Simulation-Based Inversion for the Characterization of Adhesively Bonded Joints Using Ultrasonic Guided Waves

Area of Science:

• Materials Science
• Non-destructive Testing
• Mechanical Engineering

Background:

• Adhesively bonded structures are vital in aerospace, automotive, and energy sectors.
• Assessing bond layer integrity using ultrasonic guided waves is a key research area.
• Accurate characterization of adhesive properties during curing is essential for performance.

Purpose of the Study:

• To develop and validate a finite element (FE) model for simulating ultrasonic guided waves in bonded structures.
• To accurately determine the shear modulus of an adhesive layer during its curing process.
• To assess the effectiveness of FE-based dispersion curve analysis for non-destructive evaluation.

Main Methods:

• A finite element (FE) model was developed to simulate wave propagation in an aluminum/adhesive/aluminum structure.
• Dispersion curves from the FE model were systematically compared with experimental measurements.
• An optimization procedure was employed to invert experimental data and retrieve adhesive properties with minimal prior knowledge.

Main Results:

• The FE-based forward model successfully matched experimental dispersion curves during the adhesive curing process.
• The method achieved agreement within 6% of reference values for predicted model parameters.
• The estimated optimal shear modulus at the end of curing was 1.55 GPa, close to the reference value of 1.47 GPa.

Conclusions:

• The proposed FE-based approach is effective for characterizing adhesive bond layers during curing.
• Ultrasonic guided wave analysis combined with FE modeling provides a reliable method for non-destructive evaluation.
• This technique offers a precise way to monitor adhesive properties, enhancing structural integrity assessment.