Influence of stacking sequence on leakage characteristics through CFRP composite laminates

In this paper, gas leakage characteristics of damaged carbon fiber reinforced plastic (CFRP) laminates for three stacking sequences were obtained experimentally with the use of in-plane biaxial tests. Permeability through the laminates was measured under biaxial loadings, and the damages induced by mechanical loads were identified with using ultra-sonic C-scan to acquire relationships between damage and permeability. The results of the experiments imply that onset of leakage due to development of damage is dependent on stacking sequences, and permeability under tensile loadings is an increasing function of biaxial loads. From these findings, leakage characteristics would be dominated by crack density, leak path complexity which depends on stacking sequences, and crack opening displacements which attribute to thermal and mechanical loadings.