Guided wave tomography of pipe bends based on full waveform inversion.

Area of Science:

• Materials Science and Engineering
• Non-Destructive Testing
• Structural Health Monitoring

Background:

• Pipe bends are prone to wall thinning due to flow-induced stress and velocity changes.
• Traditional ultrasonic thickness measurements are localized and can be time-consuming.
• Guided Wave Tomography (GWT) offers a more comprehensive approach to damage assessment.

Purpose of the Study:

• To implement and evaluate a GWT method based on Full Waveform Inversion (FWI) for high-resolution thickness reconstruction of steel pipe bends.
• To assess the efficacy of FWI in detecting and quantifying wall thinning defects under varying conditions.

Main Methods:

• Modeling the wavefield in an artificially anisotropic pipe bend using Thomsen parameters in a 2D domain.
• Implementing a GWT approach utilizing Full Waveform Inversion (FWI) for thickness reconstruction.
• Conducting numerical simulations and experimental validation on a pipe bend with artificial defects.

Main Results:

• The FWI-based GWT method successfully reconstructed the thickness map of smooth defects in the pipe bend.
• Defect reconstruction accuracy was maintained regardless of the defect's circumferential position.
• The method showed particular effectiveness for defects located closer to the extrados of the bend.

Conclusions:

• FWI-based GWT is a viable and effective technique for high-resolution wall thickness monitoring of pipe bends.
• This method provides a significant advancement over conventional localized monitoring techniques.
• The study demonstrates the potential for improved structural integrity assessment in critical piping components.