A Topology Optimization Method for Shell-Fill Structures

Abstract

The invention belongs to the related field of structural optimization design, and particularly discloses a topological optimization method for a of shell-filling structure. The method includes; takingthe structural flexibility as an objective function of topological optimization, setting the thickness of a shell, and initializing a macroscopic level set function and a mesoscopic level set function; Reducing the mesoscopic substructure into a super-unit, assembling the super-unit into a filling structure on a macroscopic scale, obtaining a macroscopic level set function and a mesoscopic levelset function of the next iteration after calculating macroscopic and mesoscopic sensitivities and updating design variables, calculating the structural flexibility of the next iteration, judging whether a convergence condition is met or not, and if yes, outputting an optimal shell-filling structure; And if not, repeating the above steps. The connection between the macrostructure and the mesostructure is established by adopting the super-unit technology, the optimal filling distribution can be obtained by optimizing the macroscale, the shell with uniform thickness can be automatically obtained,and meanwhile, the optimal topological structure of the filled porous structure can be obtained by optimizing the mesoscale.

Description

technical field [0001] The invention belongs to the related field of structural optimization design, and more specifically relates to a topology optimization method of a shell-filled structure. Background technique [0002] The shell-filled structure is a special structure with a solid shell on the outside and porous filling inside, which is widely used in the field of additive manufacturing. Among them, the outer shell is used to maintain the original shape of the structure, which is suitable for parts with matching requirements or structures with aerodynamic requirements, and can also protect the internal filling structure; while the internal filling is porous to reduce the weight of the structure and maintain Certain mechanical properties, the structure of this solid shell combined with porous filling has better buckling resistance. [0003] The design of the traditional shell-filled structure is mainly based on empirical methods. When planning the additive manufacturing...

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Problems solved by technology

[0003] The design of the traditional shell-filled structure is mainly based on empirical methods. When planning the additive manufacturing process, the solid shell is first produced, and then the interior of the solid shell is filled with holes. However, this manufacturing process cannot obtain the optimal mechanical properties. shell-fill structure

[0004] The multi-scale topology optimization method developed rapidly in recent years can design the optimal macro-structure and micro-porous structure. Although the designed structure is close to the shell-filled structure, there are still two problems: on the one hand, multi-scale topology optimization is not macroscopic The outer shell is not considered, and the outer shell is not integrated into the topology optimization process; on the other hand, multi-scale topology optimization generally uses the homogenization method for the design of porous structures and the equivalent calculation of macroscopic properties. One of the assumptions of the homogenization method is scale separation , this assumption means that the designed porous structure cannot guarantee a certain distribution of materials at the actual load position, and when multiple types of porous structures are used, good connectivity cannot be guaranteed between the porous structures, so that the load cannot be effectively transmitted

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