基于材料结构一体化设计的复合材料车身稳健性拓扑优化方法研究

Fiber reinforced composite materials have superior performances, such as high specific strength and high specific modulus. While layer thickness and fiber orientation can significantly affect the performance of laminate structures, their optimizations were seldom integrated with traditional topology optimization. Meanwhile, robust topology optimization for design of composite material is also a neck-bottle, which should be addressed urgently. This project aims to achieve the Material Structure Integration Design methodology for composite auto-body. Fiber orientation, layer thickness and structural topology optimization will be concurrently considered, and optimization strategies for multiple load cases in real life such as mode, stiffness and impact scenarios will also be addressed. Since the mechanical performances of composite structures are closely related to manufacturing process, the strength behavior can be affected by the component materials, interface, laminate structure, loads and external environment. This project proposes to accommodate these uncertainties in composite structures by combining robust optimization with topology optimization. Commercial softwares MATLAB and ANSYS will be implemented to develop the related algorithms. The algorithms will first be applied to the design of a hood structure and corresponding prototypes will be made and tested for validation. The ultimate goal of this project is to design a full body structure of an electrical vehicle made of composite materials. The key of this project is to address the scientific problems of integrated design of layer orientation, thickness and topology and robust optimization strategy in composite structures, which has a high value in both theoretical and application manners.

纤维增强复合材料具有比强度高、比模量高等诸多优点，其铺层厚度以及角度对于材料性能都具有至关重要的作用。鉴于目前研究中未能将铺层角度、厚度和拓扑优化结合，项目提出将复合材料层合板的铺层角度、铺层厚度以及结构拓扑优化相结合，实现材料/结构一体化设计新方法，并研究模态刚度以及碰撞等多工况拓扑优化策略。同时由于复合材料机械性能与加工制造等过程密切相关，强度行为受组分材料、界面性质、层合结构、载荷、环境等多种因素的影响和制约，项目提出将稳健性优化与复合材料拓扑优化相结合实现复合材料稳健性拓扑优化。同时利用MATLAB和ANSYS完成相应的算法，利用该算法实现发动机罩的拓扑优化设计，并将该设计进行试制以及试验验证。最终完成某微型电动车车身的复合材料拓扑优化设计。项目拟重点解决铺层角度、厚度和拓扑优化一体化设计以及稳健性复合材料拓扑优化策略等关键科学问题，具有很高的理论意义和工程实用价值。

本项目提出了将复合材料厚度变量以及角度变量同时引入拓扑优化的参数化方法，实现了材料结构一体化设计新方法，并将制造约束引入到该拓扑优化方法当中，使得优化结果更加符合制造工艺要求。为了提高计算效率，本项目提供了能够有效减少优化变量的方法从而减少计算量。考虑到结构件的实际应用情况，完成了刚度、模态等的多工况拓扑优化策略研究。另外，结构件的性能会受到制造、加工、载荷等多种不确定性因素的影响，因此本项目将稳健性优化与复合材料拓扑优化相结合实现了复合材料稳健性拓扑优化。由于很多大型结构件计算量较大，无法在MATLAB中实现有限元分析，因此本项目对有限元分析软件ABAQUS进行了二次开发，实现了MATLAB-ABAQUS的联合优化-分析，使得本项目提出的材料结构一体化设计新方法更加适用于实际工程结构件当中去。为了验证本项目所提出方法的正确性及精确性，本项目对复合材料后背门、发动机罩、新能源汽车电池吊挂点进行了拓扑优化，并将优化后的复合材料发动机罩、新能源汽车电池吊挂点进行了样件试制及试验，试验结果表明，优化仿真结果与试验结果误差均在合理范围内，证明了本课题提出的材料结构一体化算法的有效性和正确性。