Learning Forum

[Anirban Mondal]

Hi,

I am looking forward to model hexagonal honeycomb structure beam and then perform 3 point bend analysis on the beam. I am not quite familiar about the way to model it in Ansys. If someone could share some pdf/video tutorial and workshops that could help me create the model and run the simulation then it would be very helpful. Material system that I will be using is milled carbon fiber epoxy composite. Thanks for all your help.

[peteroznewman]

Read this discussion.

[Anirban Mondal]

Hi, 
Thanks for your reply. Can you please help/guide me with the very first step of how to create hexagonal honeycomb beam structure in Ansys. Please let me know the module that I need to effectively model that. Also if you have any workshop related to it please share it with me.

[peteroznewman]

https://www.youtube.com/watch?v=GmpPWFRl9-E

[peteroznewman]

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

[Anirban Mondal]

Hi Peter,

Thanks for sharing this video.

However, the shared video did not answer my question.

Question1: How do I create a beam with hexagonal honeycomb infill? Is honeycomb creator a perfect tool to create honeycomb infill patterns? Please let me know.

Question2: I am looking forward to simulate 3-point bend test on the designed beam with hexagonal honeycomb. How do I do that? Also can the software give me the moment of inertia values i.e., Ixx and Iyy.

Looking forward to hear from you.

Regards,

Anirban

 

[peteroznewman]

 

HI Anirban,

In your original post, you referred to milled carbon fiber epoxy composite so I searched for the linked document just now. I was not familiar with that term when I first answered your question. I was familar with carbon fiber epoxy composite where the carbon fiber is long strands of unidirectional fibers or woven fabrics. Layups of plies of carbon fiber make laminates.

I am familiar with aluminum honeycomb core sandwich structures that have aluminum or carbon fiber laminate face sheets that are bonded to the aluminum honeycomb core using epoxy.

You use the word “infill”, which is associated with an additive design and manufacturing process that results in printing the part in a 3D printer. Infill is the process where a thick section of solid geometry is hollowed out and an infill pattern fills the interior. The infill pattern may be automatically created by the printer or it may be more purposefully designed and be present in the geometry sent to the printer. Is this what you mean when you use the word infill?

If so, I expect you want to print the honeycomb core pattern. The hexagonal shape of the cell is created by the manufacturing process of laying down ribbons of aluminum foil with alternating patterns of epoxy to hold the ribbons together. When the stack of ribbons are stretched out, the alternating pattern of epoxy causes a hexagonal shape. But if you are printing with milled CF epoxy material, there is no need to confine yourself to the hexagonal shape. You could use a square shaped cell instead. The benefit of the square shape is that it can be aligned with the printing direction so the ribs in those directions will be smoother.

I don’t know what honeycomb creator is. I would just use SpaceClaim. Make a copy of the solid body for later. Use the Shell tool to create the outer shell for your part. Make a copy of the shell part for later. Subtract the shell solid from the original solid, now you have the interior solid. Create a pattern for the infill. For example, make a cube, copy that to a 2D grid of cubes, then copy that grid into as many layers as you need to cover the thickness of the interior part.  Subtract the 3D grid of cubes from your interior solid, that is your infill. Use the Combine tool to add the infill to the shell solid.

Once you have designed the geometry with the specific infill pattern, you can perform the 3-point bend test.

Once you have the 3-point bending result or more simply to support one end and apply a moment on the other end.  The simulation will give you the deflection of the free end where the moment was applied. Use beam deflection equations to solve for Ixx.  Apply the moment about the other axis to get the deflection to solve for Iyy.

Regards,

Peter

[Anirban Mondal]

Hi Peter,

Thanks for understanding the qurestion.

Yes, I am looking forward to create hexagonal infill pattern within the rectangular beam and perform 3 point bend test.

Moreover, using 3d printing you can directly create those hexagonal infill patterns within the beam.

Now, my objective is to create hexagonal shapes within the beam in Ansys rather than the grid patterns.

Attach is the link of the video for honeycomb creator:

How do I use spaceclaim to create hexagonal infill pattern within a specified beam dimension such that no further clean-up needs to be done while I use the model for static structural analysis for 3-point bend test.

If possible, please share some relevant videos.

Looking forward to hear from you.

Regards,

Anirban

 

[peteroznewman]

Go to the Ansys Store and download Honeycomb creator.

https://catalog.ansys.com/?q=honeycomb

Note that is was written to support V17 of Ansys. The video showed it working at V19, but we are now up to V23 and I haven't tested this add in.  What version of Ansys are you using?  Year and R number.

[Anirban Mondal]

Ansys 2022 R1.

How do I model t and 2t i.e., thickness (t) among honeycomb cells using honeycomb creator?

If possible please let me know.

Also, please let me know how you have modelled hexagonal honeycomb aluminium core in Ansys.

If possible, please share some modelling videos. 

[peteroznewman]

Honeycomb creator can model t and 2t if you want that, but if you are not using aluminum honeycomb core material which has that different thickness as a consequence of the manufacturing process, but are printing the honeycomb walls with a 3D printer, why would you need to vary the wall thickness?

I have modelled aluminum honeycomb core material by using a solid block meshed with solid elements and there is no hexagonal cells in the geometry. Instead, orthotropic material properties are applied that simulate the mechanical response of honeycomb core material sandwiched between two face sheets. This was described in detail in the discussion I linked to in my first reply in this thread.

[Anirban Mondal]

Thanks for letting me know that honeycomb creator can model t and 2t thickness. Please outline the steps of doing it.

Further, upon using 2d hexagonal infill patttern for 3d printing also replicates t and 2t thickness.

But for my case, I need to geometrically model hexagonal honeycomb structure and then apply mechanical properties E1, E2 and E3 and respective poissons ratio and then perform 3-point bend test simulation. 

[peteroznewman]

When you download honeycomb creator, it includes a pdf file of documentation which includes instructions for creating the t and 2t thickness.

But why would you do that in a 3D printer? That makes no sense.

What are E1, E2 and E3?  Are they the Young's Modulus for the two print head directions and the platen direction?

After you use honeycomb creator, you will have surface bodies. You will then create two facesheet surface bodies for the top and bottom faces and use Form New Part to combine them into a beam.