Windchill Risk and Reliability Desktop Help > Windchill RBD > RBD Calculations > RBD Redundancy Calculations
RBD Redundancy Calculations
The RBD module can handle series, parallel, and standby redundancies. The following table lists the terms used in calculating reliability (without considering repairs), failure rate, and MTTF:
Term
Description
n
The number of units in the system that are arranged in series, parallel, or standby redundancy.
k
The minimum number of operational units needed for system operation.
λ
The failure rate of the individual unit (which is constant because the distribution is exponential).
λBlock(t)
The failure rate of the block (made of redundant units).
R Unit
The reliability of an individual unit.
R Block
The reliability of the block.
MTTF Block
The MTTF (mean time to failure) of the block.
The following topics provide the equations for series, parallel, and standby redundancies: