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[NathanEmery]

Hi I am currently investigating noise simulation using Harmonic Analysis. I have multiple mechanical components enclosed in an acoustic domain generated by an enclosure in space claim following the tuning fork acoustics tutorial video on YouTube. In the tuning fork acoustics video, Peter mentions he would slice up the geometry to get more accurate meshing but I am not sure how to do this. My mesh is not generating for my acoustic domain for any settings, pre defined or ANSYS default. I think this is an issue of fine mesh at contact regions of the mechanical structures and the acoustic domain. What meshing techniques I.e. inflation or contact mesh sizing should I use in order to generate the acoustic domain mesh. Please let me know, I can also include pictures of files if needed

[Keyur Kanade]

You may want to look at 

https://www.youtube.com/watch?v=nEOC8rDnnRo

Also suggest you to go through search on community as there are may posts regarding meshing.

Regards,

Keyur

 

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[NathanEmery]

Hi Keyur, 

 

Thank you for the reference video, this is very good for various meshing techniques, however I am still facing issues with the enclosure feature to create an acoustic domain. 

 

When the FE acoustic enclosure structure surrounds another FE mechanical structure my mesh is failing. Is there any options in ANSYS that allows for an enclosure to match the surface meshing of the components it is surrounding. Please advise. 

 

Thank you, 

 

Nathan

[Keyur Kanade]

You can use face meshing. Can you please insert some images and explain more. 

Regards,

Keyur

 

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[NathanEmery]

For example here are two different failed meshes. The first image is when I allowed ANSYS to generate default mesh and the second image is when I tried to define contact sizing between the mechanical components and the acoustic domain.  The acoustic domain is a sphere and these pictures are from a sectional view. 

As can be seen in the pictures the areas of the mechanical components that meet the acoustic domain have very fine mesh. Is there any option in ANSYS to for the enclosure to match all boundary conditions mesh? 

[peteroznewman]

I recommend you take three orthogonal planes at the center of your air sphere and slice the sphere and mechanical parts using those three planes into smaller pieces. Use Shared Topology to put the pieces of air back into one part and put the mechanical parts back into another part or parts as the case may be. I think that will help the mesher to fill those volumes.

[NathanEmery]

Hi Peter, 

Thank you for the recommendation, I used the three orthogonal planes to split and share all the geometry, both acoustic and mechanical components, but the meshing still failed. 

I believe the problem may be the very small air gap areas surrounding one of the mechanical components, this is reflected by the picture in green. I have tried contact size meshing for these small areas in contact and I've also tried some inflation for the areas of concern but neither worked. 

I've attached some pictures to described my issues. Please let me know if you see any problems or if I should try another method to generate the mesh. 

Thank you, 

Nathan

 

[Keyur Kanade]

i suggest you to take only quarter of the domain for debug purpose. 

try to mesh only quarter. if meshing fails, right click on error message and select show problematic geometry. please observe the location carefully and make modifications at geometry or meshing controls. 

once you could mesh quarter of geometry, you can apply similar strategy to entire domain. 

Regards,

Keyur

 

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[peteroznewman]

 Nathan, I agree with Keyur that you should initially work on a small piece of this.

I expect you are correct about the source of the problem. I expect those thin "petals" an important part of the model.

I can see that the sphere has not been sliced by the third plane.

In any case, if you want to share your model, you can right click on the Mesh and Clear Generated Data, then File > Save, then File > Archive and then you can attach the .wbpz file after you post a reply as long as the file size is < 120 MB. Say what version of ANSYS you are using in your reply.

[NathanEmery]

Thank you both Keyur and Peter for your suggestions, I edited the mesh appropriately and figured out the meshing issues with the small air gaps.