Experimental study on the effect of waviness defects on composite material impact dynamics

The effect of pre-existing defects in composite materials on impact tolerance is poorly understood. In this study, carbon fibre reinforced polymers with waviness defects were used to explore how pre-existing defects affect impact events. An algorithm was introduced to provide insights into damage mechanics during impact experiments using damage-time maps. These maps provide information on damage: location, severity and initiation time. The morphology of damage measured using damage-time maps were compared with measurements from pulse-echo ultrasound and found to have a high level of agreement. This study found severe waviness bands acted as a barrier preventing delamination growth, resulting in a unique damage shape without causing higher damage area. By using the introduced algorithm, the amount of time required to understand complex impact events is substantially reduced.