Acousto-Ultrasonic Decay in Metal Matrix Composite Panels

Acousto-ultrasonic (A-U) decay rates (UD) were measured in metal matrix composite (MMC) panels.The MMC panels had fiber architectures and cross-sectional thicknesses corresponding to those designed for aerospace turbine engine structures.The wavelength-to-thickness ratio produced by the combination of experimental frequency setting conditions and specimen geometry was found to be a key parameter for identifying optimum conditions for UD measurements.The ratio was shown to be a useful rule of thumb when applied to ceramic matrix composites (CMC)s and monolithic thermoplastics.λ/h = 8.1