Chapter 6

Variable Failure Rates and Probability Plotting

Abstract

This chapter develops the 2 and 3 parameter Weibull models for dealing with variable failure rate. The practical application of the model to analysing data is taught and it is applied to assessing optimum discard intervals.

Keywords

Weibull
probability plotting
shape parameter
scale parameter
location parameter
significance
continuous process

6.1. The Weibull Distribution

The bathtub curve in Figure 2.7 showed that, as well as random failures, there are distributions involving increasing or decreasing failure rate. In these variable failure rate cases there is no point in considering the failure rate since it is continually changing. Only reliability and MTBF are meaningful. In ...

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