Amount of shear applied and impact force of a Kitchen blender

If you know the power (watts) and the speed (RPM) of the blender motor you can get the torque. From the torque and the diameter of the propeller (moment arm) you can get the force on the end of the blade. As the cutting edges on a blender is on the flap end of the propeller you can measure the length of the cutting edge.

Now use the force at the end of the propeller, divide this by the length of the cutting edge and the number of propeller blades and you'll get the applied shear by the propeller.

Granted this is simplistic calculation is dependent on the propeller speed which varies under load, and does not include collision forces that occur inside the blender, but it's a fair start to a solution of the problem in lieu of a detailed mathematical model. But one has to recognize an engineering mantra--one measurement is worth a thousand calculations.

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