内压容器筒体大开孔结构的弹塑性应力分析

针对内压容器筒体开有大直径孔后会产生很高的应力集中这一问题,在考虑材料塑性变形特性的前提下,对不同开孔率的内压容器筒体结构进行了一系列的弹塑性有限元分析.结果表明,内压容器在大开孔状态下,孔周边应力集中很严重,其中孔与筒体的相贯线最高点表现为强烈的周向应力特征,相贯线最低点则表现为轴向应力特征.在逐步加载过程中,加载前期孔周边应力呈线性增长,而后表现为高应力范围的扩大.对于均处于塑性阶段的结构而言,开孔率的大小对高应力区的分布范围影响较大.分析大开孔内压容器筒体结构的应力分布时,材料的非线性特性对分析结果有很大影响.

Elastic-plastic stress analysis of the vessel subject to internal pressure with the hole of great diameter

The three-dimensional elastic-plastic finite element analyses of the vessels subject to internal pressure with the different ratios of the diameter of hole to the diameter of vessel are carried out to investigate the stress concentration in the edge of the hole.The results show that heavy stress concentration is found around the hole.The hoop stress is dominant at the top of the intersecting curve of the hole with the vessel,while the axial stress is dominant in the bottom of the intersecting curve.In the process of loading,the stress around the hole linearly increases at first and then the range of the high stress area enlarges.The ratio of the diameter of hole to the diameter of vessel has greater effect on the distribution area of high stress in plastic deformation stage.In addition,the comparison of the elastic with elastic-plastic analytical results reveals that,it is necessary to consider the nonlinear performance of materials in the stress analysis of the vessel subject to internal pressure with large hole.