Characterization and modeling of ultrasonic structural noise in the multiple scattering regime

Abstract : Multiple scattering can occur when performing ultrasonic measurements on highly scattering materials such as coarse grain steel or concrete. It constitutes in general a limiting factor for NDE techniques. In this communication, a method to simulate the structural noise due to multiple scattering is described. It requires three parameters: the diffusion constant, the elastic mean free path and the correlation distance. A method to obtain these parameters based on a single measurement procedure is presented. This approach has been applied to samples of coarse grain steel. The backscattered noise has been calculated for different probes and compared to experimental signals.