mesh spheres embedded in a semi-sphere

[mountluoupc]

I'm modelling the interaction between an indenter and an organ of semi-sphere shape.

It is assumed that there are three small sphere nodules embedded in the organ. Thus there are three sphere holes in the organ part and three sphere noodles are they filled to these holes in assembly step.

But when I tend to mesh the organ part,there is an error coming out saying:"The regions highlighted in magenta cannot be meshed automatically using the assigned element shapes. They must be partitioned, assigned a tet shape, or manually meshed using the Create Bottom-Up Mesh tool." as attached to this post.The magenta regions refer to the three holes.

I followed this instruction, i.e., partitioned the part with datum planes,changed the element shape,but it still cannot be meshed.

Actually, it succeeded for once (the holes are also meshed), but when I submitted the job, there is one error saying some elements (the holes) are not assigned sections. But these holes are empty, they should not be assigned sections...

It is so confused, anyone can help me? Thanks.

 

[corus]

The regions highlighted appear not to be solid regions but edges. Is there some way you have made beam elements along these edges, or are they slithers that have been left from creating the part? In Abaqus Viewer you can view exactly the regions which haven't been meshed by selecting that set of elements in error and replacing them as the set to be viewed.

 

[mountluoupc]

Hi corus,

Thanks for your reply. Actually the highlighted area are holes embedded in the semi-sphere. Any suggestion? Thanks.

 

[rstupplebeen]

Have you tried converting to second order tets and meshing. It may not be the most computationally efficient but may be worth it to save user time and get your simulation running.

The 3 spheres are filled with a different material in the assembly? If so you can merge/combine the geometry so you have a coincident mesh.

I hope this helps.

Rob Stupplebeen

http://www.optimaldevice.com

https://sites.google.com/site/robertkstupplebeen/

 

[mountluoupc]

Hi rstupplebeen,

Thanks for your advice, I merged the nodules with the cortex. But the merged part still cannot be meshed (I used tet element type) as shown in the attached picture. Any suggestions?

 

[mountluoupc]

Due to some reason, it was meshed at last, but when I submitted the job, there is an error coming out "Error in job cubenodule: 8 elements have missing property definitions. The elements have been identified in element set ErrElemMissingSection." I think it is still due to the nodules, but I don't know how to check the element set. where to find ErrElemMissingSection? Thanks again!

 

[rstupplebeen]

Can you post your model? I'll take a look.

Rob Stupplebeen

http://www.optimaldevice.com

https://sites.google.com/site/robertkstupplebeen/

 

[mountluoupc]

Hi Stupplebeen,

Thanks for your reply, the attachment is the model.

 

[mountluoupc]

Hi Stupplebeen,

Here is the section view of the model.

 

[rstupplebeen]

I believe that you only posted images.

Rob Stupplebeen

http://www.optimaldevice.com

https://sites.google.com/site/robertkstupplebeen/

 

[mountluoupc]

Sorry for the mistake.

I thought you referred to the appearance of the model...

I uploaded the cae model to this post.

 

[rstupplebeen]

I was able to mesh your part by first merging the solids and then switching to a tetrahedral mesh. You may be able to get a hex mesh with liberal use of sectioning however it may not be worth it.

Assembly>Merge/Cut>Merge Geometry and Retain Intersecting Boundaries>Select medulla-1 and Part-6-1.

Mesh>Mesh Controls>Tet

Now you should be able to mesh your part.

I hope this helps.

Rob Stupplebeen

http://www.optimaldevice.com

https://sites.google.com/site/robertkstupplebeen/

 

[mountluoupc]

Hi rstupplebeen,

I followed your steps, it works and the part can be meshed finally!! Many thanks!

Actually, the error saying some elements (the holes) are not assigned sections happened again, but after I assigned sections to these regions it was solved!

 

[rstupplebeen]

The loss of assigned sections likely is because you had the same set names likely the default set-1 for multiple solids so when they are merged it doesn't know what to do.

I'm glad it worked for you. Your welcome.

Rob Stupplebeen

http://www.optimaldevice.com

https://sites.google.com/site/robertkstupplebeen/