Fatigue Experiment and Failure Mechanism Analysis of Aircraft Titanium Alloy Wing-Body Connection Joint

Area of Science:

• Aerospace Engineering
• Materials Science
• Mechanical Engineering

Background:

• Aircraft structural integrity is paramount for operational safety.
• Wing-body connection joints are critical load-bearing components.
• Understanding fatigue failure mechanisms in these joints is essential.

Purpose of the Study:

• To analyze the failure mechanism of a titanium alloy wing-body connection joint.
• To verify the structural safety of the joint under simulated flight loads.
• To investigate the crack initiation and propagation behavior.

Main Methods:

• Experimental testing involving random load, Class A, and ground-air-ground load tests.
• Fracture surface analysis using stereo microscopy and scanning electron microscopy.
• Quantitative analysis of fatigue crack growth using Paris' law.

Main Results:

• Fretting fatigue was identified as the primary driver for crack initiation.
• Fatigue crack growth followed Paris' law, with a calculated crack growth period life of 207,374 loadings.
• The joint exhibited ductile fracture characteristics in the final fracture region.

Conclusions:

• The wing-body joint's structural design is conservative, exceeding the 400,000 landing/takeoff requirement.
• Crack initiation life constituted 95.19% of the full life cycle, demonstrating high reliability.
• The findings confirm the structural safety and reliability of the analyzed aircraft component.