Learning Forum

[Kampanat Cheng]

Good afternoon,

I have been working on a structural project. Can anyone suggest me on how to mesh correctly because my result is not converging. I have try to fillet the sharp edge and use the refinement at the hight stress area but the result still not converge. Should I try to use non-linear material or just ignore those area.

This is my setup

This is the area where the stress is maximum

Thank in advance.

[ErKo]

 

Hi

 

These are stress singularities.

 

See here for a good article on this topic.

https://www.linkedin.com/pulse/stress-singularities-concentrations-mesh-fea-marcos-ac%C3%ADn-gonz%C3%A1lez

 

For frame type of structures like the one you show, one would use often beam elements not solid 3D parts/elements (beams do not suffer from the above like solid 3D elements do):

See here for a tutorial.

https://www.youtube.com/watch?v=hb7BUcug8wY

 

Thank you

 

Erik

 

 

 

[Kampanat Cheng]

Thank you so much, very useful and informative.

By the way by using the beam element there will be no von mises stress and safety factor in the solution. Is there a way to find the von mises stress and the safety factor of the model?

[ErKo]

 

 

 

Hi Yes, there is VM, principal,…

stress for beams – just set (beam section results) as below:

 

for safety factor user defined results say based on VM stress divided by yield say 200 E6 
SEQV/200E6

 

[Kampanat Cheng]

Thank so much, but is there a way to apply force to an area like this

cause when I create the model by using the cross section command, the model will only be transparent model and I can't edit anything to the surface so I can't apply force as above picture.

The model will only look like this.

If there is no way, I will use the 3d solid model and just ignore the area where the stress is singularity.

Thank you sir.

[ErKo]

 

 

Hi 

You just need a force there (can also be remote force if it is off the centre of the beam), the area is not really important (if it was you would need to model what is causing that force there in detail). You can just apply it to a vertex/node placed in the same length location along the line body. 

 

Erik

 

 

[Kampanat Cheng]

Okay, Thank you for helping me sir.