Detection of Debonding Defects in Concrete-Filled Steel Tubes Using Fluctuation Analysis Method

Area of Science:

• Structural Engineering
• Materials Science
• Non-Destructive Testing

Background:

• Concrete-filled steel tube (CFST) structures are widely used in construction.
• Debonding defects can compromise the structural integrity and safety of CFST elements.
• Effective methods for detecting these defects are crucial for maintenance and repair.

Purpose of the Study:

• To develop and validate a comprehensive method for detecting debonding defects in CFST structures.
• To evaluate the effectiveness of different wave propagation measurement techniques.
• To establish a quantitative approach for defect assessment and structural health monitoring.

Main Methods:

• Utilized wave propagation analysis with externally attached piezoelectric ceramic sensors.
• Conducted experimental tests and numerical simulations.
• Employed flat and oblique measurement techniques to detect debonding defects of varying sizes.
• Introduced a normalized judgment index (DI) and developed a wavelet packet energy analysis model.

Main Results:

• The flat measurement method proved effective for detecting debonding height.
• The oblique measurement method was superior for detecting debonding length.
• Sensor spacing significantly influences detection accuracy.
• A linear relationship was established between wavelet packet energy and debonding size.

Conclusions:

• The proposed method provides a reliable approach for detecting debonding defects in CFST structures.
• Integrated use of flat and oblique measurement techniques enhances detection precision for both qualitative and quantitative analysis.
• The developed mathematical model offers a scientific basis for quantitative defect detection and structural health monitoring of CFST structures.