Explore the Shaft Torsion & Angle of Twist Simulator
Apply a motor torque to a solid or hollow shaft and watch it visibly twist, with live shear stress, angle of twist, power transmitted.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
Illustration. Open the tool for the real thing.
See it in action
The Shaft Torsion & Angle of Twist Simulator with sample data entered and the result showing.
What is the Shaft Torsion & Angle of Twist Simulator?
Apply a motor torque to a solid or hollow shaft and watch it visibly twist, with live shear stress, angle of twist, power transmitted and a pass/fail safety check. It runs in your browser, so a change to a setting or a drag on an object shows up at once.
Power transmission shafts in cars, ships, wind turbines and industrial gearboxes, drill strings in oil and gas drilling, robot and machine-tool spindles, and aircraft engine shafts are all sized using this exact torsion analysis.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
Torsion twists a shaft about its own axis; the polar moment of inertia J measures how well the cross-section resists that twist, larger for a bigger or hollower-but-thicker-walled section.
Shear stress from torsion is zero at the center and rises linearly to a maximum at the outer surface (τ = T·c / J), which is why hollow shafts use material efficiently — they remove low-stressed material near the center.
The angle of twist θ = T·L / (J·G) grows with a longer shaft or a softer material (lower shear modulus G), and shrinks with a stiffer cross-section.
Switch from solid to hollow with the same outer diameter and see how much the maximum shear stress and angle of twist change.
Keep the torque fixed and swap between steel, aluminum, brass and titanium — which one twists least for the same size?
Try the design challenge: find the smallest-diameter steel shaft that can still transmit 5 kW at 1500 RPM safely.
Used for
Pick one to see how it fits.
Engineering learners
Engineering and technology students, makers, robotics clubs and teachers of design and technology.
Try it freeTeachers
For teachers: project the Shaft Torsion & Angle of Twist Simulator on the board, let students predict the result, then run it together and test this: Keep the torque fixed and swap between steel, aluminum, brass and titanium — which one twists least for the same size?. For students: change one thing at a time and write down what changes.
Try it freeHow it compares
A plain look at this tool next to the usual alternative.
| This simulation | Textbook diagram | |
|---|---|---|
| Interactive | Drag, tap and change settings | Fixed picture |
| Install | Nothing to install | Not needed |
| Cost | Free to use | Depends on the book |
Questions people ask
Why do hollow shafts transmit torque more efficiently than solid shafts of the same weight?
Shear stress is lowest near the center of a shaft, so that material barely contributes to resisting torque. A hollow shaft removes that underused material and puts more material near the outer radius where the stress — and therefore the resistance to twisting — is highest, giving a better strength-to-weight ratio.
What is the difference between shear stress and shear strain in torsion?
Shear stress (τ) is the internal force per unit area resisting the twist, and it's what you compare against the material's strength. Shear strain (γ) is the geometric distortion angle at a point, related to stress by γ = τ / G. The angle of twist θ you see the whole shaft rotate by is the accumulated effect of that strain along the shaft's length.
Why does angle of twist matter if the shaft is not overstressed?
Excess twist (angular deflection) can misalign gears, couplings or timing components even when the stress is well within the material's strength. Many real shaft designs are limited by an allowable twist per unit length rather than by stress alone.
Is the Shaft Torsion & Angle of Twist Simulator free to use?
Yes. The Shaft Torsion & Angle of Twist Simulator is free, needs no signup or download and runs in your web browser. It is part of the Engineering group of AZRS simulations.
Does the Shaft Torsion & Angle of Twist Simulator work on a phone or tablet?
Yes. The Shaft Torsion & Angle of Twist Simulator takes touch input as well as mouse input, so you can use its 7 adjustable settings with a finger. A larger screen makes the controls and graphs easier to read.
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Try the Shaft Torsion & Angle of Twist Simulator now
Apply a motor torque to a solid or hollow shaft and watch it visibly twist, with live. Free to use.
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