An Acousto-Ultrasonic NDE Technique for Monitoring Material Anisotropy
Due to their higher strength-weight ratio, greater stiffness, stronger corrosion and wear resistance, longer fatigue life, and better thermal insulation, fiber-reinforced composite materials have been widely applied, for example, in the aerospace, automobile, marine, spacecraft, and construction industries. Evaluation of material properties, detection of defects, and prediction of life of these material is important but difficult. In the last decade, considerable attention has been focused on the use of acousto-ultrasonic (AU) and Leaky-Lamb wave techniques to evaluate material properties or changes in material properties due to fiber misorientation, flaws an defects, fiber/matrix debonding, or external loading [1–4 AU approach, with bibliography, was presented by Vary setup with a personal computer (PC) used to analyze the AU waveforms was described by Kiernan and Duke . Propagation of Leaky—Lamb waves in fiber-reinforced composites was investigated theoretically and experimentally by Chimenti and Nayfeh [10, 11]. A general discussion of elastic waves in solids can be found in Ref. 9.