A model-based inverse method for positioning scatterers in a cladded component inspected by ultrasonic waves

Area of Science:

• Materials Science
• Non-Destructive Testing
• Ultrasonic Testing

Background:

• Nondestructive testing (NDT) methods are crucial for detecting, locating, and identifying defects in materials.
• Ultrasonic testing (UT) is a common NDT method, but its accuracy is challenged by complex geometries and anisotropic materials, such as cladding.
• Irregular surfaces and anisotropic cladding distort ultrasonic fields, leading to inaccurate defect localization and sizing.

Purpose of the Study:

• To develop and validate a model-based inverse method for accurate defect localization in cladded steel components.
• To address the challenges posed by irregular geometry and anisotropic cladding in ultrasonic inspections.
• To improve the reliability of defect detection and sizing in critical applications like pressure vessel inspection.

Main Methods:

• A model-based inverse method utilizing time-dependent simulation of ultrasonic propagation.
• Simulation of ultrasonic wave propagation in complex geometries and anisotropic materials.
• Minimization of a cost function comparing simulated and measured ultrasonic images to determine the most probable defect position.

Main Results:

• The developed method accurately locates defects despite geometric and material complexities.
• The inverse method effectively overcomes aberrations caused by cladding, such as beam distortions.
• Validation through application examples on actual measurements from pressure vessel inspection configurations.

Conclusions:

• The model-based inverse method provides accurate defect localization in cladded components.
• This approach enhances the reliability of ultrasonic testing in challenging industrial environments.
• The method is generally applicable to inverse ultrasonic echo-structures when forward problem simulation is feasible.