Damage and permeability evolution in CFRP cross-ply laminates

In this study, damage and permeability in CFRP cross-ply laminates were evaluated experimentally with using cruciform specimens at room temperature. Development of matrix cracks in the CFRP laminate under biaxial loadings and permeability of helium gas through the laminate were acquired. In this acquirement, the permeability was measured in relation to crack density and applied biaxial loads. The results of the experiments indicate that stacking sequences of CFRP laminate influence not only matrix crack development but also leakage prevention. Gas permeability through damaged CFRP composite laminates is influenced mainly by crack densities and crack opening displacements, because matrix cracks play a role as leakage path. Permeability through the damaged laminates increases in accordance with damage development, and increasing rate of permeability in connection with the strains is approximately dominated by the external biaxial loads.