In this work a coupled experimental-numerical approach was developed to study the anisotropic far field attenuation behavior of plate-type unidirectional carbon fiber composites. Experimentally a technique that utilizes a time-frequency analysis to determine the frequency specific far field attenuation coefficient was developed, and used to evaluate the frequency specific attenuation coefficient of the flexure mode for both principal in-plane propagation directions. Numerically a technique for tuning finite element models to match the experimentally measured anisotropic attenuation behavior via incorporating Rayleigh damping into the models was developed. The ability of numeric models to realistically capture the far-field attenuation behavior leads to the possibility of using simulation to perform probability of detection studies for a given flaw/damage type. The numeric tuning technique was found to work well over a narrow bandwidth of interest (e.g., windowed ultrasonic signals), but was not robust enough to consider broadband sources (e.g., acoustic emissions).
Proceedings Title: 19th International Conference on Composite Materials
Conference Dates: July 28-August 1, 2013
Conference Location: Montreal, -1
Pub Type: Conferences
attenuation, stress wave propagation, FEM, flexure mode, time-frequency analysis