基于故障树模型的航天器故障诊断研究

本文建立了基于故障树模型的航天器故障诊断框架，提出了航天器故障诊断的知识组织和表示方法及相应的推理控制策略，并通过对某卫星能源系统故障实验台的故障诊断验证了方法的正确性。     

机械密封的发展

本文介绍了机械密封的发展简史和近年来国外机械密封的发展动态。     

固体火箭发动机结构质量的优化设计

讨论了使星形装药固体火箭发动机的结构质量最轻和装填密度最大的优化方法，即在总冲和工作时间给定条件下，在外径一定时使发动机的质量尽可能降低，以提高整个火箭武器的质量比。     

A Study on Particle Filters for Single-Tone Frequency Tracking

In this paper, we present an online approach for frequency tracking of a noisy sinusoid using sequential Monte Carlo (SMC) methods, also known as particle filters (PFs). In addition, apart from employing the classical Cartesian formulation model, we also develop two alternative dynamical models, namely, nearly constant frequency (NCF) and Singer, which are adapted from the maneuvering target tracking discipline, to describe the evolution of time-varying frequencies, and investigate their fitness to the frequency tracking application. When compared with conventional techniques whose performance is restricted to linear Gaussian models and/or to slowly varying frequencies, PFs are more flexible to handle situations where these conditions are violated. Extensive evaluations on the proposed new models and PF tracking algorithms are conducted with different sets of frequency inputs and levels of signal-to-noise ratio (SNR). According to the computer simulation results, it is found that PFs under all investigated models consistently outperform and are less sensitive to SNR levels than the extended Kalman filter (EKF). Furthermore, the results suggest that while none of the models perfectly fits all types of frequency inputs, NCF model is more suitable for moderately varying frequencies, whereas the Singer is more suitable for rapidly changing frequencies.     

多孔材料在整流罩内中高频降噪的应用与优化研究

基于JCA模型，采用有限元仿真和声学试验获取了三聚氰胺泡沫和吸音棉的声学参数，采用统计能量分析（SEA）方法建立了某卫星-整流罩的系统级模型。通过与混响室试验结果进行对比，验证了模型的正确性；并通过仿真和试验获取了两种材料对整流罩内噪声环境的降噪效果，分析了厚度、敷设率和敷设位置对降噪效果的影响。结果表明，采用结合Biot理论的SEA方法能有效预测整流罩内中高频噪声环境及多孔材料降噪效果；总降噪量与厚度、敷设率和敷设位置关系紧密，采用多孔材料降噪时应综合考虑以上因素。     

推挂机驱动齿轮断裂浅析

对包果推挂机驱动具轮在运行过程中发生的齿根处破坏进行了宏观、微观和显微组织等方面的分析，并在原零件相应部位进行了口模拟验证试验，从而确定了零件断裂的原因。     

高热流密度燃烧室壁面阵列空气射流-燃油组合冷却结构研究

针对高热流密度燃烧室壁面热防护需求，提出了一种空气阵列射流冲击和燃油冷却肋板的集成冷却方式，在射流平均雷诺数Re_j为1×10⁴~3×10⁴，燃油进口流速v_f为2.33～5.23m/s内，采用数值模拟方法对其传热特性进行了研究，并基于壁面加热侧当量对流换热系数的概念，分析了基准肋板以及燃油冷却肋板的传热增强作用。与无肋板靶面的阵列射流冲击相比，带肋板阵列射流冲击的面积平均当量对流换热系数是前者的1.6倍，压力损失系数相对提高了约25%；采用燃油冷却肋板，加热壁面综合传热能力进一步增强，在Re_j=1×10⁴时，采用燃油冷却肋板的面积平均当量对流换热系数是基准肋板的1.5倍以上，即使在Re_j=3×10⁴时，燃油冷却肋板的传热增强比也可以达到1.2；燃油冷却肋板的出口温度相对进口温度的提升在20~50K内，其提升幅度随着射流雷诺数或燃油进口流速的增大而减小。     

面向集团企业的云制造服务平台

为推动"制造即服务"理念的发展,提出了面向集团企业的云制造服务模式,并以航天集团为例分析了集团企业制造资源的供需情况,提出了以集团为单位的"私有云"构建体系以及面向集团企业的云制造服务系统的实施方案,并对构建过程中的关键技术问题进行了讨论。最后对集团企业实施云制造的思路提出了建议。     

Optimal Delayed Control of Nonlinear Vibration Resonances of Single Degree of Freedom System

The primary resonance of a single-degree-of-freedom （SDOF） system subjected to a harmonic excitation is mitigated by the method of optimal time-delay feedback control. The stable regions of the time delays and feed- back gains are obtained from the stable conditions of eigenvalue equation. Attenuation ratio is applied for evaluating the performance of the vibration control by taking a proportion of peak amplitude of primary resonance for the sus- pension system with or without controllers. Taking the attenuation ratio as the objective function and the stable regions of the time delays and feedback gains as constrains, the optimal feedback gains are determined by using minimum optimal method. Finally, simulation examples are also presented.     

一种用于空间系绳卷取的自适应机构

针对空间绳网系统的缆绳收口要求,介绍了一种由双转子电机、双卷筒和自由导绳套筒组成的自适应缆绳卷取机构,给出了机构的设计思路。通过建立其系统动力学方程,据此得到系统各状态变量的稳态解,理论和实验分析缆绳卷取过程的特性,证实此卷取机构的有效性和一定的适应性,为类似空间绳系的卷取机构设计提供参考。