Parametric study of automotive composite bumper beams subjected to low-velocity impacts

Fuel efficiency and emission gas regulations are the main causes for reducing the weight of passenger cars by using composite structures. Bumper beams are one of the main structures of passenger cars that protect them from front and rear collisions. In this paper, a commercial front bumper beam made of glass mat thermoplastic (GMT) is studied and characterized by impact modeling using LS-DYNA ANSYS 5.7 according to the E.C.E. UNITED NATIONS AGREEMENT [UNITED NATIONS AGREEMENT, Uniform Provisions concerning the Approval of Vehicles with regards to their Front and Rear Protective Devices (Bumpers, etc.), E.C.E., 1994]. Three main design factors for this structure: shape, material and impact conditions are studied and the results are compared with conventional metals like steel and aluminum. Finally the aforementioned factors are characterized by proposing a high strength SMC [Composite and metallic crash performance, Hawaii University, 1999, Available from: http://www.eng.hawaii.edu/~nejhad/BUMPER/bumper.html] (sheet molding compound) bumper instead of the current GMT. The advantages of the proposed model: equal strength and rigidity of the structure, reduction of material, ease of manufacturing by simplifying geometrical shape and reduction of production cost are studied and proved.