结构拓扑优化的工程特征设计理论与方法研究

This project aims at developing topology optimization theories and methods for engineering feature design of structures. Considering the fact that current optimization results are too abstract, difficult to represent the engineering design intention and lack the engineering feature, we propose a novel approach that combines topology optimization method with CAD feature-based modelling theory of mechanical design. The main contents are as follows. Implicit and explicit modelling mechanisms of structure configurations are studied to develop universal modelling methods suitable to engineering feature design. Develop finite cell method with fixed mesh discretization and high analysis precision for topology optimization of generalized moving boundary problems to solve the key problems of sophisticated sensitivity analysis and analysis precision in feature design and to realize a full merging between topology optimization and structural analysis. Selection strategies of feature topology variables and their influences upon the mechanical performances of structures are studied. The relationship between the mechanical performance design and the engineering feature driven configuration evolution of structure topology is revealed in order to build up theories and methods of engineering feature driven structure topology optimization. Based on design application requirements of typical lightweight and complicated aircraft structures, investigations are made for the concurrent design of mechanical performances and engineering features. Related design theories and methods are finally validated by means of the structure prototyping and experiments.

本项目以发展面向结构工程特征设计的拓扑优化理论与方法为目标，针对目前拓扑优化结果工程特征差、结构形式加工难度大、工程设计意图难以体现等关键问题，提出拓扑优化方法与机械设计特征建模相结合的技术新途径，从计算力学角度开展系统性研究。核心内容为：研究结构拓扑优化中工程特征的隐式与显式建模机理，发展适用于工程特征设计的通用建模方法；建立面向拓扑优化广义动边界问题的有限胞元固定网格高精度建模与分析方法，保证结构在拓扑演化与工程特征设计过程中的响应计算精度与灵敏度分析精度，实现结构力学分析与拓扑优化的高度融合；研究“特征拓扑变量”的选取策略，建立力学性能设计中“特征驱动”的结构拓扑构型演化模式，发展工程特征驱动下的结构拓扑优化先进设计理论与方法。结合复杂轻质结构典型设计问题，开展结构力学性能与工程特征一体化设计的应用研究；并通过构件优化结果的制造成型实现与力学实验研究，充分验证设计理论与方法的有效性。

全球航空航天工业迅猛发展与日益加剧的竞争背景给现代设计与制造业提出了结构力学性能和工程特征一体化设计的新挑战。现阶段以力学性能为主导的结构优化设计和以工程特征为主导的机械特征设计长期以来相互割裂、彼此独立发展。针对当前结构优化设计结果工程特征差、结构形式加工难度大、工程设计意图难以体现等关键问题，本项目通过探索结构拓扑优化与机械特征设计相结合的新途径，建立了工程特征驱动的结构拓扑优化设计新方法。主要研究内容及成果包括：建立了结构形状边界和拓扑构型的显隐式工程特征通用建模方法；研究了驱动结构边界形状和拓扑构型演化的工程特征几何变换方法；发展了面向结构广义动边界问题的有限胞元固定网格高精度计算框架及固支边界条件的隐式施加方法；建立了固定网格框架下通用高效灵敏度分析方法，探索了结构力学性能设计中工程特征驱动结构拓扑构型演化机制；建立了工程特征驱动下的结构拓扑优化、多组件结构系统协同优化、结构固支及动压力边界形状与拓扑构型联合优化、宏微观多尺度结构协同优化、增材制造约束结构优化设计方法；建立了优化设计-快速制造-实验验证一体化技术途径，并在高速飞行器油箱封头、航空发动机静子承力构件等航空航天结构设计中开展了工程应用研究。本项目立足于工程设计实践需求，突破了现有结构优化设计框架，揭示了优化设计变量从网格单元→轮廓边界→工程特征不同定义的本质差异，实现了满足结构力学性能与工程特征的可控性拓扑优化，打通了建模、分析、设计之间的壁垒，对于搭建力学性能设计和工程特征设计的桥梁具有现实的科学意义和工程价值。