Design with Composites: Material Uncertainty in Designing Composites Component

Abstract

The propagation of material uncertainty of the structural response of composites using two different approaches: a first-order local method and a global sensitivity analysis supported by a variance-based method, is studied. The importance measures of input parameters on the structural response based on numerical results are established and discussed as functions of the anisotropy of composite materials. The effects of uncertainty propagation on the response of composite structures under nonlinear geometric behavior are analyzed, especially the effects of uncertainty of material properties on the response of stiffened shell composite structures supporting buckling loads. The reliability assessment of composite structures is presented, and difficulties of structural reliability definition are identified. The most probable failure point (MPP) search in composite structures introduces new uncertainty factors associated with multiple failure points influencing the structural reliability system. The reliability index is very sensitive to the uncertainty in mean values of the mechanical properties of composites. The analyzed case studies demonstrate that knowledge of uncertainty propagation and reliability analysis are two important challenges toward more realistic modeling of failure in the design of composites.