Stress imaging by guided wave tomography based on analytical acoustoelastic model

Area of Science:

• Solid Mechanics
• Nondestructive Testing
• Wave Propagation

Background:

• Characterizing stress in plate-like structures is crucial for structural integrity.
• Existing methods may be destructive or lack precision for complex stress fields.
• Acoustoelastic effects (AEEs) offer a promising avenue for nondestructive stress evaluation.

Purpose of the Study:

• To develop and validate a nondestructive method for characterizing nonuniform multiaxial stress fields in plate-like structures.
• To utilize acoustoelastic effects on Lamb and shear horizontal guided waves for stress reconstruction.
• To combine analytical modeling with tomographic techniques for enhanced stress field mapping.

Main Methods:

• Derivation of an analytical acoustoelastic model (An-AEM) to predict AEEs induced by a triaxial stress tensor.
• Utilizing acoustoelastic coefficients (AECs) independent of stress but specific to wave modes.
• Integrating the An-AEM with time-of-flight straight ray tomography for nonuniform stress field reconstruction.
• Employing numerical simulations to demonstrate and assess the stress reconstruction process.

Main Results:

• The proposed method successfully reconstructs multiaxial stress fields using AEEs on guided waves.
• Stress components and orientation can be retrieved from AEEs under certain assumptions.
• Reconstruction accuracy is shown to be high in some cases, while dependent on spatial stress orientation variations in others.
• Numerical simulations validate the feasibility of stress field reconstruction.

Conclusions:

• The developed nondestructive method provides a viable approach for characterizing complex stress states in plate-like structures.
• The combination of analytical acoustoelastic modeling and tomographic techniques enables detailed stress field mapping.
• Further research may be needed to address limitations related to stress orientation variability for optimal accuracy.