Residual strength of a glass/polypropylene composite material subjected to impact

Fibre/matrix adhesion and fibre length have a significant effect on the impact behaviour and the residual resistance of thermoplastic composites. A comparison between virgin materials and impacted materials at different speeds is given in terms of results from tensile and loading/unloading tensile tests. A parameter is proposed in which the impact rate transmitted to the materials is quantified in terms of the maximum load applied during impact. The damage generated is evaluated through measurements of elastic moduli and Poisson's ratio in tensile tests. The use of acoustic emission and microscopic observations has been necessary to identify the sources of damage.