Vibration-Based In-Situ Detection and Quantification of Delamination in Composite Plates

Area of Science:

• Materials Science
• Mechanical Engineering
• Non-Destructive Testing

Background:

• Composite materials are increasingly used in critical structures.
• Delamination is a common failure mode in composites, compromising structural integrity.
• Accurate detection and quantification of delamination are crucial for safety and maintenance.

Purpose of the Study:

• To develop and validate a new methodology for detecting and quantifying delamination in composite plates.
• To investigate the influence of delamination size and depth on detection capabilities.
• To establish a reliable non-destructive evaluation (NDE) technique for composite structures.

Main Methods:

• Utilized piezoelectric wafer active sensors for high-frequency (1-500 kHz) excitation.
• Employed a scanning laser Doppler vibrometer to measure local vibration responses.
• Performed finite-element-method (FEM) based numerical simulations and experimental validation.
• Analyzed local defect resonance frequencies and operational vibration shapes.

Main Results:

• Successfully detected and quantified delaminations of varying sizes and depths.
• Demonstrated that delamination depth has a more significant impact on detectability than size.
• FEM analysis confirmed localized vibrations within delamination regions at resonance frequencies.
• Ultrasonic C-scan was used for delamination visualization and comparison.

Conclusions:

• The proposed high-frequency vibration-based method effectively assesses delamination in composite plates.
• The technique shows good capability for evaluating delaminations with different depths and sizes.
• This approach offers a promising tool for advanced structural health monitoring of composite materials.