Designing bionic surface grid structure with base structure method

基于基结构法的机翼仿生曲面网格结构设计

¹ School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China
² Key Laboratory for UAV Technology, Northwestern Polytechnical University, Xi’an 710072, China

Received: 23 July 2021

Abstract

To improve the efficiency of the composite material wing structure of a solar-powered UAV, this paper proposed an efficient discrete structural topological optimization method based on the notion of bionic design. The method considers the features of such wing structures as discrete stiffness, high aspect ratio and ultralight. Through multi-step optimization, the grid relationship of the base structure method is established with the GRAND method, so as to obtain the design space of discrete topological optimization. First, linear programming is used to solve optimization problems and thus gives the topological relations of a wing structure. Then, by extracting the information on node dimensions of the discrete topological structure, a bionic geometric model is established with the notion of bionic design. In order to obtain the optimal topological form of the bionic surface grid structure of the wing, the finite element analysis and the structural dimension optimization are carried out with the parameterization method. On the condition that design requirements are satisfied, the optimization reduces the weight of the wing by 34.4%, compared with the traditional design methods. Results show that the structural optimization method proposed in the paper is effective for this special composite material wing structure and can be used for the lightweight design of similar structures.

摘要

以某太阳能无人机机翼结构为研究对象，结合该类结构刚度分散大、超轻质、大展弦比等特点，运用基结构离散拓扑结构优化方法与仿生思想相结合的方式，设计得到了一种新的碳纤维轻质机翼结构。利用分步优化设计思想，通过GRAND法建立基结构网格关系，得到离散拓扑优化设计空间，并运用线性方法求解优化问题，获得机翼结构的拓扑关系; 通过提取离散拓扑结构中杆件的节点尺寸信息，建立设计域内的材料权重分布; 结合仿生设计理念，以编译结构拓扑生成方式的形式，表征参数化的模型几何特征; 运用优化方法，得到最终的仿生机翼曲面网结构的最优拓扑形式。对比了该仿生结构与其他传统结构形式的结构性能，验证了所提方法对于太阳能飞机这类特殊机翼结构在超轻设计方面的可行性，在满足使用要求的前提下，实现了34.4%的结构减重。为开展此类刚度分散、碳纤维用超轻质结构研究提供了一种新的设计方法。