几种循环塑性模型的剖析和比较研究

Analysis and comparison on several cyclic plastic models

首先阐明循环塑性模型需满足的力学条件:连续与光滑条件,曼辛效应与棘轮效应.基于这些条件,对多面、无限多面、两面、单面、边界面、次加载面模型等几种常见的循环塑性模型的基本特性进行深入而系统的剖析,对它们预测材料循环加载特性的能力进行分析与比较.结果表明:多面模型与无限多面模型反映的是过强的滞回效应,无法反映变形的积累性;两面、单面与边界面模型反映的是较弱的滞回效应与较大的积累变形;次加载面模型满足循环塑性模型所要求的力学条件,可以控制曼辛系数,能较好地反映材料的循环加载特性,将次加载面思想与广义塑性力学结合,可望建立更合理的循环塑性模型.

Continuity and smoothness conditio ns,Masing effect and ratcheting eff ect as the mechanical requirements f or cyclic plastic models are first formulated.The basic characteristics of several well -known and frequently used cy clic plastic models,such as the multi,the infinite,the doubl e,the single,the bounding and the su bloading surface models,are analyzed and compared with respect to fulfillment of these requirements,and their inevitable defects and insufficiencies are ind icated.It is concluded that an excessively large hysteresis loo p and no accumulation of plastic stra in are predicted with the multi and th e infinite surface models;an extremely strong mechani cal ratcheting effect and no Masing e ffect are predicted with the two,the single and the bounding surface models.Among these models only the subloading surface model fulfills these requirements a nd is applicable to the prediction of elastoplastic deformation for cyclic loading,so a more rational cyclic plasticity model c an be built by combining the subloading surface theory with t he generalized plastic mechanics.