全复合材料无人机机翼结构优化设计

	全复合材料无人机机翼结构优化设计
	丁玲
学位类型	博士
导师	杨洪波
	2014-07
学位授予单位	中国科学院大学
学位专业	机械制造及其自动化
摘要	复合材料的广泛应用已成为解决无人机结构轻量化、高刚度设计的重要途径。机翼的结构性能对无人机的飞行性能有极其重要的影响，为了提升无人机的飞行性能，本论文针对某全复合材料机翼结构的优化设计展开了研究工作。论文的研究内容主要包括以下几个方面： 1) 根据机翼的总体设计要求及主要技术指标，基于某已研制成功的复合材料机翼结构，采用三梁多肋式作为机翼的总体布局方式；并通过研究气动场载荷到结构场载荷的转换方法，得到了机翼蒙皮表面载荷分布情况，继而确定了机翼物理模型的边界条件。 2) 建立机翼结构简化模型，对主要设计参数进行了灵敏度分析，将对机翼结构性能影响较大的翼梁及蒙皮作为目标优化部件；与此同时，针对翼梁位置变量及截面尺寸变量之间耦合的问题，提出了采用分层协调的复合形法建立翼梁的优化模型，从而确定了翼梁的主要结构参数。为复合材料结构优化设计提供了初始的机翼几何模型。 3) 采用分步优化的方式对机翼全复合材料结构进行了进一步的铺层优化设计：首先，结合有限元法建立了铺层厚度的优化模型，确定了机翼复合材料结构的铺层厚度；然后，基于遗传算法结合建立了铺层顺序优化模型，针对复合材料铺层顺序变量离散化的特点，采用整数编码方式表示设计变量，选取复合材料强度作为优化目标构造适应度函数，并提出了翼梁变截面过渡区复合材料铺层的处理方法。通过上述优化设计得到了机翼结构的最优铺层方案。仿真结果表明：经过铺层顺序优化后，机翼复合材料结构的强度比由优化前的0.98提高到1.45；机翼的最大变形由优化前的179.918mm减小到145.894mm；屈曲载荷系数由优化前的1.087提高到1.863；且优化之后机翼的应力分布更加均匀，复合材料的利用率得到了提高。 4) 分别建立了复合材料胶-螺混合连接结构的理论模型及有限元模型，通过对比两模型的分析结果得到，采用有限元模型分析复合材料的连接结构是合理的；讨论了影响复合材料连接的主要因素；结合机翼结构的特点，设计了机翼与机身的连接结构，并对连接结构进行了强度分析。 5) 针对与课题设计结构相似的某已研制成功的复合材料机翼结构分别进行了有限元仿真及静力试验。结果表明：有限元分析的最大误差在16.95%以内，说明采用有限元的方法分析复合材料机翼结构是可靠的。将课题设计机翼结构的仿真结果与某已研制成功的机翼结构的仿真结果进行了对比分析。结果表明：优化设计得到的全复合材料机翼结构完全满足设计指标及强度要求。论文的研究工作为日后复合材料机翼结构在工程上的实现提供了参考。
其他摘要	Extensive application of composite materials has become an important way to deal with the UAV structure lightweight, high stiffness design problems. Structural performance of the wing has a crucial influence on the UAV flight performance. In order to enhance the UAV flight performance, this paper launched a research work on the optimal design of the structure of an all-composite wing. The main contents of this paper include the following aspects: 1) According to the design requirements and main technical index, and a reference was also made with successfully designed wing structures, the overall layout with the three-beam and multi-wing rib was determined. The distribution of wings’ surface load was obtained through the study of the conversion from the aerodynamic loads to structural loads, and the boundary conditions of the wing in the physical model were also determined.. 2) Simplified model was set up and the sensitivity analyze was conducted. According to that, the wing beams and skin which had relatively lager impacts on the wings’ performance were chosen as the final optimization variables. Meanwhile, a hierarchical coordination complex method was proposed according to the coupling problem between variables of wing beam positions and the cross-sectional dimensions, and therefore the main mechanical parameters were determined, which provided initial wing geometry for the optimal design of composite structures. 3) Stepwise approach was applied to further optimizing of the all composite structures: firstly, the laminate thickness optimization was set up with Finite Element Method, according to which the optimal layer thickness was obtained. Secondly, the sequence optimization was conducted with genetic algorithm optimization methods, and according to discrete characters of the variables of composite stacking sequence, an integer coding genetic algorithm strategy was proposed and fitness function with structure strength of the composite material as the optimization objective was constructed, and the solution to deal with the wing beam cross-section transition zone was proposed. As a result, the best wing structure layout was obtained. The optimization results show: the strength of composite wing structure became to 1.45 from 0.98; the maximum deformation of the wing became 145.894mm from 179.918mm; and the buckling load factor became 1.863 from 1.087. Besides, stress distribution of the wing after optimization is more reasonable and the material was fully utilized. 4) Both theoretical model and finite element method model were set up and a compare study was conducted between both model and the result show that the finite element method was reliable. The main factors which had influence on composite connections were studied. According to the characteristics of the wing structure, the connections between the wing and fuselage were designed and analyzed with finite element methods. 5) Both finite element methods analysis and static test were carried out on successfully designed composite wings and the test results show that the max errors of finite element analysis were smaller than 16.95%, through which the reliability of the finite element analysis was verified. A compare study was conducted between the optimized wing and the existing wing structure, and the results showed that: the optimized all-composite wing of the UAV had fully met the design requirements. The research work in this paper provides a reference for engineering implementation of composite wing structures in the future.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41399
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	丁玲. 全复合材料无人机机翼结构优化设计[D]. 中国科学院大学,2014.

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