5.4 Accelerated Testing

In order to assure reliability of a product the design of the product should be reliable which performs its functionality under the required environmental conditions. One of the conventional methods of assuring this has been by analyzing the time to failure data obtained under normal operating conditions in order to quantify the reliability or the MTBF demanded by the customer. With the advance in technology and the competition in the market it is really difficult to capture the time to failure data under the normal operating conditions. Also one cannot capture all the hidden failure modes which may occur during the life span of the product. To assure the reliability one needs to analyze all the failures in the least possible time so that the product could be launched in the market without losing to competition. The accelerated test aims at testing the product for all its latent failures and implementing the required design changes to assure a fault free operation of the product to the extent possible in the real world.

A variety of methods which serve different purposes have been termed as accelerated life testing. They involve quantification of the life characteristics of the product at normal use conditions. The accelerated tests can be divided into two categories, namely qualitative tests and quantitative tests. The qualitative tests are

1. Shake and bake tests

2. Torture tests

3. Elephant tests

4. Environmental Stress Screening and Bum-in

The main advantage of the qualitative tests is that one can increase the reliability...