Papers by Keyword: Joint

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Authors: Da Hai Wang, Hao Ran Guo, Hui Zhao, Yan Wei Guo
Abstract: Principal influencing factors of the strength of rock mass with weak joints were studied in this paper. Dip angles of weak joints in addition with the confining pressure is studied based on strain-softening/hardening plasticity model. The broken mechanism from the perspective of plastic zone was analyzed. The strength of rock mass with weak joints is mainly under control of the joints occurrence, the joints dip and the rock strength, and great influenced by the confining pressure. A higher strength is obtained with a higher confining pressure, the broken mechanisms varies with different joints dips.
Authors: Su Yi Liu, Yun Xu, Min Yin
Abstract: According to the effect of the human joints and the motion characteristics of the models’ footstep, combining with the distribution condition of degree of freedom of biped robots lower extremity structure in and abroad, we determine the number of the degree of freedom of robots legs is 12. Hip joint which has the characteristics of left and right axial rotation at horizontal direction, anteroposterior axis rotation and vertical axial rotation has 3 degrees of freedom. Ankle joint has 2 degrees of freedom which can rotate in left, right, pre and post directions is similar with the human ankle. Knee joint has a degree of joint and it extend the legs. The key of the design of humanoid robots is the joints design. The design of degrees of freedom of the joint is very important for whether the robots can walk successfully.
Authors: Zhi Zeng Zhang, Yong Tao Li, Xiao Chang Li
Abstract: In order to study the influence on the different parts of the cavern by joints, the three-dimensional model is built by Patran and then calculated with FLAC3D after meshing. Seven working conditions about different inclination of joints (0°15°30°45°60°75°90°) are considered in the calculation. The results show that low dip joints in vault and steep joints in the sidewall are more dangerous. Therefore, some measures should be used when encountered this situation in this project.
Authors: Bin Yang, Chung Tong Cheng, Li Fang Huang
Abstract: A 3D finite element model is used to investigate the state of load stress developed in concrete pavement with dowel bar under the effect of typical pavement damages of pumping area of slab corner and pumping area of transverse joints edge. The results indicate that slab corner stress tends to decrease with the increase of slab thickness and possesses a nonlinear growth as pumping area increases; when the pumping area of slab corner is less than 1.5m×1.5m, the maximum pavement slab tensile stress is less than or close to the load stress in critical loading position. Stress in transverse joints edge also grows in a nonlinear tendency and axle load also grows gradually with the expansion of pumping area, of which the slope of the curve in the relationship between stress and void size is much greater. Whether it is a pumping area of slab corner or pumping area of transverse joints edge, pavement slab deformation and stress are significantly reduced after setting the dowel bar. Therefore, dowel bar can improve the stress state of concrete pavement obviously.
Authors: Li Jie Cao
Abstract: The residual stress fields can have strong influences on the integrity and performance of friction stir welded aluminum alloy structure, comprehensive insight into the residual stress distribution is the key to the Friction stir welding (FSW) engineering application for a wide range of materials and thicknesses improving the weld strength and fatigue life. In this paper, the current state of the residual stresses in the FSW aluminum alloy joints is reviewed, The focus is on recent advances of experimental research, the results of numerical simulation analysis, and the effects of the technological parameters(welding speed, rotational speed, shoulder geometry et al.) on residual stress fields was evaluated. In the end, The controlling technique of residual stresses from published literatures is summarized.
Authors: Zhong Chang Wang
Abstract: The rose diagram of joint is generalized by grouping the attitude of disclosed discontinuous faces in detecting cavern and measuring point coordinate. The search of movable and key blocks of surrounding rock mass for underground powerhouse is implemented, the combinations of discontinuous faces and sliding faces, the location and the parameter of stability of movable and key blocks are obtained by used of the method of stereographic projection and vector analysis of the block theory. It is shown that the numbers of movable and key blocks in the location of downriver right side wall and vault are larger than those in other location owing to numerous discontinuous faces, and the faults of F34 and F33 play a main role in the stability of movable and key blocks. The guidance for excavation and reinforce of underground caverns is provided.
Authors: Petr Fajman, Jiří Maca
Abstract: The bearing capacity of a scarf joint depends on the length of the joint and the type of connection. It is possible to use circular bolts or squared dowels. Both connection tools used in the repairs of historic timber structures are made of wood according to the requirements of the heritage authority.
Authors: Y. Miyazawa, C.S. Chang, H. Sato, Jun Suda, T. Hiraoka, Kiichi Kanda, T. Ariga
Abstract: Joining technology of CP-Titanium and Titanium alloy is very important for manufacturing field. In that case of titanium brazing, chemical compositions of brazing filler metal and brazing atmosphere are very important. In this study, CP-Ti/CP-Ti and Ti alloy/Stainless Steel were brazed with Ti-based laminated brazing filler metal by using continuous type furnace under Ar gas atmosphere containing extremely low oxygen. Laminated filler was fabricated by roll bonding technology. Chemical compositions of laminated filler metal used in this study were Ti-15Cu-15Ni and Ti-20Zr-20Cu-20Ni. Brazing temperature employed in this study was 850, 900, 950, and 1000 C. These brazing temperatures were based on thermal analysis results and alpha-beta transformation temperature of the base metal used in this study. Firstly melting properties of laminated brazing filler metal was investigated with DTA and DSC. Secondary joint characteristics were estimated by micro-structural observation at the joint and mechanical properties measurement. Sound joint was obtained in this study according to outside appearance of the specimen. Ti-20Zr-20Cu-20Ni filler had low melting point as compared with Ti-15Cu-15Ni according to thermal analysis results and fillet form-ability. Ni and Cu were diffused from molten brazing filler to base metal during brazing and Ti-Cu-Ni eutectoid reaction was took placed at the based metal during cooling after brazing.
Authors: Antonin Lokaj, Kristýna Klajmonová
Abstract: Aim of this article is in presentation of results of dynamic tests of round timber bolted connections with slotted in steel plates. Multicyclic dynamic (fatigue) tests in tension were made with round timber joints on pulsator INSTRON in laboratory of ITAM CAS Prague. Results of laboratory tests have been statistically evaluated and completed with graphical records of deformation response to loading.
Authors: Qing Jun Chen, Jian Cai, Xiao Qin Zhao, Ping Yang, Chun Yang
Abstract: Concrete filled steel tubular (CFST) column-beam joint with the column tube discontinuous in joint zone is a new type of joint. In this paper, the compressive tests on this joint were carried out after the cyclic reversed loading. First the cyclic loading experiment results were introduced briefly, then the compressive tests were presented. The bearing capacity, crack patterns, deformation, strain of the reinforcements of the specimens were studied. These specimens were also compared with the other specimens only under compressive test. The results show that the specimens have good ductility. The concrete of the reinforced concrete (RC) ring beam cracked before the yield of the steel ring bars or the buckling of the steel tube. Although the cyclic loading caused some damage on the ring beam, it had few effects on the axial bearing capacity. The RC ring beam can still confine the joint zone and ensure the capacity of the joint zone was not lower than the CFST column.
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