Scattering of ultrasonic waves by internal anomalies in plates

Real-time nondestructive testing (NDT) and nondestructive evaluation (NDE) of plate-type structures are important for structural health monitoring (SHM) applications. In this work, the wave scattering from horizontally oriented internal cavities or cracks in a plate is studied using the distributed point source method (DPSM). DPSM has gained popularity in the last few years in the field of ultrasonic field modeling. DPSM is a semianalytical technique that can be used to calculate the ultrasonic field (pressure, velocity, and displacement fields in a fluid, or stress and displacement fields in a solid) generated by ultrasonic transducers. So far, the technique has been used to model the ultrasonic field near a fluid-solid interface when a solid half-space is immersed in a fluid. This method has also been used to model the ultrasonic field generated in a homogeneous isotropic solid plate immersed in a fluid. The objective of this study is to present the theoretical modeling of the diffraction and scattering pattern of guided waves in the solid plate when transducers of finite dimension are used to generate guided waves in the defective plate.