Determination of Elastic Constants of Anisotropic Materials from Oblique Angle Ultrasonic Measurements I: Analysis

The use of oblique angle ultrasonic measurements for determination of anisotropic material elastic constants has been considered for a number of years[1–8] (ref. [1–8] are just a sample). Renewed interest in this approach is occurring because of the use of anisotropic composite materials[3–5]. However, some of the early works do not indicate a way to take into account the fact that the energy and phase vector, in general, do not coincide for anisotropic materials[1,2]. The energy and phase vector coincide for certain directions, such as symmetry planes. By restricting oblique angle ultrasonic measurements to these planes, certain elastic constants can be obtained[4,5]