Prediction of Microcracking Distributions in Composite Laminates Using a Monte-Carlo Simulation Method

Abstract

A method is presented to predict the histories of matrix crack densities, effective laminate properties, and crack distributions in the plies of general composite laminates subjected arbitrary thermomechanical loads. "Effective" flaws, whose sizes vary according to a Weibull distribution, are randomly seeded in the edges of the laminate. A shear lag method determines the stresses within the laminate. Development of flaws into "starter" matrix cracks that span the thickness of the plies is determined using an energy method. A separate energy method is used to determine crack extension across the width. The method accounts for local material variations in an approximate manner. Crack density results are compared with analytical predictions and experimental data from a previous study (Maddocks, 1995). Examination of crack distributions at selected load increments provides insight into the mechanisms by which cracks initiate and develop.