Wave Frequency Effects on Damage Imaging in Adhesive Joints Using Lamb Waves and RMS

Area of Science:

• Materials Science
• Mechanical Engineering
• Non-Destructive Testing

Background:

• Structural adhesive joints are vital across industries but prone to degradation, necessitating reliable non-destructive testing (NDT) methods.
• Lamb wave propagation is a promising NDT technique for identifying damage in adhesive joints.
• Assessing the impact of operational parameters, like wave frequency, is crucial for optimizing NDT effectiveness.

Purpose of the Study:

• To experimentally and numerically investigate the influence of wave frequency on damage identification in single-lap steel adhesive joints.
• To evaluate the effectiveness of Lamb wave propagation for defect localization and geometry determination.
• To analyze the impact of frequency on damage visualization and statistical assessment.

Main Methods:

• Excitation of ultrasonic waves at a single point and measurement across the joint area.
• Signal processing using root mean square (RMS) calculation for defect mapping.
• Experimental and numerical (Finite Element Method - FEM) analysis across a wide frequency range.
• Statistical analysis and visual assessment of damage maps.

Main Results:

• Lamb wave propagation successfully identified defects, providing their position and geometry.
• Damage detection effectiveness was found to be highly dependent on the chosen excitation frequency.
• FEM calculations corroborated experimental findings for single and multiple damage scenarios.
• Limitations of the method were identified, primarily related to frequency selection.

Conclusions:

• The effectiveness of Lamb wave-based damage identification in steel adhesive joints is strongly contingent on the selected wave frequency.
• Optimizing frequency selection is critical for successful non-destructive evaluation of adhesive joint integrity.
• Further research may explore advanced signal processing or multi-frequency approaches to overcome current limitations.