Ply Level Uncertainty Effects on Failure of Composite Structures

Composite materials are popular in aerospace engineering because of their light weight, high strength to weight ratio, stiffness to weight ratio and tailoring properties. However, the modeling of composites is still a challenging task because of its highly uncertain material properties which arise from the manufacturing process.The effect of material uncertainties in failure strength and reliability analysis for single ply and cross ply laminated composite subjected to only axial loading is studied in this work. Researchers have categorized the uncertainty at different scales. Meso-scale uncertainty, that is ply level uncertainty, is being considered here. In this paper, the ply level uncertainties are taken as basic random variables and the strength parameters of the composite are derived through uncertainty propagation considering both Tsai-Wu and Maximum stress criteria. Monte Carlo simulation is performed to quantify uncertainty effects.