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Unable to implement moment on the system!

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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


2 Replies Last Post 21.05.2013, 02:18 GMT-4

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Posted: 1 decade ago 18.05.2013, 12:52 GMT-4
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
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: https://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

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Posted: 1 decade ago 21.05.2013, 02:18 GMT-4
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
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

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