Research On The Strength, Thermal Performance And Optimal Design Of Minimal Curved Lattice Structure

Lattice structure is a spatial ordered porous structure formed by periodic arrangement of micro-elements such as bars and cells in accordance with certain rules。It has advantages of light weight,high specific strength,high specific stiffness and high energy absorption,and is Widely used in aerospace,medical and other fields。Among them,titanium alloy lattice structure has been widely used in aerospace main load bearing parts,skeleton scaffolds and other parts。With the continuous development of additive manufacturing technology and computer aided design technology,A kind of periodic lattice with minimal surface structure as its element has been widely used。The structure is modeled by implicit function,which has the advantages of simple modeling,small data volume and strong attitude adjustment Compared with the traditional bar lattice。A smooth and connected porous structure can be constructed periodically in three dimensional space,which is lightweight and has excellent bearing capacity and heat dissipation performance.Taking additive manufacturing as the background and bearing capacity and heat dissipation performance as the research objective,this paper studies the compressive bearing capacity and fluid-solid coupling heat dissipation performance of Gyriod,Diamond and Primitive three kinds of minimal surface lattice structures.Taking the geometric parameters of the cell as variables,the multi-objective optimization design of the structure’s bearing capacity and heat dissipation was carried out to explore the lattice configuration with light weight,high strength and excellent heat dissipation performance.The main research work of this paper is as follows:(1)Based on implicit function,MC algorithm is used to build Stl file to describe the surface contour.After boundary mesh processing and tetrahedral mesh subdivision,the solid model of minimal surface lattice is obtained.The size,volume fraction and model precision of lattice structure are adjusted by changing the parameters of implicit function.(2)Through quasi-static compression simulation test,the force characteristics of the minimal surface lattice structure and the relationship between mechanical properties and volume fraction are analyzed.The experimental preparation of the structure is carried out by using the laser selective melting technology and compares the experiment and simulation results to verify the correctness of the model.(3)Interface function transfer method is adopted to establish the temperature boundary condition of lattice sandwich wall of fluid-solid coupling heat dissipation model,and compares the active heat dissipation performance of the three structures under the same density.The influence of cooling fluid velocity on the heat dissipation efficiency of the structure is considered.The structure stress in the process of heat dissipation is analyzed by sequential coupling method.(4)With the lightweight、load bearing and heat dissipation performance as the optimization objective and geometric parameters of lattice structure as variables,the multi-objective optimization design of the structure was carried out.obtain the Pareto optimization solution and compare the structure performance before and after optimization.the sensitivity of each objective function to the variables was also analyzed through the distribution interval of the solution.