Topology optimization design of titanium alloy outer cylinder lug structure for landing gear

• An integrated optimization strategy combining material substitution, topology, parameter, and shape optimization is proposed for landing-gear outer cylinder lugs. • The optimized titanium-alloy lug achieves substantial stress reduction and lightweight performance while satisfying strength and fatigue requirements. • Simulation and experimental tests jointly verify the accuracy of the optimized model under static, fatigue, and residual-strength conditions. • The optimized structure maintains high integrity and a significant safety margin even after completing full-life fatigue loading. While A-100 ultra-high-strength steel is widely employed in landing gear, its mass poses a constraint for advancing aircraft performance. To overcome this, the present research introduces two key innovations: the substitution with a lightweight titanium alloy and the development of an integrated topology and shape optimization framework, specifically applied to the outer cylinder lug. This approach yielded an optimal design that reduces mass by 28.4% and confines the maximum stress to 860.6 MPa, safely under the 875 MPa allowable threshold. A comprehensive experimental validation, involving full-scale static, fatigue, and post-fatigue residual strength tests, was conducted following a complete design-to-test workflow, confirming the design’s practical robustness. The findings underscore that the integrated methodology achieves substantial mass savings while ensuring structural integrity and durability, providing a critical reference for engineering future landing gear components.