基于塑性应变能复杂应力场非比例加载疲劳寿命分析  

Fatigue Life Prediction Analysis of the Non-Proportional Loading on Complex Stress Field Based on Plastic Strain Energy

作　　者：李训涛[1] 廖霞霞 胡明敏[1] 

机构地区：[1]南京航空航天大学航空宇航学院,江苏南京210016

出　　处：《力学季刊》2017年第2期345-350,共6页Chinese Quarterly of Mechanics

基　　金：基金项目:江苏高校优势学科建设工程

摘　　要：本文提出了一种以应变能预测多轴应变加载低周疲劳寿命的新方法,该方法最大特点假设疲劳裂纹是由最大剪应力和其相对应的正应力引起,解决了其他方法不能反映非比例强化的问题;该方法建立等效内应力、外加有效应力与塑性应变能的关系,从而分析得到基于塑性应变能的多轴非比例疲劳寿命的计算模型,及多轴疲劳寿命公式中材料参数确定、剪应力及其所在平面所对应的正应力、塑性应变能等的获取方法.凭借Al5083、S460N材料光滑试件、GH4169材料缺口件、Al5083焊接件的多轴非比例加载进行寿命预测的验证,证明该模型可以预测不同材料、不同加载路径下的多轴非比例应变加载低周疲劳寿命.This paper discusses the fatigue life prediction of multi-axial strain loading based on the strain energy, and addresses the issue of inability of the existing methods in predicting the non-proportional strengthening by considering the maximum shear stress and its corresponding normal stress in the energy method. The relationship between the plastic strain energy, the internal equivalent stress, and the exerted equivalent stress have been established. A calculation formula for predicting multi-axial fatigue life was proposed. The material parameters, the shear stress and the normal stress on the corresponding plane and the plastic potential energy were determined. Through comparison with the experimental results of smooth specimens A15083, $460N, notched specimens GH4169, weld specimens A15083, it is verified that the model could well predict the low cycle fatigue life under multi-axial non-proportional strain loading.

关 键 词：多轴应变加载 塑性应变能 疲劳裂纹 缺口件 焊接件 

分 类 号：O346.2[理学—固体力学]