Metal Foams as Energy Absorbers for Automobile Bumpers 720490

Evaluations of aluminum foams show they can be efficient energy absorbers. They are especially interesting because they have virtually no rebounding characteristics. The load-compression response characteristics of the foam can be controlled by variations of alloy composition and foam density, thereby controlling foam strength and ductility. This makes foamed metals attractive candidates for a number of automotive energy-absorption applications.

The energy-absorption properties of a number of aluminum alloy foams have been studied under low and medium speed impact, up to 25 mph. The foam density, volume, and size required for a 5 mph “single shot” impact shock absorber have been determined for two automotive weight classes.

Nonshearing, columnar, high-density foam structures have been developed to withstand basal compressive loads. These columns have potential for multi-impact shock-absorbing applications.

Work is currently under way to define foamed aluminum properties and design required for use in bumpers for 50 mph barrier and pole impacts.