Mesh refinement limit
Mesh refinement limit
(OP)
Hi there!
I've been making a simple simulation of an aluminium plate.
In a previous post I already asked how to get the reactions on the supports.
My problem now is the more I refine the mesh, the higher the stresses get. This happens in a very specific area. I mean. Everything is "blue" and suddenly a big gradient in the maximum stress area.
In a first approximation I got an error of 10% with something like 30 MPa, now i have 116 MPa with a 6% global error.
I'm sure if I make the mesh finer the maximum stress will get larger and the error smaller. But, where is the limit?
thank you
regards,
http://img135.imageshack.us/g/20492407.jpg/
some pictures
I've been making a simple simulation of an aluminium plate.
In a previous post I already asked how to get the reactions on the supports.
My problem now is the more I refine the mesh, the higher the stresses get. This happens in a very specific area. I mean. Everything is "blue" and suddenly a big gradient in the maximum stress area.
In a first approximation I got an error of 10% with something like 30 MPa, now i have 116 MPa with a 6% global error.
I'm sure if I make the mesh finer the maximum stress will get larger and the error smaller. But, where is the limit?
thank you
regards,
http://img135.imageshack.us/g/20492407.jpg/
some pictures





RE: Mesh refinement limit
Rob Stupplebeen
https://sites.google.com/site/robertkstupplebeen/
RE: Mesh refinement limit
it helps, but i'm not experienced enough to decide if i can neglect this tension.
what do you mean with "plane strain detailed model"?
thank you!
RE: Mesh refinement limit
One way to avoid this for simple structures is to apply force in equilibrium. So you apply tension at one end and equalt tension at the other end. Then, you are in equilibirum. But you still need to constrain the model to avoid rigid body motion. You restrain one node with (Tx, Ty, Tz), then in the same plane, you restain a second node (Ty, Tz), and another node in Tz. (I don'T know if the order is right, but you need to constain all 6 DOF. Once you run your model, those three restraint should not react any significant force, because you model is loaded in equilibirum.
This usually applies easily for simple model. For more complicated model, I should suggest to put restraints as far away as possible of the region of interest and make sure that those big stresses are not detrimental (see with more experiences users).
RE: Mesh refinement limit
I assume from your picture that you have 2 materials or a step in the model. For the first is there a glue, is it press fit... For the second applying a fillet of appropriate size and then significantly refining the mesh may also be an option. However conventional knowledge would say not to include the fillets.
Rob Stupplebeen
https://sites.google.com/site/robertkstupplebeen/
RE: Mesh refinement limit
I'm busy with something else now, but I will try your ideas!
cheers,