考虑棘轮行为的U75V缺口圆棒局部应力-应变分析  

Numerical Analysis on the Local Stress-Strain Response of U75V Notched Bar Considering Ratchetting

作　　者：瞿开城 罗会亮[1] 阚前华[1] 康国政[1] Kaicheng Qu;Huiliang Luo;Qianhua Kan;Guozheng Kang(Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province,School of Mechanics and Aerospace Engineering,Southwest Jiaotong University,Chengdu,610031)

机构地区：[1]应用力学与结构安全四川省重点实验室,西南交通大学力学与航空航天学院,成都610031

出　　处：《固体力学学报》2024年第3期352-362,共11页Chinese Journal of Solid Mechanics

基　　金：国家自然科学基金项目(12072295)资助。

摘　　要：本文通过对U75V钢缺口圆棒在单轴非对称应力控制循环载荷作用下循环变形行为的有限元模拟,分析了缺口局部的应力-应变分布及演化情况,研究了缺口弹塑性应力与应变集中系数随循环周次的变化规律,讨论了Neuber准则对考虑棘轮行为的缺口局部应力-应变分析的适用性.结果表明:在循环变形过程中,缺口根部的局部应力产生松弛现象,应力集中系数随循环次数的增加而减小;棘轮应变主要集中在缺口位置,应变集中系数随循环次数的增加而增大;应力集中系数与应变集中系数乘积的平方根随循环次数的增加而逐步增大,并且明显不同于理论应力集中系数.这说明,在缺口根部出现明显的棘轮行为时,使用Neuber准则无法对缺口的局部应力应变行为进行准确描述.Based on the finite element simulation on the cyclic deformation of notched bar made from U75V steel under the asymmetrical uniaxial stress-controlled cyclic loading condition,the stress/strain distributions and correspondent stress/strain concentration coefficients at the notch root as well as their evolutions during the cyclic deformation are studied.Then,the applicability of Neuber rule to analyze the local stress-strain response at the notch root of the notched component is discussed with the ratchetting considered.The results show that during the cyclic deformation,the local stress at the notch root relaxes,and the stress concentration coefficient decreases accordingly;while,the ratchetting strain concentrates at the notch root and the strain concentration coefficient increases with increasing the number of cycles;The geometrical mean of the stress and strain concentration coefficients gradually increases with the number of cycles,and is significant different from the theoretical stress concentration coefficient.It is indicated that the Neuber rule cannot accurately describe the stress-strain response at the notch root of notched component if obvious ratchetting occurs.

关 键 词：缺口圆棒 应力集中系数 应变集中系数 应力松弛 Neuber准则 

分 类 号：TG142.1[一般工业技术—材料科学与工程] O344.1[金属学及工艺—金属材料]