Probabilistic Assessment of Composite and Smart Composite Structures

Abstract

A general purpose methodology for integrated probabilistic assessment of composite structures and smart composite structures is discussed and demonstrated using aircraft fuselage and wing type structures with rectangular cutouts. The computational simulation was performed for the probabilistic assessment of the structural behavior including global displacements and local stresses. The scatter in the structural response is simulated based on the inherent uncertainties in the primitive (independent random) variables at the fiber/matrix constituent, ply, laminate and structural scales that describe the composite structures. The effect of uncertainties due to fabrication process variables such as fiber volume ratio, void volume ratio, ply misalignment, and ply thickness as well as those for sensors and controls is also included. Results show that in a composite structure with rectangular cutouts the uncertainties in the longitudinal ply stress is mainly due to the uncertainty in the laminate thickness. Results also show that a smart composite wing can be controlled to minimize distortions and to have specified stress levels in the presence of cutouts.