弹塑性疲劳微弯裂纹CTOD及J积分问题

从理论上比较精确地研究了疲劳载荷作用下弯曲延伸裂纹尖端塑性区域边界上的交变正应力和交变剪应力的分布状况.综合考虑了疲劳作用应力、塑性区域交变正应力和交变剪应力,利用二阶摄动方法,研究分析了疲劳载荷作用下弯曲延伸裂纹尖端塑性区域的范围.利用二阶摄动方法与卡氏定理计算了疲劳载荷作用下弯曲延伸裂纹尖端张开位移的最大值及变化幅值.以弯曲延伸裂纹尖端塑性区域的边界曲线为积分回路,求解了疲劳载荷作用下弹塑性弯曲延伸裂纹尖端J积分的最大值与变化幅值.为有效地预测及驾驭疲劳载荷作用下工程结构裂纹的弯曲扩展提供了理论依据.

Problem of slightly curved fatigue elastoplastic crack tip opening displacement and J integral

The distribution of cyclic normal stresses and cyclic shear stresses on the boundaries of plastic area at fatigue curved extension crack tip has been studied theoretically and accurately.Plastic area at the tip of fatigue curved extension crack has been studied and analyzed.Maximum and amplitude of fatigue curved extension crack tip opening displacements are calculated by using the second order perturbation method,theorem of surname KA.Maximum and amplitude of fatigue curved extension crack tip J integral are calculated using the boundary curve of plastic area of original curved extension crack tip as an integral loop,where the effects of cyclic applied stresses,cyclic normal stresses and cyclic shear stresses on the boundaries of plastic area at fatigue curved extension crack tip are taken into considerations.And theoretical base for predicting and controlling curved extension crack growth in engineering structure under fatigue loads,is offered.