Some Elastic Moduli of Three Thick Composites

Thick composites are in use in critical applications and are proposed for still others. It is important to measure the elastic moduli of thick composites for two reasons: (1) design data on stiffness, and (2) prediction of feasible wave paths for ultrasonic waves for NDE. Except for one earlier report, (1) only relatively thin composites of relatively simple symmetries have been measured for their elastic moduli (2–6), Now, it is becoming necessary to measure thick composites of feasible engineering lay-ups. These often provide the complexity of orthorhombic symmetry locally in a specimen combined with curvature in the gross structure. In this work, specimens cut from thick structures will be treated in the same way as crystals to measure the elastic moduli by means of ultrasonic wave velocities. Results on three structures will be presented