波音737CL飞机主起落架支撑梁区域裂纹的修理

美国联邦航空局(FAA)发布新适航指令AD 2014-03-06,强制要求航空公司对波音737CL飞机的主起落架支撑梁区域进行裂纹检查。本文结合维修经验,对检查发现裂纹后的修理方法进行总结、分析。     

TC17钛合金激光喷丸应力场及支持向量机应力热松弛模型

对TC17钛合金进行了不同功率密度下激光喷丸强化,使用X射线衍射仪测试了激光喷丸冲击波诱导的残余压应力场的分布,测试了不同温度真空保温下残余压应力的热松弛规律,最后基于支持向量机理论建立了残余压应力热松弛预测模型,并用试验结果对模型进行验证.研究表明:TC17钛合金在功率密度为4GW/cm2时表层残余压应力场最佳;残余压应力在280℃和450℃真空保温150min后分别有11.24%和27.11%的松弛;在280℃和450℃交替保温160min后应力松弛33.9%;残余压应力在试验温度保温160min后有大部分剩余,可以有效提高TC17钛合金抗疲劳性能、基于支持向量机的预测模型能够较精确的表征TC17钛合金的应力松弛规律,满足工程使用要求,对其他材料表层残余压应力热松弛分析具有借鉴意义.      

基于出动方式的舰载机航空保障调度模型

为了有效解决舰载机航空保障调度问题,分析了舰载机的出动方式;根据不同出动方式下舰载机所需航空保障组织实施方式的不同,在合理假设、适当简化的基础上,建立了两种出动方式下舰载机的航空保障调度模型,为深入研究舰载机航空保障调度问题奠定了基础。     

Aero-engine fault diagnosis applying new fast support vector algorithm

A new fast learning algorithm was presented to solve the large-scale support vector machine ( SVM ) training problem of aero-engine fault diagnosis.The relative boundary vectors ( RBVs ) instead of all the original training samples were used for the training of the binary SVM fault classifiers.This pruning strategy decreased the number of final training sample significantly and can keep classification accuracy almost invariable.Accordingly , the training time was shortened to 1 / 20compared with basic SVM classifier.Meanwhile , owing to the reduction of support vector number , the classification time was also reduced.When sample aliasing existed , the aliasing sample points which were not of the same class were eliminated before the relative boundary vectors were computed.Besides , the samples near the relative boundary vectors were selected for SVM training in order to prevent the loss of some key sample points resulted from aliasing.This can improve classification accuracy effectively.A simulation example to classify 5classes of combination fault of aero-engine gas path components was finished and the total fault classification accuracy reached 96.1%.Simulation results show that this fast learning algorithm is effective , reliable and easy to be implemented for engineering application.     

基于燃油成本最小的机队规划研究

以燃油成本最小为目标,考虑航班频率限制、旅客市场需求、机队可利用时间限制、空勤人员限制及航路对机型的限制等因素,实现航空公司航线网与机队资源的最优配置,为航空公司降低运行成本,特别是中短程飞行,提供依据.并就该问题建立整数规划模型,通过算例对模型进行分析和评价.     

基于高压涡轮叶片寿命损耗的航空发动机功率控制

提出了基于高压涡轮（HPT）叶片寿命损耗计算的功率控制策略.通过飞机和发动机模型在不同环境条件下进行飞行任务仿真,得到推力需求及HPT叶片温度等参数,采用逆向工程方法进行HPT叶片寿命损耗计算.结果表明:在满足推力需求的同时,采用降低HPT叶片温度的控制策略能明显减少在不同环境条件下HPT叶片寿命损耗.通过不断调整发动机高压涡轮环境温度使之工作在推力需求基线附近,达到了有效延长发动机寿命的目的,验证了高压涡轮叶片寿命损耗计算方法简单可行.表明基于HPT叶片寿命损耗的发动机功率控制降低发动机寿命周期成本的有效性.      

Novel approach of crater detection by crater candidate region selection and matrix-pattern-oriented least squares support vector machine

Impacted craters are commonly found on the surface of planets, satellites, asteroids and other solar system bodies. In order to speed up the rate of constructing the database of craters, it is important to develop crater detection algorithms. This paper presents a novel approach to automatically detect craters on planetary surfaces. The approach contains two parts: crater candidate region selection and crater detection. In the first part, crater candidate region selection is achieved by Kanade-Lucas-Tomasi (KLT) detector. Matrix-pattern-oriented least squares support vector machine (MatLSSVM), as the matrixization version of least square support vector machine (SVM), inherits the advantages of least squares support vector machine (LSSVM), reduces storage space greatly and reserves spatial redundancies within each image matrix compared with general LSSVM. The second part of the approach employs MatLSSVM to design classifier for crater detection. Experimental results on the dataset which comprises 160 preprocessed image patches from Google Mars demonstrate that the accuracy rate of crater detection can be up to 88%. In addition, the outstanding feature of the approach introduced in this paper is that it takes resized crater candidate region as input pattern directly to finish crater detection. The results of the last experiment demonstrate that MatLSSVM-based classifier can detect crater regions effectively on the basis of KLT-based crater candidate region selection.     

大型固体助推器的低成本推进剂

固体火箭发动机要想在未来空间运输系统中得到应用,必须降低成本,才有竞争力。本文综述了锡奥科尔公司在大型固体助推器用低成本固体推进剂方面的研究成果。研究表明,HTPB/AN推进剂(88％固体,AN、R-45HT,廉价AP/Al)和HTPB/AP推进剂(88％固体,R-45HT,廉价AP/Al)与航天飞机固体助推器所用的PBAN推进剂相比,其成本分别降低了40％和15％。     

基于航空公司运行成本和公平性的停机位指派

缩短航空器在飞行区的滑行距离,可以降低航空公司运行成本,减少大气污染物排放;而均衡各航空公司的滑行距离,可以提高航空公司在机场运行的公平性,提升航空公司整体竞争力。从航空公司运行成本和公平角度出发,建立基于航空公司运行成本最小化和运行最公平的停机位多目标优化指派模型。采用生物地理学算法对模型进行仿真验证,对随机指派、成本最低、最公平、公平指数小于0.1,公平指数小于0.2等五种情况的仿真结果进行比较。仿真结果表明：当公平指数小于0.1时,停机位指派不仅有效降低航空公司运行成本,并大幅度提升航空公司间公平性,说明该模型能够更好的对停机位指派进行优化。     

2.4米跨声速风洞条带悬挂支撑试验技术研究

为提高大型飞机风洞试验时的支撑系统刚度、降低支撑气动干扰以及实现真实船尾后体流动的模拟,在2.4米跨声速风洞中建立了条带悬挂支撑试验系统.主要包括专用试验段、条带支撑机构、控制系统、天平设备、标模及半弯刀尾支撑机构研制等六部分.系统研制成功后,在2.4米跨声速风洞中开展了流场调试及标模试验,分别采用风洞试验和数值模拟方法获取了条带悬支撑的干扰量.在某飞机高速风洞试验中,采用条带支撑系统,获得了飞机模型的气动特性,并与尾撑试验结果进行了对比.以条带支撑为辅助支撑,得到了尾支撑干扰量,与腹撑试验结果进行了对比.研究结果表明,条带悬挂支撑系统具备型号应用条件,同期重复性精度高,在-2°≤α≤2°范围内,重复性精度满足σCL≤0.0012,σCD≤0.00013,σCm≤0.0005,标模试验结果与国外风洞试验相关性较好;条带支撑干扰试验结果与数值模拟吻合较好,低亚声速时支撑干扰量较小,在-4°≤α≤10°范围内,M=0.6时的支撑干扰量ΔCL≤0.005,ΔCD≤0.0008,ΔCm≤0.005.