ISSN:0748-8017    

DOI:10.1002/qre.4680020102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractConventional practice in evaluating the effect of elevated temperature upon electronic devices in either accelerated testing or stress screening is the use of the Arrhenius reaction rate equation. This equation fails to represent several key aspects of the stress. A general model that includes the reaction rate effects during heating and cooling, the mechanical effects of heating and cooling, and non‐constant activation energies is provided here. The model is based upon a general representation of a thermal cycle.Once the general model is constructed, it is shown to accommodate as special cases, acceleration when one or more of the features is assumed absent. An example illustrates this point. Then several uses for the model beyond the computation of the acceleration factor are discussed. It is suggested that the general model can be used to support test design and equipment selection decisions. The model therefore provides a more realistic portrayal of the effects of a thermal cycle and increased decision flexibility in defining thermal stress regimen

ISSN:0748-8017    

DOI:10.1002/qre.4680020103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractWith distributed loads and strengths the condition of minimum whole life cost defines uniquely the safety margin (or factor of safety) that must be used. Established empirical factors used in current deterministic design are not then relevant. It is postulated that computer‐aided design packages should incorporate a simultaneous optimization of the safety margin and maintenance policy in place of these factors, since once the design is finalized the whole life cost is finalized. The full development of stochastic CAD methods is seen as the next essential step to advance design technique

ISSN:0748-8017    

DOI:10.1002/qre.4680020104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractThis paper describes a method for estimating and forecasting reliability from attribute data, using the binomial model, when reliability requirements are very high and test data are limited. Integer data—specifically, numbers of failures — are converted into non‐integer data. The rationale is that when engineering corrective action for a failure is implemented, the probability of recurrence of that failure is reduced; therefore, such failures should not be carried as full failures in subsequent reliability estimates. The reduced failure value for each failure mode is the upper limit on the probability of failure based on the number of successes after engineering corrective action has been implemented. Each failure value is less than one and diminishes as test programme successes continue. These numbers replace the integral numbers (of failures) in the binomial estimate.This method of reliability estimation was applied to attribute data from the life history of a previously tested system, and a reliability growth equation was fitted. It was then ‘calibrated’ for a current similar system's ultimate reliability requirements to provide a model for reliability growth over its entire life‐cycle. By comparing current estimates of reliability with the expected value computed from the model, the forecast was obtained by ex

ISSN:0748-8017    

DOI:10.1002/qre.4680020105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractThe purpose of this article is to say a few kind words for numerical techniques, which have become the object of some undeserved criticism. Probability information is part of decision‐making, be it intuitive or analytical. In this age of the personal computer we do not have to go to great lengths to quantify this information, so why not do it? The failure to rescue hostages in Iran is a dramatic example that reliance on intuition can have bad results. On the side of numerical techniques, three examples of successful and practical applications are described. It is concluded that ‘the numbers game’ contributes worthwhile support to decision‐making and should continue to co‐exist with ‘shirt‐sleeve’ efforts to improve produc

ISSN:0748-8017    

DOI:10.1002/qre.4680020106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractThermal cycling and vibration tests were carried out on an intermediate processor family of machines to investigate the benefits of controlled stressing as a means of screening manufacturing defects, and to provide data for return on investment calculations. Major items to be considered were(a) low cost of test programme(b) complete unit to be stressed (complex interactions between subassemblies)(c) relatively low expected failure rate(d) limited field reporting.Stress techniques used were mild thermal cycling and pseudo‐random vibration.Analysis of field data from the stressed population showed an overall reliability improvement of 24 per cent during the first 30 days of customer operatio

ISSN:0748-8017    

DOI:10.1002/qre.4680020107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractThis is a review paper. It describes the state‐of‐the‐art of the research on reliability indicators for either electronic or mechanical components. Typical component failure patterns are presented and discussed. The concept of component screening using reliability indicators is then outlined. The paper sketches a theoretical approach to the problem of detecting flaws in components. The approach is based on an old concept of energy imbalance in flawed ob

ISSN:0748-8017    

DOI:10.1002/qre.4680020108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractThere has been much recent interest in the reliability field in the application of proportional hazards modelling. A number of practitioners and academics have recently been advocating its use and reviewing the basic theory. The technique is, however, in the early stages of application in reliability studies, and apparently no satisfactory examples of its application to reliability data are to be found in the open literature. An implication is that the enormous potential of this approach for reliability analysis, as well as the particular shortcomings and difficulties of applying it in this field are not well understood in the reliability community as a whole.In this article we discuss the application of the method to the reliability analysis of the brake discs on British Railways high speed trains. The need for such an approach arose owing to the paucity of current reliability analysis methods for the problem in hand. The proportional hazards methodology provided an effective means of exploratory analysis and the application of the method provided an explanation for a previously unresolved discrepancy between the statistical and metallurgical analyses. As a result of its use, the effects of the underlying failure mechanism and the various design and operating variables and their interactions are better understood, and British Rail's maintenance policy has been changed accordingly. On the basis of experience of this and similar applications, the potential for application of proportional hazards modelling in reliability, and the likely benefits to be obtained, are discussed.

ISSN:0748-8017    

DOI:10.1002/qre.4680020109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractWhen U.S. ROLAND production hardware was first assembled, the resulting reliability was far below the requirement. Rather than rationalizing the failures as ‘random’, each was pursued to correct the cause in design, manufacturing processes, or workmanship. A process and quality plan was implemented with improvements to such items as soldering techniques and circuit‐board fabrication. Many design improvements were also incorporated. The test programme was halted and replanned to benefit from an iterative test‐fix‐test process. The final result was an increase in the reliability to 3.6 times the cont

ISSN:0748-8017    

DOI:10.1002/qre.4680020110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0748-8017    

DOI:10.1002/qre.4680020111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY