ABSTRACT
If one is to apply the principle of energy conservation, calculating the crush energy dissipated by each vehicle in crush is not just important, but absolutely necessary. To contemplate a pile of tangled-up sheet metal that was formerly a vehicle, and take on the task of computing how much energy was required to effect the change, is a daunting task. However, the seminal paper by Campbell1 in 1974 considered a number of vehicle crash tests conducted by General Motors, made some observations about how the vehicle deformation varied with test speed. From those observations, he developed an analytical model that is the basis of most crush energy assessment methods in use today. Because his observations implied that the residual crush varied linearly with some kind of force applied to the structure, Campbell’s approach can be called a constant-stiffness model, in the same sense that a linear spring is a constant-stiffness device.
