基于部件跟踪滤波器的解析余度技术

研究一种以发动机部件跟踪滤波器(CTF)为基础的解析余度技术, 它将CTF与故障检测、隔离和适应逻辑进行了有效的综合, 以改进发动机数控系统的可靠性。仿真表明, 本文所设计的解析余度技术, 在传感器无故障时, 机载模型能正确跟踪发动机的变化。当传感器发生故障时, 在不损坏机载模型的情况下, 又能及时、有效地进行硬、软故障的检测、隔离与适应。      

搅拌对熔铸—原位反应TiB2／Al和TiC／Al复合材料微观组织的影响

研究、开发了一种熔铸－ 原位反应颗粒增强铝基复合材料制备技术,探讨了搅拌工艺对３ｖｏｌ％ ＴｉＢ２ 和３ｖｏｌ％ ＴｉＣ颗粒增强铝基复合材料微观组织的影响。结果表明,采用圆盘状叶片的搅拌装置对获得颗粒均匀分布、组织致密的铝基复合材料十分有利。     

重合网格法在复合材料分层问题中的应用

使用重合网格法(S-FEM)分析了混合模态下CFRP层合板分层问题。首先将虚裂纹闭合技术集成到S-FEM程序中,求解了复合材料分层尖端处的应变能释放率。然后把重合网格法数值结果与基于梁理论的计算结果及实验数据进行了比较。结果表明,对于单方向及多方向CFRP复合材料层合板,重合网格法都能够得到更精确的数值,是一种有效的计算复合材料裂纹尖端应变能释放率的方法。     

Vortex structures downstream a lobed nozzle/mixer

An experimental study was conducted to investigate the evolutions of unsteady vortex structures downstream a lobed mixer/nozzle.Anovel dual-plane stereoscopic PIVsystem was used to measure all 3-components of vorticity distributions to revealed both the large-scale streamwise vortices produced by the lobed mixer/nozzle and the Kelvin-Helmholtz vortex structures generated due to the Kelvin-Helmholtz instabilities simultaneously and quantitatively for the first time.The instantaneous and the ensemble-averaged vorticity distributions displayed quite different aspects about the evolutions of the unsteady vortex structures.While the ensemble-averaged vorticity distributions indicated the overall effect of the special geometry of the lobed nozzle/mixer on the enhanced mixing process,the instantaneous vorticity distributions elucidated many details about how the enhanced mixing process was conducted.In addition to quantitatively confirming conjectures of previous studies,further insight about the formation,evolution and interaction characteristics of the unsteady vortex structures downstream of the lobed mixer/nozzle were also uncovered quantitatively in the present study.      

An in situ laser induced breakdown spectroscope (LIBS) for Chandrayaan-2 rover: Ablation kinetics and emissivity estimations

A miniaturized in situ laser induced breakdown spectroscope-LIBS is one of the two lunar rover payloads to be flown in India’s next lunar mission Chandrayaan-2, with an objective to carry-out a precise qualitative and quantitative elemental analyses of lunar regolith at the proximity of the landing region. As per the imposed mission constraints and the executed design optimization studies, a compact and light-weight LIBS prototype model is developed at our premises. This paper mainly concerns with the estimation of theoretical aspects; especially on evaluation of elemental ablation parameters and signal-to-noise ratio (SNR) calculations for the designed instrument. Theoretical estimations and simulations yielded an incident laser power density of the order of 5 × 10¹⁰ W/cm² on the target surface at a defined lens-to-surface distance (LTSD) of 200 mm and revealed an SNR > 100 for most of the elements under consideration. This paper also addresses the impact of LTSD variation on detection capability. The estimation of plasma-temperatures was carried out utilizing the emission spectra obtained under high vacuum environments employing the LIBS laboratory model. Experimental investigations and the performed theoretical estimations asserted the successful operation of the configured LIBS instrument for in situ elemental analyses on lunar surface.     

压敏涂料技术在风洞中的应用研究

压敏涂料技术是重要的风洞模型表面压力测量技术之一。作者介绍了压敏涂料的研制及该技术应用于风洞试验时的自动化试验图像采集技术、试验数据处理与修正技术及实际应用中的一些经验,给出了在飞机机翼、边条、前缘襟翼、副翼表面,压敏涂料技术与常规测压孔技术测量结果的比较。     

机翼－机身－吊架－短舱的跨声速流计算

本文通过使用多块网格的嵌合体技术，计算了机翼－机身－吊架－短舱的跨声速流场。将机翼－机身－吊架－短舱流场分为机翼－机身和吊架－短舱两个子区域，根据嵌套网格结构建立机翼－机身－吊架－短舱的组合网格，分别对这两个子区域根据相应的边界条件独立求解，然后采用嵌合体技术传递两个子区域的干扰信息，通过两个流场的耦合迭代得到机翼－机身－吊架－短舱流场的计算结果，数值模拟结果与实验结果进行了比较，两者吻合较好。     

弹性飞行器对大气紊流的动力响应计算

本文采用功率谱密度技术,分别从频域模型和时域状态空间模型给出了弹性飞行器对大气紊流动力响应计算方法,并通过实例计算,说明大气紊流对弹性飞行器的影响.     

分布式航空电子软件测试系统

为了支持研制和开发高性能的分布式航空电子软件系统,软件测试系统是必备的工具之一。本文介绍了一个分布式航空电子软件测试系统。该系统采用数字仿真技术提供数据环境,由监控处理机完成测试结果的自动记录、保存和分析工作。整个系统采用标准化设计法,具有良好的可维修性和可扩充性。此外,简单有效的辅助手段,为用户提供了一个良好的应用环境。     

跨声速伽辽金有限元法所用上风技术的改进

伽辽金有限元法是解跨声速绕流的有效方法,对超临界流动,为了自动捕捉到激波,通常采用了上风技术,但导致了气流通过激波时质量守恒条件得不到满足。本文通过Bateman变分原理和加罚泛函找到了强制满足质量守恒约束条件的附加项,大大改善了用伽辽金有限元法解超临界绕流的计算结果。