Low-velocity Impact and Flexural Properties of Thermoplastic Polyurethane/Woven Glass Fabric Composite Laminates

Composite laminates based on a commercial thermoplastic polyurethane (TPU) grade and reinforced by woven glass fibers were prepared by film stacking and compression molding procedures and subjected to static and dynamic mechanical tests, at ambient and low temperatures. The results were interpreted taking into account that preliminary analysis of TPU based laminates showed a fiber volume fraction equal to 53%, 56% and 48% for plates involving 10, 16 and 22 lamina, respectively. Flexural tests, performed so far only at room temperature (RT), revealed that the intermediate thickness laminates offer the highest performances, probably for their higher volumetric fraction of reinforcement. Impact results collected, instead, also at low temperatures (-25°C and -50°C) indicated that no delamination is verified all over the considered range of impact temperatures and thickness of plates. On the contrary crack propagation phenomena are enhanced by increasing the thickness of impacted samples and/or reducing the impact temperature.