FailureProperties

R2026b

Calculated failure properties of fault tree artifact

Since R2026b

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Description

FailureProperties objects represent the failure properties calculated at a gate or event in Safety Analysis Manager fault tree documents. You generate failure properties by evaluating the fault tree document. Use FailureProperties objects to evaluate the probability and frequency calculated at the artifact.

Creation

To create a FailureProperties object, evaluate a fault tree document by using the evaluate function. The FailureProperties property of Gate or Event objects contains FailureProperties objects.

Properties

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This property is read-only.

Failure probability calculated at the gate or event, represented as a positive double between 0 and 1.

Data Types: double

This property is read-only.

Failure frequency calculated at the gate or event, represented as a double.

Data Types: double

This property is read-only.

Conditional failure intensity calculated at the gate or event, represented as a double. The CFI is the ratio of the W property over 1-Q at the gate or event:

cfi=w1−q

Data Types: double

This property is read-only.

Whether the event is active, represented as a logical 0 or 1, or a string scalar.

If the failure model uses an expression and you do not evaluate the tree, this property returns the expression as a string scalar. If you evaluate the tree, this property returns the expression value, which must evaluate to a logical 0 or 1.

Dependencies

To use this property, set the Type property of the containing FailureModel object to "logical".

Data Types: logical

Examples

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Create a fault tree that has seven basic events and three gates under the top-level gate. Specify the failure and event frequency for each event.

myTreeDoc = safetyAnalysisMgr.newDocument("fault-tree");
myFaultTree = myTreeDoc.FaultTrees(1);

myTopGate = myFaultTree.Gates(1);
event1 = createEvent(myTopGate);
event1.FailureModel.Parameters.Q.Value = 0.05;
event1.FailureModel.Parameters.W.Value = 0.05;
event2 = createEvent(myTopGate);
event2.FailureModel.Parameters.Q.Value = 0.1;
event2.FailureModel.Parameters.W.Value = 0.05;
gate1 = createGate(myTopGate);
gate2 = createGate(myTopGate,Type="and");
gate22 = createGate(gate2);

event3 = createEvent(gate1);
event3.FailureModel.Parameters.Q.Value = 0.1;
event3.FailureModel.Parameters.W.Value = 0.1;
event4 = createEvent(gate1);
event4.FailureModel.Parameters.Q.Value = 0.02;
event4.FailureModel.Parameters.W.Value = 0.01;
event5 = createEvent(gate2);
event5.FailureModel.Parameters.Q.Value = 0.2;
event5.FailureModel.Parameters.W.Value = 0.01;
event6 = createEvent(gate22);
event6.FailureModel.Parameters.Q.Value = 0.2;
event6.FailureModel.Parameters.W.Value = 0.2;
event7 = createEvent(gate22);
event7.FailureModel.Parameters.Q.Value = 0.15;
event7.FailureModel.Parameters.W.Value = 0.15;

Evaluate the fault tree document.

evaluate(myTreeDoc)

To retrieve the failure probability and frequency at the top-level gate, retrieve the Gate object of the top-level gate and get the failure properties by using dot notation.

myProperties = myTopGate.FailureProperties
myProperties = 

  FailureProperties with properties:

      Q: 0.2942
      W: 0.2081
    CFI: 0.2949

Version History

Introduced in R2026b

See Also

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