Consistency of Thermoplastic Bumper Beam Impact Performance

This paper will address several critical aspects of bumper system performance, including vehicle damage protection and crash-severity sensing considerations, energy-absorption capacity and efficiency, and low-speed impact consistency and sensitivity to temperature changes. The objective is to help engineers and designers establish a realistic perspective of the capability of the various technologies based on actual test performance. The scope of the evaluation will include a comparison of several bumper-beam material constructions when subjected to a 16-km/hr swinging barrier impact over a range of temperatures the bumper could see in service (-30 to 60C). Bumpers tested in the program include: injection- and blow-molded polycarbonate/polybutylene terephthalate alloy (IM-PC/PBT and BM-PC/PBT); compression-molded glass-mat thermoplastic composite (CM-GMT); blow-molded high-density polyethylene (BM-HDPE); extruded aluminum with an expanded polypropylene (EPP) foam energy absorber (Al/foam); and high-tensile roll-formed steel with EPP foam (Steel/foam). Since the majority of today's passenger cars use the Steel/foam bumper technology, it was selected to be the benchmark against which the other systems were compared.