Three-dimensional finite element models are used to study the influence of various parameters on the gas permeability of cross-ply composite laminate. It is shown that the intersection area, which is formed between two adjacent plies due to crack opening, is the most crucial factor in determining the permeability. It is found that the intersection areas obtained by superposing crack opening displacements of two-dimensional models are not accurate. A full three-dimensional model is required to obtain a detailed and precise prediction. The intersection area is found to be related not only to the resultant forces and thermal loads but also to the delamination shape and the delamination length. Laminates with different stacking sequence are studied, and it is found that for the same number of plies the laminate with dispersed plies shows lower permeability. Effect of temperature-dependent material properties is investigated as well.
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