Stochastic Damage Accumulation Model for Composite Laminates

Abstract

A stochastic model for the accumulation of fatigue damage in composite laminates subjected to fatigue loading is proposed. Damage accumulation is treated as an evolutionary stochastic process characterized by changes in the components of laminate compliance with the number of load cycles. Compliance changes are modeled as an embedded discrete time, finite state, nonstationary Markov process. Distributions for these changes are used in conjunction with laminated plate theory to derive distributions for the individual ply strains within a laminate. The ply-strain distributions are used to obtain a probabilistic description of the response of the laminate, as well as for input into an appropriate failure criterion to determine the evolutionary probability of failure of a laminate. The applicability of the model is illustrated through a numerical example.