Hi, as attached is thepicture of connection that makes the error "BONDED or NO SEPARATION type required for this contact configuration" appears. It is under Frictional, which I think is the problem. I read from a few articals saying Normal Langrange should be used for non-linear contacts. But when I use Normal Langrange, the error "An internal solution magnitude limit was exceeded. (Node Number 24274, Body SYS-1\Beam (Extracted Profile1), DOF UZ) Please check your Environment for inappropriate load values or insufficient supports.  You may select the offending object and/or geometry via RMB on this warning in the Messages window.  Please see the Troubleshooting section of the Help System for more information." returns. I am unable to use Normal Lagrange so far.

And for creating a Frioctional Contact between the beam and the sides of the tube, I just added it! Thanks! Though the simulation couldn't run anyway because of the connection issue.