K型热电偶冷端补偿研究

针对在热试验过程中应用K型热电偶出现温度测量异常的情况进行研究分析,确认测量异常的原因是冷端补偿出现问题。从温度测量的原理入手进行分析,通过理论与试验相结合的方式阐述了冷端补偿的重要性。     

A new model for atmospheric radiation under clear sky condition at various altitudes

Atmospheric radiation is one of the major factors that dominate the thermal behaviors of aerostats. A high-performance model is needed to evaluate the atmospheric radiation. Based on the atmospheric radiation database containing 24,862 data points compiled from 7 stations with the elevation from sea level to 2373 m and the reference code MODTRAN, a new atmospheric radiation model is proposed using regression and optimization software. It has excellent prediction accuracy with the coefficient of determination of 0.94, the root mean square error of 15.1 W/m², and the mean absolute percentage error of 4.13% for the database. Comparison with the well-known existing model shows that the new model has the highest prediction accuracy. The new model predictions agree with the MODTRAN calculations at various altitudes very well, and thus it can be used for estimating the thermal performances of a high altitude aerostat.     

HIGH CYCLE FATIGUE RELIABILITY ANALYSIS ON ROTOR HUB BASED ON APPROXIMATION TECHNIQUE

A high cycle fatigue reliability analysis approach to helicopter rotor hub is proposed under working load spectrum. Automatic calculation for the approach is implemented through writing the calculating programs. In the system, the modification of geometric model of rotor hub is controlled by several parameters, and finite element method and S-N curve method are then employed to solve the fatigue life by automatically assigned parameters. A database between assigned parameters and fatigue life is obtained via Latin Hypercube Sampling （LHS） on toler- ance zone of rotor hub. Different data-fitting technologies are used and compared to determine a highest-precision approximation for this database. The parameters are assumed to he independent of each other and follow normal distributions. Fatigue reliability is then computed by the Monte Carlo （MC） method and the mean-value first order second moment （MFOSM） method. Results show that the approach has high efficiency and precision, and is suit- able for engineering application.     

模拟月尘对巡视器车轮轮轴材料的磨损试验研究

文章以CE-3巡视器车轮轮轴为研究对象,利用北京卫星环境工程研究所的月尘环境模拟器、摩擦磨损试验机以及自行研制的模拟月尘,对车轮轮轴主要材料进行了磨损试验研究。试验样品为轮轴常用的铝合金、聚四氟乙烯及轴承钢。文章分析了试验前后样品的表面形貌,采用测试系统获得了轮轴材料在不同试验条件下的摩擦系数曲线,采用电子天平测量了材料的质量损失;分析了真空、大气、有无月尘等试验条件以及材料本身在磨损试验中的效应。研究结果可为月面巡视器等月面应用设备的研制提供可借鉴的信息。     

强5某型飞机副油箱掉落事故征候原因探析

对强5某型飞机发生的一起副油箱掉落事故征候进行了调查研究,通过大量的机上检查试验,以及对副油箱投放原理线路的分析研究,确定了事故征候原因,提出了防止此类事故征候发生的措施,并在该机上得到了落实,使飞机恢复了飞行。     

纤维预制体(织物)中反应性流体的流动行为

文摘反应性流体在纤维预制体(织物)中的流动行为对于优化工艺参数和模具设计、控制制品质量等具有重要意义。本文简述了RTM工艺的流体流动特点,介绍了RTM工艺过程中流体流动研究的理论基础,综述了RTM工艺中反应性流体流动的发展现状,并展望了其发展趋势。