Understanding Beam Boundary Conditions for a Rotating Shaft

[Ben9622111222]

Hello,

Can anyone help me find the boundary conditions of the below given beam please. Its a clamped-free beam but the overhanging sectiona and the mass makes it confusing. Actually I am puzzled about finding the initial conditions.

 

[SteamKing]

It's not clear what type of analysis you want to perform on this arrangement.

Based on what little information you have provided, it appears you have two overhanging beams, one of which has a mass attached to the end. If you want to do a static structural analysis, you can treat each beam independently. If there is some vibration analysis going on, the method of clamping may need to be considered.

 

[Ben9622111222]

Yes. I am doing vibration analysis. Do you suggest pinned arrangement instead?

 

[SteamKing]

Yes. I am doing vibration analysis. Do you suggest pinned arrangement instead?

I'm not suggesting anything at this point. I'm just trying to understand what it is you're looking for.

 

[Ben9622111222]

Kk.. Please have a look ath the link below
http://ijiet.com/wp-content/uploads/2013/02/53.pdf

You can see, that the initial conditions here are easy enough to get and also proceed forward. In my case its not, due to the overhanging section

I am trying to make an equation like equation 10 in the above link for my system.

 

[SteamKing]

Kk.. Please have a look ath the link below
http://ijiet.com/wp-content/uploads/2013/02/53.pdf

You can see, that the initial conditions here are easy enough to get and also proceed forward. In my case its not, due to the overhanging section

I am trying to make an equation like equation 10 in the above link for my system.

Is there any forced excitation of this beam? If so, where is it located?

 

[Ben9622111222]

No there is no forced vibration. The rod is flexible, and it is rotated by a motor. the motor position is the clamped support shown. So when the rotation stops there will vibration at the tip. to modal this, I need to find the beam boundary conditions.

 

[SteamKing]

No there is no forced vibration. The rod is flexible, and it is rotated by a motor. the motor position is the clamped support shown. So when the rotation stops there will vibration at the tip. to modal this, I need to find the beam boundary conditions.

You need to 'model' the beam.

Well, you have certainly been keeping things close to the vest here. Based on your earlier posts, I never would have guessed you were looking at a rotating shaft.

Since the motor is located at an intermediate point in the shaft, each portion of the shaft will have two different static deflection curves, based on the loading conditions of the beam. When the beam starts to rotate, a whirling vibration will be set up. The critical speed of the shaft can be estimated by applying the Rayleigh method or Dunkerly's method.