辐射器展开角度对航天器热控能力影响的研究

为了在有限的结构尺寸下提高航天器热控系统的散热能力,提出与流体回路耦合的可展开式辐射器热控方案,建立可展开式辐射器空间散热模型,分析辐射器不同展开角度下系统的热控特性。结果表明,随着辐射器展开角度的变化,辐射器吸收的空间热流也随之发生变化,并最终决定热控回路的流量分配。在工程应用中,基于热控流体回路,通过调节可展开式辐射器的展开角度,可以有效提高航天器热控系统的能力范围。     

基于改进的蚁群算法的亚轨道再入飞行器弹道优化

基于阻力与能量再入导引律,用改进的蚁群算法优化SLV再入阻力-能量关系剖面,其优化的性能指标为总吸热量最小,并采用LQR法跟踪参考弹道.仿真结果表明,优化方法简便易行,跟踪器性能良好.     

直升机主桨毂支臂疲劳验证技术研究

主桨毂支臂是直升机复杂关键件承受复杂疲劳载荷的代表之一,疲劳破坏是主要的失效模式。回顾了主桨毂支臂疲劳验证的发展历程,研究了球柔性主桨毂支臂疲劳验证的试验方案设计、正确性检验设计和寿命评定。对球柔性主桨毂支臂进行载荷力系研究、疲劳载荷谱分析研究、低周疲劳试验载荷设计和高周疲劳试验载荷设计,形成低周、高周全尺寸疲劳试验相结合且动态调整的疲劳验证方案,有效验证支臂各疲劳危险部位。     

热等静压温度对K447A高温合金显微组织及性能的影响

研究了热等静压温度对K447A合金显微组织及性能的影响。测试了合金的持久性能和室温拉伸性能。利用金相显微镜(OM)和扫描电镜(SUM)观察了合金显微组织。结果表明,1185～1210℃/180MPa/4h(+1185℃/2h,AC+1100℃/4h,AC+870℃/20h,AC)下,随热等静压温度的提高,合金中显微疏松逐步闭合,碳化物逐步细化和球化;γ-γ’共晶相尺寸和数量逐步减小,共晶特征趋于不明显;晶界呈不连续颗粒状;存在大、小两种尺寸的γ’相。经1185～1210℃HIP处理的合金980℃/200MPa持久性能大幅提高;经1195℃HIP的合金760℃/724MPa持久性能达到最高。经1210℃HIP处理的合金980℃/200MPa持久性能达到最高。180MPa/4h条件下,K447A合金合适的热等静压温度为1185～1210℃。     

一种中频雷达模拟器的设计

设计出了一种中频雷达模拟器的硬件,阐述了该模拟器总体组成和工作过程,以及各部分的组成和工作原理。该模拟器可以产生单脉冲体制下的一组固定目标的和、差模拟中频回波信号和动目标和、差模拟中频回波信号;可以在联机或独立2种工作状态下,产生常规脉冲、线性调频脉冲等多种雷达中频回波。该模拟器适用于相控阵雷达等多种新体制跟踪雷达的调试和训练。     

极轴式望远镜系统误差修正方法研究

为提高极轴式望远镜的测量精度,借鉴地平式望远镜的系统误差修正方法,推导了基于轴系和球谐函数的极轴式望远镜系统误差修正模型,在分析2种误差修正模型误差项不足的基础上,探索性地提出了一种新的误差修正模型——改进球谐函数系统误差修正模型。对实际测星数据进行误差修正的结果表明,进行改进球谐函数系统误差修正后,精度在时角和赤纬方向上比其他方法提高了50%。     

Study on the Behavior of Solar Array Deployment with Root Hinge Drive Assembly

In this paper, a method of using a root hinge drive assembly (RHDA) to control the solar array deployment is provided and a multi-DOF mechanism dynamic model of the system is established. In this way, the root hinge torque can be calculated iteratively. Then taking the predicted torque as a reference, a RHDA is designed for a large multiple-stage packaging and deployable solar array system. The control effect of the drive assembly is validated by ground tests. The test results indicate that the solar arrays can be deployed smoothly, and the deployment velocities are restricted by the drive assembly as expected. During the tests, the RHDA output speed and output torque are obtained. In order to examine the impact force when the yoke is lock-up with a hard stop, dynamics simulations are performed according to the actual behavior. The simulation result indicates that the designed RHDA reduces the impact force significantly and improves the lock-up reliability effectively.     

Study on Titanium Alloy TC4 Ballistic Penetration Resistance Part I:Ballistic Impact Tests

Ballistic impact test of different-scale casings is an efficient way to demonstrate the casing containment capability at the preliminary design stage of the engine. For the sake of studying the titanium alloy TC4 casing performance, the ballistic tests of flat and curved simulation casing are implemented by using two flat blades of different sizes as the projectile. The impact mechanism and failure of the target are discussed. Impact of the projectile is a highly nonlinear transient process with the large deformation of the target. On the impact, failures of the flat casing and the subscale casing are similar, concluding two parts, the global dishing and localized ductile tearing. The main localized failure mode combines plugging (shear) and petaling (shear) if the projectile perforates or penetrates, while crater (shear) if the projectile rebounds. The ballistic limit equation is verified by the test data and the results show that this empirical equation could be a practical way to estimate the critical velocity.     

等离子体激励用于两段翼型增升的试验研究

在NACA23018两段翼型上安装等离子体激励器,通过风洞测力和丝线流态试验,研究了等离子体对翼型最大升力和失速迎角的影响。研究表明,等离子体激励可以显著地增加NACA23018两段翼型的最大升力系数和失速迎角,来流风速20m/s时,最大升力系数增加52%,失速迎角增加12.4°。等离子体激励和前缘缝翼的作用类似,并且可以和后缘增升装置配合使用,在运输类飞机设计中有潜在的应用前景。     

碳硼烷/ POSS 的制备及性能

碳硼烷是一类优异的耐高温原料,POSS是一类性能优异的耐原子氧化合物.本文利用硅氢加成的方法,将两者有机结合,合成了体型交联型和线型两种碳硼烷/POSS复合材料,并对它们的耐温性能进行了热重分析.这类材料具有优异的耐高温性能,其中体型交联型碳硼烷/POSS复合物在1 200℃空气氛围下不失重,到1 400℃有约5％的增重.线性碳硼烷/POSS复合材料在1 000℃空气氛围下失重约为10％.该类材料有望应用于高速飞行器的涂层.