Experimental characterization of a defect separating two poroelastic plates

The detection of erosion is essential in engineering and material science, especially where progressive degradation can influence the performance of structures leading to stability problems. The present study investigates the potential use of acoustic waves in detecting degradation in the material and characterizing it in porous media systems. A multilayer system, where the porous plates are separated by a fluid layer, has been studied to show how variations in the fluid layer distance alter the acoustic wave behavior. Theoretical models based on Biot's theory have been used and measurements were made experimentally by incrementing the thickness of the fluid layer from 0 to 11 mm and analyzing reflection coefficients over a variety of frequencies. Experimental results are compablue with theoretical modeling and while the model aligns with experimental results, some divergence occurs, possibly due to the complex nature of the medium. The comparison of the various water-layer thicknesses gives valuable information on acoustic-wave propagation in porous materials and demonstrates a way of evaluating the degree of erosion from layer thickness spacing variations.