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Impeller Stress Calculations

Important Note regarding Stress Calculations :

Impeller failure can cause serious injury or even death to those in the vicinity.

The Impeller Stresses calculated by this program are based on two dimensional bending and hoop stresses.Care should be taken in using these results.

The stiffness requirements (Plate thickness) of the Impeller Back Plate and Front plate (shroud) should not be under estimated particularly for large fans even when the calculated stresses are very low.

The lower the stiffness the more easily the impeller can vibrate.

The majority of Impeller failures are due to fatigue problems caused by vibration or speed fluctuations. Vibration can occur from a number of sources including out of balance and natural frequency excitation. 

Fan manufacturers should be aware that natural frequency excitation results in rapid failure of the impeller even when the stresses calculated by this program are very low.

Natural Frequencies are usually determined by Finite Element Analysis or by testing the actual Impeller after manufacture.