The 1973 General Motors Hydraulic-Pneumatic Energy Absorber Bumper System

Energy absorber designs may store or dissipate energy. Storing implies a subsequent return of the impact energy in a rebound reaction (for example, springs). Dissipation can be either destructive-metal flow-or nondestructive-shearing of a working fluid.

Automotive bumper systems are of maximum value from a performance and aesthetic standpoint only when at the design position, implying “self-restoration” after impact.

This paper presents features of the General Motors energy absorber that dissipates impact energy and also self-restores. The paper also discusses the testing used to qualify the design for customer usage and compliance with federal standards on bumper systems.