基于A-V模型的改进模型及单轴棘轮效应预测

针对A-V模型预测材料棘轮效应初始阶段不理想的缺点，对其参数γ₂进行了修正，同时引入Ramberg-Osgood(R-O)模型和各向同性硬化来计算应力-应变曲线，并确定了A-V模型的材料参数，建立了一种用来描述材料循环塑性行为的改进A-V模型.通过采用改进的A-V模型对Z2CND18.12N奥氏体不锈钢和SS316L钢的单轴棘轮效应进行了预测，并研究了平均应力、应力幅值、应力比和加载历史对单轴棘轮效应的影响.结果表明，改进的A-V模型对材料的棘轮应变预测值与试验值较为一致.

Improved Model Based on A-V Model and Prediction of Uniaxial Ratcheting Effects

In view of the shortcomings of the A-V model which cannot well predict the initial stage of ratcheting effect of materials， the parameter γ₂ in the A-V model was modified and Ramberg-Osgood (R-O) model and isotropic hardening were introduced to calculate the stress-strain curve. The material parameters of the A-V model were determined， and an improved A-V model was established to describe the cyclic plastic behavior of materials. The uniaxial ratcheting effects of Z2CND18.12N austenitic stainless steel and SS316L steel were predicted by using the improved A-V model， and the influences of average stress， stress amplitude， stress ratio and loading history on the uniaxial ratcheting effect were studied. The results showed that the ratcheting strain predicted by the improved A-V model is consistent with the experimental value.