简单结构平面应力等比例加载塑性失稳研究

STUDY ON PLASTIC INSTABILITY OF SIMPLE STRUCTURES IN PLANE STRESS UNDER PROPORTIONAL LOADING

对平面应力状态下几种简单结构等比例加载条件下塑性失稳研究表明,考虑材料应变强化性能和结构非线性变形,结构塑性失稳由应变控制。对于应力—应变关系符合Swift类型的材料,可以推导几种简单结构的失稳应变,并以应变作为失效判据。同时,根据应力—应变关系,求出相应应力,进一步确定结构的最大承载能力。进行圆筒压力容器有限元计算和爆破实验,证明以应变作为结构失效判据准确合理,可应用于压力容器弹塑性应力分析。

In the presented study, it indicates that the plastic instability of simple structures in plane stress under proportional loading is governed by strain, in which the effeet of strain hardening behavior of materials and the effect of nonlinear geometry deformation of structures have been considered. For materials with stress-strain relationship of Swift type, the instability strain of some simple structures has been derived from theoretical studies. Based on the plastic instability strain, the strength of some simple structures can be obtained. FE（finite element） analysis and experimental results have good agreement with the theoretical results for pressure vessel, it has verified the plastic instability theory and can be used for elastic-plastic stress analysis of pressure vessel.