Tensile Stress Acoustic Constants of Unidirectional Graphite/Epoxy Composites

Abstract

Previously, the stress acoustic constants (SACs) of unidirectional graphite/ epoxy composites were measured to determine the nonlinear moduli of this material. These measurements were made under compressive loading in order to obtain the suffi cient number of values needed to calculate these moduli. However, because their strength in tension along fiber directions can be several times greater, most composites are used under tensile loading. Thus, it is important to characterize the nonlinear properties of these materials in tension as well.