Existing analytical methods of buried steel pipelines subjected to active strike-slip faults depended on a number of simplifications.To study the failure mechanism more accurately,a refined strain analytical methodolo...Existing analytical methods of buried steel pipelines subjected to active strike-slip faults depended on a number of simplifications.To study the failure mechanism more accurately,a refined strain analytical methodology was proposed,taking the nonlinear characteristics of soil-pipeline interaction and pipe steel into account.Based on the elastic-beam and beam-on-elastic-foundation theories,the position of pipe potential destruction and the strain and deformation distributions along the pipeline were derived.Compared with existing analytical methods and three-dimensional nonlinear finite element analysis,the maximum axial total strains of pipe from the analytical methodology presented are in good agreement with the finite element results at small and intermediate fault movements and become gradually more conservative at large fault displacements.The position of pipe potential failure and the deformation distribution along the pipeline are fairly consistent with the finite element results.展开更多
A finite element analysis, including static and buckling analysis is presented for several notable concrete spherical shells around the world. Also, the structural optimization study of these shells was performed for ...A finite element analysis, including static and buckling analysis is presented for several notable concrete spherical shells around the world. Also, the structural optimization study of these shells was performed for thickness distribution and structure shape to reduce overall tensile stress, deflection and reinforcements. The finite element analysis using Sofistik software shows that a distributed concrete thickness reduces shell stresses, deflections and reinforcements. A geometrically non-linear analysis of these structures with and without imperfections was also performed. To take into account the possible plastification of the material an analysis with non-linear material was performed simultaneously with the geometrically non-linear analysis. This helps in developing an understanding of the structural behaviour and helps to identify all potential failure causes using failure analysis.展开更多
In this paper, analytical and numerical studies are carried out on the full annular rub motions of a nonlinear Jeffcott rotor. Transition sets of the synchronous full annular rub are given with the help of averaging m...In this paper, analytical and numerical studies are carried out on the full annular rub motions of a nonlinear Jeffcott rotor. Transition sets of the synchronous full annular rub are given with the help of averaging method and constraint bifurcation theory to discuss the effects of system parameters on jump phenomena. Routh-Hurwitz criteria are employed to analyze the stability of synchronous full annular rub solution and determine the boundaries of static and Hopf bifurcations. Finally, the response and onset condition of reverse dry whip are investigated numerically, and at the same time, the influences of rotor parameters and rotation speed on the characteristics of the rotor response are investigated.展开更多
基金Project(50439010) supported by the National Natural Science Foundation of ChinaProject(DUT10ZD201) supported by the Fundamental Research Funds for the Central Universities in China
文摘Existing analytical methods of buried steel pipelines subjected to active strike-slip faults depended on a number of simplifications.To study the failure mechanism more accurately,a refined strain analytical methodology was proposed,taking the nonlinear characteristics of soil-pipeline interaction and pipe steel into account.Based on the elastic-beam and beam-on-elastic-foundation theories,the position of pipe potential destruction and the strain and deformation distributions along the pipeline were derived.Compared with existing analytical methods and three-dimensional nonlinear finite element analysis,the maximum axial total strains of pipe from the analytical methodology presented are in good agreement with the finite element results at small and intermediate fault movements and become gradually more conservative at large fault displacements.The position of pipe potential failure and the deformation distribution along the pipeline are fairly consistent with the finite element results.
文摘A finite element analysis, including static and buckling analysis is presented for several notable concrete spherical shells around the world. Also, the structural optimization study of these shells was performed for thickness distribution and structure shape to reduce overall tensile stress, deflection and reinforcements. The finite element analysis using Sofistik software shows that a distributed concrete thickness reduces shell stresses, deflections and reinforcements. A geometrically non-linear analysis of these structures with and without imperfections was also performed. To take into account the possible plastification of the material an analysis with non-linear material was performed simultaneously with the geometrically non-linear analysis. This helps in developing an understanding of the structural behaviour and helps to identify all potential failure causes using failure analysis.
基金supported by the National Natural Science Foundation of China (Grant No. 10632040)
文摘In this paper, analytical and numerical studies are carried out on the full annular rub motions of a nonlinear Jeffcott rotor. Transition sets of the synchronous full annular rub are given with the help of averaging method and constraint bifurcation theory to discuss the effects of system parameters on jump phenomena. Routh-Hurwitz criteria are employed to analyze the stability of synchronous full annular rub solution and determine the boundaries of static and Hopf bifurcations. Finally, the response and onset condition of reverse dry whip are investigated numerically, and at the same time, the influences of rotor parameters and rotation speed on the characteristics of the rotor response are investigated.
