Study of post-impact behaviour of thin hybrid carbon/epoxy and glass/epoxy woven composite laminates under fatigue tensile loading – Part I : Experimental study

Abstract

This article concerns the experimental study of post-impact damage propagation in two thin carbon/epoxy and glass/epoxy hybrid woven composite laminates loaded in fatigue tension. Low velocity normal drop weight impact tests are first performed. Post-impact fatigue tensile tests are then carried out. They are controlled in displacement. The damage propagation is monitored by RX Tomography and Digital Image Correlation. The influence of the impact energy and the displacement level variation on the post-impact damage propagation is studied. Post-impact fatigue tests are also conducted on thin carbon/epoxy and glass/epoxy mono-material woven composite laminates in order to understand the phenomenons which occur in the hybrid laminates. Two different behaviours depending on the hybrid configuration are obtained. The post-impact damage propagation in fatigue is mainly influenced by the carbon plies orientations. Levels of loading and impact energies have an influence on the initiation of the damage propagation and on the speed. They have also an influence of the damage propagation scenario when delamination occurs. The influence of the stacking sequence is also studied. The change of the carbon plies position in the hybrid laminate leads to a change of the post-impact fatigue behaviour.