Fatigue Performance Evolution Law and Reliability Assessment Methodology of Wing Structures under Coupled Complex Loads and Environmental Conditions

Abstract

The aging trend of the global civil aviation fleet has become increasingly significant, with a large number of in-service aircraft operating beyond their initial design service goals. Current deterministic damage tolerance analysis methods struggle to quantify the combined effects of multi-source uncertainties, including load randomness, environmental corrosion, and material dispersion, on structural safety. This study focuses on the fatigue performance evolution law and reliability assessment methodology of wing structures under coupled complex loads and environmental conditions. Through corrosion-fatigue coupling interrupted tests, damage constitutive modeling, time-dependent reliability algorithm development, and system reliability optimization design, this research aims to reveal the cross-scale cumulative mechanism of fatigue damage, develop efficient time-dependent reliability calculation methods for small failure probabilities, and construct a system reliability optimization theoretical framework considering failure path correlation. The findings will provide theoretical support for anti-fatigue lightweight collaborative design of next-generation civil aircraft, offer scientific evidence for aging aircraft life extension certification, and promote the transformation of aviation maintenance from scheduled inspection to condition-based maintenance.