面向火箭构型论证的运载能力快速分析方法

针对不同构型与任务条件下的运载能力快速计算问题,提出了基于高斯函数和组合神经网络的速度损失计算方法,并基于此对运载能力进行了快速分析。首先,基于状态量解析解计算分析,采用高斯函数对核心的重力速度损失项进行拟合计算;同时,为提高多构型与多任务样本的采样密度、简化数据建模过程并增强方法适应性,采用径向基网络(RBF)与深度神经网络(DNN)的组合形式进行状态量的提取与回归分析;然后将任务约束转化为需要速度增量,通过数值迭代得到运载能力。仿真结果表明,此运载能力分析方法精度偏差约为0.35%,计算耗时小于2 s,可为运载火箭总体参数快速论证与任务规划研究提供理论支撑。     

频率选择表面(FSS)柔性屏铺覆工艺对透波窗口透波性能的影响

为了研究工程中柔性FSS屏铺覆工艺对透波窗口通带插损的影响,设计并制备了几种不同工艺缺陷的平板,采用自由空间传输反射法研究了平板在不同入射角下的通带损耗.结果 表明:拼接缝隙使通带损耗在0°和60°入射角下增加了0.3dB;拼接褶皱使通带损耗在0°入射角下增加了0.77 dB,在60°入射角下增加了1.55 dB;多层...     

电子控制器PCB板电磁兼容性仿真与试验研究

随着航空发动机全权限数字控制系统的发展,电子控制器中PCB板电磁兼容性设计的重要性日益凸显.本文以某控制器PCB板为对象,在10MHz至1GHz频率范围内,对其电磁干扰使用Ansys公司的SIwave进行近场远场仿真研究,并使用容向公司EMSCAN电磁干扰扫描仅进行测试.通过测试与仿真结果的对比,验证了仿真的准确性.本文提出了一种基于仿真预测PCB板电磁干扰的实现途径,对于电子控制器PCB板的电磁兼容性设计具有参考价值.     

燃烧催化剂苯甲酸铜及其衍生物热分解研究Ⅰ──苯甲酸铜及其氨基衍生物的热分解机理

用TG和DSC方法研究了苯甲酸铜及其三种氨基衍生物的热分解历程，结果表明：它们分解反应能生成一种或两种较稳定的二聚体中间产物──双核铜络合物，脱羧和重排过程是分解的主要步骤，也是分解速率最快的过程。整个分解过程是吸热的，取代基及其在苯环上的位置都对分解历程有影响。此外，还测定了邻、间氨基苯甲酸铜的快速分解阶段的动力学参数。     

钛合金表面等离子喷涂ZrO2—NiCoCrAlY梯度涂层的抗热震行为

ＺｒＯ２－ＮｉＣｏＣｒＡｌＹ梯度涂层的成分沿厚度方向呈连续梯度化分布，提高了涂层与基体的粘结强度和涂层的内聚强度，其抗热震性能优于双层涂层。在较大热冲击应力作用下，梯度涂层整体自基体表面剥落而失效；在较小热冲击应力作用下，由于ＮｉＣｏＣｒＡｌＹ底层与ＴＣ４合金基体发生了热相互作用，改善了涂层与基体的结合状况，梯度涂层纵向断裂并部分自基体表面剥落而失效。     

SiCf+p/LY12复合材料口盖板的制备与结构刚度

介绍了利用净成型液相压渗工艺的制备的ＳｉＣ纤维与ＳｉＣ颗粒混杂增强铝合金复合材料仪器舱口盖板。利用自行设计的热外压装置，考察了口盖板在室温和４００℃一外压时的刚度变化情况。结果表明ＳｉＣｆ＋ｐ／ＬＹ１２复合材料口盖板的室温结构刚度比ＬＹ１２铝合金口板提高约５０％，４００℃下复合材料口盖板的结构刚度比ＬＹ１２铝合金口盖板提高约８０％。     

无人机动力装置的现状与发展

分析了多种无人机动力装置的应用情况;根据无人机动力的发展趋势和需要,提出了发展无人机动力装置的一些看法。     

基于前缘缝翼微型后缘装置的多段翼型被动流动控制

以麦道航空公司的三段增升构型为研究模型,采用剪切应力输运(SST)k-ω湍流模型在C-H型多块结构网格上求解二维非定常雷诺平均Navier-Stokes方程,研究了前缘缝翼微型后缘装置(MTED)在多段翼型被动流动控制中的应用。由于MTED改变了实际的缝翼缝道参数,因此首先研究了作为主要改变量的缝道宽度对该三段翼型气动性能的影响,当缝道宽度从参考构型的2.95%c增加至3.98%c时,最大总升力系数约减小4.61%。当在不同缝道宽度基本构型上增加相同MTED时,计算结果表明它对各个翼段的影响定性一致,即前缘缝翼升力增加、主翼升力减小以及后缘襟翼升力基本不变化。这些升力变化的综合作用是:MTED构型线性段总升力系数的变化不大,失速段的变化取决于缝道宽度,当缝道宽度为3.98%c时,高度为0.50%c的MTED构型的最大总升力系数约增加6.98%。     

Change rules of a stratospheric airship's envelope shape during ascent process

Stratospheric airship is a special near-space air vehicle, and has more advantages than other air vehicles, such as long endurance, strong survival ability, excellent resolution, low cost, and so on, which make it an ideal stratospheric platform. It is of great significance to choose a rea-sonable and effective way to launch a stratospheric airship to the space for both academic research and engineering applications. In this paper, the non-forming launch way is studied and the method of differential pressure gradient is used to study the change rules of the airship's envelope shape dur-ing the ascent process. Numerical simulation results show that the head of the envelope will main-tain the inflatable shape and the envelope under the zero-pressure level will be compressed into a wide range of wrinkles during the ascent process. The airship's envelope will expand with the ascent of the airship and the position of the zero-pressure level will move downward constantly. At the same time, the envelope will gradually form a certain degree of stiffness under the action of the inner and external differential pressure. The experimental results agree well with the analytical results, which shows that the non-forming launch way is effective and reliable, and the analytical method has exactness and feasibility.     

All-Electric Aircraft Nose Wheel Steering System with Two Worm Gears

As all-electric aircraft has many advantages,an aircraft nose wheel steering system would be developed to the all-electric direction.Concerning the control demand of the nose wheel steering system,based on the basic principles of nose wheel steering system and the design technique of mechanotronics,an all-electric aircraft nose wheel steering system,composed of a nose wheel steering mechanism of two worm gear and a control servo system of fly-by-wire with both steering and anti-shimmy functions is designed to meet the demand for operation control in the nose wheel steering system.Then,based on the LMS-AMESim software,the simulation model of the system is established to simulate the dynamics for the verification of its steering function.The simulation results indicate that the nose wheel steering system is reasonable,and can meet the requirements of the general project.Furthermore,the prototypes of the steering mechanism and control system are studied to validate the design,and the steering test bench is prepared to test the designed system.The test results,such as steer angle,rotate speed of motor are analyzed in details and compared with the theoretical results.The analysis and comparison results show that the design is reasonable and the property of the prototype can achieve the design objectives.