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Rosta_Spicl5-Regular Member
5-Regular Member
January 11, 2026
Solved

modal analysis of composite structure

  • January 11, 2026
  • 2 replies
  • 75 views

Dear experts

I'm just frustrated about very primitive exercise in Creo Simulate 12. See the sketch below. In creo there is an assembly contains 2 composite parts, in real glued together. The cored composite board (composites 1) is bonded on composite frame L profile (composite 2). The target is to see how the rigidity of L profile affects the modal frequencies of board.

Only composite quilts are supported in Simulate, it means the virtually gap is observed, the layup guilts are not in touch, bonded connection is not supported in this case. I have tested a lot of procedures, rigid link, spot weld...etc., but only bonded interface is closest to real surface - surface bonding.

Another test I have made, in assembly the 3rd part - glue was created, the thickness was a gap, but there is a material interference - glue + laminate in real. 

Does anybody have an idea how to fix that? What is the correct connection feature between two composite parts, or generally between two shells?

Thx a lot, Rosta 

Best answer by SweetPeasHub

Ok, yeah I do not use or have access to Creo Composite. I use normal Creo parts to simulate laminate layup designs. I am not even sure if the simulate side looks differently, but I would check on the default as bonded, or define the interfaces and use "review model" if that is available. I would think that since the normal simulate can create the links between "gapped" shells then Creo composite should also do that without having to make a separate model. There may even be additional simulate commands to ensure connectivity for Creo Composite. Sorry, that I can't help there.

 

If you want to use my technique, you would need to get the same quilts into a normal solid part(s) and use the thicken command to generate a model that can be turned into shell pairs and have the bonding where the thickened models touch. On point 3 you are assigning to the surface on the thickened part, before it is collapsed to the midplane shell representation. That property overrides the shell pair definition for thickness and adds the layup definition in the Creo simulate way of doing this. I also use this laminate layup model to add chrome plating to the surfaces on the outside of a solid part. (Copper- Nickel-Chrome layers within the laminate definition) Another example is some molded plastic part with a carbon fiber layup applied (epoxied) on some of its outside surfaces. In simulate the layup and layer orientations etc can be specified. 

 

SweetPeasHub_0-1769626755052.png

Note I cannot select the mid-surface because it is made by a shell-pair and not actually present until mesh/solve. But when I select one side of the shell-pair it assigns it to the mid-surface and overrides the shell-pair thickness and material definition with the assignment.

 

Another advantage of shell-pairs is the ability to represent the surface at a placement other than at the midplane. It mathematically shifts the layup with parallel axis theorem so the physics are correct. Thus connectivity can be maintained without using the link elements. For example one shell-pair at bottom and the lapped one at top so they align in the mesh model. I have not studied how it combines the shell properties at the overlapped area.

SweetPeasHub_1-1769627204404.png

 

 

2 replies

V
vnamboodheriCommunity Manager
Community Manager
January 19, 2026

Hi @Rosta_Spicl, 

Thank you for your question. 

Your post appears well documented but has not yet received any response. I am replying to raise awareness. Hopefully, another community member will be able to help.
Also, feel free to add any additional information you think might be relevant. It sometimes helps to have screenshots to better understand what you are trying to do.

 

Best Regards,

Vivek N
Community Moderation Team

S
SweetPeasHub17-Peridot
17-Peridot
January 26, 2026

Hi, Great question!

The correct way is to make sure of bonding using review geometry.

SweetPeasHub_5-1769436686000.png

 

SweetPeasHub_6-1769436712272.png

HOW?

1. Use thin solids made shells with shell pairs. Do not assign the shell property to just a mid-surface quilt.

2. Make sure default interface is bonded, or define the desired interfaces-bonded.

3. Apply the laminate shell property to one side face(s) of the thin solid. The property will be transferred to the midplane. Note: Loads and constraints on shell pairs are also transferred to the midplane.

4. AutoGem will show the bonding elements.

5. If you want to see the bonding elements in the results, turn them on.

 

SweetPeasHub_7-1769436904364.png

Note: the "core" was modelled as a thick solid part, with a wrap of laminate.

 

 

SweetPeasHub_2-1769435927565.png

SweetPeasHub_8-1769436999236.png

Also please refer to the last note in this help page and further pages on bonding elements linked from there.

It is all about a subtle wording difference between "shell", and "shell pair".

 

-Please mark this as a solution if this is the correct and best answer. Thanks!

 

R
Rosta_Spicl5-Regular MemberAuthor
5-Regular Member
January 26, 2026

Thanks for support

Please, could you share the creo files to analyze? I absolutely don't undestand the point 3, how to assign the laminate shell properties to shell pair midsurface. ..

 

BUT!!! in this case, the parts are modeled in Creo Composite, there is no way to import solid to Simulate, only quilts are supported. No way to define shell pairs, no way to define shells, no way to define volume regions etc...

 

S
SweetPeasHub17-PeridotAnswer
17-Peridot
January 28, 2026

Ok, yeah I do not use or have access to Creo Composite. I use normal Creo parts to simulate laminate layup designs. I am not even sure if the simulate side looks differently, but I would check on the default as bonded, or define the interfaces and use "review model" if that is available. I would think that since the normal simulate can create the links between "gapped" shells then Creo composite should also do that without having to make a separate model. There may even be additional simulate commands to ensure connectivity for Creo Composite. Sorry, that I can't help there.

 

If you want to use my technique, you would need to get the same quilts into a normal solid part(s) and use the thicken command to generate a model that can be turned into shell pairs and have the bonding where the thickened models touch. On point 3 you are assigning to the surface on the thickened part, before it is collapsed to the midplane shell representation. That property overrides the shell pair definition for thickness and adds the layup definition in the Creo simulate way of doing this. I also use this laminate layup model to add chrome plating to the surfaces on the outside of a solid part. (Copper- Nickel-Chrome layers within the laminate definition) Another example is some molded plastic part with a carbon fiber layup applied (epoxied) on some of its outside surfaces. In simulate the layup and layer orientations etc can be specified. 

 

SweetPeasHub_0-1769626755052.png

Note I cannot select the mid-surface because it is made by a shell-pair and not actually present until mesh/solve. But when I select one side of the shell-pair it assigns it to the mid-surface and overrides the shell-pair thickness and material definition with the assignment.

 

Another advantage of shell-pairs is the ability to represent the surface at a placement other than at the midplane. It mathematically shifts the layup with parallel axis theorem so the physics are correct. Thus connectivity can be maintained without using the link elements. For example one shell-pair at bottom and the lapped one at top so they align in the mesh model. I have not studied how it combines the shell properties at the overlapped area.

SweetPeasHub_1-1769627204404.png

 

 

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