Experimental characterization of the crashworthiness of carbon fiber reinforced epoxy composites

The crashworthiness of a structure is a measure of its protective capability under dynamic events by absorbing the crash energy in a controlled way. Fiber reinforced composite materials can represent a valid alternative to ductile metals as impact energy absorbers in a crashworthy structure. In fact, composites are characterized by high mechanical properties coupled with low weight, capability to be designed by tailoring the specific requirements and good energy absorption capabilities. However, the impact resistance and the damage modes of long fiber composites involve different factors (constituent materials, geometry, lay up, manufacturing process) and are difficult to predict. In addition, there are no standard experimental procedures to assess the crashworthiness of composite materials. Therefore, a large and proper experimental characterization on composites with different geometries can be useful to understand the failure mechanisms under dynamic loads.

In this work, three different kinds of carbon fiber epoxy composites have been realized by vacuum infusion process in order to investigate the effect of the width and the shape. In particular, two plane and one C-shaped composites have been manufactured and characterized with Charpy test at different impact velocity according to the three-point bending procedure. Further, in-plane compression tests on larger flat composites have been performed by using an anti-buckling fixture to evaluate the specific Energy Absorption (SEA). Results evidenced the effect of the impact velocity on the impact resistance, the greatest rigidity of the c-shaped composite and the damage modes.