微裂纹屏蔽问题中守恒积分投影关系

对连续体损伤力学在微裂纹屏蔽问题中应用的Ｊ积分守情理假设提出质疑，用理论分析和电算实践证明了远场Ｊ积分在微裂纹损伤区中的再分配关系。即ＪＫ矢量的投影守恒关系。在这一关系中，被Ｈｅｒｒｍａｎｎ所轻视的Ｊ２分量起着十分重要的作用，本文的研究表明，Ｏｒｔｉｚ理论应考虑到远场Ｊ积分在损伤区中的损失，并通过计及这一损失做出必要的修正。

THE PROJECTED RELATION OF THE CONSERVATION INTEGRAL IN MICROCRACK SHIELDING PROBLEMS

In this paper, the J integral conservation in adopting the continuum mechanics in the microcrack shielding problems is reexamined. From thetheoretical manipulation as well as the computational experiment, it is proved that there is a redistribution relation of the remote J integral in the microcracking damage region, i.e., the relation of theprojected conservation of the J k vector. In the relation, the J 2 component ignored by Herrmann and Herrmann plays an important role. It is concluded also that the elastic stiffness reduction, and the presence of strain/deformation due to the release of residual stresses are bothenergy dissipating processes which based on an energy balance approach give rise to toughening and thus crack-tip shielding.