Will *Kinematic coupling distribute mass over slave nodes?

[duonghoang]

Hello,

I am currently revising a simulation methodology in my company for Modal Analysis simulation. In the methodology, it uses mass element to declare an external mass

*MASS, ELSET=N_PUMP
9.85E-4
*ELEMENT, TYPE=MASS, ELSET=N_PUMP
1000001, 89299

Then later in the input desk, they apply *Kinematic coupling to couple the master (reference) node with the slave nodes where the external mass should be:

*KINEMATIC COUPLING, REF NODE=TANK.N_PUMP
TANK.BOT_PUMP_N,1,3

I did not see anywhere else that they declare/couple the mass element with the slave nodes/elements.

According to Abaqus documentation, *Kinematic coupling will only couple the DOF motion of the ref node with the slave nodes. In that sense, the mass of the mass element will not be distributed to the correct position at all. I can (barely) agree that for Modal Analysis, it could be fine as you still have a good total mass in your model. However, if you apply an initial displacement, this will change the behavior of those slave node as there is no mass on them. Or the gravity of the mass element will actually constrain its displacement and thus transfer the displacement due to gravity to the slave nodes.

It would be nice to hear your comments on this issue.

Sorry for my bad English! Please let me know if I am not clear enough.

Best,

Duong

 

[IceBreakerSours]

Why don't you just use the Distributing coupling?

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[duonghoang]

Indeed, that's what I am going to try. But I also wanted to understand the reason behind historical decision to use *Kinematic coupling