I tried to apply rotational displacement on the volume element, but it didn’t work!
Methods as below:
Select the node at the center position, create a node group, build a reference point on this basis, and apply a rotational displacement on the reference point, but it doesn’t seem to work.
The pmx file is too large to upload
I think you are missing a rigid body constraint between the reference point and the node-set.
@xupeiwust Check this tutorial video: PrePoMax (CalculiX FEA) - Tutorial 2 - Torsion of an elliptical bar - YouTube
There a moment load is applied but the procedure is identical for prescribed rotation except for the fact that you have to define a BC instead of a load.
thankyou ！you are right
Thanks I will refer to the tutorial you said
I tried to analyze this spinning rotor in Prepomax and got results not consistent with my past experience. I then used Lisa and got realistic results.
It is an axisymmetric model of a turbine rotor.
Since I am new, I cannot upload the input files.
Thank you for any insight.
George Montgomery
gmontgomery@nc.rr.com
The only possible axis of rotation is Y for the axisymmetric case
You could upload them to some hosting website like Google Drive, Dropbox or WeTransfer and paste the link here.
That is correct. Now why doesn’t PrePoMax rotate an axisymmetric model about the Y axis?
There seems to be a rotation vector on the screen pointing in the negative Z direction.
I have a Google drive so I will try to put the files there.
Thank you.
George
If you want to see 3D representation of an axisymmetric model, you can get it in the results (but you have to request 3D output): https://youtu.be/-ND6syxc8ow?si=hZ89xa9ViPJSzQ8c&t=259
Are you talking about the axes triad ?
https://drive.google.com/drive/folders/1VUCkXRe3RnyPiPNDp-WHjfbxSjTTzMJQ?usp=sharing
Please see if this works.
There was a change in PrePoMax v1.4.1 (you seem to be using 1.4.0) regarding centrifugal load in axisymmetric models. Check this discussion: Centrifugal Load in a Rotating Disk - #12 by Matej
I read that discussion earlier. I will get the newer version and try that.
Thank you.
George
https://drive.google.com/drive/folders/1VUCkXRe3RnyPiPNDp-WHjfbxSjTTzMJQ?usp=sharing
I used the new version of PrePoMax and got the pattern of stresses I would expect but the stresses are too high and there are displacements in the Y direction. Neither of these were expected.
Could there be a problem in my input file?
Thank you.
George
You are using imperial units here. I’m not familiar with them so it’s hard for me to check their correctness. Make sure that all values (especially regarding material properties, including density) are correct. Both in GUI and after exporting the input file (since there might be an issue with conversion).