Study on energy focusing synthesis on pipe using time reversal technique

Deliver a focused energy by utilizing guided stress waves traveling along the structure to a desired location of the structure where the physical access is prohibited or significantly difficult is required by several areas, which include (a) remotely energy charging wireless devices for structural health monitoring and (b) removing blockages in pipelines. However, the wave energy is highly scattered due to the dispersive nature of the stress wave and the multipath effect in solid structures. In order to combat the high multipath channel dispersion in solid structures, we proposed a time reversal based synthesis method to achieve energy focusing and superposition. In this paper, we investigated the channel response of piezoelectric patches attached to a copper pipe based signal transmission system and studied the stress wave propagation over the pipe channel. Experimental results demonstrate that the stress wave transmitted electric energy from different sources is successfully focused at a predetermined spot simultaneously.