Von Mises Safety Factor Calculator — Failure Criteria & Yield Strength Check
Calculate Von Mises safety factor using yield strength and Von Mises stress.
Enter the known values and review the calculated result
Input parameters
Use consistent values and select the intended engineering units.
Input mode
Stress components
Von Mises stress
Material properties
Results
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Method, application and limitations
Review the calculation method, intended application and engineering assumptions before using the result in a design decision.
Formula and calculation method
Von Mises safety factor formula:
SF = σy / σvm
Input mode logic:
- For direct input: σvm = entered Von Mises stress
- For stress components: σvm = Von Mises stress calculated from σx, σy, σz, τxy, τyz, τzx
where:
- SF — Safety factor (dimensionless)
- σy — Yield strength (Pa)
- σvm — Von Mises stress (Pa)
- σx — Normal stress X (Pa)
- σy — Normal stress Y (Pa)
- σz — Normal stress Z (Pa)
- τxy — Shear stress XY (Pa)
- τyz — Shear stress YZ (Pa)
- τzx — Shear stress ZX (Pa)
When to use this calculator
When to use this calculator:
- Check the safety factor of a part when the Von Mises stress is already known from another calculation.
- Calculate safety factor from a full 3D stress component state.
- Compare equivalent stress against material yield strength.
- Identify whether the calculated safety factor is below yield, near the warning range, or above the safe range.
- Classify the stress state when normal and shear stress components are entered.
How to interpret the result
Von Mises safety factor is defined as the ratio between yield strength and Von Mises stress.
The result depends on material yield strength and equivalent stress. Increasing yield strength increases the safety factor. Increasing equivalent stress decreases the safety factor.
- Safe — safety factor is greater than or equal to 1.5.
- Warning — safety factor is greater than or equal to 1.0 and lower than 1.5.
- Unsafe — safety factor is lower than 1.0.
- Invalid — yield strength is missing or not positive, direct Von Mises stress is missing or not positive, all stress components are zero, input mode is not selected, or the stress calculation fails.
The result is used to evaluate the margin between equivalent stress and yield strength.
Calculation example
Example:
A user checks a machine bracket with a known Von Mises stress and a selected material yield strength.
- σvm — Von Mises stress = 120 MPa
- σy — Yield strength = 355 MPa
SF = 355 / 120 = 2.958
Assumptions and limitations
- Yield strength must be a finite positive value.
- Direct Von Mises stress must be a finite positive value when direct input mode is selected.
- At least one stress component must be non-zero when stress component mode is selected.
- Missing stress components are treated as zero in stress component mode.
- The safety factor is calculated only from yield strength and Von Mises stress.