Hazard Rate Calculations
The RBD module uses the term hazard rate for conditional intensity. Conditional intensity is the instantaneous failure rate of either a repairable or non-repairable system at time t, given that the system is operational at time t. Here, the exact state of the system is unknown, which means the number or set of good components at time t is unknown.
Conditional intensity is calculated from failure frequency and system availability:
Where:
v(t) = The system failure frequency.
A(t) = The system availability.
For systems with non-repairable components, the conditional intensity of the system is equivalent to the failure rate of the system:
Where:
λ(t) = The system failure rate at time t.
For systems with repairable components, the actual failure rate of the system is less than the conditional intensity function. However, the conditional intensity function can be used to find the approximate reliability of repairable systems.
Based on the complexity of the problem and user-specified properties, conditional intensity is calculated using either an analytical method or simulation. In both cases, the intensity function is calculated directly from the failure frequency and availability functions. However, the calculations of availability and failure frequency are based on the method of computing.