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  1. Basit Shafi

    Shaft Critical Speed Calculator Based on Melvin prohls Method

    @Electricpete, so would the picture agree with what you are saying I only have these two cases for now. The only thing I don't understand from this is where is that half split coming from , is there any proof using parallel axis theorm or it is just an approximation? Thank you Basit
  2. Basit Shafi

    Ball and Roller Bearing Stiffness approximate Models for rough estimation

    Hi Tmoose, where does this typical value of 1000000 lbs / inch come from any reference? will this apply for both rollers and balls ? Thank you
  3. Basit Shafi

    Ball and Roller Bearing Stiffness approximate Models for rough estimation

    Hi, For a quick initial rotor dynamic analysis many people assume that the bearing supports have infinite stiffness and they calculate the fundamental critical speed based on this assumption which is not true. To add some reality to this , are there any simple mathematical models or free...
  4. Basit Shafi

    Shaft Critical Speed Calculator Based on Melvin prohls Method

    Hi, @electricpete, let me know when you get time. Basit
  5. Basit Shafi

    Shaft Critical Speed Calculator Based on Melvin prohls Method

    @electricpete Thanks so we are on the same page, with regards to Vo shearing force in his paper yes it cant be the shear at bearing. I had a simple quick question for you, to idealise the system into lumped mass system , where masses are concentrated at each node, for gyroscopic effects to...
  6. Basit Shafi

    Shaft Critical Speed Calculator Based on Melvin prohls Method

    @electricpete Hi , thank you once again , I understand the shear in the shaft (Except at bearing points) is due to centrifugal loading which is active not reactive , at bearings though it is a combination of centrifugal force and bearing force isn't ? Please refer to diagram attached with...
  7. Basit Shafi

    Shaft Critical Speed Calculator Based on Melvin prohls Method

    @electricpete First of all Thank you so much for your response , I greatly appreciate that! I just wanted to clarify one thing , shear force at bearings does indeed change , but logically the shear force at bearings would be as mentioned in the picture ,attached , where the shear due to...
  8. Basit Shafi

    Shaft Critical Speed Calculator Based on Melvin prohls Method

    @GregLocock , I know that bit , I just wanted to know how to add the moments properly which I have done now. Thank you for your response. @electricpete The paper that I have attached has the same essence as that of the transfer matrix method ( the initial conditions lay a chain reaction of...
  9. Basit Shafi

    High vibrations in 300kW motor during no load after tightening of foundation bolts

    electricpete , sorry I am new to this forum could you respond to a thread titled "Shaft Critical Speed Calculator Based on Melvin prohls Method "
  10. Basit Shafi

    how to make opening in tubular member in IdeaStatica

    electricpete , sorry I am new to this forum could you respond to a thread titled "Shaft Critical Speed Calculator Based on Melvin prohls Method "
  11. Basit Shafi

    Shaft Critical Speed Calculator Based on Melvin prohls Method

    Hi, I am trying to program a critical speed calculator , the prime purpose is to calculate the first critical speed as accurately as possible by taking into account the gyroscopic effects and bearing stiffness , It should also estimate to 2nd and third critical speeds in some instances where a...

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