Abstract
The load-displacement characteristics of fifteen motorcycle helmets were determined at displacement rates from quasi-static to 5M/S. Seven of these helmets had polycarbonate outer shells while the remaining shells were of fiberglass construction. The stiffness of helmets with polycarbonate shells was found to be more uniform, both with loading rate and magnitude of load, than that of fiberglass shell helmets. Use of these data to predict helmeted head force and acceleration after impact with a rigid surface is illustrated using a mathematical model.