Effect of manufacturing-induced voids on the fatigue performances of multidirectional laminates

In the present work, an overview is presented on the recent work carried out by the authors on the influence of manufacturing-induced porosity on the long-term performances of composite materials. The effect of voids was first studied in terms of fatigue damage mechanisms at the micro-scale. An extensive experimental campaign was then carried out to assess the effect of porosity on the life to crack initiation (S-N curves), crack propagation (Paris curve), crack density evolution and global stiffness drop of [0/902]S and [0/452/0/-452]S laminates. Finally, a model that allows to predict the life to crack initiation from the behaviour of the void-free material was developed, showing good accordance with the experimental results