A Probabilistic Progressive Failure Model of Composite Laminates

Abstract

This paper investigates the strength failure of composite laminates using system reliability theory. A probabilistic progressive failure model of composite laminates is proposed. The overall failure of the laminate is caused by a series of ply-level failure events. There exist many possible failure sequences of ply-level events that lead to overall laminate failure. Matrix cracking and fiber breakage are defined as the two basic failure events of each ply and a damage-modification technique is adopted to simulate the system progressive failure process. The first-order reliability method (FORM) is employed to compute the filure probability of the ply-level events. A search technique based on the branch-and-bound concept is developed to identify the significant fiilure sequences. The system failure probability is computed using reliability bounding techniques.