Orthotropic elastic constants of a boron-aluminum fiber-reinforced composite: An acoustic-resonance-spectroscopy study

Abstract

Acoustic-resonance spectroscopy was used to determine the complete elastic constants of a uniaxial-fiber-reinforced metal-matrix composite: boron-aluminum. This material exhibits orthotropic macroscopic symmetry and, therefore, nine independent elastic stiffnesses Cij. The off-diagonal elastic constants (C12,C13,C23), which contain large errors when measured by conventional methods, were especially focused on. Good agreement emerged among present results, a previous pulse-echo study, and theoretical predictions using a plane-scattered-wave ensemble-average model. Attempts to measure the internal-friction ‘‘tensor’’ failed.