INCREASING THE RIGIDITY OF THERMOPLASTIC BULK MOLDING COMPOUND COMPOSITE BUMPER BEAMS USING ORIENTED COMPOSITE SHEETS

The stiffness of randomly oriented, thermoplastic bulk molding compound (TP-BMC) composites can be increased in a 3-point loading test through the use of commingled thermoplastic materials. Bumper beams for a typical midsize vehicle produced from combinations of these 2 materials were molded and tested using a static bumper test setup that measures the applied load and resulting deflection. A design of experiments investigation based on the Taguchi methods [1] were used to compare the effects of 4 material and processing variables on static load. The optimum levels for each variable were found to achieve maximum load at 25 mm deflection, which led to a manufacturing strategy for selectively increasing the stiffness of TP-BMC composites for bumper beams. This paper details the development work.