To achieve lightweighting of the aircraft landing gear door hinge under opening and closing loads, a topological optimization model based on the variable density method was established, with structural stiffness as the constraint and minimum mass as the objective. The hinge was redesigned according to the optimized configuration, and the stiffness and strength of the design area were validated. The original aluminum alloy hinge material was replaced with lower-density polyetheretherketone (PEEK), which can be fabricated into complex structures via fused deposition modeling (FDM), thereby enhancing design freedom for topology optimization. However, FDM-printed PEEK's mechanical properties are influenced by printing parameters. This study conducted tensile tests on PEEK specimens printed with different FDM parameters (e.g., layer height, platform temperature, and infill pattern). The optimal printing parameters were determined as 0.1 mm layer height, 120 °C platform temperature, and tetrahedral infill. Subsequently, the best-performing specimens underwent heat treatment, and the effects of different annealing parameters on tensile strength were investigated. The results showed that annealing at 330 °C for 2 hours yielded the highest strength improvement. Furthermore, the hinge's loading conditions during door operation were simulated via multi-body dynamics analysis, while static simulations under peak loads identified stress concentration areas. Topology optimization was then performed to minimize material usage while maintaining mechanical performance, achieving the lightweight goal.

Additive manufacturing by direct metal fabrication represents one of the fastest-growing areas in material science and manufacturing. Modern manufacturing demands that parts be engineered to have high strength, be lightweight with complex geometrical details, and be suitable for operation upon completion. A very good example of such engineering-manufacturing involves the design and manufacturing of turbine blades for energy efficiency. On the other hand, topology-optimized lattice structures have huge potential and flexibility available to designers operating in the area of designing lightweight structures and high-strength ones at the same time, in contrast to solid form structures. The key issues involved in the research include designing graded density structures made from different lattice architectures for dense materials by characterization of the thermo-mechanical properties for a number of lattice settings in Gyroid, Diamond, Schwarz, Lidinoid, Split P, and Neovius lattices for varied parameters. This paper questions how appropriately the design structure functions in high-speed-rotating elements, such as turbine blades. The current research work will be aimed at the design, finite element analysis for simulation, and manufacturing through additive manufacturing of the turbine blades, considering several designs and lattice structures that satisfy the requirements of lightweight construction and high strength. A detailed preliminary design study has already been performed with the aim of justifying the idea presented in this paper and to create an initially validated basis. It therefore presents findings from the design of different lattice structures, supported by simulations that explain the potential, extent, and limitations of the proposed paper with regard to its general scope.