Simulation of ultrasonic TFM/FMC imaging for porosity clusters using multiple scattering modelling: Quantitative analyses and experimental comparisons

Ultrasonic imaging using the Total Focusing Method (TFM) is very useful for locating and sizing defects accurately. However, when imaging clusters of pores, the results may be distorted by multiple scattering phenomena. Several simulations are performed in a 2D context considering different scattering model approaches: single scattering, single scattering including defect shadowing, and multiple scattering. In order to reproduce clusters of pores, we use sets of side-drilled holes to impose well-controlled properties (position and size) for comparison with experimental tests. Comparisons of the simulated TFM images with the experimental ones show qualitative and quantitative improvements when using the multiple scattering model, thanks in particular to a better consideration of shadowing and other interaction effects between defects.