Lambda Tau Fault Trees
In some situations, the mission time of the system might be very large or unknown, or the age of system components might be unknown. Provided that the system is well-maintained and routinely undergoes preventative maintenance, it is often assumed that components have reached steady state behavior. In this case, rather than constructing a time dependent tree, you might want to construct a Lambda Tau tree to calculate availability and short-term reliability results.
To perform Lambda Tau analysis, two parameters are needed for each event:
• Lambda (λ). Represents the failure rate for the event.
• Tau (τ). Represents a time. This time can be an inspection interval, repair time, or mission time.
For additional information specific to constructing and calculating Lambda Tau trees, see: