Damping Measurements of a Controlled Composite Material

Abstract

Increased use of filamentary materials as reinforcements in structural components has necessitated obtaining information on the response of such material systems to a wide variety of loading conditions. One such technically important problem area is that associated with the dynamic response of composite materials to impact-type loading situations. In order to understand the phenomenon of wave trial in material systems, specific knowledge of the damping coefficient and phase velocity as a function of circular frequency is necessary. In the present paper, tests have been conducted on beam-type specimens of a steel-epoxy composite having controlled volume fractions and varying wire sizes. Measurements are reported on the damping coefficient as a function of circular frequency, a(ω), and the real part of the complex modulus, E1. The latter parameter has been further used to calculate the phase velocity, and data are presented on phase velocity, c(ω), as a function of frequency. Detailed tabular and graphical data are presented for the various specimens tested.