MP-21 · SHAFTS AND JOINTS
Shaft Combined Stress
Screen a solid round shaft under entered bending moment and torque, showing nominal bending, torsion, and von Mises equivalent stress.
Preliminary design support. Your inputs and results stay in this browser.
WHAT THIS SCREEN ANSWERS
Shafts usually carry bending and torque at the same time. A torsion-only screen can therefore understate the mechanical question when pulleys, gears, couplings, overhung loads, or bearing spans introduce bending. This page brings nominal bending and torsional stress together so an early shaft diameter can be compared under the combined loading that the layout actually implies.
Enter the bending moment and torque at the same shaft section, the solid shaft diameter, and an allowable supported by the real material condition and design context. MechPlane calculates nominal surface bending stress and torsional shear, then presents a von Mises equivalent stress. Zero torque correctly reduces the screen to the bending-only condition, but that does not make it a complete shaft analysis.
The calculation assumes a clean, uniform, solid circular section. Keyways, shoulders, splines, threads, cross holes, fillets, surface finish, corrosion, heat treatment, and fatigue cycles can dominate a real shaft. So can deflection and bearing alignment. The entered allowable is not a substitute for a material specification or a fatigue criterion.
Use this result to identify whether the section needs a fuller layout review. Continue to deflection, critical speed, keyway, bearing, and coupling checks as relevant. Confirm the actual geometry, loading, stress concentrations, fatigue model, material properties, and applicable requirements with qualified engineering review before release.