Dynamic elastic constants of anisotropic materials by resonant ultrasound spectroscopy

Resonant ultrasound spectroscopy (RUS) has been applied to the anisotropic elastic stiffness determination of SiC/Al composites and highly textured Zr -2.5Nb alloys. To determine the elastic stiffness of anisotropic materials? the resonant frequencies of a rectangular parallelepiped specimen were mea sured and compared with the calculated frequencies based on the input data of the estimated stiffness, dimensions, and density. The initial estimates of the elastic stiffness of SiC/Al composites were calculated using the Mor i-Tananka (MT) theory and the concept of effective aspect ratio of reinforc ements. For highly textured Zr-2.5Nb alloy, the initial estimates were obta ined from its orientation distribution function, determined by x-ray diffra ction, and the reported elastic stiffness of a single crystal zirconium. Th rough a comparison of calculated frequencies with those measured by RUS, el astic stiffness values have been determined very accurately by iteration an d convergence processes.