光纤陀螺可靠性工程中FMEA和FTA应用研究

文中分析了光纤陀螺仪光学有源器件、无源器件、电子线路部分、各元器件的失效模式,并对由电应力、机械应力以及与温度有关引起的失效机理进行分析;最后通过结合光纤陀螺探测器组件物理化学性能、使用环境、故障搜集,建立了探测器组件的故障树,得到探测器组件的主要故障模式是响应度降低和噪声电压变大.     

大规模红外探测器冷箱结构的优化设计

针对大规模红外探测器的封装需求,介绍了冷箱封装结构的设计方法和特点.根据不同类型的大规模红外探测器组件的用途和需求,对其封装结构、重量、热负载以及可靠性等进行了分析,并针对某型大规模红外探测器组件的封装结构开展了优化设计.以轻量化、低功耗为设计思路,采用有限元仿真工具对封装结构进行了优化设计,使其能够满足设计要求.     

星用红外探测器封装技术及其应用

本文简要介绍星用红外探测器的一些封装形式,重点阐述了红外探测器杜瓦组件封装的一些关键技术.这些技术的研究和发展,对提高红外探测器杜瓦组件封装技术水平和推进红外探测器尤其是红外焦平面的应用是至关重要的.     

深低温工作甚长波面阵红外探测器封装技术

基于甚长波红外探测器对低于液氮温度工作环境的需求,提出了一种深低温工作甚长波红外探测器封装技术。通过对杜瓦组件漏热和芯片电学引出结构的优化设计,可控制芯片在30 K低温工作时整个杜瓦组件的静态热耗为0.65 W,最冷端位置的静态热耗为0.3 W,与之适配的两级脉管制冷机冷量可以满足上述热耗需求。完成了探测器组件的封装测试。结果表明,在制冷机膨胀机热端空气冷却测试条件下,探测器芯片部分可达到35 K的温度;杜瓦的外轮廓小于Φ130 mm×180 mm。该项技术成果促进了深低温工作的甚长波面阵红外探测器封装技术的发展。     

EMMI故障定位和基于故障树的GaAs MMIC失效分析

首先通过故障树的方式,分析了某6位数控衰减器衰减态翻转速度异常的失效模式和失效机理。把故障树的顶事件2dB衰减态翻转速度异常分为开关管ESD损伤、驱动信号异常、衰减电阻异常、控制端电阻异常4个子事件,经过分析得出翻转速度异常最大可能是由于控制端电阻过大引发RC延迟现象,进而导致关断或开启延迟故障。然后通过微光显微镜和激光感应阻抗变化率对故障件进行故障定位确定了故障点,为分析结果提供了依据。     

超长线列双波段红外焦平面探测器杜瓦封装技术研究

针对拼接型短/中波的超长线列焦平面探测器与直线脉管集成耦合的要求,分析了超长线列焦平面杜瓦封装的难点。通过对超长冷平台的温度均匀性、超长冷平台支撑结构、大体积组件杜瓦低热负载、超长线列杜瓦真空寿命等封装技术进行研究,提出了多点S型冷链结合导热层的三维热输出方法,设计了桥式两基板的超长冷平台支撑结构,解决了超长冷平台高温度均匀性、集成探测器后低应力及焦深控制、超长线列探测器杜瓦组件的环境适应性、低热负载和长真空寿命等关键技术,成功研制超长线列双波段焦平面探测器制冷组件,并通过一系列空间环境适应性试验验证,试验前后组件性能未发生明显变化,满足工程化应用的要求。     

红外探测器组件封装中的引线特性研究

引线互联是红外探测器封装的关键工艺之一,而采用何种引线则会直接影响红外探测器组件的电学、力学和热学性能。引线互联需要考虑引线的材料、线径、长度和引线工艺,因而红外探测器封装中通过采用多种引线来满足不同需求。系统介绍了红外探测器封装所用引线的电学、力学和热学性能,重点测试和分析了金丝、硅铝丝、铂金丝等引线在大气和真空环境下的熔断电流。大气环境下引线的熔断电流明显大于真空环境下,并与经验公式的结果基本一致。该研究可为航天用红外探测器封装的引线选择提供参考。     

光探测器TO封装的高频分析与改进

推导了封装前后探测器的散射参数的关系,提出了探测器封装网络高频影响的两种分析方法.一种方法是直接比较封装前后探测器的频响,另一种则是从待封装探测器的反射系数和封装网络散射参数计算获得.以TO封装探测器为例,对两种方法的有效性进行了验证.分析结果表明,封装网络中电容和电感的谐振效应具有补偿作用,通过改变封装中的这些参数,改进了TO封装探测器的频响.     

光探测器TO封装的高频分析与改进

推导了封装前后探测器的散射参数的关系,提出了探测器封装网络高频影响的两种分析方法.一种方法是直接比较封装前后探测器的频响,另一种则是从待封装探测器的反射系数和封装网络散射参数计算获得.以TO封装探测器为例,对两种方法的有效性进行了验证.分析结果表明,封装网络中电容和电感的谐振效应具有补偿作用,通过改变封装中的这些参数,改进了TO封装探测器的频响.     

长线列红外探测器真空密封结构设计

针对长线列碲镉汞红外焦平面探测器封装的特点,文章设计分析相对应的探测器真空密封结构。在用于封装3000元及5000元碲镉汞焦平面红外组件研制中,详细阐明了其真空密封结构的设计和工艺实现。符合航天空间应用的高可靠性真空结构,是长线列探测器组件正常工作并完成地面相关试验验证的关键。     

Fault-tree analysis for system design, development, modification,and verification

A methodology that uses fault-tree analysis (FTA) techniques to assess the weaknesses of a new chemical/process design at any time during system development is presented. FTA provides a cost-effective means of improving or verifying the reliability and efficiency of chemical/process design. It evaluates the consequences of conceivable failure to indicate where improvements are justified. FTA techniques were used to model the failure modes of an existing control-room heating, ventilation, and air-conditioning (HVAC) system of a large production facility. The fault-tree reduction revealed 129 single-, 434 double-, and 442 triple-failure combinations, any of which could cause system failure. Single failures and double failures consisting of an equipment malfunction and an operator failure error were targeted for design and/or procedural modifications. These modifications were then incorporated into the operating system design to enhance system availability. In an iterative fashion, FTA techniques were reapplied to the modified design and used to verify the adequacy of the proposed revisions prior to implementation. This resulted in a thorough review of system vulnerabilities and a clear understanding of how to correct them     

自动测试软件可靠性量化评估技术研究

本文针对军用自动测试系统(M-ATS)测试程序软件(简称"TPS软件")在研制过程中存在的薄弱环节,对TPS软件失效模式、影响及危害性分析技术(FMECA)和TPS软件故障树分析技术(FTA)进行了研究,方便开展TPS软件可靠性量化评估.     

基于FTA的测量船惯性导航系统故障诊断研究

测量船惯性导航系统是一种组合导航系统,设备组成复杂,在故障诊断过程中通常难以做到快速、准确定位.故障树分析法是用于系统可靠性和安全性分析的工具,是一种由果到因的演绎分析方法.通过对惯导系统进行故障分析,建立了故障树,并对故障树进行了定性、定量分析.结果表明,该方法能快速准确地诊断系统潜在故障,有效提高惯导系统的可靠性.     

民机无线电导航设备安全性相关需求分析

安全性相关需求作为民机需求的重要组成,与安全性评估过程紧密关联。本文介绍了民机的安全性评估过程,针对某型构架下的民机无线电导航设备,从功能危害状态分析出发,使用故障树(FTA)等分析手段,分析推导了包括应对失效的定量可用性需求、缓解设计错误的研制保证等级(DAL)需求及衍生需求等设备安全性相关需求。本文中给出的安全性相关需求分析方法,符合SAE ARP 4754A、SAE ARP 4761等设计指南要求,对于高安全性要求的民机机载/地面设备的需求开发与确认具有重要的参考意义。     

采用变频器故障树为训练样本的BAM神经网络故障诊断方法

研究故障树分析(FTA)和双向联想记忆(BAM)神经网络在故障诊断中的应用,提出了一种融合FTA和BAM的故障诊断方法.利用FTA得到系统所有的故障模式,进而由故障模式和根据维修经验的故障分析归纳出BAM的学习样本,即故障模式和故障分析之间的对应.BAM通过联想记忆矩阵并行联想,得到诊断结果,扩展综合故障诊断能力.用上...     

Solving agreement problems with failure detectors: a survey

This paper surveys problems related to achieving agreement in distributed systems. Various agreement problems can be specified as a variant of the basic consensus problem. Unfortunately, this fundamental problem cannot be solved in asynchronous systems if crash failures can occur. In order to overcome this impossibility result, Chandra and Toueg have augmented the asynchronous system model with the notion of failure detectors. A failure detector is associated with each process of the distributed computation and is responsible for detecting external failures. Suspicions are essentially implemented using time-out mechanisms, which means that (1) the detection of a real failure is usually delayed and (2) a failure detector can make mistakes by incorrectly suspecting a process to have crashed. In this paper, various classes of failure detectors are presented. All are specified by a completeness property and an accuracy property. A completeness property puts a condition on the detection of crashed processes, while an accuracy property restricts the possible mistakes made by a failure detector. After reviewing the hierarchy of failure detector classes, two particular solutions to the consensus problem are examined. In each case, a different class of failure detectors is used. The proposed solutions have liveness properties and deliver their expected results provided that a minimal set of well-defined conditions is satisfied. After a detailed presentation of the consensus problem, various agreement problems are reviewed and their relationship with the consensus problem are underlined. Finally, for each agreement problem, we indicate under which minimum assumptions a solution can be found.     

Physical structure of molecular-beam epitaxy growth defects in HgCdTe and their impact on two-color detector performance

The flexible nature of molecular-beam epitaxy (MBE) growth is beneficial for HgCdTe infrared-detector design and allows for tailored growths at lower costs and larger focal-plane array (FPA) formats. Control of growth dynamics gives the MBE process a distinct advantage in the production of multicolor devices, although opportunities for device improvement still exist. Growth defects can inhibit pixel performance and reduce the operability in FPAs, so it is important to understand and evaluate their properties and impact on detector performance. The object of this paper is to understand and correlate the effects of macrodefects on two-color detector performance. We observed the location of single-crystal and polycrystalline regions on planar and cross-sectioned surfaces of two-color device structures when void defects were viewed by scanning electron microscopy (SEM). Compositional analysis via energy dispersive x-ray analysis (EDXA) of voids in the cross section showed elevated Te and reduced Hg when compared to defect-free growth areas. The second portion of this study examined the correlation of macrodefects with pixel operability and diode current-voltage (I–V) characteristics in mid-wavelength infrared (MWIR)/MWIR (M/M) and long wavelength infrared (LWIR)/LWIR (L/L) two-color devices. The probability of diode failure when a void is present is 98% for M/M and 100% for L/L. Voids in two-color detectors also impact diodes neighboring their location; the impact is higher for L/L detectors than M/M detectors. All void-containing diodes showed early breakdown in the I–V characteristics in one or both bands. High dislocation densities were observed surrounding voids; the high density spread further from the void for L/L detectors compared to M/M detectors.     

大面阵碲镉汞芯片的热应力分析与优化

随着红外焦平面探测器面阵规模的不断扩大,大面阵碲镉汞芯片的热应力进一步恶化,受温度冲击后更容易产生损伤,进而直接影响探测器的使用,甚至导致探测器失效.这已成为大面阵探测器生产工艺亟需解决的问题.借助仿真手段研究了大面阵碲镉汞芯片的低温损伤原因,并结合小面阵探测器进行了对比分析.结果 表明,铟柱与碲镉汞接触边缘部位因应力...     

故障树分析法在工控故障诊断中的应用

论述了工业控制系统故障诊断的意义,研究了故障树分析法的基本原理,并结合某挖泥船柴油机供给系统故障实例,应用故障树分析法构筑相应的故障树,然后对故障树模型进行定性和定量的分析。在成功排除故障的基础上,总结了应用故障树分析法分析排除故障的特点。     

故障树分析法在半导体设备故障诊断中的应用

介绍了故障树分析法的原理.以反应离子刻蚀(RIE)设备的典型故障为例,建立故障树,通过求解最小实际故障来进行定性分析.尝试扩展故障树在故障判断和改进真空系统可靠性方面的应用,得出几个有针对性的结论.该方法能提高故障诊断的效率和准确性.