Create Multiple SN Curves
The following methods are supported to create Multiple SN curves.
- From the Assign Material dialog, click the My Material tab and select your created material.
- Select Number of SN curves as Multiple.
- Select Curve Type as Multi Ratio/ Multi Mean Stress/ Multi Haigh Diagram.
- Select Input Method.
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Define any necessary parameters.
Note: The images below use the default values as a guideline.
Multi Ratio Curves
Multiple stress life curves are defined at different values of stress ratio.
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Select Input Method.
Options:
- Stress Intercept, 1-seg (multiple single sloped SN curves with respect to stress ratio)
- Stress Intercept, 2-seg (multiple two sloped SN curves with respect to stress ratio)
- XY Data (Xi, Yi data representing multiple SN curves with respect to stress ratio)
- Select Stress Type to select SN curve based on Amplitude/ Range/ Maximum Stress (Max).
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Table Data: Input Table of single sloped SN curves with respect to stress
ratio.
Note: Alternately, multiple .csv files of Stress Ratio SN curves can be imported.
- Select Curve Extrapolation as True.
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If XY Data curve:
NC : Fatigue transition point. After this point, fatigue strength is offset by the surface correction factor. Before this point, fatigue strength is proportionally reduced. (Default = 60000)
NFl : Endurance limit. Number of cycles at which damage can be considered zero. (Default = 100000000)
- Set SE to 0.0 to define Standard Error of log(Stress).
Multi Mean Stress Curves
Multiple stress life curves are defined at different values of mean stress.
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From the following, select the Input Method.
- Stress Intercept,1-seg (multiple single sloped SN curves with respect to mean stress)
- Stress Intercept,2-seg (multiple two sloped SN curves with respect to mean stress)
- XY Data (Xi, Yi data representing multiple SN curves with respect to stress ratio)
- Select Stress Type to select SN curve based on Amplitude/ Range/ Maximum Stress (Max).
-
Table Data: Input Table of single sloped SN curves with respect to mean
stress.
Note: Alternately, multiple .csv files of Stress Ratio SN curves can be imported.
- Select Curve Extrapolation as True.
-
If XY Data curve:
NC: Fatigue transition point. After this point, fatigue strength is offset by the surface correction factor. Before this point, fatigue strength is proportionally reduced. (Default = 60000)
NFl : Endurance limit. Number of cycles at which damage can be considered zero. (Default = 100000000)
- Set SE to 0.0 to define Standard Error of log(Stress).
Multi Haigh Diagrams
Multiple Haigh Diagrams are defined at different values Life.
- Select Stress Type to select Haigh Diagram based on Amplitude/ Range/ Maximum Stress (Max).
- Select Table Data: Input Life and the number of point and click .
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Enter Sm vs Sa table and click Update.
Note: Alternately, import of CV table.
- Click the Life drop-down and click Add new.
- Enter the new life and repeat the process to save New Haigh Diagram.
- Select Curve Extrapolation as True.
-
If XY Data curve:
NC : Fatigue transition point. After this point, fatigue strength is offset by the surface correction factor. Before this point, fatigue strength is proportionally reduced. (Default = 60000)
NFl : Endurance limit. Number of cycles at which damage can be considered zero. (Default = 100000000)
- Set SE to 0.0 to define Standard Error of log(Stress).