Abstract: Theoretical model and experimental research is carried out on material elastic constants inversion method of coating plates by acoustic non-destructive test. Taking advantage of the broadband line focus transducer and the precise ultrasonic nondestructive detection system established on our own, obtained the acoustic characterization of thin coating structure. A great amount of data(601 groups) of pulse-echo signals are acquired in an accurate defocusing interval(20 μm). V(f, z) analytical method is applied on the extraction of measured dispersion curves for coating sheets. Associated with the theoretical analysis of wave propagation of coating materials, a computation model of theoretical dispersion curves is established. Comparing the experimental data with the theoretical curves, the acoustic wave velocities are obtained by curve-fitting method, and finally the inversion of elastic constants, e.g. Youngs modulus and Poissons ratio, are achieved. The experimental results agree well with the theoretical ones, while it shows that the inversion method is feasible and reliable. This research laid the foundation of non-destructive evaluation of mechanical properties of coating materials.

Key words: coating structure;V(f;z) analytical technique;elastic constants;dispersion curve;non-destructive test