航天用复合材料结构高温极限承载能力试验方法

针对航天飞行器飞行特点,本文给出两种基于破坏时间的承载能力试验方法,可以获得结构在不同飞行温度和时间下的承载能力。能够充分发挥材料在传热过程中的高温承载能力,降低结构防热质量。     

模拟月壤钻进负载分析与试验研究

月壤与采样机具间的相互作用在月球自主采样器的设计、性能评价、控制和仿真等方面具有重要作用,目前对于月壤与采样机具间相互作用中的钻进负载研究尚不充分。本文基于被动土压力理论,根据不同的土体切削状态,将切削刃前土体分为堆积区和破坏区,重点分析堆积区土体和破坏区土体对总钻头负载的贡献,建立了月壤取心钻头钻进松散土体的钻进负载模型。HIT 2型取心钻头和HIT\|LS1#模拟月壤的钻进试验结果表明,钻进负载理论模型与实际情况具有较高的吻合度。     

Broglio Drag Balance for neutral thermosphere density measurement on UNICubeSAT

The nanosatellite UNICubeSAT is described, carrying a Broglio Drag Balance Instrument for neutral thermosphere density in situ measurements. The aim of the mission is to contribute to the development of accurate thermosphere models, achieving in situ, real time measurements of atmosphere density, that could be exploited for global atmosphere model validation and accurate short term (1–3 days) real time space weather forecasts. The satellite is inexpensive and swarms could be easily launched operating as a distributed sensor network to get simultaneous in situ local (not orbit averaged) measurements in multiple positions and orbit heights. The nanosatellite is based on the Cubesat standard architecture, weighing about 1 kg for 1-L volume. Atmospheric drag force is measured by the displacement of light plates exposed to the incoming particle flux seen by the spacecraft, applying the original three dimensional Broglio Drag Balance concept to a single nanosatellite axis. The instrument concept and its relation to the satellite bus is depicted, showing that many long term potential measurement error sources and biases can be removed in data processing if the spacecraft is spin stabilized. The expected accuracy in density measurements is 20%. The instrument cost is a fraction of that of accurate accelerometers. The onboard systems are based on commercial off the shelf components, in accordance with the short lifetime typical of aeronomy satellites.     

基于变频供电系统试验的模拟负载及控制的设计与研究

在民用飞机变频供电系统的设计和适航符合性验证试验中,负载特性的模拟是一项关键技术,为适应变频供电系统负载特性的综合测试和验证对负载模拟的符合性需求,论述了一种适应变频供电环境下的变频模拟负载作为模拟飞机115/200V、(360～800Hz)三相四线制变频供电系统负载的综合电气特性,并为之设计智能控制系统。通过在线优化阻抗参数,提高负载的闭环特性和自适应能力,确保变频供电系统负载电气特性参数测试的准确性。     

固体火箭发动机试验测量系统零位变化研究

介绍了测试系统推力测量中常见的零位变化现象,对零位变化的原理进行了分析,并提出了针对性的数据处理方法。     

On the Flux of Water and Minor Volatiles from the Surface of Comet Nuclei

Surface temperature and the available effective energy strongly influence the mass flux of H₂O and minor volatiles from the nucleus. We perform computer simulations to model the gas flux from volatile, icy components in porous ice-dust surfaces, in order to better understand results from observations of comets. Our model assumes a porous body containing dust, one major ice component (H₂O) and up to eight minor components of higher volatility (e.g. CO, CH₄, CH₃OH, HCN, C₂H₂, H₂S), The body's porous structure is modeled as a bundle of tubes with a given tortuosity and an initially constant pore diameter. Heat is conducted by the matrix and carried by the vapors. The model includes radially inward and outward flowing vapor within the body, escape of outward flowing gas from the body, complete depletion of less volatile ices in outer layers, and recondensation of vapor in deeper, cooler layers. From the calculations we obtain temperature profiles and changes in relative chemical abundances, porosity and pore size distribution as a function of depth, and the gas flux into the interior and into the atmosphere for each of the volatiles at various positions of the body in its orbit. In this paper we relate the observed relative molecular abundances in the coma of Comet C/1995 O1 (Hale-Bopp) and of Comet 46P/Wirtanen to molecular fluxes at the surface calculated from our model. This revised version was published online in June 2006 with corrections to the Cover Date.     

谐波阻抗调配器校准技术研究

作为负载牵引测量系统中的重要器件,谐波阻抗调配器的应用越来越广泛,但是目前国内有关该类仪器的校准工作尚无报道。本文以谐波阻抗调配器的工作原理为基础,设计了校准方法,并重点分析了矢量重复性的三种定义,提出了最佳校准方法。通过与出厂测试数据对比,验证了校准方法的可行性。     

环境压强对行波超声马达驱动特性的影响

在环境压强从常态到高真空的循环条件下,测试了45盘形行波型超声马达的转速、转矩 随环境压强的变化,并获得了其负载特性。所选择的低真空和高真空的环境压强分别为2Pa和5×10 -3 Pa。结果表明,行波型超声马达的转速和转矩均随环境压强减小而 减小。超声马达的负载越大,真空中的转速下降量越大。超声马达的负载特性随环境压强减 小而变差。从超声马达特性和摩擦学理论角度,探讨了真空下超声马达的堵转力矩比常态下小的原因。
     

PEEK卡箍载荷及耐环境性能研究

为支撑型号设计选用,针对P型和马鞍型两种结构的聚醚醚酮卡箍进行了拉伸载荷试验和多种环境试验,分析了振动与冲击、温度老化、液体浸渍、湿度、盐雾等环境试验条件对产品性能的影响,试验得到了卡箍最易失效的受力方向以及不同安装方式、不同温度条件下的拉伸载荷数据。研究表明:PEEK卡箍在试验环境温度下拉伸性能比较稳定;在湿热环境下易出现开胶现象;在振动与冲击、温度老化等环境载荷下能保证结构完整和性能稳定,可以在一定条件下代替金属箍带卡箍。     

负荷传感器频率特性校准系统

介绍负荷传感器频率特性校准系统的基本原理和试验结果 ,分析了测量结果的不确定度。该系统具有大量程、宽频带、重复性好的特点