Multi-path propagation of acoustical wave and time reversal acoustical field in solid plate

The multi-path effect of the acoustical wave, which is excited by an infinite strip on the free surface of a solid plate, is studied. The multi-reflection and wave conversion of the cylindrical compressional and shear waves in solid plate are analyzed thoroughly by the ray approach method. The concise analytical representation is obtained. The time reversal processing is then applied to the wave propagation in the solid plate and analyzed theoretically and experimentally. It is shown that the waves coming from different arrays and different paths all arrive at the original point after the time reversal operation. It indicates that the time reversal can compensate automatically the wave aberration caused by the multi-path effect. The self-adaptive focusing of the time reversal field is also analyzed quantificationally by the focusing gain and the ratio of the principal to the second lobe. The effects of the focus position and the aperture of the transducer array on the focused field are also investigated. It shows that theoretical and experimental results are consistent to each other very well.