Plate on Angles model analysis error

davefo

Please can you have a look at the attached model and tell me what i have done wrong.

I get the attached error message when i try running it.

Regards

Victor

Nodes 33 and 34 are slaves of two different bonded contacts which isn't allowed. Also, the constrained nodes at the ends of the beams aren't allowed to be bonded contact slaves at the same time.

A workaround is to extrude a small extension at the end of the elements and use one end for one bonded contact and the other end for the other one/constraint.

Sergio

I found the same error on several models, even solving wit CCX. My solution is suppress the EQUATIONS cards generates by Mecway and use TIE in place that allow both nodes be in different "gluing" relation. What is the difference between using equations or tie for sticking two components?

davefo

How do you extrude a line element?

Victor

Yea TIE is probably more permissive of this kind of thing. In the next version I'll make TIE an easier option by just ticking a box. You probably know this Sergio, but for anyone else, its weakness is that it requires the surfaces to be coincident and if they aren't, it moves the nodes around so that they are. That might be a problem in this case because it could remove the offset between the beams and the plate or somehow change the shapes of the beams significantly.

Davefo - Sorry, I just noticed the extrude tool doesn't work on the ends of line elements. The easiest way is probably to make a new node using Move/copy then put an element on it using Mesh tools -> Create -> Element.

davefo

Done all of that but now i have done an auto 2d mesh, then i got an answer

i changed the mesh to tri and quad elements, then found out i cannot use tri3 elements for a shell.

why?what are they for then?

I also wanted to use 3 node line elements to try and get better curved beam members but couldn't use them either.

I was going to change the tri3 and quad elements back to tri6 and quad8 element, but for some reason i cannot even select them now.

I've tried selecting the shells, selected all node and switched to shell mode and even selected the named selection but nothing allows me to select them.

Now I am completely stuck. 

Victor

Ooh, this is a problem with the software that it allows it to get stuck in that confusing state. What's happened is there's a very large shell offset (20.5 m) on all the shell elements so they're outside the visible range. To correct it, click the name of a component in the outline tree, which selects all its elements, then click the Element properties button on the toolbar and change the offset distance to something smaller.

Tri3 elements are useful for 2D, axi, thermal and other analysis types, as well as temporarily for construction of other meshes.

davefo

thanks, I missed that it should have been 20.5mm.