Building Diagrams in Weibull++

To add a diagram in Weibull++, choose Home > Insert > Diagram, or right-click the RBDs folder in the current project explorer and choose Add Diagram on the shortcut menu.

To add blocks to a diagram, choose Diagram > Blocks and then select the type of block you wish to add.

  Add Block adds a standard block that represents a data sheet in a life data or life-stress data folio. You can also add a standard block by dragging the data sheet of interest from the Data Sheets page of the control panel into the diagram. You can use any data sheet in any life data or life-stress data folio, as long as it has been calculated and is not using one of the competing failure modes distributions. (A red flag over a block indicates that the associated data sheet in the folio has either been deleted or needs to be calculated.)

By default, standard blocks are named after the data sheets they represent. If you want to use a different name, right-click the block and choose Rename Block.

  Add Node adds a node block that functions like a switch that diagram paths move through. A node block models an alternative form of redundancy known as k-out-of-n redundancy. A k-out-of-n node block can have n paths leading into it and requires that k out of n paths must function for the system to function. There must be at least one path leading into a node; therefore, a node block cannot be placed as the starting block for a diagram.

Double-click the node block to specify the number of paths that must reach the node in order for the system to succeed.

  Add Junction adds a junction block, which is a non-failing block. Because diagrams must flow from a single starting point to a single ending point, you may need to use junction blocks as starting and/or ending blocks (see Diagram Analysis Constraints). They can also be used anywhere within the diagram that you need a block that does not fail (i.e., does not affect the system reliability).

Once you have added blocks to the diagram, you can then use connectors to connect the blocks and build the RBD. From the RBD, you can calculate the exact system reliability equation for the system, and obtain plots and results based on that equation.