基于变密度法的无人机后机身拓扑优化设计

TOPOLOGY OPTIMIZATION OF AFT FUSELAGE BASED ON VARIABLE-DENSITY METHOD

张威

11849220

硕士

力学

单肖文

2020-05-28

2020-06-01

哈尔滨工业大学

深圳

无人机是近年来飞速发展的一个高新技术产业，随着无人机应用的普及和相关产业的发展，其使用环境对无人机整体结构的刚度和重量提出了越来越严格的要求。为了满足日益提高的结构需求，对无人机进行结构优化势在必行。结构优化可分为三个层次：尺寸优化，形状优化和拓扑优化，这三者的设计难度依次增大。减重一直是飞行器结构设计最重要的要求之一，在无人机轻量化结构设计中，除了使用更轻的材料，拓扑优化是最有效的方法，也是该领域应用最广泛，最前沿的技术。相比前两者而言，拓扑优化的设计变量更多，求解过程更为复杂，并且优化结果实现也更为困难。本文以南科大智能无人机实验室的尾座式无人机 ETS10 的后机身为研究对象，根据其试飞及姿态分析的结果得到该无人机后机身的实际工况，针对其主要承受弯矩扭矩的特点，对无人机后机身的蒙皮加强筋分布进行了拓扑优化设计。本文根据无人机实际飞行环境与飞行姿态分析了无人机后机身的实际工况和极限载荷条件，满速且水平尾翼满偏舵情况下后机身载荷最大，然后分析了无人机后机身的纯蒙皮结构和桁梁式结构在这两种边界条件下的应力与位移情况，分析了桁梁式机身的加强效果。基于变密度法的 SIMP 插值模型，以最小柔度为目标函数，建立了以体积分数为约束的拓扑优化数学模型，并利用 OC 准则法和敏度过滤求解该模型，以 2D 与3D 梁结构算例展示了拓扑优化中惩罚因子和敏度过滤半径对拓扑优化结果的影响以及边界条件对优化结果的影响。接着以满足结构刚度与轻量化为目标，对无人机后机身加强筋的分布进行拓扑优化，包括前处理与优化结果的分析，根据优化结果对机身内部加强筋重新建模处理，并将最终优化结果与普通的纯蒙皮结构和桁梁式机身结构的力学性能进行对比，包括力学仿真对比与实验对比，确定了最终的优化结构在实现轻量化设计同时较大的提升了后机身的弯曲刚度和扭转刚度，具备实际的工程意义。

Drones are a high-tech industry that has been developing rapidly in recent years. With the popularity of drone applications and the development of related industries, the use environment has put more and more stringent requirements on the stiffness and weight of the overall structure of the drone. In order to meet the increasing structural requirements, it is imperative to optimize the structure of the UAV. Structure optimization can be divided into three levels: size optimization, shape optimization, and topology optimization. These three design difficulties increase in turn. Weight reduction has always been one of the most important design requirements for aircraft. In UAV lightweight design, in addition to using lighter materials, topology optimization is the most effective method, and it is also the most widely used and cutting-edge technology in this field. Compared with the former methods, topology optimization has more design variables, the process of optimization is more complicated, and the realization of optimization results is more difficult,too. This thesis takes the back fuselage of “ETS10”( a drone of the Intelligent UAV Laboratory of SUSTech) as the research object. According to the result of test flight, theactual working conditions of the back fuselage of the drone are obtained.Topology optimization of the skin reinforcement ribs of the back fuselage of the drone is applied. This thesis analyzes the actual working conditions and ultimate load conditions of the UAV's rear fuselage based on the actual flight environment and flight attitude of the UAV. The rear fuselage load is the largest at full speed and the horizontal tail is fully deviated. The stress and displacement of the pure skin structure and truss structure of the rear fuselage under these two boundary conditions are analyzed. Based on the SIMP interpolation model of variable density method, the minimum flexibility is used as the objective function, a mathematical model of topology optimization with volume fraction as constraint is established, and the model is solved using OC criterion method and sensitivity filtering. Then 2D and 3D beam structures are taken as examples. The examples show the impact of the penalty factor and the sensitivity filtering radius on the topology optimization results in the topology optimization, and the influence of the boundary conditions on the optimization results. Then, to meet the structural rigidity and lightweight goals, the topology of the rearfuselage reinforcement of the drone is topologically optimized, including pre-processing and statistic analysis of optimization results, and the internal reinforcement of the fuselage is re-modeled according to the optimization results, and the final optimization results are compared with the mechanical properties of ordinary pure skin structure and truss-type fuselage structure, including the simulation and experiment. It is determined that the final optimized structure achieves a lightweight design while greatly improving the bending stiffness and torsional stiffness of the rear fuselage. Topology optimization has practical engineering significance.

拓扑优化 变密度法 后机身 刚度

Topology Optimization variable-density method back fuselage Stiffness

中文

联合培养

南方科技大学

张威. 基于变密度法的无人机后机身拓扑优化设计[D]. 深圳. 哈尔滨工业大学,2020.