Assessing damage progression in thermoset composites through visualization of thermal effects under impact

In the present work an investigation of impact damaging of composites with a variety of stacking sequences and thicknesses is carried out. Impact tests are performed, with a modified Charpy pendulum, at different impact energies. Any impact event is monitored with an infrared imaging device. As main results, the development of the damage, by increasing the impact energy, can be described through the appearance and evolution of hot spots/area. In particular, the thermal signature takes a different shape (spots, stripe, cross, disk, etc.) in regard to the different type of material. The impacted specimens are also non-destructively evaluated by lock-in thermography and a phased array system. At last, all the obtained results (from the different types of tests) are compared and discussed in an attempt to add new perspectives for a better understanding of the composites impact damaging mechanisms.