The “Operating Requirements” portion of the reliability element dialog allows you to define logical relationships between elements using a logic tree:
GoldSim allows you to specify either 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.
There are two types of operating requirements: external and internal. External requirements refer to the status of other elements in the model that are not sub-components of the given element. Internal requirements are used to specify the effects of failure modes on operability (by default, failure modes are added as internal requirements and hence cause the element to stop operating), and can also refer to the status of child elements (if the element is modeled as a system).
In addition to specifying operating requirements, you can also specify Resources that are required in order for the element to operate (via the Resources button).
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Defining Operating Requirements for Reliability Elements Using Logic Trees