mesh density in high stress area

mpvnaresh

Hi all

 

I am doing a structural analysis where stresses are high at the sharp corners .

can any one suggest me how can i decide the element size in this case.(as the stresses goes on increasing with the fine meshing )

suppose if i want put a fillet at the sharp corner,i even need to mesh it fine to cover the fillet.

please help me in this.(my problem is similar to the attached)

 

I tried with different szes but with decrease in element size the stress going ion increased,putting a fillet driving me to mesh it fine to cover the fillet .

please help me in this regard.

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QuyNguyenDai

When you refine the mesh, you got bigger stress, that's normal. Have a look at:

• https://www.nafems.org/join/resources/knowledgebase/001/
• https://www.comsol.com/multiphysics/mesh-refinement
• https://caeai.com/blog/how-do-i-know-if-my-mesh-good-enough

mpvnaresh

Thanks for the information sir 

In my case the highly stresses region is having a sharp corner .I cannot put fillet as it is not there in my actual model.even if i put a fillet(2 or 3mm) only for the sake of convergence i need to mesh it very fine to capture.

I even have no test data.How to handle the problem.

 

 

QuyNguyenDai

You have to refine your mesh in 'critical' area to better get stress results.

But you can not refine the mesh to infinitely, because we're in 'Finite world'.

So, as many other thing in real life, you have to found  your compromise. And you say 'with size of 1mm, I'm satisfied my results, so I stop here'.

 

Simon Križnik

This effect is called stress singularity (sharp re-entrant corner) and is not physically meaningful. For more details:

https://www.digitalengineering247.com/article/dealing-stress-concentrations-singularities

http://www.acin.net/2015/06/02/stress-singularities-stress-concentrations-and-mesh-convergence/ 

mpvnaresh

thanks sir 

Vrey useful information.

I  am working on it.