Optimization Design Of BCC Lattice Structure Based On SLM Process

China is now in the critical period of Made in China 2025,and has a high demand for R&D of high-end aerospace equipment.The aviation EHA(Electro-Hydrostatic Actuator)system is an integrated aviation hydraulic system.It is important to design lightweight actuator as it is the core of future large passenger aircraft and advanced fighter jets.In recent years,lattice structures have attracted wide attention due to their excellent properties such as high specific stiffness,specific strength,heat dissipation and energy absorption.At the same time,with the rise of additive manufacturing technology,lattice structure manufacturing means has been greatly improved,and more and more experts and scholars focus on lattice structure complex parts integrated molding.Based on the mechanical properties and forming quality of BCC lattice structure,this paper optimizes the design of BCC lattice structure and applies it to the lightweight design of aviation EHA.The main research contents of this paper are as follows:Firstly,according to the characteristics of additive manufacturing and the special configuration of lattice structure,a lattice structure was proposed to improve the surface quality and forming quality by optimizing the cross section of lattice structure.Specifically,L-BCC lattice structure was proposed for BCC lattice structure,its mathematical model was established,and finite element analysis was carried out to explore the influence mechanism of relative density and structural parameters on its mechanical properties.Secondly,based on the above structural optimization ideas,a new node-enhanced lattice structure is proposed according to the stress characteristics of the lattice structure combined with the node reinforcement idea.Specifically,the L-BCC lattice structure was parameterized to obtain the L-ZBCC lattice structure and optimize the design.Furthermore,the mathematical model is established,the mapping relationship between structural parameters and mechanical properties is analyzed,and the quasi-static test and finite element analysis are carried out to verify the correctness of the theoretical model.Thirdly,the fatigue life of BCC lattice structure before and after optimization under different stress levels is analyzed by finite element method.The fatigue characteristics of lattice structures with different parameters and relative densities are summarized and the SN curve is obtained.Finally,lightweight design was carried out for the connecting rod in aviation EHA,and different lattice structures were used to fill it.The fatigue life under random vibration load was analyzed by finite element method,which met the design requirements.