Comparative Investigation for the Performance of Steel and Carbon Fiber Composite Front Bumper Crush-Can (FBCC) Structures in Quarter-Point Impact Crash Tests

As Light weighting is the top priority for the automotive industry today, the push for reducing overall vehicle weight will likely include the consideration of materials that have not previously been part of mainstream vehicle design and manufacturing, including carbon fiber composites. Therefore, the deformation characteristics and crush performance of carbon fiber reinforced polymer (CFRP) and steel front bumper crush-can (FBCC) assemblies in Quarter-point Impact Tests are investigated in this article. The experimental tests in this study were conducted using a sled-on-sled testing method. Force-time histories, kinematic data and videos for each test were recorded using several high-speed cameras (HSCs), accelerometers and a load cell wall. The collected data was filtered with SAEJ211 CFC 180 filter and sorted to ease the comparative analysis for the performance of the steel and CFRP bumper assemblies. A similar pattern was observed in the crashworthiness characteristics (i.e. force-time history, force-displacement, crash pulse and deformation patterns) of all steel and CFRP FBCC specimens. Typical failure modes of composite bumper assemblies, which were revealed by the high-speed videos were the failure of crush-can and failure of the bumper beam due to the generation of high stresses as it gets stretched due to its curvature after hitting the sled. On the contrary, local permanent deformation of the beam and crush-can was the predominant failure mode in steel FBCCs assemblies under quarter-point loading. Results obtained from the comparative investigation show that CFRP is a more efficient yet lighter material in regard to the absorption of the impact energy.