Debonding growth evaluation in CFRP-reinforced steel structures based on correlation analysis using guided waves

Area of Science:

• Structural Engineering
• Materials Science
• Non-destructive Testing

Background:

• Externally bonded carbon fibre reinforced polymer (CFRP) is widely used for structural retrofitting.
• Debonding at the CFRP-steel interface is a critical failure mode, compromising structural safety.
• Effective monitoring of bonding conditions is essential for ensuring the serviceability of retrofitted structures.

Purpose of the Study:

• To develop and validate a linear guided wave-based method for monitoring fatigue-induced debonding in CFRP-strengthened steel.
• To quantify the extent of debonding using correlation analysis and a derived damage index.
• To predict the location of debonding using a probability-based imaging technique.

Main Methods:

• Utilizing linear guided waves to interrogate the CFRP-steel interface.
• Calculating correlation coefficients (CC) between baseline and post-loading signals.
• Developing a damage index (DI) from CC to assess debonding severity.
• Employing a probability-based imaging method for debonding localization.

Main Results:

• The guided wave method successfully monitored the growth of small-scale debonding ( < 20 mm).
• Correlation coefficients effectively indicated the progression of debonding failure.
• A damage index derived from CC provided a quantitative measure of debonding extent.
• The probability-based imaging method enabled prediction of debonding positions.

Conclusions:

• The proposed guided wave method is effective for monitoring fatigue-induced debonding in CFRP-strengthened steel structures.
• This non-destructive technique enhances structural health monitoring and ensures the long-term serviceability of retrofitted components.
• The method offers a reliable approach for early detection and localization of critical interface debonding failures.