Universal Reliability Definitions (URDs)

Universal reliability definitions (URDs) are used in BlockSim 8 to represent a set of properties that can be applied to standard blocks in RBDs and to events in fault trees. These properties can include failure behavior and maintenance tasks. URDs are resources that are available for use throughout the project and can be managed via the Resource Manager.

Note: If you apply a URD to a block in an analytical diagram, only the failure model associated with the URD will be applied to the block. If you apply a URD to a block in a simulation diagram, the failure model and all maintenance tasks associated with the URD will be applied.

The Universal Reliability Definition window allows you to create, view and edit URDs. It can be accessed by clicking the Create New or View/Edit icon in the wizard available from the URD field of the Block Properties window.

It can also be accessed from the URDs page of the Resource Manager by choosing Home > Edit > New, by selecting a URD and choosing Home > Edit > View or by double-clicking a URD.

At the top of the window, you can specify the URD name. By default, URDs are named “URD [increment]” (i.e., the first URD created is URD 1, the next is URD 2 and so on). You can replace this with your own name of up to 150 characters, if desired. Users with the "Manage other repository settings" permission can specify how these default names are created in the current database via the Define Default Name Formats window, which is accessed by choosing File > Manage Repository > Define Default Names.

Note: Two views are available for the URD Properties area. The Hierarchy tab displays information about the URD in a standard hierarchical format. Each resource directly assigned to the URD is shown, along with a subset of its properties. This view allows you to specify properties. The Filtered tab displays all resources of a specified type that are associated with the URD, either by being assigned to it directly or by being assigned to a resource that is assigned to the URD. You cannot change which resources are assigned on this tab. For more information, see the Properties Windows topic.

The table contains the following settings to configure the URD:

Model allows you to choose or create a model to describe the behavior associated with the URD. This can be a reliability model, a probability of failure model or an event occurrence model; once you have specified the model, its category will be displayed as part of the field name.
Corrective Task allows you to choose or create a corrective task for the URD. Corrective maintenance consists of the action(s) taken to restore a failed component to operational status.
Scheduled Tasks allows you to choose or create multiple scheduled tasks for the URD. These tasks may be preventive maintenance, inspections and/or on condition tasks. The tasks are displayed in their priority order, which is the order in which they will be performed; you can use the up and down arrows in the cells in this column to move the task up and down the priority list.
Identifiers allows you to enter additional identifying information that can be used to search for this resource.

Information about the creation and last modification of the URD is displayed at the bottom of the window.