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Concentric Shaft Arrangement

Question asked by Mark Thompson on Mar 21, 2013
Latest reply on Apr 2, 2013 by Mark Thompson

Good afternoon,

 

I'm looking for some advice on the best way to perform a static analysis and in the event of large stresses and/or deflections (unlikely) a non-linear analysis of the following  concentric shaft and bearing problem. Effectively I have a series of large concentric aluminum pipe sections which are designed to be supported within one another by a pair of four point contact bearings (i.e. locating LHS and non locating RHS) housing within the ends of each parent (i.e. outer) shaft. Please see attached screen grabs for an illustration of the arrangement, geometry and applied loads.

 

My question is whether the bearing connections are constraining the model as intended or whether I should opt for a differnt connection (e.g. rigid, spring, pin etc) or approximate with a cylindrical fixture (e.g. locating LHS = fixed radial/axial translation and non locating RHS = fixed radial translation). Obviously I've run simulations on both the bearing connections and cylindrical fixtures and the figures are close in each case, however, in both instances the 'bearing' restrains appear to maintain parallel axial alignment between every selected face restraint and the original assembly (datum) axis, obviously a crude approximation of such a deflection.

 

I've already preformed an analysis of each independent shaft and its applied loads including the equivalent reaction loads of the internal shafts/loads of its supported  bearing centers, however, this does not take account of the resultant deflection, although small, hence, a full assembly would be preferred.

 

Does anyone have any suggestions as to a more appropriate bearing restrain whose effective axis follows the curvature of each shaft/housing?

 

Thank you in advance.

 

 

Mark.

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