Ultrasonic Field Modeling Using Distributed Point Source Method

Abstract

Modeling of ultrasonic fields in presence of cracks, inclusions in materials is of great interest to the researchers in the field of real time non-destructive evaluation (NDE) and structural health monitoring (SHM). A semi-analytical method Distributed Point Source Method (DPSM) is adopted in this work to model elastic wave field in solid media with and without internal anomalies by using Finite size transducers placed directly on solid and also considering the solid fluid couplant interaction.Trasient state analysis has also been carried out for the same. Present work also contains wave propagation analysis for fluid (homogeneous/non homogeneous) for transducer having non normal incidence. For transient analysis, tone burst signal is used as input signal and response is observed at different target points and results are found to be matching with the wave velocities in specified media. Ultrasonic field in solid media has been modeled for circular and rectangular shapes of transducer. In later case, fluid-solid interface has been considered and is kept normal as well as non normal angle to wave propagation direction. In both cases, Fast Fourier transformation (FFT) is used to convert time domain signal into frequency domain and inverse FFT is used to again transform results into time domain.