面向增材制造的宏微结构一体化设计方法

Integrated design method for multiscale structure in additive manufacturing

针对面向增材制造的多尺度结构设计微结构之间材料连通性及尺度关联的问题,本文提出了基于自定义构型的子结构代理优化模型的宏微结构一体化设计方法。在该方法中,假设宏观结构由多个子结构构成,其子结构构型由相对密度等参数控制。利用设计域划分时子结构与宏观尺度比例关系,实现宏微结构尺度关联设计。在优化过程中,以子结构相对密度为优化设计变量,构建了以系列子结构为基础的自定义构型的微结构样本,设计了基于分段样条插值的代理优化模型,结合传统的优化准则建立了模型增材制造的宏微结构一体化设计框架,分析了代理模型的变量灵敏度及优化计算效率。通过计算实例,验证了所提方法的可行性及其所设计构型的可制造性。

This work presents an integrated design method for multiscale structure in additive manufacturing to solve the problem of material discontinuity and scale separation among microstructures.In this proposed method,the macro⁃structure is assumed to be composed of substructures with a self-defined lattice geometry pattern with different densities.The strict proportional relationship between macrostructure and microstructure is defined on the basis of the substructure theory in FEA.In the process of optimization,the density of substructure is taken as the design variable.And a surrogate model is built with the cubic spline interpolation method to map the density to the super-element stiffness matrix in the micro scale.The substructure-based optimization framework is established on the Optimality Criteria(OC)and the effi⁃ciency of the proposed model is demonstrated.An example of beam is given and the connectivity among microstructure is verified.