Skip to main content
New Sheet Tutorial

Torque and Shear Stress in a Power Transmission Shaft



  • Inputs

    This sheet calculates the torque and shear stress experienced by a solid circular shaft that is transmitting a specified power at a specified shaft speed. The three input parameters are defined below.









  • Note on Specifying Angular Velocity in EngineeringPaper.xyz

    To define the angular velocity ω in revolutions per minute, [cycles/min] is used as the unit. Note that angular velocity quantities need to be multiplied by 1 [1/rad] to force EngineeringPaper to treat radians as unitless. The results will be numerically correct without this step but the radians unit will hang around, not allowing the torque and stress unit conversions to be completed. EngineeringPaper doesn't automatically treat radians as unitless to allow proper conversions between degrees and radians. Additionally, treating radians as unitless would required treating degrees as unitless which would result in incorrect calculations involving degrees.


    Calculate Torque

    The torque on the shaft can be calculated from the power transmitted and the angular velocity by the following equation. Note that the units for the torque are being converted to [N*m] since the torque value is displayed as Joules by default since both N*M and Joules are equivalent SI units.







  • Calculate Stress

    First, the polar moment needs to first computed:





  • Finally, the peak shear stress for a transmitted torque can be calculated using the following equation: