基于改进应变能密度法的电动轮自卸车车架焊缝疲劳寿命预测  

Frame Weldment Fatigue Life Prediction of Electric Dump Trucks Based on Modified Strain Energy Density Method

作　　者：米承继[1,2,3] 谷正气 蹇海根[1] 张勇 李文泰[1] 余冰[1] MI Chengji;GU Zhengqi;JIAN Haigen;ZHANG Yong;LI Wentai;YU Bing(Department of Mechanical Engineering,Hunan University of Technology,Zhuzhou,Hunan,412007;Key Laboratory of Lightweight and Reliability Technology for Engineering Vehicle,Education Department of Hunan Province,Changsha University of Science & Technology,Changsha,410114;State Key Laboratory of Advanced Design and Manufacture for Vehicle Body,Hunan University,Changsha,410082)

机构地区：[1]湖南工业大学机械工程学院,株洲412007 [2]长沙理工大学工程车辆轻量化与可靠性技术湖南省高校重点实验室,长沙410114 [3]湖南大学汽车车身先进设计制造国家重点实验室,长沙410082

出　　处：《中国机械工程》2019年第1期96-104,共9页China Mechanical Engineering

基　　金：中国博士后科学基金资助项目(2017M622569);湖南省自然科学基金资助项目(2017JJ3059);湖南省教育厅科学研究项目(16C0488);工程车辆轻量化与可靠性技术湖南省高校重点实验室开放基金资助项目(2017KFJJ03)

摘　　要：针对复杂载荷作用下焊接结构应力应变响应出现非完全封闭而交叉的现象,考虑封闭环以外的塑性应变能密度,提出了一种改进的应变能密度计算方法。通过设计制作对接接头试验试件,开展了焊接接头机械性能和疲劳试验研究,获取了Ramberg-Osgood方程参量并构建了基于总应变能密度的疲劳损伤模型。建立了电动轮自卸车车架有限元模型,开展了车架焊缝多载荷步非线性有限元分析。结合新方法和数值模拟得到的应力应变响应计算危险点各应变能密度,依据拟合的疲劳损伤模型进行寿命预测,计算结果与实际失效位置和开裂时间吻合较好。In consideration of non-completely closed and crossed stress-strain responses for welded structures under complicated loadings,a modified strain energy density calculation method was proposed to account for plastic strain energy density being out of closed loop.The butt joints were designed and made to conduct research on mechanical performances and fatigue tests.The Ramberg-Osgood equation parameters were obtained,and a fatigue damage model was constructed based on total strain energy density.The frame element finite model of electric dump truck was built and the non-linear finite element analyses of frame weldments were conducted on simulating multi-loading steps.Combined the method herein and stress-stain response obtained from the numerical simulation,several strain energy density parameters of dangerous points were calculated to estimate the fatigue life of frame weldments according to the fitted fatigue damage model.The calculated results show well agreement with the real failure positions and cracking time.

关 键 词：电动轮自卸车 车架焊缝 应变能密度 疲劳寿命预测 

分 类 号：U463.1[机械工程—车辆工程]