Theoretical Modeling of Cylindrical Shell with Added Mass
Theoretical Modeling of Cylindrical Shell with Added Mass
(OP)
Hi guys,
For FEM validation I need to be able to come up with a theoretical solution for the vibration of a combination structure consisting of a cylindrical shell which runs into a block of comparable dimensions.
I am familiar with the theory behind the vibration of cylindrical shells, but never had to analyze combination structures.
At the moment I'm trying to use the receptance method to do so. The problem is that I'm not sure how to incorporate the block mass into the analysis. One of the reasons for this is that from all the information I have read, there is only discussion about how to do this with point masses and doesn't model the distribution of the mass around the end of the shell effectively.
I have uploaded an image of a similar type of structure.
For FEM validation I need to be able to come up with a theoretical solution for the vibration of a combination structure consisting of a cylindrical shell which runs into a block of comparable dimensions.
I am familiar with the theory behind the vibration of cylindrical shells, but never had to analyze combination structures.
At the moment I'm trying to use the receptance method to do so. The problem is that I'm not sure how to incorporate the block mass into the analysis. One of the reasons for this is that from all the information I have read, there is only discussion about how to do this with point masses and doesn't model the distribution of the mass around the end of the shell effectively.
I have uploaded an image of a similar type of structure.





RE: Theoretical Modeling of Cylindrical Shell with Added Mass
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Theoretical Modeling of Cylindrical Shell with Added Mass
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Theoretical Modeling of Cylindrical Shell with Added Mass
Is a thick walled tube the same as a thick walled shell? My interpretation was that a THIN walled shell shell neglects rotary inertia and shear deformation whilst a thick walled shell does not. Or am I completely missing the mark here, and a tube is modeled completely different to a thick shell?
RE: Theoretical Modeling of Cylindrical Shell with Added Mass
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Theoretical Modeling of Cylindrical Shell with Added Mass
the diffulty is agreeing upon how you support your model, as the stock design plays a large part in the recoil dynamics.
for machine support of the receiver, the calculation of the normal modes and natural frequencies of the barrel are described as a hollow beam with given mass distribution.
shear and rotational inertia are always a good idea