Good morning,
I am doing some tests with all the features PrePoMax has. Is there a way to use the ‘‘Pre-tension’’ BC in order to simulate a sort of ‘‘Pressfit’’? I tried imposing a contact between two cylinder and then imposing a radial pre-tension displacement. But the result is a strange behavior.
Thank you
I don’t think it can work this way. If you want to simulate interference fit without using GraphiX (like we discussed in the thread about press fit modeling) then you could do it the old-fashioned way - with thermal expansion.
Thank you. So, if I would like to analyze a pressfit of a hub and a torque transmitted by the same element, I should use two different step, isn’t it? And then use superposition effect. Then how can I merge the results coming from two different steps?
Yes, you can run a multistep analysis. As long as you aren’t using perturbation steps, the state of the model in a given step is taken from the previous one so you can simulate the history of loading without having to superimpose the results manually.
Thank you. I am trying to make a multistep analysis, but I can’t understand why it doesn’t work properly.
Here is the file :
Multistep_try.pmx (5.4 MB)
I am doing a first step with a torque applied on the hub, then a second one to simulate the pressfit by using the thermal technique. I don’t know why torque load doesn’t work with tied contact.
How can I properly simulate a pressfit thermally? By using a linear contact?
I don’t understand your simulation, could it be that first (Step 1) you must press fit the assembly by any means (thermallly or by any other bc), and then try to rotate the shaft with the torque (Step 2)???
Yes, it is what I would like to simulate.
From what I see in your file, you are applying torque first (step 1), and then the press fit (step 2)
I corrected it, thank you. But the torque doesn’t work anyway. I can’t understand where my mistake is.
The file: Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.
You don’t have to run thermo-mechanical analysis to simulate press fit, you can use a static step with a defined field of temperature type (and thermal expansion included in material properties).
To check if torsion works you can add a history output request for displacements of the reference point to which torque is applied. Then check UR1 in the results.
Thank you for the advices. I checked UR1 for that reference point and says zero. So, the pressfit step works, the second one (torque) does not.
I tried to simulate only the torque to the hub with a tied contact between the surfaces, but the hub doesn’t rotate and does this strange behavior.
Is it correct to simulate the pressfit with a tied contact?
Tie constraint or tied contact should be fine but you have to make sure that adjustment works properly and the connection is fully established. Such artifacts might be visible when the deformation is scaled significantly.
In other tests I did it worked properly. I verified every single setting and I can’t understand where is the issue.
It works fine with tie constraint in place of tied contact. Also, the torque seems to be really low.
Yes. I tried as you said and works fine. I have more questions about pressfit but i think it is not the correct thread, so I’ll make another question.
Thank you.
