Abstract

Characterisation of the branched surface breaking cracks is one of the challenges in ultrasonic Non-Destructive Evaluation (NDE) applications that may cause underestimation and misdetection. In this paper, an advanced ultrasonic imaging methodology, termed as the Multi-Mode Reverse-Time Migration (MMRTM) imaging algorithm is proposed in which any combination of wavefield modes can be used to produce an image of the complicated defects. This approach is implemented by post-processing the full matrix capture (FMC) of array data to achieve enhanced defect detection and characterization. An elastic finite difference (FD) model is used to predict the ultrasonic FMC data and demonstrate the performance of the MMRTM concept. The MMRTM of ultrasonic data requires separating longitudinal (P) and shear (S) reflections before, applying the imaging condition. The Vector-based FD model allows the decomposition of the elastic source and receiver wavefields into P and S wave vectors by decoupled elastodynamic extrapolation. Finally, the PP and PS images of branched surface breaking cracks are presented from the numerical data. MMRTM is determined as a potential technique for the evaluation of various complex defects such as fatigue cracks and stress corrosion cracks.

How to Cite:

Saini, A. ., Fan, Z. . & Fang, J. ., (2019) “Enhanced characterisation of branched surface breaking cracks using multi-mode reverse time migration (MMRTM) method”, Review of Progress in Quantitative Nondestructive Evaluation .