The Two Types of Logic Trees

There are two types of logic trees that can be defined for a reliability element: a requirements-tree (the default) or a fault-tree. A requirements tree must evaluate to true in order for the element to operate, while a fault tree must evaluate to false in order to operate.

The type of tree is selected using a drop down list in the requirements dialog:

In addition to supporting both types of logic-trees, GoldSim allows you to automatically convert from one logic-tree type to another. For example, if you have defined a requirements-tree, changing the drop down selection to a fault-tree will automatically convert the nodes in the requirements-tree into an equivalent fault-tree and vice versa.

Here is that same Operating Requirements, presented first as a Requirements tree:

and then as a fault tree:

Note that And gates have changed to Or gates, and the not (!) symbol appears before the other items. Recall that a requirements tree must evaluate to true in order for the element to operate, while a fault tree must evaluate to false in order to operate.