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中国民航飞行学院拥有各型飞机200多架,其中TB200型飞机37架.作为教练机,学员操纵时重着陆情况较多,目前发现有7架TB200型飞机零号框出现了较为严重的裂纹,需要进行修复. 相似文献
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从疲劳和损伤容限的概念出发,对某机身13长桁的框腹板进行受力情况、疲劳寿命、裂纹扩展寿命和剩余强度分析,充分讨论了与框腹板相连的接头的可靠性。在考虑精度的情况下用子模型的方式节省了很多计算时间,用扩展有限元法预测裂纹扩展的轨迹也与实验相吻合,为工程应用提供了简洁有效的途径。 相似文献
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某型飞机的某框下半框腹板发生严重的腐蚀损伤.为保证飞机安全,对该部位采取了补强修复.根据规范要求,需要进行全尺寸疲劳试验.但受条件限制,疲劳试验只能在做过高载试验的飞机结构上进行,为此,进行了高载对疲劳寿命的影响研究和全尺寸疲劳寿命试验等研究工作.研究结果表明,使用做过高载静力试验的飞机结构进行疲劳寿命试验是可行的. 相似文献
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采用简单有效的方法对复杂的飞机结构进行损伤容限评定具有重要的意义,提出一种简单有效的应力强度因子获取方法,并结合损伤容限分析的一般流程,分析某机身框地板梁缘条含裂纹修补结构的疲劳寿命及使用寿命期内结构的剩余强度。根据机身框地板梁结构受载特点建立简化的分析模型,计算单位载荷时不同长度下裂纹尖端应力强度因子,再由结构边界载荷与应力强度因子的关系确定无量纲应力强度因子;根据损伤容限分析方法编制程序,计算结构在飞行载荷谱下从初始裂纹扩展到临界长度的寿命及各裂纹长度下结构的剩余强度,给出结构检查间隔。结果表明:结构修补后的疲劳寿命及剩余强度均满足损伤容限设计要求。本文给出的损伤容限分析过程及方法可应用于工程中类似结构的损伤容限评定。 相似文献
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通过试验研究了复合材料机身框承受轴向压缩载荷下的失效模式,并与工程理论计算、有限元分析进行对比。试验研究的框构型包含"C"型框和"Z"型框,试验结果显示,复合材料机身框与蒙皮结构在承受沿框方向的轴向压缩载荷时,首先蒙皮发生局部屈曲;随着载荷的增大,框腹板和内缘也发生局部屈曲,最终导致整个框截面的破坏。对蒙皮局部屈曲采用两加载边简支、两侧边固支的层压平板屈曲工程分析方法,分析结果表明,工程理论计算与试验数据吻合良好,并且理论值具有保守性。对于框腹板及框内缘这类薄壁结构,其边界支持作用弱于简支,导致工程理论计算结果不保守。为了获得框腹板与框内缘更准确的局部屈曲结果,必须采用几何非线性有限元建模分析。 相似文献
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航空发动机结构复材化是发动机减轻质量的主要途径。针对复合材料外涵机匣服役后的损伤特点,选用胶接修复工艺进行机匣修补。研究了不同胶接修复方法的修复效果和适用范围。基于三维渐进损伤方法,使用Abaqus软件建立了复合材料外涵机匣典型件胶接修复模型,对机匣危险区域损伤孔边和翻边处模拟了复合材料损伤的产生和演化,预测了使用填胶修复和预浸料修复的典型件模型静拉伸强度和实际机匣模型的静压缩强度。结果表明:损伤深度不超过厚度的10%时采用填胶修复以恢复气动外形,损伤深于厚度的10%至贯穿时预浸料修复能同时恢复机匣的强度和刚度。 相似文献
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针对飞机地板梁腹板结构损伤.在切割补强处理时存在切除面积和应力集中的问题.对不同形状的切口进行强度特性分析,以确定切割补强修理时最佳切口的形状:在补强过程中,为了改善腹板传递剪力的路径,避免产生附加偏心弯曲应力和弯曲变形.将原补强修理中贴补加强板一分为二.分别铆接在梁腹板的两侧。利用有限元软件Abaqus进行建模,分析和研究梁腹板强度特性,所得结论表明椭圆形切口及两面补贴加强板的维修效果显著.为制定飞机地板梁腹板损伤的维修方案提供了参考和借鉴。 相似文献
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有翼高超声速再入飞行器气动设计难点问题 总被引:2,自引:1,他引:2
有翼高超声速再入飞行器是近年来的研究热点,气动设计是飞行器设计的关键。为了更清楚地认识有翼高超声速再入飞行器气动设计的难点问题,对有翼高超声速再入飞行器的发展、优势及总体任务剖面进行了介绍,从5个方面详细介绍了该类飞行器气动设计的难点问题,包括多约束复杂面对称气动布局设计、高温真实气体效应对气动特性影响、天地差异与天地换算方法、反作用控制系统(RCS)喷流干扰对气动特性的影响以及气动数据不确定度等,简要阐明了这些难点问题对总体设计的重要性以及初步的解决思路,为有翼高超声速再入飞行器气动设计提供了一些参考。 相似文献
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LUO Cheng LIU Hua YANG Jia-ling LIU Kai-xin 《中国航空学报》2007,20(3):230-235
Crashworthiness requirement of fuel tanks is one of the important requirements in helicopter designs. The relations among the protection frame, textile layer and rubber layer of the fuel tank are introduced. Two appropriate FE models are established, one is for an uncovered helicopter fuel tank without protection frame, and the other is for fuel tank with protection frame. The dynamic responses of the two types of fuel tanks impinging on the ground with velocities of 17.3 m/s are numerically simulated for the purpose of analyzing energy-absorbing capabilities of the textile layer and protection frame. The feasibility of the current crashworthiness design of the fuel tank is examined though comparing the dynamic response behaviors of the two fuel tanks. 相似文献
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The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow 总被引:1,自引:0,他引:1
This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig.Measurements of heat transfer from the discs and tangential velocities are presented.The test rig is a 70% full scale version of a high pressure compressor stack of an axial gas turbine engine.Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air.Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows(Re up to 5×106 and Rez up to 2×105).Two different builds have been tested.The most significant difference between these two build configurations is the size of the annular gap between the(non-rotating) drive shaft and the bores of the discs.The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method.The velocity measurements were made using a two component,LDA system.The heat transfer results from the discs show differences between the two builds.This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity.There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig.For the narrow annular gap,there is an increase of non-dimensional tangential velocity V/Ωr with radial location to solid body rotation V/Ωr=1.For the wider annular gap,the non-dimensional velocities show a decrease with radial location to solid body rotation. 相似文献
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波音公司面临着来自空客公司的巨大挑战,企业战略性创新才是公司成功的关键。为此波音公司的全部战略性研究集中在扩大产品的差异性上,体现在3个方面:电子化(e-Enabled)运营环境、整体复合材料机身部件的制造技术和支持波音787客机的全球协同环境(GCE)。 相似文献
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临近空间飞行器测控与信息传输系统频段选择 总被引:7,自引:0,他引:7
临近空间飞行器是高性能信息化武器平台,测控(TT&;C)与信息传输系统是其信息保障的核心,而选择合理、可行的频段是展开系统设计的前提和基础。频段选择影响到整个技术方案的制定,是一个需综合考虑、影响深远并具有战略意义的关键问题,从国际电联(ITU)国际标准、高速数传、接收信噪比(SNR)、“三抗”、超视距中继、黑障、雨衰以及设备研制成熟度8个方面全面、细致论证了近空间平台测控系统的频段选择问题,最终得出在视距链路中以Ka频段为宜,在超视距链路中以Ku/Ka双频段为宜的结论。 相似文献
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基于弯曲激波压缩系统的高超声速进气道反设计研究进展 总被引:3,自引:0,他引:3
总结了近十年来弯曲激波压缩研究的主要成果。提出了弯曲激波压缩系统的新概念,即利用特殊设计的楔形弯曲压缩面或空间弯曲压缩面,产生一系列与前缘弱激波相互交汇或叠加的压缩波系,从而使前缘激波弯曲,形成特殊的弯曲激波,它与波后的等熵压缩波来共同完成对气流的压缩。在此基础上,实现了由给定出口气动参数的超声速内流道反设计,实现了由给定压缩面压力分布和给定压缩面马赫数分布要求的型面反设计,实现了由给定激波波面的压缩型面反设计。研究证明,弯曲压缩面-弯曲激波压缩系统具有良好的综合气动性能,为高性能高超声速进气系统的气动设计提供了一种全新的设计方法。 相似文献
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Integrated Entry Guidance for Reusable Launch Vehicle 总被引:2,自引:2,他引:0
NING Guo-dong ZHANG Shu-guang FANG Zhen-ping 《中国航空学报》2007,20(1):1-8
A method for the implementation of integrated three-degree-of-freedom constrained entry guidance for reusable launch vehicle is presented. Given any feasible entry conditions, terminal area energy management interface conditions, and the reference trajectory generated onboard then, the method can generate a longitudinal guidance profile rapidly, featuring linear quadratic regular method and a proportional-integral-derivative tracking law with time-varying gains, which satisfies all the entry corridor constraints and meets the requirements with high precision. Afterwards, by utilizing special features of crossrange parameter, establishing bank-reversal corridor, and determining bank-reversals according to dynamically adjusted method, the algorithm enables the lateral entry guidance system to fly a wide range of missions and provides reliable and good performance in the presence of significant aerodynamic modeling uncertainty. Fast trajectory guidance profiles and simulations with a reusable launch vehicle model for various missions and aerodynamic uncertain-ties are presented to demonstrate the capacity and reliability of this method. 相似文献
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Wu Xianyu Li Xiaoshan Ding Meng Liu Weidong Wang Zhenguo 《中国航空学报》2007,20(6):488-494
In order to investigate the effects of fuel injection distribution on the scramjet combustor performance, there are conducted three sets of test on a hydrocarbon fueled direct-connect scramjet test facility. The results of Test A, whose fuel injection is carried out with injectors located on the top-wall and the bottom-wall, show that the fuel injection with an appropriate close-front and centralized distribution would be of much help to optimize combustor performances. The results of Test B, whose fuel injection is performed at the optimal injection locations found in Test A, with a given equivalence ratio and different injection proportions for each injector, show that this injection mode is of little benefit to improve combustor performances. The results of Test C with a circumferential fuel injection distribution displaies the possibility of ameliorating combustor performance. By analyzing the effects of injection location parameters on combustor performances on the base of the data of Test C, it is clear that the injector location has strong coupled influences on combus- tor performances. In addition, an inner-force synthesis specific impulse is used to reduce the errors caused by the disturbance of fuel supply and working state of air heater while assessing combustor performances. 相似文献
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(高)超声速流动试验技术及研究进展 总被引:1,自引:1,他引:1
近年来,与高速飞行器相关的(高)超声速流动受到了极大的关注。这类流动所具有的非定常性、强梯度和可压缩性对试验方法和风洞设计技术提出了挑战。超声速纳米示踪平面激光散射(NPLS)技术是由作者所在团队研发的非接触光学测试技术。它能够以较高的空间分辨率来揭示超声速三维流场的一个瞬态剖面的时间解析的流动结构。介绍了NPLS技术以及基于NPLS开发的密度场测量、雷诺应力测量和气动光学波前测量等方法,并回顾了这些技术在超声速边界层、超声速混合层、超声速压缩拐角、激波/边界层相互作用和光学头罩绕流等流动中的应用,清晰地再现了边界层、混合层、激波等典型流场结构及其时空演化特性。另外,为了模拟和研究高空大气条件下边界层自然转捩和超声速混合层的转捩特性,介绍了高超声速静风洞、超-超混合层风洞的设计技术以及层流化喷管的设计方法。 相似文献