POISSONS RATIO AND THE INTERFACIAL BEHAVIOR OF COMPOSITE-MATERIALS

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 delet erious 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 w ere developed for composites having 5, 25 and 50 vol% of fibres. Both compressive and tensile transverse loading were applied to the simulat ed composite systems. This particular mode of loading was considered d ue to the often low fracture strength of many composites in the transv erse direction. The US Bureau of Mines is studying such problems to en able the design of new impact and abrasion resistant composite materia ls.