Mass Represented by Lumped/Concentrated Mass Element in FEA 2

[struclearner]

When mass of the structure is represented by Lumped Mass or Concentrated Mass element in finite element analysis, it does not add any stiffness of the structure.
When the structure is subjected to inertial loading, i.e., gravity or acceleration loading, this concentrated mass is converted to weight and act as a force.
When there is no inertial load, only mechanical loads, like force, in a static fea, what this lumped or concentrated mass does.
It does nothing, because mass only comes into play when there is inertial loading.

Thanks for your clarification and valuable input.

 

[GregLocock]

In the presence of gravity it adds staic loads to the structure. in the presence of vibration it adds dynamic loads.

Cheers

Greg Locock


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[struclearner]

When the analysis has no gravity loads, no vibration or vibration analysis, only static analysis with mechanical loads in the form of force, and the calculation of the force like reaction at the tire of a vehicle has already included the masses of the supporting structure, then the including of these masses in the form of concentrated masses at their respective centers of gravity in the fe model/analysis, does not do anything at all.

 

[rb1957]

masses produce load only when a body force (or acceleration) is applied.

masses in a model loaded by forces do (should do) as you say "nothing at all".

assuming we're talking about the same FEA … linear static. If you're using a dynamic FE then yes load would be produced as the FE reacts the applied force with inertial acceleration of the mass.

another day in paradise, or is paradise one day closer ?

 

[struclearner]

Hello GregLocock and rb1957,
Thanks for the confirmation and clarification.