Crack density-based semi-quantitative estimation for leak rate of composite laminates with thin-plies

Abstract

To predict the leakage of composite fuel tanks due to matrix cracks, this paper proposes novel simulation schemes: (1) A semi-quantitative leak rate estimation method is developed based on the crack intersection area; (2) The semi-analytical damaged constitutive model is obtained by a small amount of micro-mechanical finite element analysis (FEA); (3) The mixed mode crack density is estimated by using the FEA of laminates, which involves the progressive damaged properties; (4) The crack intersecting area is estimated based on the crack density and the crack opening displacement (COD), which is considered as the product of the average unit COD and the strain component. Two sets of simulations are set at room temperature to validate the method in detail, to verify the mechanics of leakage due to the matrix cracks, and to find out the effect of the thin-plies on the leakage. This paper aims at providing new simulation schemes for damaged constitutive model, crack density prediction and leak rate estimation of the composite laminates.