the stomp angle,but also increase the folding of the legs as well as the swing speed.Amplify the swing angle and improving the pawing power also play an important role in perfecting the stride capabilities and the stride frequency.%采用信息技术等研究方法,以第17届仁川亚运会男子百米决赛中苏炳添和张培萌为研究重点,使之与博尔特的百米技术特征进行比较并分析他们百米技术中与博尔特之间存在的差异。结果表明:苏炳添和张培萌与博尔特的百米技术差距主要体现在步长能力,他们应在步频不大幅降低的前提下,以加大步长作为提高运动成绩的突破口;较高的步频指数揭示了苏炳添和张培萌百米技术呈现出步长与步频不均衡发展特征,他们应注意根据自身技术特点,提高步长指数,使步长和步频协同发展;加大支撑腿缓冲幅度与后蹬时膝关节角度,增加摆动腿折叠程度、加大前摆角度与提高扒地力量是苏炳添和张培萌完善步频与步幅能力的关键。

  4. Experimental Research on the Performance of Coalmine -used Anchor Bolt Cutting by a Fore -Hybrid High-pressure Abrasive Water-jet%前混式高压磨料水射流切割锚杆性能实验研究

    Institute of Scientific and Technical Information of China (English)

    王从东

    2015-01-01

    In order to study coalmine -used anchor bolt cutting by high -pressure water jet , by using a fore-hy-brid high-pressure abrasive water -jet cutting system built by our own , the anchor bolt cutting experiment was conducted .Based on the study of the influence of jet pressure , abrasive parameters , traversing speed , and jet target distance on cutting , it was concluded that the jet pressure and cutting depth can be simplified as a linear relationship and nozzle traversing speed and cutting depth as a inverse relationship , and there is the optimum val-ue of the abrasive parameters and the target distance .At the same time , the optimal process parameters of cutting were obtained .%为了研究高压水射流切割煤矿锚杆的问题 ,利用自行搭建前混式高压磨料水射流切割系统对煤矿用的锚杆进行切割试验,通过对射流压力、磨料参数、横移速度和喷射靶距等参数对切割能力影响的探讨,得出射流压力与切割深度可以简化为线性关系,喷嘴横移速度与切割深度可以简化为反比关系,以及磨料参数和靶距存在最优值等结论,同时获取了切割所需的最佳工艺参数.

  5. Q460等级高强度钢材螺栓抗剪连接孔壁承压性能有限元分析%Finite Element Analysis of Bolted Connection in Q460 Grade High Strength Steels Under Static Shear

    Institute of Scientific and Technical Information of China (English)

    潘斌; 石永久; 王元清

    2012-01-01

    运用三维实体有限元数值模拟方法,对9组Q460等级高强度钢材螺栓抗剪连接试验进行材料、几何、接触非线性分析,详细介绍了建立有限元模型的具体方法,给出了极限承载力的求解全过程,提出了影响其模拟精度的重要因素.根据端距、边距和螺栓间距的不同,采用有限元模型模拟出了连接板发生的孔壁承压破坏、净截面破坏等不同的破坏模式,通过有限元分析得到的极限承载力计算值与试验值十分接近.结果表明:建立的有限元模型能够准确模拟高强度钢材孔壁承压性能,选择合适的应力-应变关系和接触刚度是影响计算精度的关键.%A finite element model with three-dimensional solid elements was established to stimulate the bolted connection in nine groups of Q460 grade high strength steels. Non-linear material, geometrical and contact analysis were carried out to predict the load-displacement curves. The model-building procedure and solution programs were introduced in detail. Due to various end distance, edge distance and pitches, different failure modes were observed including end tear-out, bearing resistance and net-section facture. The effectiveness of the performed finite element analysis was verified by the comparison between calculation results and the experiment results. The results show that the finite element model in the paper can simulate bearing resistance of bolted connection in high strength steels. It's found that the appropriate stress-strain relations and contact stiffness are important parameters for accurate prediction.

  6. Research and application of U-shaped steel plate-concrete composite open-web sandwich slab structure with high strength bolts%U形钢板-混凝土高强螺栓连接组合空腹夹层板楼盖结构研究与应用

    Institute of Scientific and Technical Information of China (English)

    胡岚; 马克俭

    2012-01-01

    提出一种多层大跨度结构体系——U形钢板-混凝土高强螺栓连接组合空腹夹层板楼盖,该结构体系由U形钢板-混凝土组合下肋、钢筋混凝土上肋和上下肋间设置的钢筋混凝土剪力键形成的需考虑夹芯层剪切变形的空间楼盖。介绍了该楼盖结构体系的简化计算模型、弹性连续化理论分析方法和实用分析方法,通过仿真模型试验及实际工程应用,验证了弹性连续化理论分析方法与实用分析方法的正确性。研究结果表明:采用由上、下表层薄膜刚度和具有一定抗剪刚度的剪力键夹芯层组成的U形钢板-混凝土高强螺栓连接组合空腹夹层板楼盖简化计算模型进行弹性连续化理论分析,其分析结果与仿真模型试验结果基本相符,相对误差最大不超过5%;按等强和等刚度原则将U形钢板-混凝土组合空腹夹层板折算成钢筋混凝土实腹梁的实用分析方法,其计算结果与仿真模型试验结果基本相符,相对误差最大不超过4%。以黑龙江中医药大学文体中心B区57 m×39 m+57 m×36 m双跨多层(地下1层、地上3层)工程为算例,并与原位测试结果进行比较,说明U形钢板-混凝土高强螺栓连接组合空腹夹层板楼盖安全可靠,且具有较好的经济性。%A system of multilayer large span structure, the U-shaped steel plate and concrete composite open-web sandwich slab floor with high strength bolts was put forward. The structural system is composed of the U-shaped steel plate and concrete composite upper rib, the reinforced concrete bottom rib and the reinforced concrete shear keys between upper and bottom ribs, resulting in a sandwich layer of shear deformation of space floor. This paper comprehensively introduced the simplified calculation model of the structural system using the elastic continuum theory method and the practical analysis method, and verified the effectiveness of the model through the simulation

  7. Distribution of Stress on Bonded Length of Tension-type Rock Bolt Based on Theory of Elasticity%基于弹性理论的拉力型锚杆锚固段应力分布规律研究

    Institute of Scientific and Technical Information of China (English)

    彭辉; 袁超; 向德强

    2013-01-01

    视锚杆和周围介质为弹性材料,在弹性半空间里,利用Mindlin位移解,根据拉力型锚杆实际工作状态,推导出拉力型锚杆锚固段轴向应力和弹性粘结应力分布的方程。并分析相关岩土参数对锚固段轴向应力和剪应力的分布的影响,得出影响较大的几个因素,为拉力杆的力学分析和工程设计提供理论依据。%This research provides a theoretical basis for the pull rod mechanics analysis and en-gineering design. In accordance with the above,we can analyse related geotechnical parameters on the axial stress and shear stress distribution of the anchorage segment,and influence of sev-eral factors can be concluded. According to tensile type anchor rod under the actual working condition,we can deduce the equation about the distribution of axial stress and elastic bond stress of tensile type anchor's anchoring section when the anchor bolt and the surrounding me-dium are elastic materials by Mindlin's displacement solution in elastic half-space.

  8. 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

    Energy Technology Data Exchange (ETDEWEB)

    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

  9. 锚杆支护动态信息设计法在煤巷快速掘进中的应用%Application of Bolt Support Dynamic information Design Method of Coal RoadWay in the Speedy DriVage

    Institute of Scientific and Technical Information of China (English)

    黄霆; 张学锋

    2014-01-01

    Anchor dtnamic information design method can adapt to the complexitt and variabilitt of the geological conditions of surround-ing rock of roadwat,the design principle and idea of the method has been accepted bt domestic and foreign,it can be suited to the charac-teristics of the coal roadwat bolting design method;it introduced sandvik MB670 ttpe digging anchor machine can realize cutting,loading, supporting,parallel operation into a lane at a time in changcun coal Mine. S6-8 Track Lane adopts advanced MB670 digging anchor all-in-one device and anchor dtnamic information design method can realize Quick safett and efficienct in coal roadwat drivage.%锚杆动态信息设计法可以适应巷道围岩地质条件的复杂性和多变性,该方法的设计原理和思路已为国内外所接受,成为适合煤巷特点的锚杆支护设计方法;常村煤矿引进的山特维克MB670型掘锚一体机可以实现截割、装载、支护平行作业,一次成巷。S6-8轨道巷采用先进的MB670型掘锚一体机设备和锚杆动态信息设计法可以实现煤巷安全高效快速掘进。

  10. 我国男子百米训练理论创新趋势研究——以博尔特为例%Innovative Trend of the Men's 100m Training Theory in China——A Case Study on Bolt

    Institute of Scientific and Technical Information of China (English)

    朱泉池; 陶于

    2012-01-01

    通过文献资料法、录像观察法、专家访谈法和逻辑分析法,在分析博尔特身体特点、生理特点、心理特点和技术特点的基础上,提出了狠抓训练细节、创新力量训练方法,由周期训练向板块训练转变、被动恢复走向主动恢复、重视心理调适训练,最终实现训练的人本化与科学化相结合的训练方法,旨在科学指导短跑运动选材,更新训练观念,提高我国的百米竞技运动水平.%Through the method of literature review, experts' interviewing, video observation and logical analyses, based on the analysis of the physical, physiological, psychological and technical features of Bolt, this paper proposed some new training methods such as paying close attention to training details, creating innovative strength training, transfering from periodical training to section training, from passive recovery to active recovery, and emphasizing psychological adjustment training, which will eventually contributing to a new training practice combined with humanity and science. This paper was set as a scientific guidance for athletes to select training materials, to update training concepts and finally to improve the competitive level of 100 sprint in our country. Aims to scientific guidance short run sports material, and update training concepts, improve China's competitive sports level.

  11. Numerical Analysis on Key Structure of Super High Pressure Hydraulic Bolt Stretcher for Conventional Island of Nuclear Power%核电常规岛用超高液压螺栓拉伸器关键结构的数值分析

    Institute of Scientific and Technical Information of China (English)

    张澄东; 浦琪琦; 张江涛; 李萍

    2014-01-01

    针对核电常规岛用螺栓拉伸器具有超高压、超小空间作业工况的特性,提出一种基于数值分析与实验相接合的设计方法,运用ANSYS软件对螺栓拉伸器关键结构---缸体与螺帽进行有限元校核,并与测定的应变实验数据进行对比;同时分析参数Rm、D对螺帽结构的优化特性。研究结果表明:初设的缸体强度和刚度满足材料的要求,但螺帽在“L型”截面拐点处出现“负”安全系数;优化螺帽结构尺寸,当Rm =8 mm,D=60 mm时与初设参数相比应力减小了121.2%,应变减小了58%,安全系数得到极大提高,这为该设备的可靠性和安全性提供了设计依据。%Aiming at the characteristics that the bolt stretcher for conventional island of nuclear power has the ultra high pres-sure,ultra small space operation conditions,a design method based on numerical analysis and experiment was presented,the ANSYS software was used to check the cylinder block and blind nut,and the analysis results were compared with the experimental strain data. The optimization characteristices of the parameters Rm ,D on the blind nut were analyzed. The results show that:the strength and stiff-ness of first set of cylinder block can meet the material requirements,but the blind nut has“negative”safety factor in the inflection point of“L”section;optimizing the blind nut structure size,when Rm and D are equal to 8 mm and 60 mm respectively,the stress de-creases by 121.2% and the strain decreases by 58% comparing with initial parameters,the safety coefficient is heightened,which pro-vides design basis for the reliability and safety of the equipment.

  12. Parameter estimation and investigation of a bolted joint model

    Science.gov (United States)

    Shiryayev, O. V.; Page, S. M.; Pettit, C. L.; Slater, J. C.

    2007-11-01

    Mechanical joints are a primary source of variability in the dynamics of built-up structures. Physical phenomena in the joint are quite complex and therefore too impractical to model at the micro-scale. This motivates the development of lumped parameter joint models with discrete interfaces so that they can be easily implemented in finite element codes. Among the most important considerations in choosing a model for dynamically excited systems is its ability to model energy dissipation. This translates into the need for accurate and reliable methods to measure model parameters and estimate their inherent variability from experiments. The adjusted Iwan model was identified as a promising candidate for representing joint dynamics. Recent research focused on this model has exclusively employed impulse excitation in conjunction with neural networks to identify the model parameters. This paper presents an investigation of an alternative parameter estimation approach for the adjusted Iwan model, which employs data from oscillatory forcing. This approach is shown to produce parameter estimates with precision similar to the impulse excitation method for a range of model parameters.

  13. Nuts and Bolts - Techniques for Genesis Sample Curation

    Science.gov (United States)

    Burkett, Patti J.; Rodriquez, M. C.; Allton, J. H.

    2011-01-01

    The Genesis curation staff at NASA Johnson Space Center provides samples and data for analysis to the scientific community, following allocation approval by the Genesis Oversight Committee, a sub-committee of CAPTEM (Curation Analysis Planning Team for Extraterrestrial Materials). We are often asked by investigators within the scientific community how we choose samples to best fit the requirements of the request. Here we will demonstrate our techniques for characterizing samples and satisfying allocation requests. Even with a systematic approach, every allocation is unique. We are also providing updated status of the cataloging and characterization of solar wind collectors as of January 2011. The collection consists of 3721 inventoried samples consisting of a single fragment, or multiple fragments containerized or pressed between post-it notes, jars or vials of various sizes.

  14. Using Impact Modulation to Identify Loose Bolts on a Satellite

    Science.gov (United States)

    2011-10-21

    damping parameters can be extracted. Bowden and Dugundji [33] and Esteben and Rogers [34] also identified stiffness and damping parameters in a beam...M. Bowden and J. Dugundji . Joint damping and nonlinearity in dynamics of space structures. AIAA Journal, 28(4):740–749, 1988. [34] J.Esteban and C. A

  15. Altering Cardiac Function via Transgenesis A Nuts and Bolts Approach.

    Science.gov (United States)

    Robbins, J

    1997-08-01

    Transgenesis provides a means to modify the mammalian genome. By directing expression of a engineered protein to the heart, one now is able to remodel effectively the cardiac protein profile and study the consequences of a single genetic manipulation at the molecular, biochemical, cytological, and physiologic levels. Often, a particular pathology or even a global remodeling process such as hypertrophy is accompanied by the upregulation or downregulation of a gene or set(s) of genes. What is not known is whether these changes represent a beneficial compensatory response or contribute to the continued degeneration of normal heart function. The ability to perform genetic manipulations on cardiac gene expression via transgenesis offers one a rapid and effective means of extending the correlations noted to the mechanistic level. Now, one can, in theory, express a candidate protein at a particular developmental time and determine the direct consequences of its appearance. Similarly, one can explore structure-function relationships, both between different forms of a protein family and in terms of active domains within a protein, by expressing a transgene that encodes a suitable mutation or ectopic protein isoform. This review explores the practical considerations of the transgenic approach in terms of what is important for a successful experiment from the necessary animal husbandry to designing constructs that will express at appropriate levels in the heart. (Trends Cardiovasc Med 1997;7:185-191). © 1997, Elsevier Science Inc.

  16. "Nuts and Bolts" of Laboratory Evaluation of Angioedema.

    Science.gov (United States)

    Farkas, Henriette; Veszeli, Nóra; Kajdácsi, Erika; Cervenak, László; Varga, Lilian

    2016-10-01

    Angioedema, as a distinct disease entity, often becomes a clinical challenge for physicians, because it may cause a life-threatening condition, whereas prompt and accurate laboratory diagnostics may not be available. Although the bedside diagnosis needs to be established based on clinical symptoms and signs, family history, and the therapeutic response, later, laboratory tests are available. Currently, only for five out of the nine different types of angioedema can be diagnosed by laboratory testing, and these occur only in a minority of the patient population. Hereditary angioedema with C1-inhibitor (C1-INH) deficiency type I can be diagnosed by the low C1-INH function and concentration, whereas in type II, C1-INH function is low, but its concentration is normal or even elevated. C1q concentration is normal in both forms. Acquired angioedema with C1-INH deficiency type I is characterized by the low C1-INH function and concentration; however, C1q concentration is also low, and autoantibodies against C1-INH cannot be detected. Complement profile of acquired angioedema with C1-INH deficiency type II is similar to that of type I, but in this form, autoantibodies against C1-INH are present. Hereditary angioedema due to a mutation of the coagulation factor XII can be diagnosed exclusively by mutation analysis of FXII gene. Diagnostic metrics are not available for idiopathic histaminergic acquired angioedema, idiopathic non-histaminergic acquired angioedema, acquired angioedema related to angiotensin-converting enzyme inhibitor, and hereditary angioedema of unknown origin; these angioedemas can be diagnosed by medical and family history, clinical symptoms, and therapeutic response and by excluding the forms previously described. Several potential biomarkers of angioedema are used to date only in research. In the future, they could be utilized into the clinical practice to improve the differential diagnosis, therapy, as well as the prognosis of angioedema.

  17. Like a bolt from the blue: phthalocyanines in biomedical optics.

    Science.gov (United States)

    Sekkat, Nawal; van den Bergh, Hubert; Nyokong, Tebello; Lange, Norbert

    2011-12-23

    The purpose of this review is to compile preclinical and clinical results on phthalocyanines (Pcs) as photosensitizers (PS) for Photodynamic Therapy (PDT) and contrast agents for fluorescence imaging. Indeed, Pcs are excellent candidates in these fields due to their strong absorbance in the NIR region and high chemical and photo-stability. In particular, this is mostly relevant for their in vivo activation in deeper tissular regions. However, most Pcs present two major limitations, i.e., a strong tendency to aggregate and a low water-solubility. In order to overcome these issues, both chemical tuning and pharmaceutical formulation combined with tumor targeting strategies were applied. These aspects will be developed in this review for the most extensively studied Pcs during the last 25 years, i.e., aluminium-, zinc- and silicon-based Pcs.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    Ventriculostomy is one of the most common neurosurgical procedures and an important tool in the treatment and monitoring of elevated intracranial pressure. Low accuracy has frequently been reported in the literature with risk of drain misplacement over 20% and with a need for reinsertion in up to...

  19. Texture analysis of Napoleonic War Era copper bolts

    Science.gov (United States)

    Malamud, Florencia; Northover, Shirley; James, Jon; Northover, Peter; Kelleher, Joe

    2016-04-01

    Neutron diffraction techniques are suitable for volume texture analyses due to high penetration of thermal neutrons in most materials. We have implemented a new data analysis methodology that employed the spatial resolution achievable by a time-of-flight neutron strain scanner to non-destructively determine the crystallographic texture at selected locations within a macroscopic sample. The method is based on defining the orientation distribution function of the crystallites from several incomplete pole figures, and it has been implemented on ENGIN-X, a neutron strain scanner at the Isis Facility in the UK. Here, we demonstrate the application of this new texture analysis methodology in determining the crystallographic texture at selected locations within museum quality archaeological objects up to 1 m in length. The results were verified using samples of similar, but less valuable, objects by comparing the results of applying this method with those obtained using both electron backscatter diffraction and X-ray diffraction on their cross sections.

  20. Analysis of WWER 440 SG primary collector bolted joint damage

    Energy Technology Data Exchange (ETDEWEB)

    Matocha, K.; Wozniak, J. [Vitkovice J.S.C., Ostrava (Switzerland); Pochman, K. [NPP Dukovany (Switzerland)

    1997-12-31

    The susceptibility of CHN35VT-VD and 08CH18N10T stainless steels to stress corrosion cracking in water environment, simulating water solution found in threaded holes, was investigated using rising load line displacement tests of precracked C(T) specimens. To judge the role of oxidant on stress corrosion cracking of both stainless steels, the effect of dissolved oxygen content (fully deaerated water, water aerated at the beginning of the test) was studied. 7 refs.

  1. Community Colleges and the State Budget: The Nuts and Bolts.

    Science.gov (United States)

    Lay, Scott

    2003-01-01

    This article provides insight into the California state budget process and gives an overview of California's growing deficit. The author examines the decline in personal income gained from stock options and capital gains as a means of illustrating the economic factors that resulted in a $28 billion deficit. Next, the author turns his attention to…

  2. 深度破坏软岩巷道修复的锚架组合承载壳原理及实践%Load-Bearing Shell Principle of Trusses Combined with Bolts in the Repairing of Soft Rock Roadway with Large Destruction and Its Application

    Institute of Scientific and Technical Information of China (English)

    高明仕; 闫高峰; 杨青松; 孟宪义; 张明华

    2011-01-01

    The -593 m air-return crosscut of No. 11 coal mine in Pingdingshan Mining Group had been repaired repeatedly, the loose and destroy zone of the surrounding rock was between 2. 5 to 4. 0 m, and even reached 6. 0 to 7. 0 m in local region, which had been greatly in excess of the conventionally anchorage zone. In that case, some active supports (anchor bolt, cable, et al) couldn't control the deformation of the roadway surrounding rock, and the roadway condition got worse after repeated repairing, which seriously affected and restricted the development stretching and supersedure of mining levels. By adopting the load-bearing shell principle of anchor-shed-grout, on the base of active long cable support and passive U-steel shed support, as well as grouting to strengthen the roadway between anchors and sheds, a small region of load-bearing shell of anchor-shed-grout, with certain thickness and strength, is formed within the superficial surrounding rock of large loose and destroy zone, to maintain the stability of roadway effectively and chronically. After the air-return crosscut being repaired for one year,the maximal roof convergence and two sides convergence was 324 mm and 354 mm, respectively. The engineering application shows that the established parameters of the repairing technology were reasonable and then the maintenance effect of roadway was remarkable, which can be applied as a reference in the repairing practice of similar destructive roadways.%平煤十一矿-593回风石门反复破坏反复维修,围岩松动破坏范围为2.50~4.0 m,局部达到6.0~7.0m,大大超过了常规的锚固支护范围,使得锚杆、锚索等主动支护不能有效控制巷道围岩变形,致使该巷道越修越坏,严重影响和制约了矿井开采水平的开拓延伸和正常接替.采用锚架注组合承栽壳原理支护技术,在长锚索主动支护的基础上,结合被动形式的U型钢棚支护,并在锚架之间进行注浆密实加固,形成大范围松

  3. HYSTERETIC BEHAVIOR STUDY ON CONNECTION OF PEC COLUMNS-STEEL BEAM WITH END PLATES AND PRETENSION HIGH-STRENGTH PENETRATING BOLTS%薄钢板PEC柱-钢梁端板对拉螺栓连接滞回性能试验研究

    Institute of Scientific and Technical Information of China (English)

    马吉; 方有珍; 陆承铎; 韩昌标; 孙国华

    2013-01-01

    The PEC column fabricated with thin-walled built-up section-steel beam connections with reduced cross sections,end plates and pretension high-strength penetrating bolts,the column layout and reduced cross-section location were taken as the design parameters,and 3 specimens were designed and fabricated by 1 ∶ 0.625 scale,which represented the middle joints.The test of the specimens was conducted under lateral cyclic loading in the column strong or weak axis,the test process was observed and the hysteretic curves were obtained.Based on the test results,the joints' global responses were analyzed,including the hysteretic behaviors,degradation of strength and flexural stiffness,energy-dissipation capacity,the ductility property and the failure mode.The conclusion showed that the specimens exhibited various degrees of self-centering functions,sound ductility and energy-dissipation capacity; the failure mode formed primary induced by yielding in the reduced cross-section or near the welding position of a steel beam.The study provides an experimental basis for amending the specification and engineering practice adopting the structure comprised of PEC columns-steel beams.%薄钢板组合截面PEC柱-钢梁连接中节点,采取工字梁端截面削弱、端板与预拉对穿高强螺栓的连接方式,考虑组合柱布置与梁削弱截面位置变化作为设计参数,对3个PEC柱-削弱梁、短端板对穿螺栓连接中节点1∶0.625缩尺模型进行低周反复荷载下的滞回性能试验.观察各个试件试验中的破坏过程,通过实测数据分析,得到了该类框架连接节点的滞回性能、强度与转动刚度退化、延性与耗能能力和破坏模式.结果表明:由于预拉对穿螺栓的设置,所有试件均表现出不同程度的自复位效果和良好的转动与耗能能力;节点的破坏模式为钢梁削弱截面或连接部位附近截面屈服.研究进一步丰富了PEC柱-钢梁连接的研究成果,为PEC柱-钢梁组合

  4. Stress-related hormones in horses before and after stunning by captive bolt gun.

    Science.gov (United States)

    Micera, Elisabetta; Albrizio, Maria; Surdo, Nicoletta C; Moramarco, Angela M; Zarrilli, Antonia

    2010-04-01

    In this work the slaughter-linked plasma modifications of some stress-related hormones in horses subject to standardized butchering procedures were investigated in order to highlight the compromised animal welfare during pre-slaughter handling. During pre-slaughter, animals show strong hardship behavioural patterns, probably due to being under life-threatening conditions. Blood samples from 12 male horses, ageing from 3 to 5 years, were collected before slaughtering in lairage, and during exsanguination after stunning. Catecholamines, cortisol and beta-endorphin concentrations were assessed in plasma samples by EIA. Results show that plasma beta-endorphin concentration did not increase significantly after stunning, while cortisol (Pstress response. Moreover these results suggest that, under stress, the release of beta-endorphin could be different from that of ACTH.

  5. Strength Analysis of Composite and Metallic Plates Bolted Together by a Single Fastener.

    Science.gov (United States)

    1985-08-01

    computer code, are presented in the following sections. !’.1 NX 0 0o y x Y2s.ructur xy2 Computation of the Magnitude and Orientation of Load at Every...Tensslee 1 .Al0;l.8j0;.ICS0 ITerowro20 S33 2 0.312S 0.937SI 1.87S 818464.5-*SAM cam . 1 .la.81IS Toe-quo- 34 20 0.3123 0.937𔃽 1.875 518464-51 CO RP. I...FAILURE LOAD (KIPS) TEST FAILURE LOAD (KIPS) CAD EO CASE) E8EX 8 AND 9o0 PLES) EXPT. ANAL.* ANAL.( (REF. 6-I) (REF. 4-.) 0.S-t) (RF. L -1) 60140110 i2

  6. Design Methodology for Bonded-Bolted Composite Joints. Volume I. Analysis Derivations and Illustrative Solutions

    Science.gov (United States)

    1982-02-01

    Laboratory (AFWAL/ FIBRA ) February 1982 AF Wright Aeronauti cal Laboratori eý IS NUMBER Of PAGES Wright-Patterson AFB, OH 45433 99 IT7MOITORING AGENCY...the software should be submitted in accord- ance with AFSC Sup 1 to AFR 300-6 (DOD Dir 4160.19 dtd 2 Apr 73). Requests must be submitted to AFWAL/ FIBRA , Wright-Patterson AFB, OH 45433. 89

  7. Strength Analysis of Laminated and Metallic Plates Bolted Together by Many Fasteners

    Science.gov (United States)

    1986-07-01

    January 1086. Other requests for this document must be referred to AFWAL/ FIBRA , WPAFB, OHIO 48433-0883 WARNING-This document contains technical...ORGANIZATION Northrop Corporation Flight Dynamics Laboratory (AI𔃾AL/ FIBRA ) Aircraft Division ________Air Force Wright Aeronautical Laboratories Sc...Joints in Composite Structures." S2. Please contact the undersigned if you have any questions regarding this letter. G. DOBEN cc: AFWAL/ FIBRA Chief

  8. Nuts & Bolts of a District Improvement Effort in Maryland Centers on the Staff Development Teacher

    Science.gov (United States)

    Hemphill, Sharon; Duffield, Judy

    2007-01-01

    The staff development teacher facilitates the evolution of a school-based professional learning community focused on improving teaching and learning by being a catalyst for teacher change and reflection. These teacher leaders needed the knowledge and skills to transform individual school staffs into professional learning communities focused on…

  9. The Key for Holding a Successful ELT Conference: Some Nuts and Bolts

    Science.gov (United States)

    Sadeghi, Karim; Modirkhameneh, Sima

    2013-01-01

    Conferences are gatherings that attract attendants from various places and serve both academic and social purposes. Organizing an international conference is, accordingly, a very challenging, demanding and time-consuming task. In order for the conference organizers to hold a successful conference, there is a need for a comprehensive guide to use…

  10. 77 FR 32698 - Proposed Extension of Existing Information Collection; Safety Standards for Roof Bolts in Metal...

    Science.gov (United States)

    2012-06-01

    ... FURTHER INFORMATION CONTACT: Greg Moxness, Chief, Economic Analysis Division, Office of Standards... that: Evaluate whether the collection of information is necessary for the proper performance of the.... OMB Number: 1219-0121. Affected Public: Business or other for-profit. Cite/Reference/Form/ etc. 30...

  11. The BBN (Bolt Beranek and Newman) Knowledge Acquisition Project. Phase 1. Functional Description; Test Plan.

    Science.gov (United States)

    1987-05-01

    21] began to address the issue of declarative representations for procedures in the course of developing a mechanism to teach valid steam plant...scan V127-disk (This teaches the FEP about disk restore ) Then type disk restore The machine will then ask if you’ve done Set Disk Type. Answer y The...HOST If the machine has identity problems it thinks it is still at BBN ). the simplest way to deal with them is to unplug the ethernet before booting

  12. “抽苔”还是“抽薹”%The Chinese Translation of Bolting

    Institute of Scientific and Technical Information of China (English)

    戴金旺

    2014-01-01

    Term use is important for the language normalization. If there are mistakes in terms themselves, users would be puzzled and thus result in disorder of term use. The Chinese word“bolting”, for example, was recommended as choutai (抽苔) instead of choutai (抽薹) by mistake. In this paper, the author analyzed the source of the error and put forward amendment advices.%正确使用科技术语,对语言文字规范化具有非常重要的意义。如果术语本身有误,就会让使用者感到困惑,继而造成使用上的混乱。“抽薹”误作“抽苔”便是其中一例。文章分析了错误产生的原因,并提出修改建议。

  13. The Nuts and Bolts of Low-level Laser (Light) Therapy

    Science.gov (United States)

    Chung, Hoon; Dai, Tianhong; Sharma, Sulbha K.; Huang, Ying-Ying; Carroll, James D.; Hamblin, Michael R.

    2011-01-01

    Soon after the discovery of lasers in the 1960s it was realized that laser therapy had the potential to improve wound healing and reduce pain, inflammation and swelling. In recent years the field sometimes known as photobiomodulation has broadened to include light-emitting diodes and other light sources, and the range of wavelengths used now includes many in the red and near infrared. The term “low level laser therapy” or LLLT has become widely recognized and implies the existence of the biphasic dose response or the Arndt-Schulz curve. This review will cover the mechanisms of action of LLLT at a cellular and at a tissular level and will summarize the various light sources and principles of dosimetry that are employed in clinical practice. The range of diseases, injuries, and conditions that can be benefited by LLLT will be summarized with an emphasis on those that have reported randomized controlled clinical trials. Serious life-threatening diseases such as stroke, heart attack, spinal cord injury, and traumatic brain injury may soon be amenable to LLLT therapy. PMID:22045511

  14. Delivering the nuts without the bolts: the plight of clinical psychology practice.

    Science.gov (United States)

    Cummings, Nicholas A

    2005-09-01

    A vision as bold as that expressed by C.R. Snyder and Timothy R. Elliott in their target article, "Twenty-First Century Graduate Education in Clinical Psychology: A Four Level Matrix Model" (this issue, pp 1033-1054), should make the long-awaited breakthrough in training that would include development, implementation, and evaluation of large-scale health delivery systems. The realization that clinical psychology is part of the health care industry, and not just psychotherapy or mental health, would enable psychologists to go beyond the laboratory and become important decision makers in the health care arena and thus command a greater share of health care funding.

  15. The "nuts and bolts" of implementing shared medical appointments: the Harvard Vanguard Medical Associates experience.

    Science.gov (United States)

    Berger-Fiffy, Jill

    2012-01-01

    Harvard Vanguard Medical Associates (Harvard Vanguard) decided to develop a Shared Medical Appointment (SMA) program in 2007 for a variety of reasons. The program has launched 86 SMAs in 17 specialties at 12 sites and has exceeded 13 000 patient visits. Currently, the practice offers 54 SMAs and is believed to be the largest program in the country. This article provides an overview regarding staffing, space and equipment, project planning, promotional materials, training programs, workflow development, and the use of quality improvement (ie, LEAN) tools used to monitor the work to be completed and the metrics to date.

  16. Automated bolting and meshing on a continuous miner for roadway development

    Institute of Scientific and Technical Information of China (English)

    van Duin Stephen; Meers Luke; Donnelly Peter; Oxley Ian

    2013-01-01

    Automated installation of primary roof support material can potentially increase productivity and operator safety in the roadway development process within underground coal mining.Although the broader manufacturing sector has benefited from automation,several challenges exist within the Australian underground coal industry which makes it difficult to fully exploit these technologies.At the University of Wollongong a series of reprogrammable electromechanical manipulators have been designed to overcome these challenges and automatically handle the installation of roof and rib containment consumables on a continuous miner.The automated manipulation removes personnel from hazards in the immediate face area,particularly those associated with working in a confined and unstable working environment in close proximity to rotating and moving equipment.In a series of above ground trials the automated system was successfully demonstrated without human intervention and proven to be capable of achieving cycle times at a rate of 10 m per operating hour,consistent with that required to support high capacity longwall mines.The trials also identified a number of refinements which could further improve both cycle times and system reliability when considering the technology for underground use.The results have concluded that conventional manual handling practices on a continuous miner can be eliminated,and that the prototypes have significantly reduced the technical risk in proceeding to a full underground trial.

  17. (Pea)nuts and bolts of visual narrative: structure and meaning in sequential image comprehension.

    Science.gov (United States)

    Cohn, Neil; Paczynski, Martin; Jackendoff, Ray; Holcomb, Phillip J; Kuperberg, Gina R

    2012-08-01

    Just as syntax differentiates coherent sentences from scrambled word strings, the comprehension of sequential images must also use a cognitive system to distinguish coherent narrative sequences from random strings of images. We conducted experiments analogous to two classic studies of language processing to examine the contributions of narrative structure and semantic relatedness to processing sequential images. We compared four types of comic strips: (1) Normal sequences with both structure and meaning, (2) Semantic Only sequences (in which the panels were related to a common semantic theme, but had no narrative structure), (3) Structural Only sequences (narrative structure but no semantic relatedness), and (4) Scrambled sequences of randomly-ordered panels. In Experiment 1, participants monitored for target panels in sequences presented panel-by-panel. Reaction times were slowest to panels in Scrambled sequences, intermediate in both Structural Only and Semantic Only sequences, and fastest in Normal sequences. This suggests that both semantic relatedness and narrative structure offer advantages to processing. Experiment 2 measured ERPs to all panels across the whole sequence. The N300/N400 was largest to panels in both the Scrambled and Structural Only sequences, intermediate in Semantic Only sequences and smallest in the Normal sequences. This implies that a combination of narrative structure and semantic relatedness can facilitate semantic processing of upcoming panels (as reflected by the N300/N400). Also, panels in the Scrambled sequences evoked a larger left-lateralized anterior negativity than panels in the Structural Only sequences. This localized effect was distinct from the N300/N400, and appeared despite the fact that these two sequence types were matched on local semantic relatedness between individual panels. These findings suggest that sequential image comprehension uses a narrative structure that may be independent of semantic relatedness. Altogether, we argue that the comprehension of visual narrative is guided by an interaction between structure and meaning.

  18. CARDIOVASCULAR ABNORMALITIES IN PATIENTS WITH HIV INFECTION: A BOLT IN BLUE

    Directory of Open Access Journals (Sweden)

    Anita

    2015-12-01

    Full Text Available One of the consistent findings among various studies on HIV has been simultaneous multiorgan dysfunction. Cardiovascular disorders are now most common cause of mortality worldwide. With more effective and widespread treatment of HIV in resource-rich settings, morbidity and mortality from non-AIDS-related events have surpassed those from AIDS-related events with cardiovascular diseases emerging as an important cause of death in HIV-infected patients relative to the decreasing incidence of opportunistic disease. Various studies have reported a 1.5-fold increase in the rate of cardiovascular events in HIV-infected individuals compared to control populations. MATERIAL AND METHODS The aim of the study was to the find the prevalence and types of different cardiovascular abnormalities in HIV positive patients and assess their association with CD4 counts. Consecutive 82 patients, HIV positive patients fulfilling the inclusion criteria and giving informed consent were included in the study. All patients were subjected to history taking and a detailed physical examination. Blood counts, renal function tests, lipid profile and CD4 counts were estimated and patients were subjected to 12-lead ECG, chest X-ray and 2D/Colour Doppler Echocardiogram. RESULTS Of the 82 patients studied 47.46% had evidence of cardiovascular involvement, out of which 12% had clinical features of heart failure while electrocardiographic changes were seen in 35% of patients in the form of sinus tachycardia (27%, QTc prolongation (10% and left sided chamber enlargements (6%. Echocardiographic abnormalities were noted in 39 patients (47.56% including fractional shortening associated with systolic dysfunction (26.8%. The mean CD4 count in patients with echocardiographic abnormalities was found to be 58.87±29.80, whereas in patients without echocardiographic abnormalities it was 136.53±38.80 (p<0.0001. CONCLUSION High frequencies of cardiac abnormalities, both symptomatic and asymptomatic were detected in the HIV/AIDS patients in our study. Furthermore, the study concluded that a careful initial and periodic cardiac evaluation to detect early involvement of the cardiovascular system in the HIV disease is recommended. Since the HIV-infected population is relatively young and actual cardiovascular events are infrequent, more long terms studies are needed

  19. Rocket ranch the nuts and bolts of the Apollo Moon program at Kennedy Space Center

    CERN Document Server

    Ward, Jonathan H

    2015-01-01

    Jonathan Ward takes the reader deep into the facilities at Kennedy Space Center to describe NASA’s first computer systems used for spacecraft and rocket checkout and explain how tests and launches proceeded. Descriptions of early operations include a harrowing account of the heroic efforts of pad workers during the Apollo 1 fire. A companion to the author’s book Countdown to a Moon Launch: Preparing Apollo for Its Historic Journey, this explores every facet of the facilities that served as the base for the Apollo/Saturn missions. Hundreds of illustrations complement the firsthand accounts of more than 70 Apollo program managers and engineers. The era of the Apollo/Saturn missions was perhaps the most exciting period in American space exploration history. Cape Canaveral and Kennedy Space Center were buzzing with activity. Thousands of workers came to town to build the facilities and launch the missions needed to put an American on the Moon before the end of the decade. Work at KSC involved much more than j...

  20. (Pea)nuts and Bolts of Visual Narrative: Structure and Meaning in Sequential Image Comprehension

    Science.gov (United States)

    Cohn, Neil; Paczynski, Martin; Jackendoff, Ray; Holcomb, Phillip J.; Kuperberg, Gina R.

    2012-01-01

    Just as syntax differentiates coherent sentences from scrambled word strings, the comprehension of sequential images must also use a cognitive system to distinguish coherent narrative sequences from random strings of images. We conducted experiments analogous to two classic studies of language processing to examine the contributions of narrative…

  1. The nuts and bolts of PROSPERO: an international prospective register of systematic reviews

    Directory of Open Access Journals (Sweden)

    Booth Alison

    2012-02-01

    Full Text Available Abstract Background Following publication of the PRISMA statement, the UK Centre for Reviews and Dissemination (CRD at the University of York in England began to develop an international prospective register of systematic reviews with health-related outcomes. The objectives were to reduce unplanned duplication of reviews and provide transparency in the review process, with the aim of minimizing reporting bias. Methods An international advisory group was formed and a consultation undertaken to establish the key items necessary for inclusion in the register and to gather views on various aspects of functionality. This article describes the development of the register, now called PROSPERO, and the process of registration. Results PROSPERO offers free registration and free public access to a unique prospective register of systematic reviews across all areas of health from all around the world. The dedicated web-based interface is electronically searchable and available to all prospective registrants. At the moment, inclusion in PROSPERO is restricted to systematic reviews of the effects of interventions and strategies to prevent, diagnose, treat, and monitor health conditions, for which there is a health-related outcome. Ideally, registration should take place before the researchers have started formal screening against inclusion criteria but reviews are eligible as long as they have not progressed beyond the point of completing data extraction. The required dataset captures the key attributes of review design as well as the administrative details necessary for registration. Submitted registration forms are checked against the scope for inclusion in PROSPERO and for clarity of content before being made publicly available on the register, rejected, or returned to the applicant for clarification. The public records include an audit trail of major changes to planned methods, details of when the review has been completed, and links to resulting publications when provided by the authors. Conclusions There has been international support and an enthusiastic response to the principle of prospective registration of protocols for systematic reviews and to the development of PROSPERO. In October 2011, PROSPERO contained 200 records of systematic reviews being undertaken in 26 countries around the world on a diverse range of interventions.

  2. The nuts and bolts of behavioral observation of marital and family interaction.

    Science.gov (United States)

    Margolin, G; Oliver, P H; Gordis, E B; O'Hearn, H G; Medina, A M; Ghosh, C M; Morland, L

    1998-12-01

    Despite considerable discussion in the literature about the advantages of observational research and the relative benefits of different coding systems and strategies, little is written about the actual implementation of this assessment strategy. This paper presents an overall framework as well as the essential components involved in collecting (selection of task, setting, unit of analysis, and coding system) and coding (transcribing, selecting and training coders, transforming data, and analyzing reliability) of observational data. To achieve success with observational methods, we emphasize several issues, including (a) the research question as the motivator for all decisions, (b) the interrelatedness of tasks, and (c) the implications of decisions early in the process for later stages of analysis and interpretation. Investigators are encouraged to communicate the details of their observational and coding procedures so that these methods are readily accessible for purposes of replication and comparison.

  3. Mentoring Students with Mild Disabilities: The "Nuts and Bolts" of Program Development.

    Science.gov (United States)

    Campbell-Whatley, Gloria D.

    2001-01-01

    This article provides step-by-step guidelines for developing a mentoring program for students with disabilities. The benefits of mentoring, role of the mentor, mentor screening, and program development are discussed. Suggested mentor and student activities are outlined, including communication, reading, leisure, and academic activities. (Contains…

  4. A Process-Oriented Nuts and Bolts Tutorial for Implementing Manpower and Personnel Integration (MANPRINT) Evaluations

    Science.gov (United States)

    2008-11-01

    Concept Team ( ICT ) or an Integrated Product Team (IPT) test. For the most part, the primary responsibility of the MANPRINT analyst to whom this...Products Using ELT /4000 [A)Create Graphic Image, B)View/Manipulate Image Using ELT /4000, C)Download Secondary Imagery, D)Display Camera Icon, E...5 6 Completely Disagree N/A=0 40.) Adding annotations to ELT Completely Agree 1 2 3 4 5

  5. Results of tests of MTA-2 TPS on the SRB hold-down bolt blast container

    Science.gov (United States)

    Dean, W. G.

    1982-01-01

    The four solid rocket booster (SRB) hold-down posts are fastened to the mobile launch platform (MLP) with four large nuts. At liftoff the nuts are split with explosive changes to release the SRB/Shuttle. A blast container is placed over the nuts to protect the vehicle from flying debris. The blast container is a reusable part and has to be protected from aerodynamic heating during flight. The thermal protection system (TPS) used to protect these blast containers is cork. Fitting the flat cork sheet to this hemispherical shaped blast container is both time consuming and expensive. Another problem is removing the charred cork and epoxy glue from the blast containers. Replacements of this cork with another TPS material such as MTA-2 was examined. Heating rates along the centerline of the forward facing areas of the blast container were determined. The feasibility of using 1/2 in. MTA-2 on the SRB blast containers for protection from ascent, plume impingement and reentry heating is demonstrated.

  6. Implementing the chemical weapons convention: The nuts and bolts of compliance

    Energy Technology Data Exchange (ETDEWEB)

    Tanzman, E.A.

    1995-03-01

    This paper is a presentation prepared for the American Bar Association in which the author discusses the issue of rights to privacy in the United States in the face of implementing the Chemical Weapons Convention inspections. The author points out that there are no clear precedents in law which deal with all the issues which will result from international inspections for verification which are required by the treaty. In particular as inspections tread on the issue of personal rights or private property there is a fairly ill defined legal area which needs to be developed to allow such inspections in the face of constitutional guarantees.

  7. 75 FR 35622 - Airworthiness Directives; Bombardier, Inc. Model DHC-8-400 Series Airplanes

    Science.gov (United States)

    2010-06-23

    ... retention bolt, a reverse orientation of the retention bolt and a rework of the weight on wheel (WOW... a new retention bolt, a reverse orientation of the retention bolt and a rework of the weight...

  8. 77 FR 63268 - Airworthiness Directives; Airbus Airplanes

    Science.gov (United States)

    2012-10-16

    ... link bolts, center sway link bolts, and thrust link bolts on the forward engine mounts. This proposed... bolts and thrust link bolts of the General Electric (GE) CF6-80A3 forward engine mounts. This condition... mount bolts [and possible damage to an engine or wing]. For the reasons described above, this...

  9. 采掘锚、掘锚一体化快速掘进成巷技术%Speedy roadway development technology integrating the mining,drivage and bolting or the drivage and bolting

    Institute of Scientific and Technical Information of China (English)

    牛宝玉

    2003-01-01

    根据我国煤巷、半煤岩巷综合机械化掘进生产线的现状,分析了目前综掘生产线存在的问题,从巷道掘进、支护与生产线设备配备等进行了分析比较,介绍了采掘锚与掘锚一体化快速成巷设备及技术.

  10. From Nothing to Something: The Nuts and Bolts of Building a Mentoring Program in a Health Sciences College

    Science.gov (United States)

    Franko, Debra L.

    2016-01-01

    In this paper, I report the development of a mentoring program in a College of Health Sciences comprised of schools of nursing, pharmacy, and health professions (which include physical therapy, speech pathology and audiology, applied psychology, and physician assistant programs) at a large private university. Although university-wide mentoring…

  11. Experimental study on the bolt-cable combined supporting technology for the extraction roadways in weakly cemented strata

    Institute of Scientific and Technical Information of China (English)

    Meng Qingbin; Han Lijun; Sun Jingwu; Min Fengqing; Feng Wei; Zhou Xing

    2015-01-01

    Aiming at the characteristics of the poor steady ability, the short stable time and severe deformation behavior of weakly cemented soft surrounding rock around extraction roadway, a bolt–cable combined supporting technology was proposed. Numerical simulation was performed by using FLAC3D software to study the effects of different supporting systems. The simulation result proves that those supporting systems have good practical values. Based on real-time monitoring and analysis of the deformation of surrounding rock and the stress of supporting structure, real time information of deformation of sur-rounding rock and stress state of supporting structure of extraction roadway within weakly cemented strata was obtained. Monitoring results show that large deformation and failure of surrounding rock of extraction roadway within weakly cemented strata can be effectively controlled by the bolt–cable com-bined supporting technology, which ensures the long-term stability and safety of surrounding rock and supporting structure.

  12. Effect of Temperature and Viscoelastic Creep on the Clamp-Up Load in Hybrid Composite/Metal Bolted Joints

    Science.gov (United States)

    2009-08-17

    ester fiber reinforced polymer composites manufactured using the vacuum-assisted resin transfer molding ( VARTM ) method. A total of eight panels...ambient cured VARTM EGlass/vinyl ester resin composites are significantly affected by the degree of cure and conversion of 14 resin constituents. Given...panel was manufactured at the University of Maine Crosby Laboratory, using the VARTM (Vacuum assisted Resin Transfer Molding) process. The results of

  13. Brief Introduction About Nuts & Bolts Tools Module%Nuts & Bolts工具组件使用简介

    Institute of Scientific and Technical Information of China (English)

    杨永战

    2000-01-01

    @@ Nuts & Bolts软件是一个运行于Win9X系统的、用于系统维护和测试的工具组件.该组件包含了注册表的备份、恢复、优化、修理等诸多功能,提供图形界面,按钮操作,使用户操作更加方便、快捷、灵活.下面对该组件的主要功能作一简单介绍.

  14. A Nuts and Bolts Guide to College Success for Students Who Are Deaf or Hard of Hearing

    Science.gov (United States)

    PEPNet 2, 2012

    2012-01-01

    Beginning your college education means you'll be exploring a new place, making new friends, learning new things and setting your own priorities. You are going to face a lot of big changes in a short time. That's exciting--and challenging. The more prepared you are for college when you get there, the more ready you'll be to address these new…

  15. The "nuts & bolts" of becoming an aesthetic provider: part 3-maximizing your aesthetic practice and client outcomes.

    Science.gov (United States)

    Brennan, Connie

    2014-01-01

    The final installment of this 3-part series of articles on becoming an aesthetic provider centers on the steps necessary to maximize an aesthetic medical practice and tips for optimal client outcomes. We discuss the importance of education for the aesthetic provider, the staff, and the client, as well as how to create client loyalty. On the basis of years of experience, "pearls and pitfalls" are discussed, so the novice, intermediate, and advanced aesthetic providers can minimize mistakes and maximize their success in this exciting and growing profession.

  16. Numerical investigation on the position of holes for reducing stress concentration in composite plates with bolted and riveted joints

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    This paper studies the effects of fiber orientaion and holes position on stress concentration and the determination of weakened areas in the composite of glass fiber reinforced epoxy resin around the hole for joints by using the finite element method.In this study,for the observation of areas affected by stress concentration Tsai-Wu failure criterion is used to determine the failed elements and ANSYS Software is implemented for modeling.In order to compare the effect of geometric parameters on stress concen...

  17. The Fallacy of the Bolted Horse: Changing Our Thinking about Mature-Age Aboriginal and Torres Strait Islander University Students

    Science.gov (United States)

    Plater, Suzanne; Mooney-Somers, Julie; Lander, Jo

    2015-01-01

    The aim of this article is to critically review and analyse the public representations of mature-age university students in developed and some developing nations and how they compare to the public representations of mature-age Aboriginal and Torres Strait Islander university students in Australia ("students" also refers to graduates…

  18. An investigation into the relation between wheel/rail contact and bolt tightness of rail joints using a dynamic finite element model

    NARCIS (Netherlands)

    Oregui, M.; Li, Z.; Dollevoet, R.P.B.J.

    2012-01-01

    Rail joints have a shorter service life than most other railway track components. The discontinuity between rail ends turns the rail joint into a weak spot, and consequently, into a track component demanding more frequent maintenance measures, which result in high maintenance costs. Moreover, diffic

  19. Analysis of Dynamic Information Designing Method of Bolt Support%锚杆支护动态信息设计法浅析

    Institute of Scientific and Technical Information of China (English)

    解华兵

    2003-01-01

    介绍了动态信息设计的原理,结合在常村矿胶带运输大巷的实际应用,分析了煤矿巷道锚杆支护动态信息设计的方法与过程,提出了巷道支护设计贯穿巷道整个服务期的新概念.

  20. Papel de Early Bolting in Short Days (EBS) en la regulación de la dormición de semillas en Arabidopsis thaliana

    OpenAIRE

    Narro Diego, Laura

    2014-01-01

    Tesis doctoral inédita, leída en Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología. Fecha de lectura: 24/04/2014 El adenocarcinoma pancreático es una neoplasia maligna del páncreas exocrino, siendo la cuarta causa principal de muerte relacionada con cáncer en todo el mundo. Se ha planteado la hipótesis de que un subconjunto de células tumorales con pro...

  1. Research Status of Brittle Fracture of High Strength Steel Bolt%钢结构高强螺栓脆性断裂的研究现状

    Institute of Scientific and Technical Information of China (English)

    宋志慧; 郑慧敏

    2012-01-01

    介绍了当前高强螺栓的研究现状及动态,论述了钢材脆性断裂理论、研究动态以及脆性断裂的影响因素和高强螺栓的脆性断裂理论、研究方法.提出了当前尚需解决的问题.

  2. 全煤锚杆支护巷道的矿压观测%Strata Control Observation of Full-Seam Roof-Bolted Roadway

    Institute of Scientific and Technical Information of China (English)

    程计多; 肖栋; 彭担任

    2007-01-01

    通过对唐山矿区9煤层T2291溜子道全煤锚杆支护巷道的矿压观测,证实了同煤岩层内不同部位处巷道应力和同巷道应力条件下不同煤岩强度处围岩变形的差异,通过分析,得出9煤层锚杆支护巷道的围岩变形规律,提出锚杆巷道设计及施工的指导性意见.

  3. The high-strength bolt connection construction technique on the lightweight steel%轻钢结构高强度螺栓连接施工技术

    Institute of Scientific and Technical Information of China (English)

    谭延伟; 杨继明

    2010-01-01

    结合GB 50017-2003钢结构设计规范和GB 50205-2001钢结构工程施工质量验收规范,详细介绍了轻钢结构高强度螺栓连接施工技术,包括技术性能,施工工艺,竣工验收等内容,以期指导施工人员合理施工,保证施工质量和结构安全.

  4. 水下突击步枪枪机运动分析%Motion Analysis of Firearm Bolt in Underwater Assault Rifle

    Institute of Scientific and Technical Information of China (English)

    陈静; 王昌明

    2006-01-01

    采用实验和计算相结合的方法确定水下突击步枪枪机的运动规律.在实验装置上安装感应测速传感器和应变式测压传感器,和其他测量仪器组成测量系统,分别测定运动构件(实验装置中模拟枪机的构件)的速度和气室压力;在不同阶段,列出水下突击步枪枪机的运动方程,利用实验数据,获得理论运动曲线.

  5. 汽车万向节电镀锌螺栓断裂的原因分析%Fracture analyse for electroplating zinc bolt of automobile cardan joint

    Institute of Scientific and Technical Information of China (English)

    黄纪蓉; 王宝棣; 温静娴

    2005-01-01

    汽车万向节紧固螺栓(以后简称螺栓)在镀锌处理后机械性能下降,在试运行过程中就已断裂。为探讨镀锌螺栓断裂的原因,对断裂螺栓进行了测试分析。

  6. Wheel loaders as a basis for shotfiring vehicles, drilling jumbos and rock-bolt setting vehicles; Radlader als Basis fuer Sprengfahrzeuge, Ankerbohr- und -setzwagen sowie Hilfsfahrzeuge

    Energy Technology Data Exchange (ETDEWEB)

    Paus, Franz-Josef; Kaufmann, Martin [Hermann Paus Maschinenfabrik GmbH, Emsbueren (Germany); Rautenstrauch, Wolfgang [Moessinger+Wolter Maschinenbau GmbH, Bochum (Germany)

    2011-03-15

    Starting with a review of development of the Paus shotfiring vehicles a wheel loader serving as a basic machine for diverse applications in the mining industry is described in the contribution. (orig.)

  7. Enlargement of a rectangular bolted roadway by use of the longwall machinery; Erweiterung einer Rechteckankerstrecke zur Strebstartstrecke durch den Einsatz der strebeigenen Gewinnungseinheit

    Energy Technology Data Exchange (ETDEWEB)

    Zilligen, W. [Bergwerk Auguste Victoria/Blumenthal der Deutschen Steinkohle AG (DSK), Marl (Germany)

    2004-09-09

    The modern coal-face installation, with its high-performance face supports, requires a cavity up to 9.5 m in width to serve as a set-up chamber. The single-phase excavation of wide-section roadways with rockbolt support tends to pose problems in terms of the drivage method used and the stability of the roadway during its service life. The positive experience acquired from the conventional drivage of rockbolted set-up chambers has now led to the development of a new system for the mechanized excavation of cavities of this type. A DSK colliery has now for the first time successfully deployed the existing SL 300 drum shearer loader to cut the extension for the set-up chamber. The success of this project has meant that the same technique will now be used in subsequent coal panels. (orig.)

  8. 78 FR 7261 - Airworthiness Directives; Airbus Airplanes

    Science.gov (United States)

    2013-02-01

    ... bolts, center sway link bolts, and thrust link bolts on the forward engine mounts. This AD requires... the General Electric (GE) CF6-80A3 forward engine mounts. This condition, if left uncorrected, could result in a deterioration of the structural integrity of the front engine mount bolts . For the...

  9. Aachen international mining symposia: 5. International symposium on roofbolting in mining. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The authors of the symposium report on the following topics: roofbolting in German, Australian, British, Indian, Chinese coal mines, historical aspects, research programs, concrete lining, cable bolts, bolting machines, rectangular roadways,shear behavior of bolts, rock mechanics, resin grouted bolts, effects of earthquakes, support design guidelines, strata movements, numerical modelling, safety aspects. (uke)

  10. Nuclear reactor fuel element. Kernreaktorbrennelement

    Energy Technology Data Exchange (ETDEWEB)

    Lippert, H.J.

    1985-03-28

    The fuel element box for a BWR is situated with a corner bolt on the inside in one corner of its top on the top side of the top plate. This corner bolt is screwed down with a bolt with a corner part which is provided with leaf springs outside on two sides, where the bolt has a smaller diameter and an expansion shank. The bolt is held captive to the bolt head on the top and the holder on the bottom of the corner part. The holder is a locknut. If the expansion forces are too great, the bolt can only break at the expansion shank.

  11. The method of the maximum entropy for the reconstruction of the distribution bolt the bolt of the neutrons flow in a fuel element; O metodo da maxima entropia para a reconstrucao da distribuicao pino a pino do fluxo de neutrons em um elemento combustivel

    Energy Technology Data Exchange (ETDEWEB)

    Ancalla, Lourdes Pilar Zaragoza

    2005-04-15

    The reconstruction of the distribution of density of potency pin upright in a heterogeneous combustible element, of the nucleus of a nuclear reactor, it is a subject that has been studied inside by a long time in Physics of Reactors area. Several methods exist to do this reconstruction, one of them is Maximum Entropy's Method, that besides being an optimization method that finds the best solution of all the possible solutions, it is a method also improved that uses multipliers of Lagrange to obtain the distribution of the flows in the faces of the combustible element. This distribution of the flows in the faces is used then as a contour condition in the calculations of a detailed distribution of flow inside the combustible element. In this work, in first place it was made the homogenization of the heterogeneous element. Soon after the factor of the multiplication executes and the medium values of the flow and of the liquid current they are computed, with the program NEM2D. These values medium nodal are, then, used upright in the reconstruction of the distribution pin of the flow inside the combustible element. The obtained results were acceptable, when compared with those obtained using fine mesh. (author)

  12. 75 FR 13682 - Airworthiness Directives; Bombardier, Inc. Model DHC-8-400 Series Airplanes

    Science.gov (United States)

    2010-03-23

    ... and a rework of the weight on wheel (WOW) proximity sensor cover to provide clearance for the re... new retention bolt, a reverse orientation of the retention bolt and a rework of the weight on...

  13. Joint voltages resulting from lightning currents.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, William Arthur; Warne, Larry Kevin; Merewether, Kimball O.; Chen, Kenneth C.

    2007-03-01

    Simple formulas are given for the interior voltages appearing across bolted joints from exterior lightning currents. External slot and bolt inductances as well as internal slot and bolt diffusion effects are included. Both linear and ferromagnetic wall materials are considered. A useful simplification of the slot current distribution into linear stripline and cylindrical parts (near the bolts) allows the nonlinear voltages to be estimated in closed form.

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

    NARCIS (Netherlands)

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

    2007-01-01

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

  15. 75 FR 43876 - Airworthiness Directives; Fokker Services B.V. Model F.28 Mark 0100 Airplanes

    Science.gov (United States)

    2010-07-27

    ... to stress corrosion, attributed to excessive bolt torque. Investigation of the recently failed bolts... this proposed AD, contact Goodrich Corporation, Landing Gear, 1400 South Service Road, West Oakville... to stress corrosion, attributed to excessive bolt torque. Investigation of the recently failed...

  16. 75 FR 27956 - Airworthiness Directives; Airbus Model A300 B4-600, B4-600R, and F4-600R Series Airplanes, and...

    Science.gov (United States)

    2010-05-19

    ... complete nose landing gear (NLG) shock absorber bolts failure were reported to the manufacturer. In both cases, the crew was unable to retract the gear and was forced to an In Flight Turn Back. In one case... identified ] being due to a bolt(s) over-torque. The investigation has highlighted that the design of the...

  17. 75 FR 60611 - Airworthiness Directives; Airbus Model A300 B4-600, B4-600R, and F4-600R Series Airplanes, and...

    Science.gov (United States)

    2010-10-01

    ...: * * * * * Two cases of complete nose landing gear (NLG) shock absorber bolts failure were reported to the manufacturer. In both cases, the crew was unable to retract the gear and was forced to an In Flight Turn Back... failure has been identified being due to a bolt(s) over-torque. The investigation has highlighted that...

  18. 75 FR 50867 - Airworthiness Directives; Airbus Model A330-223, -321, -322, and -323 Airplanes

    Science.gov (United States)

    2010-08-18

    ... (PW) forward (FWD) engine mount pylon bolts. * * * * * Dual-bolt fractures could lead to inability for mount assembly to sustain loads which may lead to an engine mount failure and consequently to engine... one of the Pratt & Whitney (PW) forward (FWD) engine mount pylon bolts. Investigation has...

  19. 75 FR 9809 - Airworthiness Directives; Airbus Model A330-243, -341, -342, and -343 Airplanes; and Model A340...

    Science.gov (United States)

    2010-03-04

    ... (FWD) and aft (AFT) engine mount link pin retention bolts have always been higher than the design value. These bolts retain the washers that maintain the engine mount vertical load pins in position. If bolts... engine mount which could potentially lead to engine separation. The proposed AD would require...

  20. 国产化"模诺"钻具机械制造工艺攻关与研究%Development efforts of 'bolt orientation' dies in home manufacturing conditions

    Institute of Scientific and Technical Information of China (English)

    许锷铭

    1993-01-01

    @@ 以"模诺"(Moineau)传动原理设计制造的泵与马达一经问世就受到工程技术界的重视,因其传动精度高和制造难度大,至今仅有少数技术发达国家(如美国、德国和原苏联)能够制造及有商品出售.

  1. Parameterization Research on Guide Rail's Slope Angle of Gatling Gun Bolt Carrier%转管炮机心体导轨倾角的参数化研究

    Institute of Scientific and Technical Information of China (English)

    徐健; 薄玉成

    2010-01-01

    为了研究转管炮机心体导轨倾角对主滚轮驱动压力的影响并改善驱动条件,进行了主滚轮以及机心组动力学分析.运用动量矩定理及牛顿第二定律分别对滚轮回转以及机心组纵向运动列写动力学方程,在保持机心体横向宽度不变的情况下,通过参数化机心体导轨与水平方向夹角的方法,编程求解.计算结果表明,机心体导轨倾角的存在会增大主滚轮驱动压力峰值,但不会改变主滚轮压力峰值出现的时机;驱动压h峰值与导轨倾角基本呈线性关系且单调递增;回转体转速较高时,驱动压力峰值与倾角关系曲线斜率更大.在高转速的转管炮机心体设计时,仅从驱动压力方面,应优先考虑水平导轨.从驱动和磨损后定位方面,应适宜搭配加速度较小的炮箱曲线槽以及倾角较小的导轨.

  2. Investigation of EMAT Base System for the Detection of Bolt Hole Type Cracks. Part 1. Detection of Cracks in the Inaccessible Lower Half of Wing Lap Joints Using EMATS

    Science.gov (United States)

    1980-07-01

    ptPateron Air Force Base, Ohio 45433 67 4. .IOI CftNG CENY .AN & OONS~ iVf ditf.,..,t from Co.ntrotllng Office) Is. SECURfITY CLASS. (of (hit report...are buffered I , and bandpass filtered in order to suppress higher harmonics which degrade signal to noise. Thus,the ideal output of the processor may

  3. 顶底角钢自复位钢框架M-θr关系的研究%RESEARCH IN M-θr RELATIONSHIP OF SELF-CENTERING STEEL CONNECTION WITH BOLTED TOP AND SEAT ANGLES

    Institute of Scientific and Technical Information of China (English)

    惠宽堂; 巨晶

    2013-01-01

    提出一种得到顶底角钢自复位节点M-θr关系的实用计算方法.基于对连接破坏机构的研究,通过组件法推导出自复位节点各个阶段的承载力,采用基于Eurocode 3和Kishi-Chen函数模型拟合得到连接的弯矩-转角关系,并对各个阶段提出设计应注意的问题.对文中方法计算结果与有限元分析结果、已有试验结果进行比较,结果吻合良好,从而验证文中方法的有效性.在有限元分析中,节点表现出较好的自复位性能,同时转动中心附近的柱腹板应力集中明显,需合理设计加劲肋和加强板,保证板件的局部稳定.

  4. Anchoring a Defined Sequence to the 55' Ends of mRNAs : The Bolt to Clone Rare Full Length mRNAs and Generate cDNA Libraries porn a Few Cells.

    Science.gov (United States)

    Baptiste, J; Milne Edwards, D; Delort, J; Mallet, J

    1993-01-01

    Among numerous applications, the polymerase chain reaction (PCR) (1,2) provides a convenient means to clone 5' ends of rare mRNAs and to generate cDNA libraries from tissue available in amounts too low to be processed by conventional methods. Basically, the amplification of cDNAs by the PCR requires the availability of the sequences of two stretches of the molecule to be amplified. A sequence can easily be imposed at the 5' end of the first-strand cDNAs (corresponding to the 3' end of the mRNAs) by priming the reverse transcription with a specific primer (for cloning the 5' end of rare messenger) or with an oligonucleotide tailored with a poly (dT) stretch (for cDNA library construction), taking advantage of the poly (A) sequence that is located at the 3' end of mRNAs. Several strategies have been devised to tag the 3' end of the ss-cDNAs (corresponding to the 55' end of the mRNAs). We (3) and others have described strategies based on the addition of a homopolymeric dG (4,5) or dA (6,7) tail using terminal deoxyribonucleotide transferase (TdT) ("anchor-PCR" [4]). However, this strategy has important limitations. The TdT reaction is difficult to control and has a low efficiency (unpublished observations). But most importantly, the return primers containing a homopolymeric (dC or dT) tail generate nonspecific amplifications, a phenomenon that prevents the isolation of low abundance mRNA species and/or interferes with the relative abundance of primary clones in the library. To circumvent these drawbacks, we have used two approaches. First, we devised a strategy based on a cRNA enrichment procedure, which has been useful to eliminate nonspecific-PCR products and to allow detection and cloning of cDNAs of low abundance (3). More recently, to avoid the nonspecific amplification resulting from the annealing of the homopolymeric tail oligonucleotide, we have developed a novel anchoring strategy that is based on the ligation of an oligonucleotide to the 35' end of ss-cDNAs. This strategy is referred to as SLIC for single-strand ligation to ss-cDNA (8).

  5. Application of 3-D elastoplastic damage model with bolts in XILUODU underground power house%三维加锚弹塑性损伤模型在溪洛渡地下厂房工程中的应用

    Institute of Scientific and Technical Information of China (English)

    张强勇; 向文; 朱维申

    2000-01-01

    本文根据断续裂隙岩体的损伤机制,建立了三维弹塑性损伤本构模型反映裂隙岩体的损伤变形特性.考虑断续裂隙岩体的岩锚支护效应,建立了空间损伤锚柱单元模型模拟锚杆的支护效果.最后将建立的模型应用于溪洛渡水电站地下厂房,进行了洞室群开挖弹塑性损伤及岩锚支护三维非线性有限元计算,获得了一些有益的工程结论.

  6. 潜油电泵连接螺栓预紧力与传递扭矩分%Analysis on the Pre-tightness Force of Bolt in Connection of Electric Submersible Pump and the Transmitted Torque

    Institute of Scientific and Technical Information of China (English)

    丁宇奇; 刘巨保

    2008-01-01

    潜油电泵各机组由螺栓连接而成,螺栓预紧力的大小不仅与螺检和连接件强度有关,还直接影响到连接件传递扭矩能力和机组工作安全性能.为此,基于ANSYS有限元软件的接触非线性分析功能,建立潜油电泵接头及连接螺栓的三维有限元模型.采用温度法来模拟螺柱预紧力和轴向变形,分析计算螺柱不同预紧条件下潜油电泵机组传递扭矩的极限值,在6个螺栓预紧力达66.5 kN时,传递扭矩极限值为1.233 kN·m.

  7. Identification of AFLP and SCAR Molecular Markers Linked to Bolting Trait in Radish%萝卜抽薹基因连锁的AFLP和SCAR分子标记鉴定

    Institute of Scientific and Technical Information of China (English)

    徐文玲; 王淑芬; 牟晋华; 王翠花; 刘贤娴

    2009-01-01

    本文运用AFLP分子标记技术,结合BSA法,对萝卜抽薹基因相连锁的AFLP分子标记进行研究,获得两个与萝卜耐抽薹基因相连锁的AFLP标记,遗传距离分别为14.6 cM和9.1 cM.序列测定和Blast分析表明,标记ACG-CAG(123 bp)与拟南芥中锌指蛋白3(zinc finger protein 3,ZFP3)的cDNA同源性为89%,期望值为6e-23;标记ACT-CTG(175 bp)与拟南芥中的Copia类反转录转座子AtRE1基因的同源性为83%,期望值为4e-42.并将其中一个标记转化为简单易行的SCAR标记,遗传距离为7.5 cM.

  8. 围岩松动圈锚注联合支护技术研究与应用%Research and Application of Surrounding Rock Loosen Zone Bolting Grouting United Support Technology

    Institute of Scientific and Technical Information of China (English)

    李飞鹏; 郜建明

    2014-01-01

    为解决赵庄煤业西翼胶带巷极破碎软岩的变形控制技术问题,对西翼胶带巷两帮和底板进行了探地雷达松动圈测试,得出了巷道围岩松动圈范围和破碎情况,基于松动圈测试及分析,提出了由预留变形量让压、初次全锚索网喷支护、深浅孔注浆加固、底角锚注加固组成的锚注联合支护体系,并在西翼胶带巷进行了应用。数值模拟和现场围岩变形监测结果表明,全锚索及深浅孔注浆加固下,巷道围岩强度提高,整体性较好,围岩破坏范围大幅减小,巷道表面变形得到有效控制,能够较好地满足巷道的使用,成功地解决了胶带巷大松动圈极破碎软岩条件下的巷道稳定控制问题。%In order to solve the problem of the deformation control technology in the Zhao Zhuang coal mine west wing belt roadway with bro-ken soft surrounding rock , the GPR loose circle testing was carried on two sides wall and bottom of the roadway surrounding rock and got the loose circle range and broken rock conditions. Based on the analysis of the loose circle testing , a combined support system was proposed with a reserved deformation pressure first, the anchor net spray support, deep-shallow hole grouting reinforcement and bottom anchor grouting re-inforcement, which were applied in the West Wing belt roadway. Deformation monitoring and the numerical simulation results show that under the deep-shallow hole grouting reinforcement, the surrounding rock strength is improved, integrity is better, rock damage range is greatly re-duced, the roadway surface deformation is effectively controlled, which means the scheme can better meet the roadway operating requirement, successfully resolved the conveyor broken roadway stability control problem of soft rock conditions.

  9. 冷拔圆钢锚杆杆体的技术分析及制作工艺改进%Technical Analyse of the Bolt Body of Coal Drawing Steel Rod

    Institute of Scientific and Technical Information of China (English)

    孟爱凤; 王雅蒂

    2004-01-01

    用金属材料拉伸理论对冷拔滚丝方法生产的普通圆钢麻花锚杆杆体工艺过程及其力学性能进行了分析,并对提高其延伸率的问题提出了改进方案,从而为等强锚杆的生产工艺提出了新的方法.

  10. Application of Dynamic Information Design Methods of Bolt Support in Reinforcing Conveying Roadway%应用锚杆支护动态信息设计法加固运输大巷

    Institute of Scientific and Technical Information of China (English)

    李保林

    2004-01-01

    巷道支护技术是煤炭开采中的一项必要条件.煤科总院北京开采所与常村煤矿共同提出的锚杆支护加固动态信息设计法,不仅适用于常村煤矿,也适用于相似开采环境矿井巷道支护的设计.

  11. Analysis of roadway stability adopted bolt supporting based on dynamic information design%基于动态信息设计法的锚杆支护巷道稳定性分析

    Institute of Scientific and Technical Information of China (English)

    汪占领

    2004-01-01

    针对煤巷锚杆支护中的巷道稳定性问题,通过实例分析,利用最大Lyapounov指数判断了巷道的动态稳定状况,论证了动态信息设计法在下沟矿煤巷锚杆支护中的应用效果

  12. Multibeam collection for BOLT02MV: Multibeam data collected aboard Melville from 2008-11-09 to 2008-11-20, departing from San Diego, CA and returning to San Diego, CA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  13. Innovative modular system for plant engineering. Bolted support system with variable pipe supports enhances plant engineering flexibility; Innovativer Systembaukasten fuer den Anlagenbau. Geschraubtes Traegersystem mit variablen Rohrhalterungen erhoeht die Flexibilitaet im Anlagenbau

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, U. [Sikla, Villingen-Schwenningen (Germany). Geschaeftsbereich Simotec

    2000-05-01

    Time pressure, cost reduction and a high level of flexibility are challenges which now also continuously confront the traditional plant-engineering sector. New products must be launched in the shortest possible time. For planning and construction of production facilities, this means that the production processes continue to be optimized in parallel to pipe design for as long as possible and that deadline pressure is correspondingly high. The modular system discussed here for support structures achieves a high level of flexibility in the design and construction of plants, also making it possible to respond quickly and with only little trouble and expense to changes as they occur. (orig.) [German] Zeitdruck, Kostenreduzierung und ein hohes Mass an Felxibilitaet sind Anforderungen mit denen auch der traditionelle Anlagenbau in der heutigen Zeit staendig konfrontiert wird. Neue Produkte sollen in moeglichst kurzer Zeit auf dem Markt erscheinen. Fuer die Planung und Erstellung von Produktionsanlagen bedeutet dies, dass das Herstellungsverfahren solange wie moeglich parallel zur Rohrplanung optimiert wird und der Termindruck entsprechend hoch ist. Mit dem vorgestellten Systembaukasten fuer Unterstuetzungskonstruktionen wird eine hohe Flexibilitaet bei der Planung und Erstellung von Anlagen erreicht, die es auch ermoeglicht auf kurzfristige Aenderungen schnell und mit wenig Aufwand reagieren zu koennen. (orig.)

  14. Influence of stiffness in bolted connections in wooden plane structure of truss type Influência da rigidez de ligações parafusadas em estruturas planas de madeira do tipo treliça

    Directory of Open Access Journals (Sweden)

    André L. Christoforo

    2011-10-01

    Full Text Available Trusses are structural systems commonly used in projects, being employed mainly in roof structures, present in most rural buildings. The design of trusses, as well as other structural systems, requires the determination of displacements, strains and stresses. However, the project is developed from an ideal model of calculation, considering free rotation between the elements of a connection. This paper presents a computer program for the analysis of bidimensional wooden trusses with connections formed with two screws per node. The formulation is based on the flexibility method, taking into account the influence of the effect of semi-rigid connections formed by two screws. An example of a structure is presented and analyzed by the program developed here, highlighting the importance of behavior analysis on semi-rigid connections.Treliças são sistemas estruturais comumente utilizados em projetos, empregadas principalmente em estruturas de cobertura, presentes na maioria das construções rurais. O dimensionamento de treliças, assim como o de outros sistemas estruturais, requer a determinação dos deslocamentos, esforços, tensões e deformações atuantes em seus elementos constituintes. O cálculo é desenvolvido com base em um modelo ideal, considerando-se o giro livre entre os elementos componentes de uma ligação. Este trabalho objetiva apresentar um programa computacional destinado à análise de treliças planas de madeira com ligações formadas com dois parafusos por nó. A formulação é fundamentada no Método da Flexibilidade, levando-se em consideração a influência do efeito semirrígido das ligações formadas por dois parafusos. Um exemplo de estrutura auxiliar de cobertura é apresentado e analisado pelo programa desenvolvido, evidenciando-se a importância da análise do comportamento semirrígido sobre as ligações.

  15. Hysteretic Behavior of Beam-to-column Bolt in Steel Frame%钢框架梁柱高强螺栓连接节点的滞回性能

    Institute of Scientific and Technical Information of China (English)

    段祺成; 李知兵; 蒋沧如

    2007-01-01

    通过对钢框架梁柱高强螺栓连接节点在循环荷载作用下的拟静力试验,分析了各类连接的刚度、承载能力、延性系数和能量耗散机制,并讨论了剖分T型钢连接、顶底角钢腹板双角钢连接和顶底角钢连接的差别.试验结果表明,T型钢翼缘厚度是影响剖分T型钢连接节点性能的主要因素;在计算顶底角钢腹板双角钢连接的连接刚度和抗弯承载力时,应考虑双腹板角钢的影响.

  16. Analysis of the race rhythm of Usain Bolt in 100-meter sprint%博尔特三夺世界百米冠军的全程节奏分析

    Institute of Scientific and Technical Information of China (English)

    毛旭江; 钟杭伟; 潘慧炬; 朱娟红

    2014-01-01

    通过文献资料法、信息技术法和技术录像解析法对博尔特2008北京奥运会、2009柏林世锦赛、2013莫斯科世锦赛三次夺得世界百米冠军的全程节奏进行解析,并与2013年世锦赛跑进l0s的前5名选手的节奏进行对比.结果显示:1)与接近身高的选手比,博尔特步长、步频均有优势;2)传统的步频、步长指数技术风格分类方法,已不能满足区分当今世界顶级百米选手之间技术风格差异的需要;3)博尔特在第6 ~ 30步甚至35步之间的步频几乎不变,最后10步步频下降较少,仍能高于起跑后第2~5步的步频,可见其长时间维持步频的能力较强,而其余选手在跑的过程中步频增减较明显.

  17. Projected dual-purpose use of a rectangular bolted section at a depth of 1200 m in the D2/C seam; Geplante Doppelnutzung einer Rechteckankerstrecke in 1200m Teufe im Floez D2/C

    Energy Technology Data Exchange (ETDEWEB)

    Breinig, F.; Opolony, K. [Deutsche Steinkohle AG (Germany)

    2004-07-01

    The report gives an insight view to the planning of excavation and support design in seam D2/C at the Lippe mine. Starting with the first rectangular rockbolted tailgate from panel 328 and the subproject rectangular rockbolted roadways for advanced mining'' up to the design of rockbolting pattern for re-use of the maingate of panel 330 in the D2/C seam. The engineering and development of a combined support and casing-unit for recent roadside packages are descibed as well as experience in new dimensioning based upon numerical and physical modelling. Finally the operational experience of the first use are displayed and analysed.

  18. Test Study of High Frequency Quenching Process of EMU Localization Bolt%动车组国产化螺栓的高频淬火工艺试验研究

    Institute of Scientific and Technical Information of China (English)

    李正强; 王欣; 程鑫; 黄峻; 勒晓波

    2014-01-01

    对动车组制动系统国产化部件中要求做表面高频淬火的一种螺栓进行了工艺试验研究,通过大量的试验,对工艺参数进行优化后,最终生产出了满足图纸中表面淬火技术要求的零件.

  19. In vitro Expression and on the Interactions between FLC and SVP from Repressors of Bolting in Brassica oleracea L.%甘蓝抽薹开花抑制因子FLC与SVP体外表达及相互作用

    Institute of Scientific and Technical Information of China (English)

    杨朴丽; 张丹华; 刘智宇; 许俊强; 王志敏; 汤青林; 宋明

    2013-01-01

    甘蓝抽薹开花抑制因子FLC与SVP可能存在相互作用,从而调节开花时间.为进一步的验证该相互作用,以甘蓝‘ZQ’为材料,扩增了594 bp的FLC cDNA和726 bp的SVP cDNA序列,它们分别编码197和241个氨基酸,且均属MIKC型蛋白.NCBI比对发现FLC与BoFLC3同源性高达98%,SVP与BoSVP-a同源性高达99%.将甘蓝FLC和SVP分别与原核表达载体pET43.1a融合,构建重组质粒pET43.1 a-FLC、pET43.1 a-SVP,并转化宿主菌大肠杆菌BL21,均能够在体外表达目的蛋白.利用免疫共沉淀的原理及pET43.1 a-FLC、pET43.1a-SVP融合蛋白序列中的6×His标签能与Ni+结合的特点,结合SDS-PAGE,检测到体外表达蛋白FLC与SVP能相互作用并形成复合体,这为深入研究FLC与SVP互作机理及探讨其与抽薹开花因子的相互作用提供了理论依据和技术基础.

  20. 锚杆框格梁在高压送电线路边坡支护中的应用%The application of the bolt frame pier on the slope support of high-tension-overhead line

    Institute of Scientific and Technical Information of China (English)

    张亮亮

    2010-01-01

    针对广东省某220 kV送电线路塔位出现的浅层滑坡,采用Geostudio软件进行了边坡稳定性分析,根据分析计算结果确定采用锚杆框格梁支护的加固方案,以确保送电线路的安全稳定,对同类工程具有一定指导意义.

  1. Zero torque gear head wrench

    Science.gov (United States)

    Mcdougal, A. R.; Norman, R. M. (Inventor)

    1976-01-01

    A gear head wrench particularly suited for use in applying torque to bolts without transferring torsional stress to bolt-receiving structures is introduced. The wrench is characterized by a coupling including a socket, for connecting a bolt head with a torque multiplying gear train, provided within a housing having an annulus concentrically related to the socket and adapted to be coupled with a spacer interposed between the bolt head and the juxtaposed surface of the bolt-receiving structure for applying a balancing counter-torque to the spacer as torque is applied to the bolt head whereby the bolt-receiving structure is substantially isolated from torsional stress. As a result of the foregoing, the operator of the wrench is substantially isolated from any forces which may be imposed.

  2. Flexible roof drill for low coal. Volume 2. Phase III and Phase IV

    Energy Technology Data Exchange (ETDEWEB)

    Shoup, N.H.

    1977-09-01

    Design specifications were developed for a flexible drilling and bolting system. The system configuration is based on the use of the Galis dual-boom roof drill as a vehicle for the drilling/bolting system. The WSU Flex-drill drivehead is mounted on the Galis drill boom and the Galis parts are modified to accommodate the revised system. The flexible drillhead supports a bolt bender/inserter designed by Bendix Corporation and is integrated into the system operation. A supplemental bolt thruster was designed to complete insertion of the roof bolt following operation and removal of the Bendix bender from the bolt shank. The complete cycle of drilling a 1-3/8-in. diameter bolt hole, bending a roof bolt into the hole, thrusting the bolt head and washer to the roof surface, and final torquing of the bolt is manually controlled by the operator located in the new position behind the bolting line. The new operating position is beneath newly bolted roof in a safer location in back of the stab jack ad roof jacks positioning the drill boom and drivehead. The Flex-drill/bolting system prototype was constructed from both purchased components and parts specially fabricated in the shops for this design. This unit was assembled and test-operated with appropriate support equipment in a laboratory test stand. Numerous test holes were drilled in blocks of concrete at feed rates of 5 ft/min with drill rotation speeds of 360 rpm. The drill feeds uniformly and cuts smoothly with no difficulty in collection of dust or clogging of the drill bit. The holes drilled were straight, as evidence by passage of a 1-1/4-in. diameter bar full depth into the hole with no binding or evidence of curvature. The flexible drill is capable of drilling 8-ft-deep roof bolt holes in low coal 36 in. in height.

  3. Relaxation behaviour of gasketed joints during assembly using finite element analysis

    Indian Academy of Sciences (India)

    Muhammad Abid; Saad Hussain

    2010-02-01

    Gasketed bolted flange pipe joints are always prone to leakage during operating conditions. Therefore, performance of a gasketed flange joint is very much dependent on the proper joint assembly with proper gasket, proper gasket seating stress and proper pre-loading in the bolts of a joint. For a gasketed flange joint, the two main concerns are the joint strength and the sealing capability. To investigate these, a detailed three-dimensional nonlinear finite element analysis of a gasketed joint is carried out using gasket as a solid plate. Bolt scatter, bolt bending and bolt relaxation are concluded as the main factors affecting the joint’s performance. In addition, the importance of proper bolt tightening sequence, number of passes influence of elastic and elasto-plastic material modelling on joint performance are also presented. A dynamic mode in a gasketed joint is concluded, which is the main reason for its failure.

  4. Pseudo-Dynamic Response Tests on Self-Returning Joint Mechanism Using Ni-Ti-Co Alloy

    Science.gov (United States)

    Choi, Jae-Hyouk; Ohi, Kenichi

    This paper deals with a beam-to-column connection using mechanical fasteners made of shape memory alloy, abbreviated as 'SMA bolt' hereafter. A flush-type endplate connection at beam-ends is arranged by use of SMA bolts, and the connection works as a super-elastic joint mechanism. This paper describes sub-structure pseudo-dynamic response tests on a super-elastic frame system with fictitious tension-bar diagonal braces. For the comparison, a similar structural system bolted by ordinary mild-steel bolts is also tested pseudo-dynamically. It was observed that the SMA bolt system returned to its original position, while the ordinary bolt system showed some permanent set after earthquakes. Additionally, response analysis based on a nonlinear-elastic model and a slip model is performed and compared with the test results.

  5. Stability at the half pin–frame interface on external fixation constructs

    OpenAIRE

    Alexios Dimitrios Iliadis; Parag Kumar Jaiswal; Jay Meswania; Gordon Blunn; David Goodier; Peter Calder

    2016-01-01

    Abstract A mechanical study investigating the use of two different methods (grub and bolt screws) to secure external fixation half pins to circular frames. A four part experiment: (1) Grub and bolt screws were used to secure half pins in Taylor Spatial frames. Loosening torques were measured using a calibrated torque wrench. (2) Using universal testing machine (UTM), axial loading was applied to establish thresholds for loosening in grub and bolt screw constructs. (3) We established the appli...

  6. Summary of Federal Aviation Administration Responses to National Transportation Safety Board Safety Recommendations.

    Science.gov (United States)

    1982-01-01

    main gear assembly disclosed that the safety pin in the apex bolt of the main gear torque link had sheared and the nut on the apex bolt had been forced...Douglas performed a failure analysis of the recovered apex bolt which indicated that the safety pin failed or fell out and that the apex attachment nut...Operators Letter (AOL) 9-1261 on April 24, 1981, to change the method of securing the apex bolt attachment nut by replacing the safety pin , washer and cotter

  7. Black Butte Lake, Stony Creek, California Geologic and Seismologic Investigation.

    Science.gov (United States)

    1986-01-01

    Geologic Harlan Miller Tate (1982) Great Valley NNE NNW Vertical Weak Lomnitz & Seismologic Bolt (1967) Margin N75E N15W Vertical Geologic Bolt et al...of Engineers, Sacramento District, California. 78 Bolt, B.A., Lomnitz , C., and McEvilly, T.V., 1968. Seismolo gical Evidence in the Tectonics of...Division of Hines and Geology Special Report 124, R.W. Sherburne and C.J. Hagne, Editors. 83 Lomnitz , C., and Bolt, B.A., 1967. Evidence of Crustal

  8. Alignment Pins for Assembling and Disassembling Structures

    Science.gov (United States)

    Campbell, Oliver C.

    2008-01-01

    Simple, easy-to-use, highly effective tooling has been devised for maintaining alignment of bolt holes in mating structures during assembly and disassembly of the structures. The tooling was originally used during removal of a body flap from the space shuttle Atlantis, in which misalignments during removal of the last few bolts could cause the bolts to bind in their holes. By suitably modifying the dimensions of the tooling components, the basic design of the tooling can readily be adapted to other structures that must be maintained in alignment. The tooling includes tapered, internally threaded alignment pins designed to fit in the bolt holes in one of the mating structures, plus a draw bolt and a cup that are used to install or remove each alignment pin. In preparation for disassembly of two mating structures, external supports are provided to prevent unintended movement of the structures. During disassembly of the structures, as each bolt that joins the structures is removed, an alignment pin is installed in its place. Once all the bolts have been removed and replaced with pins, the pins maintain alignment as the structures are gently pushed or pulled apart on the supports. In assembling the two structures, one reverses the procedure described above: pins are installed in the bolt holes, the structures are pulled or pushed together on the supports, then the pins are removed and replaced with bolts. The figure depicts the tooling and its use. To install an alignment pin in a bolt hole in a structural panel, the tapered end of the pin is inserted from one side of the panel, the cup is placed over the pin on the opposite side of the panel, the draw bolt is inserted through the cup and threaded into the pin, the draw bolt is tightened to pull the pin until the pin is seated firmly in the hole, then the draw bolt and cup are removed, leaving the pin in place. To remove an alignment pin, the cup is placed over the pin on the first-mentioned side of the panel, the draw

  9. ABSTRACTS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Based on engineering practice, this paper applies the finite element method to model the SAC test results of bolted endplate connection. The ductility capacity of a new extended bolted end-plate connection for industrial buildings and structures is analyzed, and the analysis results can be used in engineering design and the development of specifications concerned.

  10. 螺栓

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Bearing behavior of mechanically fastened joints in composite laminates-Part II: failure mechanisms;Block cycle fatigue life simulation and correlation with test for an automotive hood latch-supporting component;Bolt load compressive stress retention testing of magnesium alloys;Brittle elastoplastic damage constitutive model for jointed rockmasses and computation concerning bolt-reinforcement……

  11. 75 FR 74132 - Notice of Intent To Grant Buy America Waiver to Northern New England Passenger Rail Authority To...

    Science.gov (United States)

    2010-11-30

    ... denied, commenting that Dyson Corporation and Chicago Nut & Bolt could provide the specified track nuts.... 3. Dyson Corp. The NNEPRA confirmed that Dyson Corp. could in 12 to 16 weeks post- contract award... process to procure the track nuts. Neither Chicago Track Nut and Bolt nor Dyson Corp. came forward at...

  12. 75 FR 63045 - Airworthiness Directives; BAE SYSTEMS (OPERATIONS) LIMITED Model BAe 146 and Avro 146-RJ Airplanes

    Science.gov (United States)

    2010-10-14

    ... thread. Examining the wear pattern on the seating surfaces of the bolt and nut to determine if the bolt... Rulemaking Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety... in any category. Subject (d) Air Transport Association (ATA) of America Code 57: Wings. Reason...

  13. 76 FR 1556 - Airworthiness Directives; Bombardier, Inc. Model CL-600-2C10 (Regional Jet Series 700, 701 & 702...

    Science.gov (United States)

    2011-01-11

    ... of loose or detached main landing gear torque link apex pin locking plate and the locking plate retainer bolt. This condition could result in torque link apex pin disengagement, heavy vibration during... detached main landing gear torque link apex pin locking plate and the locking plate retainer bolt....

  14. 75 FR 16696 - Airworthiness Directives; Airbus Model A330-223, -321, -322, and -323 Airplanes

    Science.gov (United States)

    2010-04-02

    ... of the Pratt & Whitney (PW) forward (FWD) engine mount pylon bolts. Dual-bolt fractures could lead to inability for mount assembly to sustain loads which may lead to an engine mount failure and consequently to... shank filet radius in one of the Pratt & Whitney (PW) forward (FWD) engine mount pylon...

  15. 78 FR 18925 - Airworthiness Directives; Airbus Airplanes

    Science.gov (United States)

    2013-03-28

    ... torque check of forward engine mount bolts, and replacement if necessary. We are proposing this AD to... unsafe condition for the specified products. The MCAI states: The forward mount engine pylon bolts, Part... series engines. However, the engine mount system is considered to be part of aeroplane...

  16. 75 FR 37991 - Airworthiness Directives; Airbus Model A330-243, -341, -342, and -343 Airplanes; and Model A340...

    Science.gov (United States)

    2010-07-01

    ... washers that maintain the engine mount vertical load pins in position. If bolts, as a consequence of the... loss of the primary and/or secondary load path of the forward and/or aft engine mount which could...-Royce Trent 500 and Trent 700 forward (FWD) and aft (AFT) engine mount link pin retention bolts...

  17. 78 FR 68352 - Airworthiness Directives; Airbus Airplanes

    Science.gov (United States)

    2013-11-14

    ... engine mount bolts, and replacement if necessary. We are issuing this AD to detect and correct loose or... an unsafe condition for the specified products. The MCAI states: The forward mount engine pylon bolts... PW4000 series engines. However, the engine mount system is considered to be part of...

  18. A review on the performance of conventional and energy-absorbing rockbolts

    Institute of Scientific and Technical Information of China (English)

    Charlie C.Li; Gisle Stjern; Arne Myrvang

    2014-01-01

    This is a review paper on the performances of both conventional and energy-absorbing rockbolts manifested in laboratory tests. Characteristic parameters such as ultimate load, displacement and energy absorption are reported, in addition to loadedisplacement graphs for every type of rockbolt. Conven-tional rockbolts refer to mechanical rockbolts, fully-grouted rebars and frictional rockbolts. According to the test results, under static pull loading a mechanical rockbolt usually fails at the plate;a fully-grouted rebar bolt fails in the bolt shank at an ultimate load equal to the strength of the steel after a small amount of displacement;and a frictional rockbolt is subjected to large displacement at a low yield load. Under shear loading, all types of bolts fail in the shank. Energy-absorbing rockbolts are developed aiming to combat instability problems in burst-prone and squeezing rock conditions. They absorb deformation energy either through ploughing/slippage at predefined load levels or through stretching of the steel bolt. An energy-absorbing rockbolt can carry a high load and also accommodate significant rock displacement, and thus its energy-absorbing capacity is high. The test results show that the energy absorption of the energy-absorbing bolts is much larger than that of all conventional bolts. The dynamic load capacity is smaller than the static load capacity for the energy-absorbing bolts displacing based on ploughing/slippage while they are approximately the same for the D-Bolt that displaces based on steel stretching.

  19. Newly Discovered Transmission Pathway of Bursaphelenchus xylophilus from Males of the Beetle Monochamus alternatus to Pinus densiflora Trees via Oviposition Wounds.

    Science.gov (United States)

    Arakawa, Yoh; Togashi, Katsumi

    2002-12-01

    The transmission of Bursaphelenchus xylophilus from Monochamus alternatus males to Pinus densiflora trees via oviposition wounds has been determined. Nematode-infested males, with mandibles fixed experimentally to prevent feeding, were placed for 48 hours with pine bolts containing oviposition wounds that had been made by nematode-free females. After removal of the nematode-infested males, the pine bolts were held for 1 month and then examined for the presence of nematodes. Reproducing nematode populations were recovered from pine bolts that were exposed to male beetles carrying a high number of nematodes. No reproducing nematode population could be recovered from pine bolts exposed to beetles with a small number of nematodes. Nematode reproduction in the pine bolts was not related to the number of oviposition wounds per bolt. Fourth-stage dispersal B. xylophilus juveniles, collected from beetle body surfaces, were inoculated on pine bolt bark 0, 5, 10, and 15 cm away from a single artificial, small hole. These dauer juveniles successfully entered some bolts. The probability of successful nematode reproduction decreased with increased distance between inoculation point and artificial hole. The results indicated that B. xylophilus can move a significant distance to oviposition wounds along the bark surface and enter a tree via the wounds. The new transmission pathway is considered important for the nematode to persist in pine forests such as in North America where pine wilt disease does not occur.

  20. Seismic Discrimination of Earthquakes and Explosions, with Application to the Southwestern United States

    Science.gov (United States)

    1979-03-22

    southern Cali- fornia region. Bull. Seism. Soc. Am., 55, 753-795. Bolt, B. A., C. Lomnitz , and T. V. McEvilly (1968). Seismological evidence on the...75-4, Teledyne Geotech. (ADA 025349) Bolt, B. A., C. Lomnitz , and T. V. McEvilly (1968). Seismological evidence on the tectonics of central and

  1. A Hands-On Classroom Simulation to Demonstrate Concepts in Enzyme Kinetics

    Science.gov (United States)

    Junker, Matthew

    2010-01-01

    A classroom exercise is described to introduce enzyme kinetics in an undergraduate biochemistry or chemistry course. The exercise is a simulation in which a student acts as an enzyme that "catalyzes" the unscrewing of a nut from a bolt. With other students assisting, the student enzyme carries out reactions with bolt-nut substrates under different…

  2. 49 CFR 180.416 - Discharge system inspection and maintenance program for cargo tanks transporting liquefied...

    Science.gov (United States)

    2010-10-01

    ... couplings. (v) Loose or missing bolts or fastenings on bolted hose coupling assemblies. (2) No operator may... actuate. (iv) Rubber hose flexible connectors with any condition outlined in paragraph (g)(1) of this section. (v) Stainless steel flexible connectors with damaged reinforcement braid. (vi) Internal...

  3. The force, power, and energy of the 100 meter sprint

    Science.gov (United States)

    Helene, O.; Yamashita, M. T.

    2010-03-01

    At the 2008 Summer Olympics in Beijing, Usain Bolt broke the world record for the 100 m sprint. Just one year later, at the 2009 World Championships in Athletics in Berlin he broke it again. A few months after Beijing, Eriksen et al. [Am. J. Phys. 77, 224-228 (2009)] studied Bolt's performance and predicted that Bolt could have run about one-tenth of a second faster, which was confirmed in Berlin. In this paper we extend the analysis of Eriksen et al. to model Bolt's velocity time dependence for the Beijing 2008 and Berlin 2009 records. We deduce the maximum force, the maximum power, and the total mechanical energy produced by Bolt in both races. Surprisingly, we conclude that all of these values were smaller in 2009 than in 2008.

  4. Clinical Evaluation of Casting Bolt Post-core and Amalgam-silver Alloy-glass Ionomer Post and Core in Restoration of Severely Defected ;Molars%铸造插销式分体桩核与银汞-银粉玻璃离子桩核修复磨牙残冠的临床研究

    Institute of Scientific and Technical Information of China (English)

    林奋; 岑国超; 曹凯华

    2014-01-01

    Objective:To compare the effect of two post and core materials in restoration of severely defected molars. Method:Forty-five patients with 61 severely defect molars were randomly divided into two groups,and they were treated with cast metal post-core and amalgam-silver alloy-glass ionomer post-core respectively. The repair effect after 3 years was evaluated. Result:In the 20 patients with 25 teeth in cast metal post-core was no crown off,root fracture and pile fracture,the success rate was 100%;In the 25 patients with 36 teeth in amalgam-silver alloy-glass ionomer post-core group, one tooth appeared post fracture,no shedding,crown root fracture,the success rate was 97.2%. There was no significant difference between the two groups (P>0.05). Conclusion:For severe molar defect cases,both cast metal post-core and amalgam-silver alloy-glass ionomer post-core can be used,but amalgam-silver alloy-glass ionomer post-core cost less.%目的:比较两种桩核材料用于磨牙冠缺损的修复效果。方法:临床选择45例患者共61颗患牙的磨牙缺损,按照随机数字表法分为两组,分别进行铸造插销式分体桩核和银汞-银粉玻璃离子桩核金瓷冠修复,3年后对修复效果进行评价。结果:铸造插销式分体桩核组共20例患者25颗患牙,未出现桩冠脱落、根折和桩折等,成功率100%;银汞-银粉玻璃离子桩核组共25例患者36颗患牙,出现桩折1颗患牙,未出现桩冠脱落、根折等,成功率97.2%。两组成功率比较差异无统计学意义(P>0.05)。结论:对于重度磨牙缺损病例,选用铸造插销式分体桩核和银汞-银粉玻璃离子桩核金瓷冠修复均可,但对于患者希望减少就诊次数、经济费用以及临床操作简便的,选用银汞-银粉玻璃离子桩核更合适。

  5. 机心体左右导轨的高度差对转管炮驱动性能影响分析%Influence Analysis of Bolt Carrier Left-Right Guide Rail Altitude Difference on Driving Performances of Gatling Gun

    Institute of Scientific and Technical Information of China (English)

    徐健; 薄玉成

    2010-01-01

    通过参数化机心体左右导轨高度差的方法,编程循环求解.计算结果表明:机心体左右导轨高度差的存在与否不会改变主滚轮压力峰值出现的时机,但驱动压力峰值的大小与导轨高度差基本呈线性关系且单调递减,回转体转速较高时,驱动压力峰值与导轨高度差关系曲线斜率更大.从炮尾方向向前看,如果转管炮是顺时针旋转,则左侧导轨适宜布局得高一些;反之,若转管炮是逆时针旋转,则右侧导轨适宜布局得高一些,这样才能合理地利用导轨高度差来降低滚轮驱动压力.

  6. Seismic behavior of shear dominant bolted endplate steel coupling beam of composite coupled shear wall%剪切机制耗能端板螺栓连接组合联肢剪力墙钢连梁抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    伍云天; 代崇民; 周忠亮; 姜凯旋

    2014-01-01

    将端板螺栓连接构造引入钢-混组合联肢剪力墙中,用于连接钢连梁与混凝土墙肢.设计并制作了1组(2个)小剪跨比连梁双肢组合剪力墙试件,分别采用端板螺栓连接和传统直插式的连梁-墙肢连接构造形式,进行低周往复加载试验,以研究两种连接构造形式下钢连梁与混凝土墙肢连接试件的滞回性能、刚度与承载力退化特征以及破坏模式.试验结果表明:用端板螺栓连接代替直插式连接构造,能够有效减轻钢连梁-墙体连接区域混凝土损伤程度,屈服后非线性变形主要集中在钢连梁端部,且钢连梁能够达到美国AISC 341-05规范要求的0.08 rad非线性转角限值,充分发挥滞回耗能作用,刚度、承载力退化不明显,延性好,与传统直插式钢连梁-墙肢连接具有相同甚至更好的抗震性能.

  7. Break Analysis and Treatment of the Flange Bolt Connected the Turntable with Column in Model 8-25 Floating Crane%8-25浮吊转台转柱连接螺栓断裂故障分析及处理

    Institute of Scientific and Technical Information of China (English)

    姜明鸿

    1999-01-01

    @@ 1 前言 某发电厂一台8-25浮吊频繁发生转台、转柱法兰连接螺栓断裂等故障.大修后,将原4m3抓斗改为3m3,并调整了其死配重.但使用不到一个月,又出现此故障.

  8. 复合稀土Al2O3/沸石分子筛催化合成邻苯二甲酸二丁酯%Synthesis of Dibutyl-1,2-phthalate Ester with Complex Rare-earth Aluminium Oxide Zeolite Molecule Bolt as Catalyst

    Institute of Scientific and Technical Information of China (English)

    王运; 刘绪峰

    2001-01-01

    用复合稀土AI2O3/沸石分子筛催化合成邻苯二甲酸二丁酯,实验结果表明,该催化剂具有较高的活性和选择性,在优化反应条件下,邻苯二甲酸二丁酯的产率为96.6%。

  9. Identificarea armelor de vânătoare lise în funcție de caracteristicile impactului dintre cuiul percutor și capsa de inițiere [ Identification of hunting firearms depending on the characteristics of the impact bolt and staple initiation

    Directory of Open Access Journals (Sweden)

    Lesenciuc I

    2016-08-01

    Full Text Available Hunting firearms with smoothbores use multiple missiles (buckshots or unique missiles (brenneke. As these types of guns have a smooth bore hole, no imprints can be spotted clearly on the missiles, so as to establish the certain type of gun which they belong to. Also, the cartridge cases can be reused, manufacturing manually the ammunition. In this case, it is needed a new primer, which is mounted on the back side of the cartridge case. In fact, the primer represents that part of the cartridge hit by the firing pin, which deforms it irreversibly. On the other hand, the design characteristics of each firearm brand differ from one manufacturer to another. For this reason, it was studied the dynamics of the impact between the firing pin and the primer, at three European firearms brands: IJ, Zastava, Sauer-Bereta. The study focused on the differences which may occur at the impact characteristics (forces, time, and which can lead at least to the identification on the firearm brand.

  10. 三维加锚弹塑性损伤模型在大型山体边坡工程中的应用%Application of 3-D elastoplastic damage model with bolts to a large-sized rockmass slope engineering

    Institute of Scientific and Technical Information of China (English)

    张强勇; 向文

    2000-01-01

    首先根据节理岩体的损伤机制,建立了三维弹塑性损伤本构模型反映节理岩体的损伤变形特性,然后考虑节理岩体的岩锚支护效应,建立了空间损伤锚柱单元模型模拟锚杆的支护效果,最后将建立的模型应用于三峡船闸高边坡,进行了边坡加锚节理岩体开挖卸荷三维非线性有限元计算,获得了一些有益的工程结论.

  11. Back to the Future of Dental Education: "Lock up your libraries if you like, but there is no gate, no lock, no bolt that you can set upon the freedom of my mind"
Virginia Woolf, A Room of One's Own, 1929.

    Science.gov (United States)

    Reynolds, Patricia A

    2014-03-01

    Our students are like beacons, a bright light on the horizon, but with some way to go. Our educational methods that bring them safely into harbour have seen the test of time, but do we allow them enough freedom and creativity to sail their boats in the climate change of the digital era? Our students are chosen because they are smart and capable and we hope will bring credit to our institutions, but do we maximize their potential educationally? We need to go back to the future to begin to consider this.

  12. 用超声波探伤鉴定20Cr1Mo1V(Nb)TiB粗晶螺栓的研究%Study on Identifying 20Cr1Mo1V(Nb)TiB Macrocrystal Bolts by Ultrasonic Detection

    Institute of Scientific and Technical Information of China (English)

    王立新; 孙常明; 田峰; 王海学

    2008-01-01

    介绍了用超声波鉴定粗晶螺栓的原理.用A型脉冲反射式超声波探伤方法对材质为20CrlMolV(Nb)TiB的粗晶螺栓(晶粒级别为1~2级)和细晶螺栓(晶粒级别为5~7级)进行了3种不同频率的检测,结果表明粗晶螺栓对超声波的散射衰减影响显著,且这种散射衰减会随着探头频率的增大而增大,确认用超声波可以有效对粗晶螺栓进行鉴定和区分.

  13. 牙冠延长术联合插销桩在病损达龈下的后牙修复中的应用%Observation on the Restoration of Subgingival Fractured Molars by Crown Lengthening Surgery Combined with Anatomy Bolt Post-core Crown

    Institute of Scientific and Technical Information of China (English)

    陈晓珠; 谢逸瑞; 徐汉林; 郑洁莲

    2012-01-01

    目的:利用插销桩烤瓷冠辅以牙冠延长术修复纵折或龋坏至龈下的磨牙,以提高此类后牙修复的成功率.方法:对4 例劈裂,11 例邻面龋至龈下的磨牙拔除牙折片后采用镍铬合金桩核加烤瓷冠进行修复,配合牙冠延长术,随访观察12~26 个月.结果:纵折磨牙拔除牙折片后采用桩核烤瓷冠直接修复和配合牙冠延长术修复,随诊观察1 年后的修复有效率100%.结论:修复劈裂至龈下的纵折磨牙采用桩核烤瓷冠配合牙冠延长术是一种有效的治疗方法.

  14. 非标V3安装电机端盖紧固螺栓的强度计算%Strength Caleulation of the Binding Bolt on the End-plate of Motors with Non-standard V3 Installation

    Institute of Scientific and Technical Information of China (English)

    苏简柏; 赵代夫

    2011-01-01

    按照国标GB/T997-2003中要求,V3安装电机设计结构形式为电机端盖上带凸缘,凸缘上有通孔,轴伸向上垂直安装.在行业中,中心高H63~160电机按普通电机制造,中心高H160以上的V3电机结构需要特殊设计.其中,螺栓连接的强度计算是螺栓连接使用场合需要考虑的重要前提和基础.

  15. Application of High Prestressed Bolt and Cable Combinations Support Technology in Transport Downhill Excavation Support%高预应力锚杆锚索组合支护技术在运输下山掘进支护中的应用

    Institute of Scientific and Technical Information of China (English)

    贾林波

    2013-01-01

    Fusheng coal in a mining area transportation down as engineering background ,using FLAC3D simulated roadway roof in the high prestressed anchor anchor combined support under the stress field distribution ,research results and their proliferation is prestressed anchor play a proactive role in supporting the key factors anchor ,anchor and anchor combined support can significantly expand the ef -fective compressive stress zone ,and on this basis ,the use of dynamic information design method to design high prestressed anchor an -chor combined support parameters used in the underground ,the supporting results are satisfactory .%以阜生煤业一采区运输下山为工程背景,采用FLAC3D模拟了巷道顶板在高预应力锚杆锚索组合支护作用下的应力场分布特征,研究得出预应力及其扩散是锚杆支护发挥主动锚固作用的关键性因素,锚杆与锚索组合支护能显著扩大有效压应力区范围,并在此基础上运用动态信息设计法设计出高预应力锚杆锚索组合支护参数应用于井下,支护效果理想。

  16. Strength analysis of rivet and bolt joint structure in aluminum alloy car body of high-speed train%高速列车铝合金车体中铆钉和螺栓联接结构的强度分析

    Institute of Scientific and Technical Information of China (English)

    肖守讷; 贾宇

    2004-01-01

    铆钉和螺栓联接结构是铝合金车体中不同金属之间及铝合金之间联接的重要方式.通过铝合金车体强度计算实例,介绍了使用耦合和约束方程建立铆钉和螺栓联接结构有限元模型的方法,提出了铆钉和螺栓联接结构强度的验收标准,以及对铆钉和螺栓联接结构计算结果进行分析的方法.

  17. 高地压软岩巷道"锚锚"联合支护技术及矿压观测分析%Combined Support Using Rock Bolt and Cable Anchor" for Soft Rock Roadway with High Gorund Pressure and Analysis on Strata Control Observation

    Institute of Scientific and Technical Information of China (English)

    张浩

    2010-01-01

    淮北矿区地质条件复杂,且采深大、地应力高,软岩巷道支护极为因难.以改革支护技术为主要手段,应用以锚杆主动支护为基础的联合支护技术,结合巷道设计优化、施工工艺改进、高性能支护材料应用等,实施围岩综合治理,逐步形成符合矿区实际的高地压软岩巷道围岩综合控制技术体系,治理软岩巷道达74 000多m,有效推进了矿井安全、高效建设.

  18. Causes and prevention of looseness of connecting bolts for cardan shaft flanges of DF7 type locomotive%DF7型机车万向轴法兰联接螺栓松动的原因及防止

    Institute of Scientific and Technical Information of China (English)

    苏永军

    2002-01-01

    @@ DF7型机车具有功率大、牵引性能好的特点,应用于大型编组站和重载列车调车作业.在厂修试验过程中,机车工况转换频繁,柴油机转速升、降幅度较大,使辅助传动系统承受较大的冲击载荷,致使该系统的故障增加.从机车的运用和日常检修情况分析,万向轴法兰联接螺栓松动是DF7型机车辅助传动系统的惯性故障.

  19. Application of One-Step-bolts in drill and blast heading and roadheader development at the collieries Ost and Prosper-Haniel; Einsatz von One-Step-Ankern in Spreng- und TSM-Vortrieben auf den Bergwerken Ost und Prosper-Haniel

    Energy Technology Data Exchange (ETDEWEB)

    Reinewardt, K. [Deutsche Steinkohle AG, Bottrop (Germany). Bergwerk Prosper-Haniel; Kroker, J. [Deutsche Steinkohle AG, Hamm (Germany). Bergwerk Ost

    2006-09-21

    After successful trials in selected engine roads and conventional development headings completed in mid-2004, One-Step-roofbolts are now being used in the 'Ost' and 'Prosper-Haniel' collieries. Efficient driving with roofbolting combined with headway supporting methods is an essential prerequisite for high quality parallel roads to panel entries in seams characterised by their deepness. Subject to appropriate framework conditions, One-Step roofbolts make it possible to achieve a distinct drive rate increase when using the Type A combination supporting method. (orig.)

  20. On the Speed Barrier of Human Beings——Firstly Uncover the Recipe of Jamaican Athlete Usain Bolt, the Creator of Sprint World's Record%论人类速度极限——初揭创造短跑世界纪录牙买加运动员博尔特的秘诀

    Institute of Scientific and Technical Information of China (English)

    程其练; 窦榕滨; 李宏明; 张知超; 黄玲

    2009-01-01

    2008年8月16日晚在北京国家体育场牙买加运动员博尔特以惊人的9.69 s,再次打破了由他自己保持的9.72 s 100 m世界纪录,把人类速度极限带入9.70 s之内,由此,打乱了业内人士的思绪,提出了质疑和争议.笔者在此就人类速度极限问题,阐明博尔特天赋条件和现代科学技术理念,揭示博尔特创造人类速度极限的秘诀.

  1. Combined and interactive effects of interference fit and preloads on composite joints

    Institute of Scientific and Technical Information of China (English)

    Liu Longquan; Zhang Junqi; Chen Kunkun; Wang Hai

    2014-01-01

    The combined and interactive effects of the bolt-hole fit conditions and the preloads of the fasteners on the load carrying capacity of single-lap composite-to-titanium bolted joints have been investigated both experimentally and numerically. Quasi-static tests of the hybrid joints with different fit conditions are implemented, and a three dimensional finite element progressive failure analysis model is proposed to predict the influences of the bolt-hole fit conditions and fastener’s pre-loads on the mechanical behaviors of the joints. Based on the experimental validated simulation method, a multi-factor, mixed levels orthogonal design table and the analysis of variance method are used to arrange the simulation conditions and to further study the interactive effects of preloads and fit conditions. Through the analysis of the results, for the researched double bolt, single-lap composite-titanium joints, it is found that:the effects of both the interference fit and the preloads change from positive into negative mode with the increase of the interference fit values or preload values; appropriate bolt-hole fit conditions and preloads can improve the bolt-hole contact conditions of the loaded joints, and then retard the fiber failures around the fastener holes, and increase the load carrying capacity of the joints eventually; the interactive effect of the bolt-hole interference fit conditions and preloads cannot be ignored and the parameters need to be considered together and synthetically as the joints are being optimized.

  2. HANFORD DOUBLE SHELL TANK THERMAL AND SEISMIC PROJECT SEISMIC ANALYSIS IN SUPPORT OF INCREASED LIQUID LEVEL IN 241-AP TANK FARMS

    Energy Technology Data Exchange (ETDEWEB)

    TC MACKEY; FG ABATT; MW RINKER

    2009-01-14

    The essential difference between Revision 1 and the original issue of this report is in the spring constants used to model the anchor bolt response for the anchor bolts that tie the steel dome of the primary tank to the concrete tank dome. Consequently, focus was placed on the changes in the anchor bolt responses, and a full reevaluation of all tank components was judged to be unnecessary. To confirm this judgement, primary tank stresses from the revised analysis of the BES-BEC case are compared to the original analysis and it was verified that the changes are small, as expected.

  3. Failure Mode/Mechanism Distributions

    Science.gov (United States)

    1991-09-01

    nsc. Modas /Mach Dist. Dist. Suurce(,%)/Detai19 Bolt, MahineSources :1 Brcikon 𔃺.1% 59.0% Broken Bolt(s) (25j01-(000,Qty:l) C25101-000,Qty:Ij., Part...Center (RAC) * 201 Mill St., Rome, NY 13440 * 315-337-0900 3-114 Failure Distribution Summaries FMD-91 ? art Failure Norm Fail Data Docm. Mode/Moch Dist... Deco . Mode/Mech Dist. Dist. Source(s)/Details Lamp,Bulb Sourcent 4 Lamp Failure 68.8% 53.8% Light Bulb Failure (23038-00l,Qty:3) (23038-004,Qty:l

  4. Analysis of Modeling Parameters on Threaded Screws.

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-01

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

  5. 29 CFR 1918.62 - Miscellaneous auxiliary gear.

    Science.gov (United States)

    2010-07-01

    ... than 5 percent; when a link is bent, twisted or otherwise damaged; or when a link has a raised scarf or... for hoisting shall be bolts and nuts, drive screws (helically threaded nails), annular threaded...

  6. Construction of a Pendentive Grid Crossing Vault

    OpenAIRE

    Palacios Gonzalo, Jose Carlos; Bravo Guerrero, Sandra Cynthia

    2012-01-01

    Nuts & bolts of construction history : culture, technology and society :[proceedings of the Fourth International Congress on Construction History, Paris, 3-7 July 2012. ISBN: 978-2-7084-0929-3 . Vol 1 págs 81 a 88

  7. 78 FR 46315 - Foreign-Trade Zone (FTZ) 247-Erie, Pennsylvania, Notification of Proposed Production Activity, GE...

    Science.gov (United States)

    2013-07-31

    ... assemblies; cylinder head assemblies; doors; orifices; master rod assemblies; piston rod assemblies; piston...; side sheets; skirts; snubbers; step assemblies; stiffeners; straps; strips; traction pins; walkway...; lock assemblies; side bolts; hinges; mounting flanges; casting; bracket assemblies; support...

  8. 78 FR 79403 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to...

    Science.gov (United States)

    2013-12-30

    ... substrate. Barnacle recruits and cyprids are collected on PVC plates covered in non-slip tape and bolted to... present, which will avoid mother/pup separation and trampling of pups. Of the three marine mammal...

  9. 49 CFR 213.119 - Continuous welded rail (CWR); plan contents.

    Science.gov (United States)

    2010-10-01

    ... following items: (i) Loose, bent, or missing joint bolts; (ii) Rail end batter or mismatch that contributes... amount and length of rail end batter or ramp on each rail end; the amount of tread mismatch; the...

  10. One long tie bar broken after 3 days because of hydrogen contamination.

    CERN Multimedia

    H. Gerwig

    2000-01-01

    The tie bars have been produced with a high yield strength. As known for these type of high strength bolts, and hydrogen contamination during manufacture or heat treatment could lead to rupture under stress after several days.

  11. Reliability Assessment of IGBT Modules Modeled as Systems with Correlated Components

    DEFF Research Database (Denmark)

    Kostandyan, Erik; Sørensen, John Dalsgaard

    2013-01-01

    configuration. The estimated system reliability by the proposed method is a conservative estimate. Application of the suggested method could be extended for reliability estimation of systems composing of welding joints, bolts, bearings, etc. The reliability model incorporates the correlation between...

  12. Reference: 796 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available ceedings of the National Academy of Sciences of the United States of America DeBolt...required for normal microtubule dynamics and organization in Arabidopsis. 46 18064-9 19004800 2008 Nov Pro

  13. Sensor and Guidance Technology Related to Mobile Robots.

    Science.gov (United States)

    1987-06-01

    at Erection of steel beams, a given location and precast elements, orientation formwork , scaffolding 2 Connecting Connecting a component Bolting...Warszawski.’ These applications include shotcreting, tunneling , concrete pouring, rock drilling, spraying fire-proofing material, tree harvesting

  14. 40 CFR 89.109 - Maintenance instructions and minimum allowable maintenance intervals.

    Science.gov (United States)

    2010-07-01

    ... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION... of idle speed, governor, engine bolt torque, valve lash, injector lash, timing, lubrication of...

  15. 40 CFR 86.094-25 - Maintenance.

    Science.gov (United States)

    2010-07-01

    ...-25 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED..., timing, adjustment of air pump drive belt tension, lubrication of the exhaust manifold heat control valve, lubrication of carburetor choke linkage, retorqueing carburetor mounting bolts, etc.) may be performed...

  16. 36 CFR 7.71 - Delaware Water Gap National Recreation Area.

    Science.gov (United States)

    2010-07-01

    ..., carabiners or snap links, ropes, expansion bolts, or other mechanical equipment are used to make the climb... otherwise designated, fishing in any manner authorized under applicable State law is allowed....

  17. 49 CFR 231.16 - Steam locomotives used in switching service.

    Science.gov (United States)

    2010-10-01

    ..., end sill or tank frame by not less than two 7/8-inch bolts. (iv) If side footboards are used, a..., wrought iron or steel. Minimum clearance, 4 inches, except at coupler casting or braces when...

  18. Experimental Study of Deformation of Surrounding Rock with Infrared Radiation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong-jun; AN Li-qian; REN Run-hou; FAN Shi-min; MA Nian-jie; LI Jian-hui; JI Yuan-ming

    2005-01-01

    According to the practical conditions of coal roadway in Changcun Coal Mine of Lu'an Mining Group, the deformation of rock surrounding roadway was experimentally studied by means of thermal infrared (TIR) imaging system in the process of confined compressions. It is found that the model surface TIR temperature (TIRT) changes with the increase of load. Furthermore, TIRT changes non-synchronously in different ranges such as the roof, floor, wall, corners and bolted ranges. The TIRT is higher in the location of stress concentration and bolted ranges than that in the location of stress relaxation and broken ranges. The interaction ranges of bolt and rock are determined preliminarily according to the corresponding relationship of TIRT fields and the strain fields of the surrounding rock. The new method of TIR image processing has been proved to be effective for the study of bolt support and observation of roadway stability under mine pressure.

  19. 30 CFR 18.31 - Enclosures-joints and fastenings.

    Science.gov (United States)

    2010-07-01

    ... Volume Volume of empty enclosure Less than 45 cu. in. 45 to 124 cu. in. inclusive More than 124 cu. in... closed with a plug secured by weld or braze. Bolts shall be provided at all corners. 8 The...

  20. Summary of Calculations Performed to Evaluate the Structural Integrity of the 6-Pack Container Pallet

    Energy Technology Data Exchange (ETDEWEB)

    Hrousis, C.A.

    1999-10-01

    The 6-Pack Container Pallet is a space-frame structure, designed by Mason & Hanger Corp. to hold six AL-R8 containers together in a convenient bundle. The AL-R8 containers hold nuclear weapon components that require special care and consideration. The primary purpose of the 6-pack assembly is storage, but there is some manipulation as the 6-pack is loaded, moved and stacked. Recently, there has been an upgrade to a new AL-R8-SI container that is heavier than its predecessor was. The analysis discussed herein was conducted to ensure that the increased stresses due to the heavier containers are within design safety limits. At this time, however, there is disagreement as to what the strength requirements for the 6-pack pallet are. Depending on which classification applies to the structure, a factor of safety (yield stress over design stress) of 3.0 or more may need to be satisfied. This report documents strength analyses of loaded 6-packs performed at Lawrence Livermore National Laboratory (LLNL). The entire 6-pack assembly was discretized into a mesh with a total of 38682 first-order finite elements. The stresses were found for four characteristic load cases using the implicit code NIKE3D. This was a static strength analysis only. Dynamic loading was not considered. Stability, also, was not addressed. There are two 6-pack pallet designs under consideration: one that uses 1/2 inch diameter bolts and one with 3/8 inch bolts. In both cases, the maximum torque applied to the bolts is 55 in-lbf. This analysis finds the minimum factor of safety based on yield to be less than 3.0 in the main load path of both the 1/2 inch and 3/8 inch diameter bolt designs. In general, the peak stresses found in the 1/2 inch bolt design are less than those of the 3/8 inch bolt design. At the welded ends of the main tube section that spans the length of the pallet, the minimum safety factor is 2.14 when 1/2 inch bolts are used and 1.77 when 3/8 inch bolts are used. Minimum safety factors of

  1. Experimental Aspects of In-Plane Displacement Measurement Using a Moire Fringe Technique.

    Science.gov (United States)

    1986-06-01

    withdrawn. The J-integral specimen was loaded in a portable Hounsfield Tensometer . A tension load was applied through the two bolt holes of the specimen...after cold working. The Hounsfield Tensometer , in which the J-integral . * - , specimen was loaded, was mounted on the concrete block in front of the...Kodak HC- 110 fine grain developer at a dilution of I part to 19 parts water. , For the cold-worked bolt hole specimen, Kodak D19 developer was adequate

  2. Stability at the half pin–frame interface on external fixation constructs

    Directory of Open Access Journals (Sweden)

    Alexios Dimitrios Iliadis

    2016-10-01

    Full Text Available Abstract A mechanical study investigating the use of two different methods (grub and bolt screws to secure external fixation half pins to circular frames. A four part experiment: (1 Grub and bolt screws were used to secure half pins in Taylor Spatial frames. Loosening torques were measured using a calibrated torque wrench. (2 Using universal testing machine (UTM, axial loading was applied to establish thresholds for loosening in grub and bolt screw constructs. (3 We established the application torque to produce failure at the head–driver interface using these two methods. (4 Grub and bolt screw constructs were created controlling torque. Using UTM, axial loading was applied to establish thresholds for loosening. Statistical analysis was conducted using SPSS v20.0.0. (1 Higher torque is employed when bolt rather than grub screws is used to secure half pins on Rancho cubes (p < 0.05. (2 Loading threshold for loosening is higher in bolt screw constructs when the torque applied to secure the constructs is not controlled (p < 0.05. (3 Torque required for failure at the head–driver interface was 5.3 Nm for grub screws and 9.9 Nm for bolts. (4 Loading threshold for loosening is higher in grub screw constructs when the same torque was applied to secure them (p < 0.05. Bolt screws can be employed to secure the half pin–frame interface. They offer good stability and reduce failure at the head–driver interface. Further research is needed to determine the mechanical properties of such constructs in vivo.

  3. China’s Development of Asymmetric Warfare and the Security of Taiwan, Republic of China

    Science.gov (United States)

    2004-12-01

    thanks to my loving and devoted wife, Anita . Her patience, understanding, and remarkable ability to maintain a pleasant, comforting home during this...should arise (Bolt, Brenner , 2004, p.130). Information warfare technology can delay a United States response and commitment in the Taiwan Strait in...destruction of C4 systems by missiles, airpower, and high-energy weapons (Bolt & Brenner , 2004, p.133). Perhaps the most astonishing view of the PRC’s IW

  4. Conceptual design for PSP mounting bracket

    Energy Technology Data Exchange (ETDEWEB)

    Ransom, G.; Stein, R. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States)

    1991-12-31

    Protective structural packages (PSP`s or overpacks) used to ship 2 1/2-ton UF{sub 6} product cylinders are bolted to truck trailers. All bolts penetrate two longitudinal rows of wooden planks. Removal and replacement is required at various intervals for maintenance and routine testing. A conceptual design is presented for mounting brackets which would securely attach PSP`s to trailer frames, reduce removal and replacement time, and minimize risk of personnel injury.

  5. Cronus: A Distributed Operating System.

    Science.gov (United States)

    1983-11-01

    423 machine interface. -24- -- mass- Report No. 5086 Bolt Beranek and Newman Inc. standard operating systems (e.g., a Digital Equipment Corporation VAX...One from Ungermann-Bass, Inc. o ProNet from Proteon Associates -120- Report No. 5086 Bolt Beranek and Newman Inc. o PolyNet from Logica , Inc. o...configuration. Polynet from Logica , Inc. Polynet is a commercial version of the Cambridge University Ring Network that has become quite popular in the

  6. A review on the performance of conventional and energy-absorbing rockbolts

    Directory of Open Access Journals (Sweden)

    Charlie C. Li

    2014-08-01

    Full Text Available This is a review paper on the performances of both conventional and energy-absorbing rockbolts manifested in laboratory tests. Characteristic parameters such as ultimate load, displacement and energy absorption are reported, in addition to load–displacement graphs for every type of rockbolt. Conventional rockbolts refer to mechanical rockbolts, fully-grouted rebars and frictional rockbolts. According to the test results, under static pull loading a mechanical rockbolt usually fails at the plate; a fully-grouted rebar bolt fails in the bolt shank at an ultimate load equal to the strength of the steel after a small amount of displacement; and a frictional rockbolt is subjected to large displacement at a low yield load. Under shear loading, all types of bolts fail in the shank. Energy-absorbing rockbolts are developed aiming to combat instability problems in burst-prone and squeezing rock conditions. They absorb deformation energy either through ploughing/slippage at predefined load levels or through stretching of the steel bolt. An energy-absorbing rockbolt can carry a high load and also accommodate significant rock displacement, and thus its energy-absorbing capacity is high. The test results show that the energy absorption of the energy-absorbing bolts is much larger than that of all conventional bolts. The dynamic load capacity is smaller than the static load capacity for the energy-absorbing bolts displacing based on ploughing/slippage while they are approximately the same for the D-Bolt that displaces based on steel stretching.

  7. Effects of Strain Path on the Microstructure of Aluminum Alloys During Equal Channel Angular Pressing (ECAP)

    Science.gov (United States)

    2007-12-01

    nut seized onto the bolt. This caused a revisitation of the torque calculations. Upon a closer look, although Shigley recommends that a Torque...to be considered, using Shigley as a reference once again [24]. Bolt size (d) 1/2 in Maj. Dia. Area (Ad) 0.1963 2in Tensile Stress Area...Handbook Volume 4: Heat Treating, Ninth Edition, p. 708. [24] J.E. Shigley , C.R. Mischke: Mechanical Engineering Design, Fifth Edition, McGraw-Hill, 1989

  8. Deformation mechanism of surrounding rocks and key control technology for a roadway driven along goaf in fully mechanized top-coal caving face

    Institute of Scientific and Technical Information of China (English)

    李学华

    2003-01-01

    The variation of the stress in the bolted surrounding rocks structure of the roadway driven along goaf in a fully mechanized top-coal caving face with moderate stable conditions are studied by using numerical calculation. The essential deformation characteristics of the surrounding rocks in this kind of roadway are obtained and the key technology of bolting support used under these conditions is put forward.

  9. Deformation mechanism of surrounding rocks and key control technology for a roadway driven along goaf in fully mechanized top-coal caving face

    Energy Technology Data Exchange (ETDEWEB)

    Li, X. [China University of Mining and Technology, Xuzhou (China). School of Energy Science and Engineering

    2003-06-01

    The variation of the stress in the bolted surrounding rocks structure of the roadway driven along the goaf in a fully mechanized top-coal caving face with moderate stable conditions are studied by using numerical calculation. The essential deformation characteristics of the surrounding rocks in this kind of roadway are obtained and the key technology of bolting support used under these conditions is put forward. 3 refs., 2 figs., 1 tab.

  10. Investigation of the Corrosion Mechanism and Determination of the EMS Estimated Service Life at Site 81

    Science.gov (United States)

    2013-02-01

    and total dissolved solids. The raw groundwater filtering through the Portland cement has dissolved these elements, causing their increase in the...The technique uses a two-wire probe to measure the concrete resistivity which is inversely related to the moisture content. A series of moisture...was used to en- sure each bolt was firmly cemented into the underlying concrete. Follow- ing setting of the bolts in locations #1 and #2, a concrete

  11. Investigation into Hydrogen Diffusion and Susceptibility of Hydrogen Embrittlement of High Strength 0Cr16Ni5Mo Steel

    Institute of Scientific and Technical Information of China (English)

    Yong-wei SUN; Ji-zhi CHEN; Jun LIU

    2015-01-01

    High strength bolt steel 0Cr16Ni5Mo was charged with hydrogen by means of electrochemical technique to evaluate the hydrogen diffusion behavior. The bolt steels were investigated by a combination of electrochemical hydrogen permeation, thermal desorption spectroscopy (TDS), slow strain rate test (SSRT) and microstructure observation. The hydrogen concentration of both 10.9 grade (Rm=950—1 150 MPa) and 12.9 grade (Rm=1 150—1 250 MPa) bolt steels increases with increasing the hydrogen charg-ing current densities and charging time. The 12.9 grade bolt steel has higher apparent diffusion coefifcient than 10.9 grade steel, corresponding to the value of 4.7×10—7 mm2/s. By means of TDS tests, the activation energies of the two experimental steels are 17.74 kJ/mol and 18.92 kJ/mol, respectively. The hydrogen traps of both grade bolt steels are dislocations and crystal lattice. The notch tensile strength of the steels is reduced with the hydrogen concentration carried out by SSRT. The fracture morphologies of the steels after hydrogen charging present ductile dimple and quasi-cleavage characteristic.

  12. The improved damping of superconductor bearings for 35 kWh superconductor flywheel energy storage system

    Energy Technology Data Exchange (ETDEWEB)

    Han, Y.H., E-mail: yhhan@kepri.re.kr [KEPCO Research Institute, 105 Munji-Ro, Yuseong-Gu, Daejeon 305-760 (Korea, Republic of); Park, B.J.; Jung, S.Y.; Han, S.C.; Lee, W.R.; Bae, Y.C. [KEPCO Research Institute, 105 Munji-Ro, Yuseong-Gu, Daejeon 305-760 (Korea, Republic of)

    2013-02-14

    Highlights: ► We made a 35 kWh superconductor flywheel energy storage system. ► The damping coefficient of the superconductor bearing was increased over 3000 N s/m. ► The source of damping was discussed. -- Abstract: A 35 kWh Superconductor Flywheel Energy Storage system (SFES) using hybrid bearing sets, which is composed of a high temperature superconductor (HTS) bearing and an active magnet damper (AMD), has been developed at KEPCO Research Institute (KEPRI). Damping is a source of energy loss but necessary for the stability of the flywheel system. We found that the damping of HTS bearings can be improved by thermal insulating bolts, which play a role of passive type external damper. To investigate the source of the increased damping, damping coefficients were measured with HTS bearings using insulating bolts made of three kinds of polymer materials. The damping coefficient was raised over 3000 N s/m in the case of PEEK bolts. The value was almost a quarter of the AMD. In this study, thermoelastic and Coulomb friction damping mechanisms are discussed. The main damping mechanism was the thermoelastic damping of the bolts themselves. And interfacial gap between the insulating bolt and metal chamber, which increased during the cooling process, was considered to be the cause of the anisotropic damping coefficients. Finally, the effects of the HTS bearings on the first critical speed are shown.

  13. Grainex Mar-M 247 Turbine Disk Life Study for NASA's High Temperature High Speed Turbine Seal Test Facility

    Science.gov (United States)

    Delgado, Irebert R.

    2015-01-01

    An experimental and analytical fatigue life study was performed on the Grainex Mar-M 247 disk used in NASA s Turbine Seal Test Facility. To preclude fatigue cracks from growing to critical size in the NASA disk bolt holes due to cyclic loading at severe test conditions, a retirement-for-cause methodology was adopted to detect and monitor cracks within the bolt holes using eddy-current inspection. For the NASA disk material that was tested, the fatigue strain-life to crack initiation at a total strain of 0.5 percent, a minimum to maximum strain ratio of 0, and a bolt hole temperature of 649 C was calculated to be 665 cycles using -99.95 percent prediction intervals. The fatigue crack propagation life was calculated to be 367 cycles after implementing a safety factor of 2 on life. Thus, the NASA disk bolt hole total life or retirement life was determined to be 1032 cycles at a crack depth of 0.501 mm. An initial NASA disk bolt hole inspection at 665 cycles is suggested with 50 cycle inspection intervals thereafter to monitor fatigue crack growth.

  14. Replacement of nickel sealing rings by expanded graphite sealing rings -upgrading of SG primary collector flange connection

    Energy Technology Data Exchange (ETDEWEB)

    Cikryt, F.; Bednarek, L.; Kusyn, L. [Vitkovice, Ostrava (Switzerland)

    1997-12-31

    One of the most loaded parts of a steam generator of VVER 440 MW type are the bolts and thread holes of the primary collector cover sealing set. The strength calculations and tensometric measurings performed during operation proved the high degree of a load on the bolts. The conditions of the stress limitation are not met in some cases according to the pertinent standards. The untightnesses at nickel rings occurred during putting the units of Jaslovske Bohunice and Dukovany nuclear power stations into operation. With regard to improve the reliability, the producer has taken measures to improve the quality of the rings and users have introduced more strict regulations for bolts tightening. Due to these measures the high reliability of the set has been obtained from point of view of the tightness, but substantial reduction of bolts and holes threads loading have not been obtained. Several years operation experience proved relatively low service of bolts, damage of thread holes and sealing grooves. As the degree of mechanical load is one of the vital parameters influencing the damage of sealing set, in 1996 we started with the works aimed at a possibility of nickel sealing rings replacement for a more modern type of sealing which assure the higher reliability and service life of the individual part of sealing set under the reduced load.

  15. Shape memory alloy-based moment connections with superior self-centering properties

    Science.gov (United States)

    Farmani, Mohammad Amin; Ghassemieh, Mehdi

    2016-07-01

    Superelastic shape memory alloys (SMAs) have the potential to create a spontaneous recentering mechanism on the connections of a structural system under seismic actions, which results in mitigation of the damage in the main structural members. In this article, innovative types of steel beam-to-column moment connections incorporating SMA bolts and plates are introduced and studied through a numerical approach. First, SMA bolted end-plate connection model is produced and analyzed by means of the finite element method to validate the numerical analysis against the prior experimental results. Then, the performance of eleven different end-plate moment connection models subjected to cyclic loading is investigated. By selecting the lower values for the moment capacity based on bolts strength in comparison to the flexural resistance of the beam, the plastic hinge is transferred from the beam section to the beam-column interface. Hence, employing superelastic materials at the connection interface could be potentially effective in providing the desired self-centering effect in the connection. To this end, the impact of utilizing superelastic SMA bolts and end-plates instead of using the conventional structural steel on the overall cyclic response of the connections is evaluated in this study. Results show that extended end-plate connections equipped with SMA bolts and end-plates, if properly proportioned and detailed, not only exhibit a clear reduction in the residual drifts after a seismic event, but also can meet the ductility requirements with good energy dissipation and sufficient stiffness.

  16. In-service fatigue cracking of the propeller shafts joined by a spline-pinned construction to the engines of AN-24, AN-26, and IL-18 aircrafts

    Directory of Open Access Journals (Sweden)

    A. Shanyavskiy

    2014-10-01

    Full Text Available The paper delivers a critical review of the research data on the crack initiation and crack growth patterns characteristic of the components of the spline-bolted joints between the propeller shaft and reducer shaft at An-24, An-26, and Il-18 aircrafts. Cracks in the shafts nucleated because of reduced bolt-fastening force. Actually, the bolt (bolts failed first (also by fatigue and then fatigue cracks nucleated and grew in the shafts, the spline surface fretting zones and/or sharp edges of the attachment (bolt-conducting holes making the crack origin sites. The crack growth history shows itself through the regular Macro-Beach Marks, each mark sequentially pointing to the next loading event of the propeller shaft, i.e., to each next flight. The cracks cease growing for some while in the airscrews and their shafts just replaced to another aircraft. For the airscrew shafts, the critically assessed data show the crack growth period Np ranging as five to ten percent of a total running period Nf . We recommend performing nondestructive inspection of the airscrew shafts on every 250- hour running period to ensure the safety flights.

  17. The improved damping of superconductor bearings for 35 kWh superconductor flywheel energy storage system

    Science.gov (United States)

    Han, Y. H.; Park, B. J.; Jung, S. Y.; Han, S. C.; Lee, W. R.; Bae, Y. C.

    2013-02-01

    A 35 kWh Superconductor Flywheel Energy Storage system (SFES) using hybrid bearing sets, which is composed of a high temperature superconductor (HTS) bearing and an active magnet damper (AMD), has been developed at KEPCO Research Institute (KEPRI). Damping is a source of energy loss but necessary for the stability of the flywheel system. We found that the damping of HTS bearings can be improved by thermal insulating bolts, which play a role of passive type external damper. To investigate the source of the increased damping, damping coefficients were measured with HTS bearings using insulating bolts made of three kinds of polymer materials. The damping coefficient was raised over 3000 N s/m in the case of PEEK bolts. The value was almost a quarter of the AMD. In this study, thermoelastic and Coulomb friction damping mechanisms are discussed. The main damping mechanism was the thermoelastic damping of the bolts themselves. And interfacial gap between the insulating bolt and metal chamber, which increased during the cooling process, was considered to be the cause of the anisotropic damping coefficients. Finally, the effects of the HTS bearings on the first critical speed are shown.

  18. Solid Rocket Booster Hydraulic Pump Port Cap Joint Load Testing

    Science.gov (United States)

    Gamwell, W. R.; Murphy, N. C.

    2004-01-01

    The solid rocket booster uses hydraulic pumps fabricated from cast C355 aluminum alloy, with 17-4 PH stainless steel pump port caps. Corrosion-resistant steel, MS51830 CA204L self-locking screw thread inserts are installed into C355 pump housings, with A286 stainless steel fasteners installed into the insert to secure the pump port cap to the housing. In the past, pump port cap fasteners were installed to a torque of 33 Nm (300 in-lb). However, the structural analyses used a significantly higher nut factor than indicated during tests conducted by Boeing Space Systems. When the torque values were reassessed using Boeing's nut factor, the fastener preload had a factor of safety of less than 1, with potential for overloading the joint. This paper describes how behavior was determined for a preloaded joint with a steel bolt threaded into steel inserts in aluminum parts. Finite element models were compared with test results. For all initial bolt preloads, bolt loads increased as external applied loads increased. For higher initial bolt preloads, less load was transferred into the bolt, due to external applied loading. Lower torque limits were established for pump port cap fasteners and additional limits were placed on insert axial deformation under operating conditions after seating the insert with an initial preload.

  19. Silicon force sensor and method of using the same

    Science.gov (United States)

    Galambos, Paul C.; Crenshaw, Thomas B.; Nishida, Erik E.; Burnett, Damon J.; Lantz, Jeffrey W.

    2016-10-04

    The various technologies presented herein relate to a sensor for measurement of high forces and/or high load shock rate(s), whereby the sensor utilizes silicon as the sensing element. A plate of Si can have a thinned region formed therein on which can be formed a number of traces operating as a Wheatstone bridge. The brittle Si can be incorporated into a layered structure comprising ductile and/or compliant materials. The sensor can have a washer-like configuration which can be incorporated into a nut and bolt configuration, whereby tightening of the nut and bolt can facilitate application of a compressive preload upon the sensor. Upon application of an impact load on the bolt, the compressive load on the sensor can be reduced (e.g., moves towards zero-load), however the magnitude of the preload can be such that the load on the sensor does not translate to tensile stress being applied to the sensor.

  20. Silicon force sensor

    Science.gov (United States)

    Galambos, Paul C.; Crenshaw, Thomas B.; Nishida, Erik E.; Burnett, Damon J.; Lantz, Jeffrey W.

    2016-07-05

    The various technologies presented herein relate to a sensor for measurement of high forces and/or high load shock rate(s), whereby the sensor utilizes silicon as the sensing element. A plate of Si can have a thinned region formed therein on which can be formed a number of traces operating as a Wheatstone bridge. The brittle Si can be incorporated into a layered structure comprising ductile and/or compliant materials. The sensor can have a washer-like configuration which can be incorporated into a nut and bolt configuration, whereby tightening of the nut and bolt can facilitate application of a compressive preload upon the sensor. Upon application of an impact load on the bolt, the compressive load on the sensor can be reduced (e.g., moves towards zero-load), however the magnitude of the preload can be such that the load on the sensor does not translate to tensile stress being applied to the sensor.