Reliability estimation test sequence

[Sandrine]

Hello,

A few parts are getting a sequence of different stresses but there is no failure for the moment.
We have put these parts on testing for last 1 year
Now , we would like to analyse system reliability with "Design of Reliability Test" .
My question is :

1/ Is the system reliability calculated with total test time ( eg: time of test 1 + time of test 2...)?
where test1+test 2... represent a sequence of different stresses ?
So, We have R(t1+t2+..)

2/ or each test have a reliability R1 (with test 1, R2 (with test2).and in this case I don't know calculate system reliability ?
We have R1(t1), R2(t2),...

Thank you for your help
Best regards
Sandrine

[Pantelis]

I am not sure I follow. Are you doing an accelerated test on the parts? If so where does the system analysis come in?

[tarik]

see answer under "Reliability -O failure" post