Weibull and Reliability/Failure Time Analysis - Introductory Overview
A key aspect of product quality is product reliability. A number of specialized techniques have been developed to quantify reliability and to estimate the "life expectancy" of a product. The methods described below, and accessible via the Weibull analysis and reliability/failure time analysis facilities from the Process Analysis Procedures Startup Panel, provide the full set of relevant tools for this purpose. Standard references and textbooks describing these techniques include Lawless (1982), Nelson (1990), Lee (1980, 1992), and Dodson (1994); the relevant functions of the Weibull distribution (hazard, CDF, reliability) are also described in the Weibull CDF, reliability, and hazard functions section. Note that very similar statistical procedures are used in the analysis of survival data (see also the description of the Survival Analysis module), and, for example, the descriptions in Lee's book (Lee, 1992) are primarily addressed to biomedical research applications. An excellent overview with many examples of engineering applications is provided by Dodson (1994).
- Weibull and Reliability/Failure Time Analysis - General Purpose
The reliability of a product or component constitutes an important aspect of product quality. Of particular interest is the quantification of a product's reliability, so that one can derive estimates of the product's expected useful life. For example, suppose you are flying a small single engine aircraft. It would be very useful (in fact vital) information to know what the probability of engine failure is at different stages of the engine's "life" (e.g., after 500 hours of operation, 1000 hours of operation, etc.). Given a good estimate of the engine's reliability, and the confidence limits of this estimate, one can then make a rational decision about when to swap or overhaul the engine. - Process Analysis Sampling Plans - General Purpose