Poisson's ratio and the interfacial behaviour of composite materials

Abstract

Composite materials have Poisson's ratios that can range from 0.2 for ceramics to as high as 0.49 for pure elastomers. In this work, Poisson's ratio is shown to influence the magnitude and the location of deleterious stress concentrations that arise along a frictionless interface around a cylindrical reinforcement (i.e. fibre-reinforced materials). Due to the non-linear nature of this problem, finite element models were developed for composites having 5, 25 and 50 vol% of fibres. Both compressive and tensile transverse loading were applied to the simulated composite systems. This particular mode of loading was considered due to the often low fracture strength of many composites in the transverse direction. The US Bureau of Mines is studying such problems to enable the design of new impact and abrasion resistant composite materials.