Research On Topology Optimization Method Of Heat Dissipation Structure Based On Substructure Condensation Theory

There is a high demand for the heat dissipation performance of structures in industry.Lattice structure,fin structure and other configurations with a large number of fine size features have the characteristics of light weight,high specific stiffness and large surface area,which are often used in lightweight design of heat dissipation bearing structures.These configurations are difficult to manufacture by traditional machining methods because of complex topological structures.In recent years,the rapid development of additive manufacturing technology provides an effective way to process this kind of structure.A multilevel topology optimization model based on substructure static condensation method is proposed to optimize the structure with fine features.In the proposed model,the high-level structure is divided into a series of low-level substructures.The material distribution of the high-level structure is obtained by a densitybased topology optimization approach.The low-level configuration is determined by structural geometric parameters.The static condensation method is adopted to condense the internal degrees of freedom of the lowlevel structural and the low-level variable topology design is realized by optimizing structural parameters.The applicability of the proposed method is illustrated with design problems considering load bearing and heat transfer properties.The influence of different condensation strategies on the optimization results is also discussed.In order to eliminate the phenomenon of material accumulation at the boundary of design domain when the variable density topology optimization method considering convective heat dissipation is used to optimize the heat dissipation structure,the influence of convective parameters on the optimization result configuration and objective function in the modeling method of convective heat transfer coefficient based on density gradient interpolation are discussed.A model of convection continuous transition from top and bottom convection to side convection is proposed to eliminate the materials accumulated at the boundary of design domain in the modeling method of convective heat transfer coefficient based on density gradient interpolation.By controlling the convection weight coefficient,the convection type is gradually transformed from top and bottom convection to side convection in the optimization process,so as to avoid the material accumulating at the boundary due to the excessive density gradient at the boundary of the initial structure.The influence of main control parameters on optimization results and objective functions in continuous transition method are discussed.The effectiveness of the proposed method is verified by an example of planar heat dissipation structure.