Once you get yielding through the entire cross section of your pipe the analysis will fail. This is due to the fact that any more load will result in an infinite displacement because you are perfectly plastic. I've done this exact type of analysis before by using time steps to "sneak" up to...
If the boundary conditions, loads and geometry are the same in both models, then I would look at the material properties. Possibly different units or a typo?
It was even wierder than I thought, the parts would mesh if they were far enough apart. The solutiion I found was to create a volume region on the flange part, basically creating a tube within the flange. Now they mesh just fine. Autogem must have struggled with the fact that the tube wall...
Hello All,
I have a two piece assembly consisting of a tube with a flange welded onto it. The flange was placed first,with the tube mated to it. When I meshed, only the flange would mesh and no elements were created for the tube. When I opened up the tube by itself, it meshed without any...
I ran into this problem very recently. When you created your design study, did you check the "nonlinear" checkbox. Doing this opens up the "include contacts" checkbox. I wasted a whole day trying to get anything but bonded contact to work until I discovered this.
Marcus
Well a few things that come to mind are:
1) your model does not capture the test correctly
2) there is something wrong with your material properties
there are many more possibilities but without more specific information that's where I would start looking.
Marcus
Peter,
I'm not sure what software you're using, but you can do what you want with ANSYS. You can do it by a RESTART or creating Load Steps, look in the help for these. I'm not sure how other FEA programs do this.
Hope this helps,
Marc
Zartan,
Yes, if you go to Solution, and then select Restart, you can then continue your analysis. Look in the Ansys help file for Restarts.
Hope this helps,
marc
Hi Gill,
If you go to www.ansys.net or the xansys group on yahoo you can download the macro bilinear.mac. This macro runs your problem once, determines which elements are in compression/tension, then reruns the problem assigning the appropriate modulus. Hope this helps.
Marcus
Thanks for the tip. I actually took it a step further and reduced the yield stress and the stresses along the curve by 75 percent. The results matched well with the physical data. The test now is wether the model predicts the correct deformed shape (which I haven't seen yet) and if it can...
In our testing, the seals are compressed to a height of 0.051". The load is removed and the final height of the seal is 0.0535", giving a springback of 0.0025". The load to get this compression was 330lbs.
I was given true stress-true strain data for my model. My biso model...
