An Experimental Approach for Investigating Fatigue-Induced Debonding Propagation in Composite Stiffened Panels Using...

Area of Science:

• Materials Science
• Mechanical Engineering
• Aerospace Engineering

Background:

• Composite materials are vital in aerospace due to their high strength-to-weight ratio.
• Fatigue-driven debonding between composite layers (skin-stringer) is a critical failure mode.
• Understanding damage propagation is essential for ensuring structural integrity and safety.

Purpose of the Study:

• To experimentally investigate fatigue-driven debonding in a skin-stringer composite structure simulating aeronautical panels.
• To monitor damage evolution during fatigue compression using lock-in thermography.
• To accurately quantify delamination extent and shape for validating predictive models.

Main Methods:

• An experimental setup was designed to simulate aeronautical panel structures with skin-stringer debonding.
• Fatigue compression tests were conducted on the composite specimens.
• Lock-in thermography was employed to monitor damage evolution in real-time.
• Thermographic phase maps were analyzed to measure delamination area and shape.

Main Results:

• The study successfully monitored the progression of fatigue-driven debonding.
• Lock-in thermography provided accurate measurements of the delaminated area and its evolving shape.
• The technique allowed for detailed graphical analysis of damage over fatigue cycles.

Conclusions:

• Lock-in thermography is a crucial non-destructive testing (NDT) method for quantifying debonding in composites.
• The experimental data generated can validate numerical fatigue prediction models.
• This research contributes to developing damage-tolerant composite structures for aerospace applications.