Let’s Play Twister!
Strain gage sensors have been used for many years for determining the torsion applied to cylindrical shafts.
When the shaft is loaded in torsion, it creates a state of pure shear and the applied torque can be found by orienting rosettes where the gridlines are positioned at 45 degrees to the axis of the shaft. Some common applications can be found in pulp and paper mills for measuring efficiency, output shafts for large ships for optimum engine setup, and even power monitoring for cyclists so they can determine how much energy was expended during training, and, of course, there are many others. For most of the these applications, the strain gages are used to construct a full Wheatstone bridge circuit to double the sensitivity to torque and cancel unwanted effects due to axial or bending load components.
Following are two of our most popular strain gages for torque measurements:
187UV- Common Tab Shear pattern:
250US “Windmill pattern”
So the next time you have a shaft under torsion, let strain gages help you to untie the knots!