Mesh Convergence Issue
Mesh Convergence Issue
(OP)
Hello, I'm new to FEA/FEM and was wondering if anyone has encountered the following problem with mesh density sensitivity before:
For some background, I'm using ABAQUS to model seismic isolation bearings to determine stability/critical behavior at various displacement levels.
Anyway, I've created 3 mesh sizes: a coarse mesh with roughly 3000 elements, a medium mesh with roughly 18000, and a fine mesh with roughly 72000 elements. The models have resulted in the solution from the fine mesh being somewhere in between the solutions of the coarse and medium, i.e. the solutions are not asymptotically approaching some value like I've seen in most literature (not on this subject, but in general). Is this "oscillation" of results indicative of something typical (such as accumulation of error from a mesh that's "too fine") -- does anyone have any suggestions or insight? I can provide more information regarding the model if needed.
Thanks in advance.
For some background, I'm using ABAQUS to model seismic isolation bearings to determine stability/critical behavior at various displacement levels.
Anyway, I've created 3 mesh sizes: a coarse mesh with roughly 3000 elements, a medium mesh with roughly 18000, and a fine mesh with roughly 72000 elements. The models have resulted in the solution from the fine mesh being somewhere in between the solutions of the coarse and medium, i.e. the solutions are not asymptotically approaching some value like I've seen in most literature (not on this subject, but in general). Is this "oscillation" of results indicative of something typical (such as accumulation of error from a mesh that's "too fine") -- does anyone have any suggestions or insight? I can provide more information regarding the model if needed.
Thanks in advance.





RE: Mesh Convergence Issue
I guess another question I had was should I just invest time in creating a 4th mesh somewhere in between the current medium and fine (or perhaps beyond the fine mesh).
Thanks again.
RE: Mesh Convergence Issue
RE: Mesh Convergence Issue
In the former case, the mesh refinement could be involved, but the interest in it could be minor; in the latter, with so much difference in an undisturbed portion of the model, there would be serious worries as to the validity of your approach.
I would use one model only, not certainly a fourth one, to be satisfied of the general distribution of stresses before going on, then a second model to analyze changes, mainly whether they are generalized or only local.
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RE: Mesh Convergence Issue
It is also important to ask if you are looking at stresses from averaged elements. Generally speaking the difference in stress between fully averaged and no averaging in an element should not fluctuate more then %5 for a refined mesh.
RE: Mesh Convergence Issue
RE: Mesh Convergence Issue
b2: medium mesh results
b3: fine mesh perspective
The main difference between the meshes is the number of elements radially and the bias of each element outward to maintain an aspect ratio of approximately unity.
RE: Mesh Convergence Issue
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b4: finer
b5: even finer?
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KTOP
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Thanks.
RE: Mesh Convergence Issue
Meshing a Cylinder
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