Lock-In Thermography for Investigation of Impact Damage in Hybrid Polypropylene/Glass Composites

In this contribution, the impact damage modes of a new class of hybrid systems, obtained by the coupling of polypropylene (PP)-based laminates with different interlaminar interface strength and coded as interlaminar-graded interphase strength (IGIS) laminated structures, have been investigated. Several specimens were fabricated by suitably alternating the reinforcement layers with films of the matrix having different intrinsic natures; some specimens were impacted at two energies. All the specimens (impacted or not) have been nondestructively evaluated with lock-in thermography (LT) that is a noncontact, noninvasive technique [10]. The obtained results have been analysed to obtain information on the role played by both the matrix and fibre-stacking sequence on the damage modes, as well as on the overall damage relevance.