Failure cause
- Last UpdatedDec 02, 2024
- 3 minute read
A failure cause in Asset Strategy Optimization determines the way and the condition under which a component may fail. A component may have more than one failure cause. The failure cause may be linked to a failure mode to dictate the way in which the parent level part is affected by the failure. As the failure mode can define the impact of the failure on the business objectives, as soon as a failure cause is linked to a failure mode, the failure cause properties will list both the failure mode and its effects on the business objectives.
For a failure cause, it is possible to create one or more types of maintenance. The following types are available (they are explained in detail below):
FBM – Failure Based Maintenance action; primary maintenance action to repair or replace the component when it fails (or the part as a whole).
UBM – Use Based Maintenance action; a preventive action based on the usage of the component.
CBM – Condition Based Maintenance action; a preventive action (typically an inspection), to check the condition of the component.
FFT – Failure Finding Task; specific inspection action applied to discover hidden failure.
Note: typically, the result of a preventive action is usually the action defined as the FBM, as this will resolve the failure. This type of action is referred to as a follow-up action.
Creating a failure cause
Creating a failure cause is similar to the steps in Create an FMECA system.
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FIELD |
DESCRIPTION |
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Description |
Users are free to enter any description for the object. The logical option is to describe how the component will fail. |
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Condition |
Describe the condition under which the component would fail, for instance because of corrosion or wear. |
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MTTF Correction Applied |
Set if the mean-time-to-failure of this failure cause is dependent upon the media used. For more information, refer to Effect of Media value on MTTF - MTTF Correction. |
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MTTF |
Indicate mean-to-failure for this failure cause to occur, including the unit of time. |
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Hidden |
Example: If the warning sign for low motor oil level in a car were defected, it would not be obvious that an FBM action should be initiated. This situation can be modeled using this field Hidden. By default, failure should be dealt with immediately by applying the linked FBM action. If the option Hidden has been set to true, failure would not be noticed during simulation, so no FBM action would be initiated. Especially for security and back-up systems it is common that failures will occur unnoticed. With this option set to true, while a failure would cause a downtime of 100%, this would mean that the whole serial section the failure is part of would be taken down. The section would only come back up when a preventive maintenance action would be applied to the failure. In general, this situation does not occur in availability calculations (those types of failures would be signaled immediately), but in models for security calculations. Note: Hidden is commonly used in combination with redundancy. |
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Failure mode |
Associate this failure cause with one of the defined failure modes for this part. Alternatively, in the tree, use drag and drop to draw a blue line from the failure cause to the desired failure mode to make this association. |
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List of Business Objectives |
A list of business objectives and the effects that the failure mode will have if the failure cause occurs, is derived from the failure mode, and is repeated here for convenience. |