某型系留无人机复合材料机体结构优化设计与分析

OPTIMIZATION DESIGN AND ANALYSIS OF COMPOSITE AIRFRAME OF A CERTAIN TETHERED HOVERING UNMANNED AERIAL VEHICLE

系留无人机是一种依靠地面系留线缆供电与通信,可长时间留空飞行的无人飞行平台。系留供电方法有效解决了当前多旋翼无人机续航时间过短的问题,适用于军事监控、公共安全、消防等领域。在无人机机体结构设计方案中,为提高无人机飞行高度,必须减轻结构重量,所以机体外壳多采用复合材料设计。复合材料在比强度和比刚度、加工制造等方面优于其他传统材料,在无人机结构中得到了广泛的应用。由于复合材料层合板在生产加工过程中具有可设计性,在复合材料中已经成为使用最多的一种结构形式。以某型系留无人机机体外壳为研究对象,将系留无人机机体结构进行有限元模型简化处理,以模型总体质量作为优化的最终目标函数,以无人机结构外壳的复合材料失效因子作为约束条件,应用工程优化软件对复合材料机体外壳进行自由尺寸优化,整个优化过程需要同时满足复合材料强度及刚度要求。最终从自由尺寸优化结果可以看出,机体结构材料的层间厚度发生了显著变化。与结构设计初期方案比较,经过优化的复合材料铺层厚度降低,最终减轻了无人机总体重量。

Tethered hovering unmanned aerial vehicle is a long time hovering platform which is secured by a cable serving as power supply and wideband data link.The purpose of tethered power supply method is to resolve the short time endurance problem of tradition UAV.Hovering platform is now applied in surveillance for military,public security,fire control etc.For increasing the hovering height of the UAV,the weight of structures has to be declined in the preliminary design program.Consequently,composite materials are always used in the airframe structure.Composite material has been widely used in UAV structures because of the various excellent performances,such as strength and stiffness ratio,as well as the performances in the process of manufacturing.Meanwhile,composite laminate has excellent designable property in the process of manufacturing.So,it is widely used among all the types of composite materials.In this paper,the airframe structure of a certain tethered hovering unmanned aerial vehicle is selected as the research objective,and the finite element model of a composite airframe is created.Then the mass of the structure is chosen as the objective function,the failure index are chosen as constraints,and the composite airframe structure is optimized by using the engineer software,where the results should meet the demand of strength and stiffness during the optimization.The final optimization results show that the ratio and thickness of plies of the composite material has been redesigned.Compared with the previous designing scheme,the weight of airframe is obviously reduced after the free-sizing optimization,which could achieve the objective of optimization.