The Fatigue Check Plot alerts you if certain regions of your model are likely to fail due to repeated loading and unloading over infinite time. The plot is based on a single constant-amplitude fatigue event with a fully-reversible or zero-based loading.
To display this PropertyManager, run a static study. Right-click Results and select Define Fatigue Check Plot. You need a Simulation Professional or Simulation Premium license to see this option.
The Fatigue Check plot is not available for composite shells or beams.
Bodies to Check
| Select all bodies |
Enables selection of all bodies in your model. |
| Select body |
Selects the body to include in the Fatigue Check Plot. |
Modifying Factors
Apply the reduction factors to the fatigue strength of the selected bodies. Once the reduction factors are determined, the fatigue strength, FS(component), of the selected components in their working condition is evaluated as:
FS(component) = FS(material) x Surface Finish Factor x Loading Factor x Size Factor
The material fatigue strength, FS(material) , equals half the material's tensile strength.
| Loading type |
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Applies zero-based fatigue loading to determine the mean and alternating stresses.
Mean stress = Alternating stress = ½ * max [P1 or (P1-P3)/2)]
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Applies fully-reversed fatigue loading to determine the mean and alternating stresses.
Mean stress = 0
Alternating stress = max [P1 or (P1-P3)/2]
P1,P2, P3 are the first, second, and third principal stresses, respectively.
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| Calculate |
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Specifies the fatigue strength reduction factors. |
| Surface Finish Factor |
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Specifies the correction surface finish factor. A surface finish correction allows the estimate of the fatigue strength of the part in its working condition. Select an appropriate surface finish type from the list or select Other to enter a user-defined value. The range is from 0.1 to 1. |
| Loading Factor |
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Specifies the correction loading factor. Fatigue limits are usually determined from test specimens under bending. A specimen loaded in tension has a lower fatigue limit. Select a loading type from the list, or select Other to enter a user-defined value. The range is from 0.1 to 1. |
| Size Factor |
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Specifies the correction sizing factor. Based on experimental results, larger parts have lower fatigue limits than smaller parts. The range is from 0.1 to 1. |
| Specify |
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Sets the fatigue strength cumulative reduction factor which is equal to: Surface Finish Factor x Loading Factor x Size Factor
The range is from 0.001 to 1. |
Material
The material description and fatigue strength are shown when you select a single body. The fatigue check plot calculations are performed, and you are notified if your model is susceptible to fatigue failure.
A green icon indicates that the model is safe, and will not fail under repeated cycles of loading. All selected bodies appear blue in the graphics area.
A red icon alerts you that parts of your model could fail due to cycling loading. The regions of your model that are susceptible to fatigue are shown in red. Run a Fatigue study to access the safety of your design in more details.
| Scale all fatigue strength |
Multiplies the fatigue strength of the selected components by the given factor. The range is from 1 to 100. |
| Minimum safety factor |
Divides the fatigue strength of the selected components by the given safety factor. The range is from 1 to 10. |
The modified fatigue strength of the component is:
Modified fatigue strength = FS(component) * Scale factor / Safety factor
Type a scale factor or safety factor larger than 1 and click in the graphics area. The fatigue check plot is calculated and the color of the the selected components is updated in the graphics area.