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Prescribed Velocity on one surface of a part

Posted Mar 31, 2017, 9:20 a.m. EDT Geometry, Modeling Tools & Definitions, Parameters, Variables, & Functions, Structural Mechanics Version 5.2a 4 Replies

Remi Shah
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I have a 3D cylinder and need to use a prescribed velocity acting on just the top surface. The part is formed of two imports that have been combined and converted to a solid. I am only able to model the prescribed velocity on the whole part and can't just select one surface.

Is there a way that I can enable individual surfaces to be selected for prescribed functions?

Thanks,
Remi
4 Replies Last Post Apr 3, 2017, 9:12 a.m. EDT
Josh Thomas Certified Consultant
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Posted: 8 years ago Mar 31, 2017, 9:27 a.m. EDT
Remi-

You can apply many of these constraints on domains, boundaries, edges, or points.

I think you just need to dig a little deeper into the menu. The name is the same on the feature but make sure you select the appropriate geometric entity level when adding the feature from the Ribbon or by right-clicking on Solid Mechanics in the Model Builder window.

--
Best regards,
Josh Thomas
AltaSim Technologies
Remi- You can apply many of these constraints on domains, boundaries, edges, or points. I think you just need to dig a little deeper into the menu. The name is the same on the feature but make sure you select the appropriate geometric entity level when adding the feature from the Ribbon or by right-clicking on Solid Mechanics in the Model Builder window. -- Best regards, Josh Thomas AltaSim Technologies
Remi Shah
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Posted: 8 years ago Mar 31, 2017, 11:39 a.m. EDT
Thank you, I am now able to make a prescribed velocity for just one surface however I am still left with the problem of the prescribed velocity overriding the 'free' setting in solid mechanics. The 'free' is overridden by my fixed constraint which is correct as I do not want the fixed constraint to move freely. However I do need to top surface with the prescribed velocity to be able to move. The velocity overriding the 'free' is stopping this from happening.

Thanks,
Remi
Thank you, I am now able to make a prescribed velocity for just one surface however I am still left with the problem of the prescribed velocity overriding the 'free' setting in solid mechanics. The 'free' is overridden by my fixed constraint which is correct as I do not want the fixed constraint to move freely. However I do need to top surface with the prescribed velocity to be able to move. The velocity overriding the 'free' is stopping this from happening. Thanks, Remi
Josh Thomas Certified Consultant
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Posted: 8 years ago Mar 31, 2017, 1:04 p.m. EDT
You are contradicting yourself when you say you want to specify velocity but also let it move freely. You can't have both at the same time.

You can specify a load on the top surface to get the top surface to move "freely" but you cannot specify accelerations/velocities/displacements and at the same time expect these boundaries to move freely.

--
Best regards,
Josh Thomas
AltaSim Technologies
You are contradicting yourself when you say you want to specify velocity but also let it move freely. You can't have both at the same time. You can specify a load on the top surface to get the top surface to move "freely" but you cannot specify accelerations/velocities/displacements and at the same time expect these boundaries to move freely. -- Best regards, Josh Thomas AltaSim Technologies
Remi Shah
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Posted: 8 years ago Apr 3, 2017, 9:12 a.m. EDT
I see what you mean. I do want the top surface to move but only in the vertical direction at the rate defined by the velocity. I believe the overriding of the 'free' constraint is stopping the top surface from being able to move downwards in the z direction.

I have been able to achieve my desired effect when I build my geometry in COMSOL, but the problem occurs when I use a geometry imported from Solidworks.

Thanks,
Remi
I see what you mean. I do want the top surface to move but only in the vertical direction at the rate defined by the velocity. I believe the overriding of the 'free' constraint is stopping the top surface from being able to move downwards in the z direction. I have been able to achieve my desired effect when I build my geometry in COMSOL, but the problem occurs when I use a geometry imported from Solidworks. Thanks, Remi

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