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Estimating Device Reliability: : Assessment of Credibility - Franklin R. Nash

Estimating Device Reliability:

Assessment of Credibility

Hardcover Published: 30th November 1992
ISBN: 9780792393047
Number Of Pages: 214

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Estimating Device Reliability: Assessment of Credibility is concerned with the plausibility of reliability estimates obtained from statistical models. Statistical predictions are necessary because technology is always pushing into unexplored areas faster than devices can be made long-lived by design. Flawed reliability methodologies can produce disastrous results, an outstanding example of which is the catastrophic failure of the manned space shuttle CHALLENGER in January 1986. This issue is not whether, but which, statistical models should be used. The issue is not making reliability estimates, but is instead their credibility. The credibility questions explored in the context of practical applications include:

  • What does the confidence level associated with the use of statistical model mean?
  • Is the numerical result associated with a high confidence level beyond dispute?
  • When is it appropriate to use the exponential (constant hazard rate) model? Does this model always provide the most conservative reliability estimate?
  • Are the results of traditional `random' failure hazard rate calculations tenable? Are there persuasive alternatives?
  • What model should be used to describe the useful life of a device when wearout is absent?
  • When Weibull and lognormal failure plots containing a large number of failure times appear similar, how should the correct wearout model be selected?
  • Is it important to distinguish between a conservative upper bound on a probability of failure and a realistic estimate of the same probability?
Estimating Device Reliability: Assessment of Credibility is for those who are obliged to make reliability calculations with a paucity of somewhat corrupt data, by using inexact models, and by making physical assumptions which are impractical to verify. Illustrative examples deal with a variety of electronic devices, ICs and lasers.

Introductionp. 1
Probabilityp. 9
One-Device Unitp. 9
Two-Device Unitp. 11
N-Device Unitp. 20
Redundancyp. 23
Samplingp. 29
Binomial Formulaep. 29
Poisson Formulaep. 31
Confidence Levelsp. 33
Reliability Functions and the Bathtub Curvep. 49
Human Mortality Datap. 50
Survival and Failure Functionsp. 50
Probability Density Functionp. 54
Hazard Ratep. 58
Component Bathtub Curvep. 63
Exponential (Constant Hazard Rate) Modelp. 69
A Derivation of the Survival Functionp. 69
A Useful Approximate Form of the Hazard Ratep. 73
Limitations on the Use of the Exponential Modelp. 74
Confidence Levelp. 78
Effective and Average Hazard Ratesp. 84
Models of Useful Lifep. 87
Traditional Approachp. 87
Modified Traditional Approachp. 89
Critique of Conservative Approachesp. 91
Declining Hazard Rate Weibull Model versus the Exponential Modelp. 92
Wearoutp. 123
Commonly Employed Modelsp. 125
Example: Electromigration Failuresp. 127
Example: Light Bulb Failuresp. 127
Example: Laser Failuresp. 144
Device Qualificationp. 163
Prequalificationp. 163
Qualificationp. 165
Indexp. 211
Table of Contents provided by Blackwell. All Rights Reserved.

ISBN: 9780792393047
ISBN-10: 079239304X
Audience: Professional
Format: Hardcover
Language: English
Number Of Pages: 214
Published: 30th November 1992
Publisher: Springer
Country of Publication: NL
Dimensions (cm): 23.5 x 16.51  x 1.91
Weight (kg): 0.45