The Effect of Fatigue in Polyurethane Foam Cushions on Patients Confined to Wheelchairs

Abstract

A classic example of fatigue in polyurethane foam was recently provided by the failure of a cushion designed to relieve pressure from a decubitus sore. Comparative measurements on old and new cushions confirmed the lack of pressure relief in the fatigued sample and a mechanical investigation of foam properties provided an explanation of the mechanism. Further work indicated that polyurethane foam properties can be stabilized if the material is crushed a number of times prior to use. This can be done straightforwardedly between parallel rollers or even a mangle.