复合材料角型材结构固化变形研究

本文提出了一种分析模型和计算公式，用于预测Ｌ型碳／环氧复合材料构件的固化变形。用直角型材模具制备的试件在室温下呈锐角，当重新加热至固化温度时，构件的角度不能合回复到直角状态。作者认为：复合材料角型材结构的经变形不仅与复合材料的热膨胀行为有关，还与树脂基体固化时的一积收缩效应有关。     

玻璃纤维增强酚醛基复合材料平均线胀系数测试影响因素

研究了保温时间、升温速率、预处理温度等对玻璃纤维增强酚醛基复合材料线胀系数测试的影响。结果表明,玻璃纤维增强酚醛基复合材料在加热条件下进一步固化,造成样品收缩与样品受热膨胀相抵消,升温曲线出现平台。因此,测试前应对样品进行预处理,处理温度高于试样最终的测试温度,低于样品固化温度,以免材料内部结构发生变化;设置合适的升温速率,升温速率低,增加了时间成本,升温速率太高,测温热电偶引入的误差增加,且不均匀的加热使试样产生热应力,影响试验结果。     

多频能量分散的CFRP层合板微波固化温度场控制方法

碳纤维增强树脂基复合材料（Carbon fiber reinforced polymer,CFRP）轻质高强,已成为航空航天领域减重增效的优选材料。固化是制造兼具几何外形与承载性能的CFRP构件的关键。与传统的传导加热固化/修补方法相比,微波加热固化/修补方法具有控温灵敏、周期短、能耗低等优势。然而微波会在腔体内谐振形成驻波,使得CFRP层合板面内存在大量冷、热点,温度不均匀,构件易变形,严重时甚至发生局部烧蚀或固化不完全。本研究提出了多频能量分散的CFRP层合板微波固化温度场控制方法,通过将加热所需能量分散到多种频率的微波以弱化单一频率驻波的影响,同时利用多种频率驻波间的叠加效应,提升CFRP层合板微波固化过程中的温度均匀性。试验结果表明,在仅采用915 MHz和2.45 GHz两种频率微波进行加热的情况下,CFRP层合板的最大温差相比单频微波加热降低了26%。     

分区自加热复合材料模具设计与应用

直接使用复合材料制成的模具可大幅度减少模具–构件热膨胀系数不匹配导致的构件固化变形。复合材料模具自加热技术是实现构件高质、高效固化的重要发展方向,然而现有模具自加热方法难以避免地引入大量加热元件和线缆,在反复热循环后易导致模具结构失效,寿命缩短。针对上述问题,提出了一种基于电各向异性层合结构的复合材料模具分区自加热技术,通过向碳纤维层合板层间插入电导率调制层形成单向导电的碳纤维层合结构,直接对其局部通电形成若干可独立控温的条带状加热区域,最终在不引入任何加热元件、线缆的前提下,实现模具温度场的分区控制。相较传统自加热模具,分区自加热复合材料模具面内温度均匀性提高了92.1%,固化C型构件的回弹变形量减小了27.0%。分区自加热复合材料模具在满足与构件的热膨胀系数匹配的同时,实现了温度场的分区控制,为构件的高质高效固化提供了新思路。     

固化工艺参数对聚酰亚胺复合材料性能影响

采用热压罐成型工艺制备了MT300/902聚酰亚胺复合材料,测试了加压温度、加压大小和固化温度下复合材料的力学性能,分析了不同固化工艺参数对复合材料力学性能的影响规律。结果表明:MT300/902聚酰亚胺复合材料固化时的最佳加压时机为240～260℃、加压不小于1.2 MPa、固化温度在310～330℃为最佳。按照最优的成型工艺参数制备的复合材料构件质量高,缺陷能够控制在2%以下,力学性能进一步提高。     

飞机复合材料修理中固化技术的探讨

对飞机复合材料固化工艺中热固化、微波固化、电子束固化、紫外光固化等技术的机理和研究现状进行了分析对比。     

碳纤维/环氧树脂复合材料微波固化试验

采用微波固化技术,对碳纤维/环氧树脂复合材料NOL环试样进行固化试验研究。通过开展力学性能测试、电镜扫描及CT扫描,对比分析了热固化与微波固化试样宏观力学性能及微细观形态。结果表明:微波固化与热固化的固化机理不同,微波固化提高了固化反应速率,固化周期缩短了57%;微波固化试样的拉伸强度和层间剪切强度与热固化试样基本相当,但微波固化试样力学性能离散系数更小,碳纤维表面有更多的树脂基体粘附,这是由于微波固化的选择性加热造成的;微波固化试样孔隙率为0.78%～1.05%,稍低于热固化试样。     

光纤布拉格光栅监测碳纤维复合材料固化成型过程

碳纤维复合材料固化成型时,温度和内应力对成型质量的影响巨大.鉴于碳纤维复合材料厚度通常为几毫米,传统的热电偶和电阻应变片等温度应变传感器由于体积较大,无法实现嵌入式监测.为了获得成型过程中材料内部实时的温度和应变,采用光纤布拉格光栅(Fiber Bragg Grating,FBG)传感器进行监测.试验中使用两个FBG传感器,一个作为温度传感器,另一个作为应变传感器,内嵌于碳纤维预浸料铺层之中,分别用于监测碳纤维复合材料固化过程中内部的温度和应变等参量.试验结果表明,采用两个光纤光栅传感器分别用来监测碳纤维复合材料固化过程中内部温度和应变的变化是可行的.     

预固化对复合材料层压板弯曲性能的影响分析

研究经预固化后的复合材料层压板的弯曲性能对复合材料结构的设计和修理技术是非常重要的。对于各种固化温度和时间对弯曲性能的影响分析，使得设计师优化这些参数，以得到阶段固化件的最优弯曲性能，对制件的最终性能进行控制。     

复合材料卫星整流罩端头成型工艺研究

本文介绍了一种复合材料卫星整流罩端头的浸胶，铺层，固化工艺。研究表明，大尺寸，变厚度复合材料端头采用阴模铺层和热压罐化工艺，成型后的产品外表面平整，光滑，无皱折，不仅满足了气动加热表面的质量要求，力不性能也满足了要求。     

有翼高超声速再入飞行器气动设计难点问题

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。     

Simulation and Analysis of Crashworthiness of Fuel Tank for Helicopters

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.     

突破技术趋同，波音再现竞争优势

 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）。     

The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow

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.      

临近空间飞行器测控与信息传输系统频段选择

 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。     

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。     

Experimental Study on Effects of Fuel Injection on Scramjet Combustor Performance

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.     

(高)超声速流动试验技术及研究进展

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。     

Research on Auto-detection for Remainder Particles of Aerospace Relay Based on Wavelet Analysis

Aerospace relay is one kind of electronic components which is used widely in national defense system and aerospace system. The existence of remainder particles induces the reliability declining, which has become a severe problem in the development of aerospace relay. Traditional particle impact noise detection (PIND) method for remainder detection is ineffective for small particles, due to its low precision and involvement of subjective factors. An auto-detection method for PIND output signals is proposed in this paper, which is based on direct wavelet de-noising (DWD), cross-correlation analysis (CCA) and homo-filtering (HF), the method enhances the affectiv-ity of PIND test about the small particles. In the end, some practical PIND output signals are analysed, and the validity of this new method is proved.