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Von Mises Stress simulation
Von Mises stress is the single number every design engineer checks before signing off on a part. It takes a complex multiaxial stress state (σx, σy, τxy) and reduces it to one equivalent value.
If that value crosses the material's yield strength, the part permanently deforms.
This interactive simulation lets you set normal stresses σx and σy, shear stress τxy, and the material yield strength using sliders. The Von Mises stress, safety factor, and yield percentage update in real time.
The left panel shows a color-coded stress element with arrows for every component. The right panel plots the Von Mises yield ellipse in the σx vs σy plane with your current stress state as a moving dot.
When the dot crosses the ellipse boundary, the material has yielded. A dashed Tresca hexagon is overlaid for comparison so you can see why Von Mises is less conservative. Presets include uniaxial tension, pure shear, biaxial equal, and general 2D stress.
Built for mechanical engineering students learning failure theories, FEA post-processing interpretation, GATE and PE exam preparation, and practicing engineers who want a quick visual stress check before running a full simulation.
Adjust the compression ratio from 4:1 to 14:1 and see how efficiency, peak pressure, and peak temperature change instantly. Every state point is calculated using actual isentropic relations (PVγ = constant) and constant volume heat addition.
Try this simulation yourself
Start with all sliders at zero. Von Mises stress reads 0 MPa, safety factor is infinite, gauge bar is at 0%. The stress element is empty and the dot sits at the origin inside the yield ellipse. No load, no risk.
Drag σx to 200 MPa. The element shows blue horizontal arrows pulling outward (tension). Von Mises stress jumps to 200 MPa. The dot moves right on the ellipse plot. The gauge bar fills to 80%. Safety factor drops to 1.25. You're approaching yield with just one stress component.
Now drag σy to -200 MPa (compression). The element adds green arrows pushing inward. Von Mises stress jumps to 346 MPa, well past the 250 MPa yield. The gauge bar hits 100%, the element turns red, and the info bar says "YIELDED." Opposite-sign stresses are the worst case for Von Mises. The dot has crossed the ellipse boundary.
Reset σy to zero and drag τxy to 120 MPa. Red shear arrows appear on all four edges of the element. Von Mises reads 208 MPa. Pure shear produces Von Mises stress equal to √3 × τxy. That √3 factor (1.732) is the reason shear yield strength is 57.7% of tensile yield. You can see it directly.
Try the Biaxial equal preset: σx = σy = 150 MPa, τxy = 0. Von Mises reads 150 MPa, not 300. Equal biaxial tension produces the same Von Mises as uniaxial. The dot sits on the 45° diagonal of the ellipse, the safest direction. This is why pressure vessels can handle more than you'd expect.
Drag the σ_yield slider from 250 down to 100 MPa. Watch the ellipse shrink on the right panel. The same stress state that was safe at 250 MPa yield is now deep in the failure zone. This is what happens when you pick the wrong material.
Compare the purple Von Mises ellipse to the dashed Tresca hexagon inside it. Tresca always yields first. The difference is largest at pure shear (about 15% more conservative). Most FEA software defaults to Von Mises because it matches experimental data better for ductile metals.