Accelerated life testing in product design and prototyping

This paper provides an introduction to accelerated life testing and its role in product design and prototyping. The author uses an illustrative worked example to introduce the terminology and fundamental concepts of this technique, which arises from a consideration of items which operate satisfactorily for long periods of time; the relatively small number of failures occurring in any reasonable test period cause obvious difficulties for quantifying long-term reliability. The basic idea is the use of laboratory conditions to subject items to severe stresses, so that items under test have much shorter lives than usual; the results from these experimental data are then extrapolated to provide information on performance at more typical stresses. An example is that of electrical vacuum pumps, which are usually affected by the operating environment, so that increases in temperature, humidity and pollution all produce considerable reductions in the lives of pumps