Damage resistance and damage tolerance of dispersed CFRP laminates: Effect of the mismatch angle between plies

Damage resistance and damage tolerance to impact events is the most demanding criteria in sizing several aeronautical composites. Tailoring the laminate ply sequence represents an effort towards improving those properties. In this work, the effect of the mismatch angle between the adjacent plies on the damage resistance and damage tolerance of CFRP composites was investigated. Three configurations were considered: a standard configuration (mismatch angle of 45 degrees), a dispersed laminate with small mismatch angles (between 10 degrees and 30 degrees) and another with larger mismatch angles (55-80 degrees). Compared to the other studies in the literature, the main difference is to assess the damage resistance and the damage tolerance for specimens with the same bending stiffness characteristics and the same number of interfaces. It is worth remarking that without using the dispersed laminates, it is impossible to design laminates with the same bending stiffness. The results showed that the dispersed configuration with small mismatch angles had a superior response compared to the other configurations, with respect to the indentation, the dissipated energy and the residual compressive strength (up to 30\% increment). These improvements can be justified by the possible effects of the mismatch angle on the damage initiation and/or the damage propagation. (C) 2013 Elsevier Ltd. All rights reserved.