High strain rate properties of Cycom 5920/1583 cloth glass/epoxy composites

Abstract

Polymer matrix composites offer excellent properties such as high speci® c strength and stiffness, which make them attractive for many naval, aerospace, and automotive applications. Although they are candidate materials for many applications where high strain rate loading is probable, little is known of the material responses to shock loading for most composite materials. Because mechanical properties vary signi® cantly with strain rate, the use of static properties in the analysis and design of structures that undergo dynamic loadings can, on one hand, lead to a very conservative overweight design or, on the other hand, can lead to designs that fail prematurely and unexpectedly. The use of dynamic material properties will ensure the design of composite structures, which are weight ef® cient and structurally sound when they are subjected to dynamic loads. A split Hopkinson pressure bar is used to obtain compressive mechanical properties of Cycom 5920/1583, an uniaxial cloth, E-glass/rubber toughened epoxy composite being used presently by the Electric Boat Division of General Dynamics for undersea structures. Yield stress, yield strain, ultimate stress, ultimate strain, and modulus of elasticity values are presented and analyzed wherein the strain rates vary from 60 to 1150 s i 1 .