Time domain finite element modeling of SH-mode propagation in elastic plates with deposits
Shear horizontal (SH) mode propagation in a steel plate with a deposit layer of either uniform or non-uniform thickness is considered. The influence of the deposit layer on the received time signals is studied, comparing the uniform and non-uniform thickness deposit layer cases. Time domain finite element simulations are used for the analysis.
The model has been compared with measurements for the case of a plate without deposit layer. For the case with uniform deposit layer, it is observed that there are minima in the Fourier (FFT) spectrum of the time signal, at distinct frequencies with regular spacing, which correspond to plate modes for the deposit layer. For the cases with non-uniform deposit layer, many similarities with the uniform layer case are seen in the corresponding FFT spectra of the time signals, especially regarding the first minima. The results indicate that there may be potential for determining deposit thickness using SH modes even for non-uniform deposit layers, as long as the material properties of the deposit layer are known, and there is proper bonding between the layer and the plate.