MICRO-MACRO CRACK INTERACTION IN COMPOSITES

The interaction of a macro-crack and a micro-crack is the subject of t his study. The cracks considered are: matrix micro-crack (straight and kinked at 45 degrees) interacting with matrix macro-cracks of differe nt lengths, and a matrix micro-crack (straight and kinked at 45 degree s) interacting with delamination macro-cracks of different lengths. A two-dimensional (2D) stress and crack analysis is carried out, using f inite element method. Twenty-noded quarter-point solid elements are us ed as singular elements at the crack front to accurately determine the stress distribution. The J-integral is used as the crack characteriza tion parameter. Results show that the presence of the micro-crack redu ces the available energy for the propagation of the macro-crack.