Hello "Mecway Wold", at first I´m a newbie in using Mecway for FEM. After searching at the 35 Forum pages for combining loads and looking into the manuels for preloads, I would like to ask you directly for any kind of support/ help. I´m looking for a possible calculation method for rotationally symmetric rubber bushing(Outer diameter~Ø60mm). The rubber bushing has an outer and inner sleeve out of metal. It should be calibrated by radial force(or pressure) at first( for approximately 3mm of diameter) and than I would like to add some additional radial force onto it to calculate the radial stiffness. Inside the manual of Mecway I found the pre-tension method only. Do you see any possibility to conduct such analysis? Like, conducting the calibrating at first and save the results to use it for further analysis, or combining the calibration and radial force in one analysis depending on time steps? Looking forward hearing from you Alex
Comments
¿What do you mean by preloading the bushing?.
I have done an example like loading in one direction first and then radially on a rubber bushing. ¿Is it like what you are looking for?
It needs ccx to run.
File edited
https://drive.google.com/drive/folders/1BNMXJYl-5QSG4qEw49QTRvr0yvvjuDiV?usp=sharing
Be carefull in case you include the outer/iner rings, as CCX will promediate the stress between rubber and metal at the interfaces if you use coincident nodes.
I will also recommend getting to know the hyper elastic material models, they can be useful.
1) Cool down the part from mold to room temperature (so the temperature and restrain is a lot more). The rubber will get streched in this kind of assembly as in your model
2) Mechanical swage or assembly operation, so normally the outer sleve is pressed fit radially, in part to reduce the stresses due to 1), and to keep it in place. The rubber will get without stress or better, with a little of compresive stress
3) Now that the part is at room temperature and at assembly condition, you can apply the main loads (radial, axial, torsional, conical... or any combination). Sometimes you have a preload step with the gravity loads of what you are keeping with the bush, and then yes, the main load acting in the part.
You are right. My simulation could be a bracelet on a cold day. .
I hope AlexJagow didn’t take it too much verbatim.
I couldn’t figure what was the real application for that. I couldn’t access to your example as I was linked to google drive and I’m not registered. I will try to adjust numbers to make everything meaningful now you have explain the procedure and everything has more sense. This could be some kind of silent block isn’t it ?¿.
I think most of the steps ,boundary conditions and external actions are still ok to make it work. I can only foresee one delicate step ,..the rubber assembly to recover some of its flat shape after shrinking. I have an idea on how to solve it that could be interesting if it works.
Thanks again for your comments.
The transform Card is new for me and it works perfectly. I wasn’t able until today to apply a radial displacement properly.
How I feared the most tricky part is that adjustment to set the Rubber in place again and out of stress.
I found that the price to pay is that the external sleeve ends up in a large compressive stress due to the displacement but I can imagine the Rubber is the main object of interest.
I will do a second try to see if there is some workaround.
@John Thanks also for the comment. I still do not understand your trick for a quick "press fit".
“apply a frictionless boundary condition on the radial surface, but use an actual value to displace/crush”
¿Does it avoid the Compressive stress remaining on the Outer Sleeve.?
I think the "REF" node is still there but rigid body and shell elements ...mmhh, not yet...and if I convert them to solids the model had more than 1.000 nodes.
AlexJagow could give it a try for sure.
From Victor solution ( https://mecway.com/forum/discussion/1180/two-concentrated-loads-fluxes-different-amplitudes)
"Version 16/17 applies shell edge forces in a more accurate way that includes moments that account for the geometry change due to the curvature. It looks like CCX has trouble with these moments in this case.
A workaround is to change the two forces on the shell edges to be on the nodes instead. It should be pretty close to the same thing since these are linear elements. Then it does solve."