Relation Of Ultrasonic Energy Loss Factors And Constituent Properties In Unidirectional Composites Graphite Epxoy Composite Materials

A model is developed relating composite constituents properties with ultrasonic energy loss factors for longitudinal waves propagating in the principal directions of a unidirectional graphite/epoxy fiber composite. All the constituents are assumed to behave as linear viscoelastic materials with energy dissipation properties defined by loss factors. It is found that by introducing a new constituent called the interface material, the composite and constituent properties can be brought into consistency with simple series and parallel models. An expression relating the composite loss factors to the loss factors of the constituents is derived and its coefficients are evaluated. Williams, J. H., Jr. and Lee, S. S. and Nayebhashemi, H. Unspecified Center NASA-CR-3181 NSG-3210