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How apply forces in nodes
Posted May 23, 2017, 3:05 p.m. EDT 2 Replies
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Dear all,
I have a questione for you. I'm a new user of Comsol. I would try to perform a frequency response function of a classical alluminum plate by applying a force in a node of the mesh and measuring as output the accelerations of some nodes. I tried to do it but I am not able to select nodes and so I can Apply the force only on the grids of the geometry. How can I apply the force on some nodes that are not grids?
And hence, at same time, how can I require an output (acceleration) on a node and not a grid?
I have a questione for you. I'm a new user of Comsol. I would try to perform a frequency response function of a classical alluminum plate by applying a force in a node of the mesh and measuring as output the accelerations of some nodes. I tried to do it but I am not able to select nodes and so I can Apply the force only on the grids of the geometry. How can I apply the force on some nodes that are not grids?
And hence, at same time, how can I require an output (acceleration) on a node and not a grid?
2 Replies Last Post May 24, 2017, 12:11 p.m. EDT
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Posted:
7 years ago
Hi
from your question one could expect you are used to "classical FEM programmes" of the older types, those starting with A or N or M ... Here the first thing you talk about is mesh elements and nodes. In COMSOL we are talking about physics, Domains of material, and their Boundaries (these are the COMSOL Entities).
So to apply a given load (in FEM this is a pressure or a force DENSITY N/m^2 you need a boundary or a given area onto which you apply the load. The TOTAL force is then the integrated pressure over the load area.
So you need to define a Boundary (Area in 3D, line in 2D with a default depth, ...) onto which you apply your force density. And then you will get there.
In COMSOL the discretization or meshing process is the last you do before you solve NOT the initial work. This allows you to easily set up your physics (on Domains and BC or Bou8ndaries) and then adapt your mesh afterward at your will and need WITHOUT redoing the full model. A major advantage of COMSOL and a huge gain in time :)
--
Good luck
Ivar
from your question one could expect you are used to "classical FEM programmes" of the older types, those starting with A or N or M ... Here the first thing you talk about is mesh elements and nodes. In COMSOL we are talking about physics, Domains of material, and their Boundaries (these are the COMSOL Entities).
So to apply a given load (in FEM this is a pressure or a force DENSITY N/m^2 you need a boundary or a given area onto which you apply the load. The TOTAL force is then the integrated pressure over the load area.
So you need to define a Boundary (Area in 3D, line in 2D with a default depth, ...) onto which you apply your force density. And then you will get there.
In COMSOL the discretization or meshing process is the last you do before you solve NOT the initial work. This allows you to easily set up your physics (on Domains and BC or Bou8ndaries) and then adapt your mesh afterward at your will and need WITHOUT redoing the full model. A major advantage of COMSOL and a huge gain in time :)
--
Good luck
Ivar
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Posted:
7 years ago
If you really WANT to apply a point force all you need to do is to define a point in the geometry specification. Then you will be able to specify the force at that point.
For outputs you can either define additional points in the geometry OR define a Cut Point under Results > Data Sets.
D. W. Greve
DWGreve Consulting
For outputs you can either define additional points in the geometry OR define a Cut Point under Results > Data Sets.
D. W. Greve
DWGreve Consulting