Reliability Prediction Techniques for Complex Systems

As electronic systems continue to evolve into more and more complex structures, the search for better and more efficient reliability prediction techniques naturally takes on added momentum. Needed are not only systematic methods of mathematical model building that will simplify the procedures involved but also noncomplex ways of obtaining solutions to many practical problems. This paper illustrates the applicability of transition diagram in describing the state space of a complex system, repairable or nonrepairable, and shows the methodology of writing the set of first-order linear differential equations representing the system performance by inspection of the transition diagram. A discussion of some applicable properties of linear signal-flow graphs is included. Methods of solving problems by inspection techniques are clearly explained and specific examples are given to illustrate the concepts. The mean time Tm for a system to pass for the first time from its initial state to a failed state is usually a statistic of prime interest. Certain properties of Laplace transform are used to illustrate how Tm of a general complex system, repairable or nonrepairable, can be obtained by solving a set of simultaneous algebraic equations. Flow graph techniques of solution by inspection are shown to be a valuable tool in obtaining analytical solutions for Tm of many practical systems.     

武器装备的全寿命周期可靠性预计

阐述了周全地考虑武器装备寿命周期可靠性的必要性，给出了全寿命周期可靠性预计方法和模型。以某机载武器为例，预计其全寿命周期可靠性，并分析、改进了原设计方案，使其满足规定的可靠性指标。     

高复杂度综合系统的可靠性预计

针对装备可靠性工作的焦点问题,在各个设备的可靠性要求的框架下,依据国家军用标准及美军标手册MIL-HDBK-217<电子设备可靠性预计手册>的应力分析法,采用比较实用、高效的ITEM ToolKit可靠性平台对某高复杂度仪器设备进行可靠性预计,在任务实施中探索一种比较实用、...     

A New Real-Time Reliability Prediction Method for Dynamic Systems Based on On-Line Fault Prediction

While a specific system is in use, its reliability will decrease gradually after the infant mortality period because of the components' degradation, or external attacks. Thus, reliability is a natural characteristic of a system's health, and can be used for condition monitoring & predictive maintenance. This paper introduces a new real-time reliability prediction method for dynamic systems which incorporates an on-line fault prediction algorithm. The factors that may reduce a system's reliability are modeled as an additive fault input to the system, and the fault is assumed to be varying linearly with time, approximately. The time-varying fault is roughly estimated based on a modified particle filtering algorithm at first. Then, as a time series, the fault estimate sequence is smoothed, and predicted by an exponential smoothing method. Mathematical analysis shows that the effects of the system, and measurement noises on the fault estimates are greatly reduced by exponential smoothing, which indicates that the comparatively high accuracy of the fault estimates & predictions is guaranteed. Based on the particle filtering & fault prediction results, the whole system's predictive reliability is computed through a Monte Carlo simulation strategy. The effectiveness of the proposed real-time reliability prediction method is validated by a computer simulation of a three-vessel water tank system.     

一种CCD工作寿命预计方法

介绍了一种适用于电荷耦合器件(CCD)的工作寿命预计方法。对CCD的失效模型进行了分析,并进行加速寿命试验,试验结果与理论分析结果较好地吻合。试验结果表明,对于一款成熟应用的CCD,其工作寿命值与其质量等级有直接的关系;质量等级越高的器件,其工作寿命值也越长。     

CORS连续运行参考站系统的雷电防护设计

文章根据CORS系统的基本结构和雷电入侵的主要途径,从外部雷电防护和内部雷电防护两个角度进行综合雷电防护设计,保障了CORS系统的稳定运行。     

Reliability for Sparsely Connected Consecutive-k Systems

We introduce the system of consecutive failures with sparse d which is a natural extension of consecutive-k systems. Then a series of generalizations of consecutive-k systems are discussed, such as consecutive-k-out-n:F systems with sparse d, M consecutive-k-out-of-n:F systems with sparse d, and (n, f, k) :F systems with sparse d. We present the formulation for the system reliability of these generalized consecutive-k systems with various component settings in terms of the finite Markov chain imbedding idea, along with two numerical examples.     

Reliability Bounds for Decomposable Multi-component Systems

This paper obtains lower and upper bounds for decomposable multi-component complex systems. Some particular cases are discussed.     

通信产品系统可靠性预计和分配

本文主要介绍系统可靠性建模、可靠性分配和预计的一种思路,便于在今后的产品设计过程中加强可靠性系统设计。     

螺旋线行波管可靠性预计串联模型研究

通过对国产螺旋线行波管在现场使用的可靠性数据的收集、整理、分析,建立螺旋线行波管可靠性预计的串联模型。并比较串联模型、回归模型以及299C关于某型行波管的预计值与实际值的接近程度。通过故障模式影响及危害性分析,找出对行波管可靠性影响较大的故障模式。     

侵彻引信电路的可靠性预计

引信电路的可靠性预计在整个引信设计过程中起着重要的作用。可靠性的预计是一个复杂的工程,其中包括可靠性参数的选择、可靠性模型的建立以及可靠性的计算。在不同的引信设计阶段,应采用不同的预计方法。为了得到引信电路的可靠性,根据设计的引信电路,绘制了引信的可靠性框图,选取合适的可靠性参数,运用不同的可靠性预计方法,对处于不同设计时期的电路可靠性进行了预计。     

多晶硅微悬臂梁断裂的可靠性预测模型

分析了多晶硅微悬臂梁断裂失效机理,利用威布尔分布理论建立了多晶硅微悬臂梁在轴向拉抻和垂直两种受力方式下的断裂可靠性预测模型,模型考虑了由于实际加工工艺所带来的残余应力因素,模型所得的预测曲线与实验数据比较吻合。     

Reliability Evaluation and Prediction for Discrete Semiconductors

The use of accelerated step-stress and constant stress-in-time test techniques is demonstrated for generating models for predicting reliability at use conditions. Reliability prediction models were obtained for a signal diode, signal and power transistors, silicon trolled rectifier, and metal oxide varistor. Each of these device types follows the Arrhenius model for reliability prediction. Techniques are demonstrated for determining 1) the acceleration factor between extremely high acceleration testing conditions and field operating conditions on the signal diode; and 2) the acceleration or multiplying factor between high level stresses and use conditions which can be used to predict the performance of the signal diode over time. The effect of relative humidity on reliability is discussed. Devices under power operation have a lower relative humidity (RH) than the environment. This low RH suppresses humidity activated mechanisms. A transistor high-reliability screen which removes devices with early manufacturing type defects is described. This screen was effective, efficient and economical for improving the reliability of systems. A technique of combining acceleration factors for a number of items which affect reliability was demonstrated for the diode. This same technique should be useful for most device reliability predictions. The acceleration factors, however, can not be extrapolated into stress levels much above maximum ratings where new failure modes may appear that override the established failure rate relation with stress. The straight line plots of failure rates in this paper are terminated before these threshold limits.     

可靠性预计方法及思考

本文介绍了可靠性预计的目的,并对当前较为常见的可靠性预计模型或方法做了比较和说明,也对造成可靠性预计局限性的原因做了分析,最后对在可靠性工程工作中对待可靠性预计的态度做了探讨.     

Microelectronic System Reliability Prediction

The paper reviews the US MIL-HDBK-217 (MH-217) method of part stress-analysis failure-rate prediction for microelectronic systems and investigates the extent to which the MH-217 failure-rate formula is compatible with the physics of actual failure modes. A new formula is proposed which takes account separately of the reliability of the microelectronic devices in a system and of the system-level determinants of reliability. It is simpler than the current MH-217 formula, and more useful. It enables the system level aspects such as reliability program activities to be taken into account in the prediction, and allows better correlation to be made between part test and system test data. An example applies the new formula to a typical microelectronic system. By considering separately the failure physics of parts and the system level determinants, reliability prediction can be made a more useful tool both for part stress analysis and for reliability program management. The model would enable better correlations to be made between part and system test results. More work needs to be done to refine and validate the parameters. For high-reliability programs with closely controlled maintenance or with no maintenance, the use of a decreasing failure rate model for part failures should be considered. The failure rate formulae for other electronic parts used in microelectronic systems would also need to be reviewed, but apart from removal of the environmental factor and reduction in the failure rate values proportionate to that proposed for microelectronic parts, no changes should be necessary.     

Interconnect Lifetime Prediction for Reliability-Aware Systems

Thermal effects are becoming a limiting factor in high-performance circuit design due to the strong temperature dependence of leakage power, circuit performance, IC package cost, and reliability. While many interconnect reliability models assume a constant temperature, this paper analyzes the effects of temporal and spatial thermal gradients on interconnect lifetime in terms of electromigration, and presents a physics-based dynamic reliability model which returns reliability equivalent temperature and current density that can be used in traditional reliability analysis tools. The model is verified with numerical simulations and reveals that blindly using the maximum temperature leads to too pessimistic lifetime estimation. Therefore, the proposed model not only increases the accuracy of reliability estimates, but also enables designers to reclaim design margin in reliability-aware design. In addition, the model is useful for improving the performance of temperature-aware runtime management by modeling system lifetime as a resource to be consumed at a stress-dependent rate