Recent content by StructuralFEA

Yes to the finer mesh, and to the stress discrepancy in the "glue" model. Would you please explain what Kt stands for? I ran the model with the "pipe surfaces broken at the tube" with the same mesh size as the "glue" model, i.e. both models have a shell element size=0.125. An apple-to-apple...

rb1957 (Aerospace), Here is the file with the stresses based on glue.http://files.engineering.com/getfile.aspx?folder=73e6de4d-6d7d-4344-afdd-b7ff867ef121&file=Interface_between_pipe_and_tube-Stresses_based_on_Glue.png

rb1957 (Aerospace), I finally got it to work! As you and I know, both FEMAP and NASTRAN can be pretty finicky! The results are similar to those I got by using glue, though a little better, i.e. lower stresses at the interface. Interpretation of such stresses is needed irrespective of the method...

I am giving it one more try. I have just added the pipe to the tube (as non-manifold) while meshing as discussed before, and NASTRAN didn't complain. It's currently running. Let's see whether it solves all the way. Thanks.

I've tried, and I've even started the model from scratch. Ultimately, NASTRAN gives error messages about "All plate elements must have the same face ID", and "User fatal message 4297" about quad elements. I believe that this is de to the complex geometry at that "round" corner of the tube where...

Thanks. I see. That makes sense. You are right in that the program DOES understand that you want to mesh both of them together and yields the skewed elements near the interface. However, when it comes to connections, if you don't use glue, and you have two separate parts, i.e. the pipe and the...

OK. It turned out that adding surfaces to surfaces of solids is a non-manifold operation, as I just got the answer from technical support. It is ironic that the program just adds the surfaces without "complaining" when there are only two parts as mentioned above. Anyway, I am currently running...

I just saw that I could add the surfaces as: Geometry, Surfaces, Non Manifold Add. Is this a better way or the right way of adding the pipe and the tube? Thanks.

Second File:http://files.engineering.com/getfile.aspx?folder=4050d7bd-a7b4-43fa-96a4-141c70d51603&file=Adding_the_pipe_and_the_tube.png

Thanks. FeMap doesn't like it when, after breaking the pipe at the tube (Please see attached file), I try to add the pipe to the tube (to make them one piece per your suggestion so that I don't have to use glue). It gives me the message "OK to allow this operation to result in a Non-Manifold...

No. I'm still modeling the pipe as 2D. I am breaking the pipe/cylinder at the tube by using the command" Geometry, Curve-From Surface, Intersect. The I select the first as the pipe and the second as the tube. Thanks.

I don't know why, but FEMAP doesn't like the extended pipe past the tube and asks whether it is ok to add the solids as non manifold. Any idea why? Thanks.

rb1957, I isolated the pipe and tube. I meshed it again, did not use glue, and it worked. Now, I will try it on the whole model. Thanks.

Thank you. I succeeded in extending the pipe past the tube, and getting those "distorted or skewed" elements. I did not mesh the inside part as you suggested, however this caused issues. Please see the attached file. Thank you...

rb1957, thank you. Yes, however, I am not sure that the glue is taking care of the gap. The reason is that there is a stress concentration around that area. I have, in fact, used 2D elements for both the tube and the pipe. I had also run the model with all solids prior to that. The 2-D elements...