总结了X形变截面橡胶密封圈的特点,基于有限元分析理论,借助软件ANSYS对X形变截面橡胶密封圈进行有限元分析。建立了X形变截面橡胶密封圈有限元模形,比较了X形变截面和X形橡胶密封圈最大综合等效应力情况。结果显示:X形变截面密封圈的...总结了X形变截面橡胶密封圈的特点,基于有限元分析理论,借助软件ANSYS对X形变截面橡胶密封圈进行有限元分析。建立了X形变截面橡胶密封圈有限元模形,比较了X形变截面和X形橡胶密封圈最大综合等效应力情况。结果显示:X形变截面密封圈的应力集中部位主要集中在组合面尖角处,特别是内尖角处更易损坏。在同等条件下,此类X形变截面密封圈比X形密封圈最大等效压力值都大。在压缩率一定条件下,其最大Von M ises应力随油压而增加。在油压一定条件下,最大Von M ises应力并不总随压缩率而增加。展开更多
A multi-casing structure in drilling engineering can be considered as an inhomogeneous body consisting of many different materials. The mechanical behavior of the inhomogeneous body in an infinite domain is very com- ...A multi-casing structure in drilling engineering can be considered as an inhomogeneous body consisting of many different materials. The mechanical behavior of the inhomogeneous body in an infinite domain is very com- plicated. In this paper, a detailed expression about the fictitious stress method of the boundary element method （BEM） is demonstrated for the inhomogeneous body. Then the fictitious stress method is deployed to investigate the stresses for the multi-casing structure under non-uniform loading conditions and an irregular wellbore. Three examples of the multi-casing structure in the borehole imply the high effectiveness of BEM for complex geometries related to the borehole in an infinite formation. The effects of casing eccentricity and the interfacial gap on the stress field are discussed. The eccentric casing takes the potential yield when the eccentric orientation is along the direction of Sh. Under different eccentric orientations, the yon Mises stress in the casing increases with increasing degree of eccentricity. The radial stress in the multi-casing structure is always continuous along the radius, but the circumferential stress is discontinuous at the interface. The radial stress decreases and the circumferential stress increases with the increasing of the interfacial gap between the adjacent materials.展开更多
Longitudinal shear problems of collinear rigid line inclusions (sometimes calledhard crack or inverse crack problems) in anisotropic materials are dealt with. By usingthe conplex variable method, we present the formul...Longitudinal shear problems of collinear rigid line inclusions (sometimes calledhard crack or inverse crack problems) in anisotropic materials are dealt with. By usingthe conplex variable method, we present the formulation of the general problem and the closed form solutions to some problems of practical importance, The atressdistribution in the immediate vicinity of the rigid line end is examined. The corresponding formulation and solutions for isotropic materials can be arrived at fromthe special cases of those in the present paper, some of which are in agreement with the existing results￣[1].展开更多
The stress state around circular openings,such as boreholes,shafts,and tunnels,is usually needed to be evaluated.Solutions for stresses,strains and ultimate bearing capacities of pressurized hollow cylinder are common...The stress state around circular openings,such as boreholes,shafts,and tunnels,is usually needed to be evaluated.Solutions for stresses,strains and ultimate bearing capacities of pressurized hollow cylinder are common cases.Stress analytical method for plane problem of a double-layered thick-walled cylinder subjected to a type of non-uniform pressure on the outer surface and uniform radial pressure on the inner surface is given.The power series method of complex function is used.The stress analytical solution is obtained with the assumption that two layers of a cylinder are fully contacted.The distributions of normal and tangential contact stress along the interface,tangential stress on the inner boundary and stresses in the radial direction at θ=0°,45° and 90°,are obtained.An example indicates that,when the elastic modulus of the inner layer of a double-layered thick-walled cylinder is smaller than that of the outer layer,the tangential stress is smaller than that in the corresponding point for a traditional cylinder composed of homogeneous materials.In that way,stress concentration at the inner surface can be alleviated and the stress distribution is more uniform.This is a capable way to enhance the elastic ultimate bearing capacity of thick-walled cylinder.展开更多
文摘总结了X形变截面橡胶密封圈的特点,基于有限元分析理论,借助软件ANSYS对X形变截面橡胶密封圈进行有限元分析。建立了X形变截面橡胶密封圈有限元模形,比较了X形变截面和X形橡胶密封圈最大综合等效应力情况。结果显示:X形变截面密封圈的应力集中部位主要集中在组合面尖角处,特别是内尖角处更易损坏。在同等条件下,此类X形变截面密封圈比X形密封圈最大等效压力值都大。在压缩率一定条件下,其最大Von M ises应力随油压而增加。在油压一定条件下,最大Von M ises应力并不总随压缩率而增加。
基金supported by the China National High Technology Research and Development Program 863 (Grant No. 2013AA064503)The China Scholarship Council
文摘A multi-casing structure in drilling engineering can be considered as an inhomogeneous body consisting of many different materials. The mechanical behavior of the inhomogeneous body in an infinite domain is very com- plicated. In this paper, a detailed expression about the fictitious stress method of the boundary element method （BEM） is demonstrated for the inhomogeneous body. Then the fictitious stress method is deployed to investigate the stresses for the multi-casing structure under non-uniform loading conditions and an irregular wellbore. Three examples of the multi-casing structure in the borehole imply the high effectiveness of BEM for complex geometries related to the borehole in an infinite formation. The effects of casing eccentricity and the interfacial gap on the stress field are discussed. The eccentric casing takes the potential yield when the eccentric orientation is along the direction of Sh. Under different eccentric orientations, the yon Mises stress in the casing increases with increasing degree of eccentricity. The radial stress in the multi-casing structure is always continuous along the radius, but the circumferential stress is discontinuous at the interface. The radial stress decreases and the circumferential stress increases with the increasing of the interfacial gap between the adjacent materials.
文摘Longitudinal shear problems of collinear rigid line inclusions (sometimes calledhard crack or inverse crack problems) in anisotropic materials are dealt with. By usingthe conplex variable method, we present the formulation of the general problem and the closed form solutions to some problems of practical importance, The atressdistribution in the immediate vicinity of the rigid line end is examined. The corresponding formulation and solutions for isotropic materials can be arrived at fromthe special cases of those in the present paper, some of which are in agreement with the existing results￣[1].
基金Projects(50874047,51074014,51174014)supported by the National Natural Science Foundation of China
文摘The stress state around circular openings,such as boreholes,shafts,and tunnels,is usually needed to be evaluated.Solutions for stresses,strains and ultimate bearing capacities of pressurized hollow cylinder are common cases.Stress analytical method for plane problem of a double-layered thick-walled cylinder subjected to a type of non-uniform pressure on the outer surface and uniform radial pressure on the inner surface is given.The power series method of complex function is used.The stress analytical solution is obtained with the assumption that two layers of a cylinder are fully contacted.The distributions of normal and tangential contact stress along the interface,tangential stress on the inner boundary and stresses in the radial direction at θ=0°,45° and 90°,are obtained.An example indicates that,when the elastic modulus of the inner layer of a double-layered thick-walled cylinder is smaller than that of the outer layer,the tangential stress is smaller than that in the corresponding point for a traditional cylinder composed of homogeneous materials.In that way,stress concentration at the inner surface can be alleviated and the stress distribution is more uniform.This is a capable way to enhance the elastic ultimate bearing capacity of thick-walled cylinder.
