Multiaxial Strain-Life Analysis

If needed, please go to the Constant Amplitude section for a review of the general terms and terminology related to Strain-Life fatigue analysis.

What is the difference between Multiaxial Fatigue Calculators and Multiaxial Fatigue Analyzers? Multiaxial Fatigue Calculators are used for constant amplitude loading where the largest cycle is assumed to do all of the fatigue damage. The Multiaxial Fatigue Analyzer counts cycles and sums fatigue damage for all cycles. Both use the same cyclic plasticity models. More damage models are available with the Multiaxial Fatigue Calculators.

Supported File Types | Working With Files

Enter as much data as you know. If it is not enough, you will be asked for more. Fields with a light blue/gray background represent the minimum required data to begin calculations. Other data may become necessary as calculation proceeds. Pressing the button provides help in the form of an equation or default information for a parameter.

Experienced user mode is off. Turn experienced user mode on for a more concise form.

Click on the button below to learn by example:

Loading

You may enter the loading in a spreadsheet, paste from the clipboard or enter as a sine wave.

Use the Plot button below to verify that the correct loading information was entered.

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Enter up to ten points. You may paste tab-delimited text (such as would be copied from a spreadsheet) into a box, and it will be expanded out automatically.

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Material

You may load a material from the database by selecting it and clicking on "Load Material", or browse the database by clicking the "Material Property Finder" button, or specify individual properties directly. Clicking "Material Property Estimator" will show the default properties that are computed from the input values.

For registered users, the Material Property Estimator will display a plot of the data. Registered users may also save this material in their personal database by clicking the "Save Material" button.

Name
Type
Fatigue Strength Coefficient σf′ =
Fatigue Strength Exponent b =
Fatigue Ductility Coefficient εf′ =
Fatigue Ductility Exponent c =
Elastic Modulus   E =
Fatigue Limit   SFL =
Fatigue Limit Reversals   2NFL = Reversals
Cyclic Strength Coefficient   K′ =
Cyclic Strain Hardening Exponent n′ =
Ultimate Strength Su =

Shear

Shear Fatigue Strength Coefficient τf′ =
Shear Fatigue Strength Exponent bγ =
Shear Fatigue Ductility Coefficient γf′ =
Shear Fatigue Ductility Exponent cγ =
Nonproportional Hardening Coefficient αNP =
Poisson's Ratio ν =
Shear Modulus G =

Damage Model

Fatemi-Socie k k =
Brown-Miller S S =

Surface Finish

Fatigue usually starts at the surface so that the quality of the surface finish is very important. The surface finish becomes even more important as the strength of the material increases.

Either specify the surface factor directly or choose a finish from the drop-down box. If you don't know, a default value of 1 will be used.

Surface Factor kSF = or

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