Hi.I am writing to kindly ask you help me make a conclusion on shell to solid contact (or shell to shell contact) in ABAQUS.
Firstly, for shell to solid (surface to surface) contact, I concluded that a tie constraint can be used. I defined solid surface as the master and the shell reference plane (top or bottom depending on the side connecting to solid) as the slave. I found that if I tie mid-plane of the shell to solid, results are not accurate because half of the shell thickness is in the solid. If it is required to use mid-plane of the shell as the reference, shell should be translated half of its thickness. I should note that both approaches are the same for modal analysis (also compatible with very fine solid-solid model) but for static analysis results are different with solid-solid model. I would like to know your whether using first approach (using top of bottom reference plane) for modal based dynamic analyses is correct or not.
Secondly, for three shells (surface to surface contact) by tie constraint, one possibility is to tie mid-plane of all three shells with translating the side shells. Therefore, the total thickness of three shells doesn’t change; I found that the important factor is preserving the thickness of the real structure in FE model. The other suggestion is using top and bottom reference plane for two shells in addition to one translation for connecting the third. Am I considering modeling of three shells correctly?
Hi Hossein,
It would be great if you can upload some figures to demonstrate your problem.
As a general suggestion, I would say General Contact is a more efficient way to deal with contact problem.
Thank you Michael for your reply.
The point is shell to solid coupling defines a constraint between a shell EDGE and a solid SURFACE. I want to define a constraint which is surface to surface. Consider a sandwich panel where the core is solid and the faces are shell. For such case, shell to solid coupling constraint doesn't work.
Hi Hossein,
It would be great if you can upload some figures to demonstrate your problem.
As a general suggestion, I would say General Contact is a more efficient way to deal with contact problem.
Hi hossein
It s very important how connect solid and shell to each other.
Solid elements have 3 transitional degrees of freedom,but shell elements
have 6 transitional and rotational degrees of freedom,tie contact can connect
These two elements with some condition that transitional degrees reduct to rotational Degrees. Simple connection or rigid connection is very important.
Thank you Majid for your response.
What will ABAQUS consider for 3 rotational DOFs if I tie a shell surface (6 DOFs) to a solid surface (3 DOFs)?
What I want to ask is that when transitional DOFs are constrained, does it make a difference whether shell has rotational DOFs or not?
Hi Mr Bayat,
The reason is related to our type of analeses. We are performing Modal based Analyses which are linear and there is not a chance to use a nonlinear constraints!
It is still a linear analysis if you use frictionless interaction property.
Hi
If your model is a metal deck or similar, I recommend using the skin mode instead of the shell to solid coupling option. for more information please visit this website :
https://info.simuleon.com/blog/using-skins-and-stringers-to-create-shell-layer-or-beam-edge-reinforcements-with-abaqus-fea
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