幂硬化对准静载弹塑性弯曲裂纹塑性区的影响  

IMPACT OF HARDENING ON PLASTICITY AREA AT THE SLIGHTLY CURVED ELASTICITY-PLASTICITY CRACK TIP UNDER QUASI-STATIC LOADS

作　　者：杨大鹏[1,2] 王建勋[1] 赵耀[2] 

机构地区：[1]郑州职业技术学院机械工程系,郑州450121 [2]华中科技大学船舶与海洋工程学院,武汉430074

出　　处：《机械强度》2015年第3期556-561,共6页Journal of Mechanical Strength

基　　金：国家自然科学基金重大研究计划项目(91016026);郑州地方高校特聘高层次人才项目资助~~

摘　　要：主要研究准静载荷作用下的硬化材料弹塑性弯曲裂纹尖端的塑性区问题。综合考虑了准静作用应力,塑性区域边界上正应力与剪应力,利用二阶摄动方法计算了硬化材料弹塑性弯曲裂纹尖端的塑性区。用数值解法计算出弹塑性弯曲裂纹尖端硬化塑性区于裂纹直线部分延长线上的投影长度,作图分析了弹塑性弯曲裂纹尖端塑性区尺寸与材料硬化指数之间的变化关系。在幂硬化材料中,弹塑性弯曲裂纹尖端塑性区随着材料硬化指数n的增大而减少,当n等速均匀增加时,弹塑性弯曲裂纹尖端塑性区尺寸加速减少,减少的幅度越来越大。当材料的硬化指数相同时,弯曲裂纹尖端塑性区尺寸随外载荷的不断减小而逐渐减小。建立了一个计算硬化材料弹塑性弯曲裂纹塑性区尺寸的崭新理论模型。In this article, elastic-plastic curved crack tip plasticity area in hardened material under quasi-static loads has been mainly studied, and curved crack tip plasticity area has been calculated as a practical application of a second order perturbation method, where the effects of quasi-static applied stresses and quasi-static normal and shear stresses on the boundaries of plasticity area are synthetically taken into considerations. Projected length of elastic-plastic curved crack tip hardened plasticity area on straight crack extension line portion has been calculated by numerical solutions, diagrams have been constructed to analyse the transformation relationships between curved crack tip plasticity area size and hardening exponents. Curved crack tip plasticity area size will decrease when hardening exponents increase in hardened material. The decrease extent of curved crack tip plasticity area size will be more and more severe when hardening exponents increase evenly. Curved crack tip plasticity area size will decrease when external loads decrease with the same hardening exponents. A new theoretical model where curved crack tip plasticity area size was calculated has been established in hardened material.

关 键 词：幂硬化材料 弯曲裂纹 塑性区 准静作用应力 二阶摄动方法 

分 类 号：TB301[一般工业技术—材料科学与工程]