材料不均匀层对垂直裂纹的作用

A VERTICAL CRACK PENETRATING AN INHOMOGENEOUS MATERIAL INTERLAYER

界面层（或界面相）断裂行为是复合材料细观力学的一个重要问题。本文研究裂纹垂直侵入双材料之间刚度性质呈单调变化的界面层的断裂问题。近似分析与大规模有限元计算均表明：当裂纹从软相一侧跨越界面层时，裂尖应力强度因子不断上升；当裂纹从硬相一侧跨越界面层时，裂尖应力强度因子不断下降。

Interlayer(or interphase) fracture constitutes an important issue of the micromechanics of composite materials,The present paper studies the fracture behavior of a crack penetrating vertically to an interlayer where the stiffness varies monotonically from one material phase to another material phase.Analytical estimate and full-scaled FEM calculation both indicate that the crack-tip stress intensity factor increases when a crack penetrates the interlayer from the soft material side,and decreases when a crack penetrates the interlayer from the stiff material side of the bimaterial.