Improved semi-analytical simulation of UT inspections using a ray-based decomposition of the incident fields

Abstract

Abstract. Semi-analytical models are often used for computationally efficient ultrasonic simulations. They typically apply plane-wave or quasi plane-wave approximations to the ultrasonic fields at the location of flaws in order to calculate diffraction coefficients. In favorable cases, the plane-wave approximations used for echo computations in the Civa software yield satisfying results. However, it can lead to inaccuracies in unfavorable cases, such as for wide probe apertures, outside of the focal region, or for beam-splitting or distortion due to irregular geometries. This communication presents an improved model, implemented in a development version of the software. The new approach describes the ultrasonic field as a sum of rays and applies the plane-wave approximation to each ray instead of the entire field. It significantly improves the accuracy of echo computations. However, it implies that the diffraction is calculated for each pair of incident and diffracted rays instead of being calculated only once: a specific algorithm has been developed in order to avoid a significant increase in computation times. Benefits of the new approach are illustrated by comparing its results and computation times to those of the former plane-wave model in several cases of interest. They are also compared to those of a coupled finite element model (Civa-Athena).

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

“…The modifications allow comparing three ways to compute the echoes from a cluster of cylinders. All of them rely on the ray-based simulation described in [23]. Its general principle is to compute incident and observed ultrasonic fields using a paraxial ray technique [24], and then to compute echoes by summing the interactions of each pairs of incident and observed rays with the scatterer.…”

Model benchmarking and reference signals for angled-beam shear wave ultrasonic nondestructive evaluation (NDE) inspections

“…Note, no prior model benchmarking work was found to date using focused probes with SDHs. Lastly, Dorval et al recently presented an improvement to the beam model for semi-analytical simulation of UT inspections using a ray-based decomposition of the incident fields [15]. This option was considered in this paper.…”

“…As discussed in prior work, this model difference is likely primarily associated with an existing approximation in the scattering model, where the incident beam on each point on the sampled SDH surface is modelled by using the same waveform and time of flight [14]. A new beam model option [15] provided in CIVA UT 2016 was also tested here. However, the echodynamic curve results for CIVA UT 2015 and 2016 are nearly the same.…”