METALLIC ENERGY DISSIPATING SYSTEMS.

This review is principally concerned with the relatively slow speed (of the order of, say, 50 m/sec) dynamic impact of metallic structures and dwells on the large deformation plasto-mechanics of the simple structure elements frequently used as parts of complete devices. The design aim is to dissipate kinetic energy irreversibly rather than convert and store it elastically and in particular, restitution is to be avoided. The aim is to safeguard people, cargo, machinery or even the vehicle itself from suffering an excessively high rate of retardation or degree of damage. Devices used to this end are usually one-shot items, i. e. , once having been deformed, they are discarded and replaced. The implication of designing an energy-absorbing device on the basis of its quasi-static loading response is that inertia effects within the device itself are unimportant and hence the kinetic energy is considered converted into plastic work in a quasi-static deformation mode. Exceptions to this behavior will be mentioned where appropriate. Besides a brief statement concerning strain-rate effects and other general features, we conclude with some comments concerning nonmetallic systems for absorbing impact energy.