Test Failure Continue Test or Restart Test

[tom c]

I am interested in setting up a fixed duration time terminated reliability test in which I will allow zero failures in the test time interval (test time is based on 90% conf limit). The test article happens to be a complex electronic system and I cannot afford to test more than one system. If I do get a failure during my test interval, is it preferred to: a) replace the failed LRU and continue testing or b) repair the failed LRU and repeat testing in its entirety or c) do something else (must be specific here).

Thanks
TC

[RS Support]

A) If this is a zero failure demonstration test and you get a failure -- then the test is over.

B) If the question is as to a general quide on a testing scheme of a complex system then one may want to consider the following:

B.1) Replacing the LRU allows for a greater sample size (i.e. you will be testing a larger amount of LRU’s).

B.2) Repairing the LRU allows other non-failed components (within the LRU) to operate longer thus providing more info as to how the other non-failed components age.

[Muthukumar.R.]

Dear Sirs,
In the recently released IEC 60605 series of stanards for reliability testing, the operating characteristic curves for sequential testing is provided for various test plans. The OC characteristic is drawn with probability of acceptance of the samples on the Y-axis and true MTBF divided by acceptable MTBF ratio on the X-axis. The resultant curve is a S-curve. Can you please help me with the formulae for the probability of acceptance. Expect your reply soon with request.

Thanking you,

Yours faithfully,
R.Muthukumar
Joint Director
Centre for Reliability
Chennai, INDIA

[Pantelis]

I am not sure I exactly follow.

It might be helpful to look at the entire document and or get further details. If you wish to do so you can email the material to the support@Reliasoft.com email address, referencing this posting (and my name).