Inertia/Body Loads for a FE Model using Symmetry

[struclearner]

Dears,

When the symmetry is used for FE analysis of a model with mechanical load, for s half symmetric model, half the load is used, when loads, geometry and restrains of the model are symmetric about the plane of symmetry.

When a symmetric model also have inertia/gravity/body load acting on the whole structure, how that load will be applied to a model having a single plane of symmetry, if the symmetry will be used for analyzing the model.

Thanks for your input.

 

[karachun]

Use full gravity load, but check is gravity load is symmetric.

 

[Erik Panos Kostson]

Yes, distributed loads are fine (do not need modification, of course as karachun says they need to be symmetric with respect to the symmetry plane). If you have though say a beam with a point nodal load (e.g., 4 N) in the centre, and one only models half of it, then the nodal force at the symmetry point needs to be halfed (2 N), in order to get the same results between the half-symmetry model (2 N) and the full beam with a point force (4 N) in the centre.


This goes also for a point-force applied to a 3D rigid link cluster/model that has its central spider node on the symmetry plane (it is fine to use a rigid link cluster on a symmetry plane when applying a load there, see attached image, light blue rigid link cluster marked)