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Henry Arrigo June 1, 2012 11:17

Morpher Problem
 
Hello all;
I use rigid body morpher to enforce a cylinder to move in a sinusoidal manner. but the problem is that although the equation has the amplitude of 0.02, the cylinder move more than this value (even more that 0.1). is there any extra setting that I should do? I don t know what the difference between "Displacement" and "Rigid Body" options in morpher model.
tnx

arun7328 December 11, 2013 11:02

Hey Henry,
I know it is a late reply. But did you find out how to do it? If you have not I have done a similar problem of cylinder heaving,swaying and rolling sinusoidally at a free surface.

Thanks
Arun

Henry Arrigo December 27, 2013 16:11

thanks arun. No i haven t done that yet. I had several attempts but non of them was successful. when I set the predefined position the body movement overpasses the limitation of the position, like when i defined z=0.2sin(t) m the body movement become more than 0.2 m. what was the strategy you chose?

nico7 February 3, 2014 03:45

I'm pretty sure the issue is that you're specifying the position while you should be specifying the displacement.
I.e. displacemen at time t = position at time t - position at time t - 1

Josh August 25, 2014 23:12

Hi Arun,

I'd love to have a copy of that simulation if you still have it and don't mind sharing. I, too, have a forced rolling object at the free surface.

As of now, I have a Rotation Motion specified with a field function. Unfortunately, CCM+ requires an angular frequency input and I only have the displacement equation:

[angular displacement at time t] = [angular amplitude] * sin([angular frequency]*[time])

I'm not sure how to go about specifying angular amplitude to generate the desired displacement.

Cheers!

arun7328 August 26, 2014 04:39

Dear Josh,

That is not a problem at all. Can you send me your e mail id and I shall send the models for heave, sway and roll.

Thanks
Regards
Arun


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