Deciding Element Size
Altair EmployeeRecently I meshed a model, almost Rectangular block with size 850 X 200 X 200 with an element size of 10 and carried of analysis. After extracting stress values I again meshed the model with element size of 8. I observed that by changing the element size values(decreasing) my stress results were changing drastically and kept increasing. I was not able to conclude to a point and unable to decide the correctness of my analysis. How shall I decide element size?
Answers
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With increase in number of elements(decreasing the size of elements) the stress value must converge this is called convergence study.It depends on you how much accuracy you want in your case.If the result is not converging then it might be the case of stress singularity.
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Hi,
Mesh density and solution convergence are closely related and the factors which determine that relationship can be controversial. The correct mesh, from a numerical accuracy standpoint, is one that yields no significant differences in the results when a mesh refinement is introduced.
Please go through https://altairuniversity.com/wp-content/uploads/2014/02/meshing.pdf which explains the same.
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if you are doing linear static analysis, its better to use higher number of nodes, because of less computational time. if your are doing crash or non-linear simulation with same number of nodes, it consumes lot of time. so deciding the element size or number of nodes is based on type of analysis too.
if you want to play with the element size, at least you should have past experience in the same domain so that you can easily decide the elem size. But if you are doing meshing first time for that model, you should have experimental results to match with the numerical, if both are matching closely then fine, otherwise you have to play with the elem size.
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