Composed reliability We wish to study the reliability of a system constituted of 2 basic modules (noted Mi) interconnected according to diverse 'series' and

'parallel' reliability diagrams. The reliability of each module is modeled by an exponentiallaw with a constant failure rate J....: Ri(t) = e -Ait.

1. Determine the reliability of a 'series' reliability diagram of these modules.

Calculate the global MTTF. Study the particular case where the two failure rates are identical.

2. Carry out the same study for a 'parallel' diagram.

3. Consider the previous questions with J.... = 10-4, and compare the reliability of these structures at time t = 1000H.