Process design for multi-stage stretch forming of aluminium alloy aircraft skin

A process design approach for multi-stage stretch forming was proposed by combining the strain distribution method and finite element method (FEM) to determine the minimum stage number and deformation amount of each stage. The strain distribution method was used to calculate the deformation amount of each stage and evaluate the formability through a safety criterion. FE simulation was taken as an analysis tool to reveal the deformation behaviour, to predict the strain contour and to determine the process parameters at each stage. To evaluate the effect of heat treatment after pre-strain on occurrence of deformation defects during the subsequent deformation, a multi-stage uniaxial tension test for 2B06 aluminium alloy sheet was carried out. A case study demonstrates that the approach has high reliability and good practicability.     

飞机腹鳍根部型材疲劳断裂强度分析

针对某型飞机腹鳍根部型材疲劳断裂问题,依据腹鳍的结构和工作特点,应用疲劳断裂理论进行定量分析,排除了因飞行中所受空气动力引起的静载和动载造成损伤的可能性,分析了其裂纹产生原因并提出使用维修建议.     

一种基于SOH的机载蓄电池地面维护设备的实现

机载蓄电池的健康度（State-Of-Health,SOH）是评判电池是否可以继续使用的重要评价参数。针对其受多重因素影响,难以估计准确值的特点,文中提出了一种简单可靠、测量精度理想、易于实现的地面维护设备设计方案,适用于对机载蓄电池进行地面维护。文中从设备设计角度分析了其功能需求关系,实验结果印证了该方法的可行性。     

基于四旋翼飞行器的改进金字塔LK光流算法的研究

针对四旋翼飞行器在飞行过程的水平漂移问题,提出利用改进的金字塔LK光流算法予以改善.首先,通过VisualStudio2013仿真,确知改进的金字塔LK光流算法比传统金字塔LK光流算法对图像的速度信息提取精度更高.然后,再建立四旋翼飞行器的动力学模型,将两种光流算法导入MATLAB的仿真模型中,得出:四旋翼飞行器能有效根据改进的金字塔LK光流算法获得速度信息以降低水平漂移.最后,通过在轴距为430 mm的四旋翼飞行器的平台上进行飞行试验,结果表明:采用改进的金字塔LK光流算法能使四旋翼飞行器的水平漂移程度降低,可实现较为稳定的悬停.     

往返式穿经法织造一端圆滑的经向截面立体织物

为得到一端圆滑的经向截面立体织物,采用往返式穿经法进行织造,克服了传统整经方法得到的织物两头都是毛头的缺陷.由于一根经纱在前端返回穿经作两次使用,立体织物的前缘呈光滑的圆弧状,因而具有更好的力学性能.     

先进的民用飞机机载系统集成流程分析

为解决现有民用飞机机载系统设计流程难以在设计前期发现顶层设计偏差的问题,对现有的瀑布式设计流程、V形设计流程及螺旋形设计流程进行了详细分析及对比,总结了各自在系统设计中的优势和局限性,提出采用螺旋形流程对V形流程进行改造的设计方法.该方法强调在设计前期采用模型对设计结果进行充分仿真验证,发现前期设计偏差,进行反复迭代,完善设计;在后期系统综合各阶段进行充分的综合测试验证,并根据结果对系统设计进行修正,确保系统满足前期各项需求.经详细分析表明,该流程集中了传统设计方法的优点,能在设计初期发现各种问题,具有很好的可行性.     

飞行器气动参数辨识软件开发需求与关键技术研究

飞行器气动参数辨识技术在飞行器设计、飞行模拟仿真中起着越来越重要的作用,而这一技术的工程应用却受制于其软件平台的开发.在分析国内外现状的基础上,剖析了飞行器气动参数辨识软件开发的使用需求与技术要求,研究了气动参数辨识的关键技术,建立了软件平台开发基本流程,最后展示了软件平台开发及应用实例,对该类型软件的架构确立与技术实...     

HVOF coatings for heavy-wear, high-impact applications

The aircraft hookpoint used for an arrested landing is exposed to various forms of heavy wear and impact. Nowhere is this more true than training field landings, where the hookpoint is subjected to drag along a concrete runway for possibly thousands of feet while flying at high speeds and heavy downloads. After extensive screening, a series of materials were subjected to special impact tests and concrete wear tests. Ten coatings, applied by thermal spray, were selected for future arrestment testing on the basis of these results.