When Enable duty cycle for blocks is selected under RBD in the System file properties, you can specify a duty cycle percentage on the Failure page in its Calculation Properties window. For more information, see Failure Page.

The reliability of a block or component with a duty cycle is calculated by modifying the time in the reliability equation. Let d * 100% be the duty cycle percentage where d represent the fraction corresponding to the duty cycle. For example, if the duty cycle is 50%, then d is 0.5. The system reliability at time t with duty cycle d * 100% is calculated using the reliability equation where time is t'= t * d and duty cycle is 100%: