Basic reliability cookbook
Serial Reliability
Elements E1,
E2,
… EN
have individual reliability P1,
P2
… PN.
The combined reliability of the elements is P1
* P2
* … * PN.
For example, E1
has reliability 0.9, E2
has reliability 0.85 and E3
has reliability 0.95. The
serial reliability of a system composed of E1,
E2
and E3
is 0.90 * 0.85 * 0.95 = 0.72675.
In the special case
where all of the elements are identical, the serial reliability of N
elements with reliability P is PN.
For example, five identical elements with reliability 0.8 have a
combined serial reliability of 0.32768.
The reliability of a
system composed of serial elements is always less than or equal to the
reliability of the least reliable element.