基于内禀耗散理论的高周疲劳双尺度伤演分析  

Two-scale Analysis of High-cycle Fatigue Damage Based on Intrinsic Dissipation Theory

作　　者：张伟 李如俊 葛士涛 彭艳 ZHANG Wei;LI Rujun;GE Shitao;PENG Yan(National Engineering Research Center for Equipment and Technology of Cold Strip Rolling,Yanshan University,Qinhuangdao 066004)

机构地区：[1]燕山大学国家冷轧板带装备及工艺工程技术研究中心,秦皇岛066004

出　　处：《机械工程学报》2024年第20期120-133,共14页Journal of Mechanical Engineering

基　　金：国家自然科学基金(52075471);河北省自然科学基金(E2021203011)资助项目。

摘　　要：金属构件高周疲劳裂纹萌生于内部的部分晶粒,经典唯象损伤理论无法揭示细观晶粒尺度上的损伤形态和演化过程,难以建立损伤真实描述。基于唯象损伤力学内禀耗散理论和Lin-Taylor假设,建立一种表征晶粒不可逆应变耗散的细观塑性耗散势,并利用细观积分思想获得晶粒尺度累积塑性应变的宏观当量表征,进一步建立了一种高周疲劳损伤演化双尺度模型。该模型同时考虑了损伤驱动力循环特性和裂纹闭合行为的单双边效应,适用于单轴、多轴比例以及多轴非比例加载工况。通过ABAQUS实现构件受载工况,使用UMAT子程序嵌入计算损伤驱动力。最后利用航空工业常用的金属材料铝合金LY12CZ、5%铬钢和C35钢在不同加载路径下的试验数据来评估和验证所提出的双尺度模型,并与多个已有模型进行对比验证,结果表明,新建模型具有良好的寿命预测效果。新模型揭示细观力学行为与唯象损伤演化的主要关联,为解决金属材料疲劳损伤破坏这类涉及多尺度行为的复杂力学问题提供了新思路。The high-cycle fatigue cracks of metal components start from some internal grains.The classical phenomenological damage theory can not reveal the damage morphology and evolution process on the micrograin scale,and it is difficult to establish a true description of the damage.Based on the intrinsic dissipation theory of phenomenological damage mechanics and the Lin-Taylor hypothesis,a microplastic dissipation potential was established to characterize the irreversible strain dissipation of grains,and the macroscopic equivalent characterization of the cumulative plastic strain of grain size was obtained by using the microscopic integral idea,and a two-scale model of high-cycle fatigue damage evolution was further established.The model is suitable for uniaxial,multi-axial proportional and multi-axial non-proportional loading conditions,considering both the cyclic characteristics of damage driving force and the single-bilateral effect of crack closure behavior.The load condition of the component is realized by ABAQUS,and the damage driving force is calculated by UMAT subroutine.Finally,the experimental data of aluminum alloy LY12CZ,5%chromium steel and C35 steel used in aviation industry under different loading paths are used to evaluate and verify the proposed two-scale model.The results show that the new model has a good life prediction effect.The new model reveals the main relationship between micromechanical behavior and phenomenological damage evolution,and provides a new way to solve complex mechanical problems involving multi-scale behavior such as fatigue damage and failure of metal materials.

关 键 词：高周疲劳 内禀耗散 累积塑性应变 双尺度 寿命预测 

分 类 号：O346[理学—固体力学]