Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Unable to implement moment on the system!
Posted 17.05.2013, 04:09 GMT-4 Structural Mechanics Version 4.3a 2 Replies
Please login with a confirmed email address before reporting spam
Hi,
I am simulating a model of a structure which has a central rotating shaft and other components attached to it. The shaft is rotating by a motor and hence the other components should rotate with it too. I am facing a couple of problems with this model:
1. When I carry out a Stationary Analysis, it returns the error:'The relative residual is greater than the relative tolerance.'
2. Then, when I try with Time dependent Analysis instead, it computes the results, but incorrectly, as the shaft doesn't rotate but the other components attached to it move under their own weight.
I am unable to understand where I am going wrong. I have attached the model . Any kind of help would be appreciated.
Thanks in advance!
Regards,
Amitosh
I am simulating a model of a structure which has a central rotating shaft and other components attached to it. The shaft is rotating by a motor and hence the other components should rotate with it too. I am facing a couple of problems with this model:
1. When I carry out a Stationary Analysis, it returns the error:'The relative residual is greater than the relative tolerance.'
2. Then, when I try with Time dependent Analysis instead, it computes the results, but incorrectly, as the shaft doesn't rotate but the other components attached to it move under their own weight.
I am unable to understand where I am going wrong. I have attached the model . Any kind of help would be appreciated.
Thanks in advance!
Regards,
Amitosh
Attachments:
2 Replies Last Post 21.05.2013, 02:18 GMT-4
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Hello,
I have just tried your model with a stationary study step, and has worked. The error can be easily resolved, see here some possibilities: community.cmc.ca/docs/DOC-1453
Besides, take a look at the unit of measure in Solid Mechanics > Motor, since in the equation Rho_steel*pi*((Shaft_dia/2)^2)*(Shaft_len)*(((RPM/60)*2*pi)^2)*((Shaft_dia/2)^2) you should get [N] but actually you have [J].
Regards
Fabio
I have just tried your model with a stationary study step, and has worked. The error can be easily resolved, see here some possibilities: community.cmc.ca/docs/DOC-1453
Besides, take a look at the unit of measure in Solid Mechanics > Motor, since in the equation Rho_steel*pi*((Shaft_dia/2)^2)*(Shaft_len)*(((RPM/60)*2*pi)^2)*((Shaft_dia/2)^2) you should get [N] but actually you have [J].
Regards
Fabio
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Hi,
Thanks for the reply. I shall try running the model again with the suggestions you have made. I was having another problem that the shaft isn't rotating. It remains fixed to the spot as the other components move due to gravity. Do you know how to implement a torque on the shaft so as to give the system a rotational effect.
Thanks again,
Amitosh Dash
Thanks for the reply. I shall try running the model again with the suggestions you have made. I was having another problem that the shaft isn't rotating. It remains fixed to the spot as the other components move due to gravity. Do you know how to implement a torque on the shaft so as to give the system a rotational effect.
Thanks again,
Amitosh Dash