ID Fan Steel Base FEA

[Hossam abdelkhalek]

Dear all what is the most suitable method for calculating the modal harmonic response for a steel base for a centrifugal fan
shall we put the bearings on the model and how to represent the fan that rotates for example 1000 rpm
thank you

 

[NRP99]

Here is rough guidline for your reference. Work out the details yourself.
1X Frequency=rpm/60
-IMO no need of modelling bearings for structure check
-Do the modal analysis
-Followed by harmonic/frequency response analysis for 0.5 X, 1X, 2X,3X etc.
-Check the response for frequency range near resonance frequency (mostly first 3 to 6 modal values)
-Should be ok if response of structure is within allowable criteria.

Edit:- This can also be done analytically(again rough guideline) by assuming fan base upto bearings as vertical beam fixed at base and finding natural frequencies for this. And checking the forcing frequency range(1X, 2X etc) against this value and modifying "beam" design to shift natural frequency away from the forcing frequency.