Design of Ultra-High Strength Sheet Steel Beams

Cold-rolled sheet steels with yield strengths from 50 to 180 ksi have been used for bumper reinforcement beams. As yield strength increases, thickness can be decreased. However, at reduced sheet thickness, the maximum load capacity of a given beam is influenced by local buckling. Ultra-high strength sheet steel beams were tested in bending to establish a data base from which an empirical relationship to predict the maximum load could be derived.

A statistical relationship is shown to exist between sheet thickness, overall beam height, tensile strength, and the observed maximum load with an error of ±12%. The equation to predict maximum load is valid for a number of loading arrangements. Using the relationship developed, beams of lesser height and greater thickness can be designed and still maintain similar maximum load capacity.