Modeling the compressive fracture behavior of foams for energy absorption

Abstract

Polymeric foams and foams in general have a wide variety of applications ranging from energy absorption, noise and vibration absorption, and thermal insulation. In some segments of transportation applications, foams are used specifically for energy absorption during a vehicle crash. These foams are designed for one-time use to protect vehicle occupants where recoverability of the foam is not prescribed. Recently, it has been identified that a ‘square-wave’ load versus displacement response is desired for these applications. Observations of foam crushing during compression have demonstrated the need for an appropriate phenomenological model for foam failure. Current foam—structure—property models do not go all the way to final failure and can predict the early stage of load—displacement relationship. But, in terms of energy absorption, the model which covers the extensive load—displacement relationship is very important. This article will detail the development of a structure—property model used throughout the development of a new family of lightweight, space efficient, energy absorbing foams.