For expensive components and expensive tests, sudden death tests involve a few components that tie-up a test frame as they are heavily loaded under the same test loads/conditions with several items being run at the same time. When one of the items fails the entire test frame is shut down so that you have 1 failure (this is the sudden death!) and several suspensions because the unfailed units are survivors as the test is halted until the test frame is loaded with new samples for resumption of the life test. Opening the test frame (instead of tying up the frame until all samples have failed) is cost effective. If three units can be tested simultaneously and the test is halted on the first failure, then perhaps we will literally have only 4 failures and 8 suspensions for preparing the Weibull analysis. Will the 4 sample + 8 suspension data set be different than if all 12 samples had been run to failure?-the answer is yes, they will be different, but will they be significantly different-the answer is no to the significant difference. So, as with simultaneous testing the suspensions (censored data) become important details for use in the statistical analysis. Most sudden death tests are accelerated to generate the data in a short period of time although this carries the risk of introducing unexpected failure modes (but this can also be useful information for anticipating field failures).
Why: Sudden death testing is all about the economics and shorter elapsed time for results.
When: Sudden death testing is used for product acceptance tests.
Where: It is a quick test for many products and the on-going test for production lots.
These definitions are written by H. Paul Barringer and are also posted on his web site at www.barringer1.com
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