IN-SITU DETERMINATION OF ELASTIC STIFFNESS CONSTANTS OF THICK COMPOSITES

We summarize in this paper some of the challenges of making ultrasonic measurements in thick composites and, in particular, in determining n on-destructively the matrix of elastic constants of such materials. Th e procedure relies on the point-source/point-receiver measurement tech nique by which various wave modes are simultaneously generated over a broad angular spectrum in a test specimen. A procedure is described fo r analyzing the measured wavespeeds to determine the elastic symmetry of a composite test specimen and its matrix of elastic moduli. (C) 199 7 Published by Elsevier Science Limited.