Damping measurements of a controlled composite material

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 travel 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 are reported for 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. Subject Classification: 40.20, 40.22.