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Contact definitions: shell to shell & shell to solid.

Contact definitions: shell to shell & shell to solid.

Contact definitions: shell to shell & shell to solid.

Hello everyone,

I want to model the following case and I use LS-DYNA for my simulation:

1) Two cylinders made of shell elements have to be connected by the edges. They have the same diameter, but are made of different materials. I tried TIED_SURFACE_TO_SURFACE, but they seem not to be tied.

2) There is a ring inside the cylinders. Its made of solids and the offset between the ring and the cylinder is half the thickness of the shell elements (5 mm). For this I have chosen TIED_SURFACE_TO_SURFACE_OFFSET, but unfortunately I have initial penetrations, which are quite big. Only reducing the contact thickness by 50% (which is by default the shell thickness) has lead to a significant reduction of the initial penetration. Still 50% seem very big.

Has anyone any experience or idea how to handle this two problems? I am helpfull for any advice! The meshes are very fine btw., so I do not think the problem can be solved by a further refined mesh.

Many thanks in Advance and have a nice day!


Here is a piceture of the problem. The diamater of the cylinders is 350 mm. The outer diameter of the ring is 345 mm, so the gap betweens the shells and solids is 2.5 mm. The shell thickness is 5 mm.

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