The Principle of Detection and Location of a Target in Solid-Liquid Layered Media by Using the Tr-Rtm Mixed Method

Target or defect has been detected and located in the liquid-liquid layered media by using a time reversal (TR) - reverse time migration (RTM) mixed method that can better suppress the effects of reflection signal of interface. In this paper, this method is extended to the case of solid-solid and liquid-solid layered media and the detection and location of the target can be obtained by establishing the acoustic field distribution. Because solids are different from liquids, both longitudinal wave and shear wave exist in solids. Therefore, four kinds of scattered wave in solid-liquid or liquid-solid layered media are recorded by receivers. Time reversal (TR) and reversed time migration (RTM) mixed method is used to establish the acoustic field distributions of four waves, respectively. The location of the target is interpreted as the position of the maximum value in these acoustic field distributions.