8.
Assessing Product Reliability
8.4. Reliability Data Analysis


Acceleration models can be fit by either graphical procedures or maximum likelihood methods  As with estimating life distribution
model parameters, there are two general approaches for estimating acceleration
model parameters:


Sometimes it is possible to fit a model using degradation data  Another promising method of fitting acceleration models is sometimes possible when studying failure mechanisms characterized by a stressinduced gradual degradation process that causes the eventual failure. This approach fits models based on degradation data and has the advantage of not actually needing failures. This overcomes censoring limitations by providing measurement data at consecutive time intervals for every unit in every stress cell. 