The structural all-composite class 8 bumper

Traditional bumper construction for Class 8 heavy-duty truck vehicles has been the mirrored look of chrome-plated steel. There are several designs in these stamped structures ranging from simple carbon steel to stainless steel clad aluminum. However, many of the aerodynamic tractor designs incorporate the axle-back, swept around bumper and it is difficult to obtain a deep draw in the steel stamping process. Plastic bumpers have been the solution. Today's plastic bumpers can be defined under two classifications: the SMC bumper with a supporting steel skeleton, and the multi-part shelled injection molded bumper. Neither construction has the strength of a steel bumper. Delphi Automotive Systems and Hendrickson International have teamed to determine whether a structural, oriented fiber composite bumper could be made which has the integrity of a steel bumper and the aesthetics of plastic at a fraction of the weight. A prototype composite bumper was constructed and displayed at the Great American Trucking Show in November 2000. Compared to its steel counterpart bumper, the composite had a higher natural frequency (>30 Hz), was only 25% of the weight, and could support a 1000 Newton load at each end. This paper will also discuss potential design applications for OEM tractors.