Abstract

In the thesis, a combined experimental and stochastic finite element analysis methodology that can incorporate the material property variabilities and based on these, predict the stochastic characteristics of the Stress Intensity Factor (SIF) and the Strain Energy Release Rate (G) of composite laminates, is developed. Using this methodology, the probabilistic fracture analysis of laminated composites is performed. The material and geometric properties of the laminate are described in terms of homogeneous two-dimensional spatial stochastic fields and random variables that are established based on material property tests. In the finite element formulation, the elasticity matrix for the laminate is obtained based on the laminate theory. This matrix, in contrast to the deterministic finite element analysis, will be a stochastic matrix that has different values at different Gauss point locations within the same element. The fracture behavior of the laminate is quantified through the two parameters, Stress Intensity Factor (SIF) and Energy Release Rate (ERR). A formulation for determining the reliability of composite laminates based on the probabilistic characteristics of stress intensity factor and that of the fracture toughness, is described. Different types of orthotropic laminates are analyzed.