How to impose an initial velocity on a rigid body?

Altair Forum User

Hello everyone,

 

I define a rigid body by selecting three components as slave nodes and the primary node is selected as calculated node. An initial velocity and gravity load were wanted to be imposed. I tried, but it didn't work. So I want to know how to impose initial velocity and gravity load on rigid body correctly? And how to select the master node of the rigid body?

 

Best Wishes!

Roy Duan

Altair Forum User

Hi Roy Duan,

While imposing the initial velocity and gravity to the models, select the nodes option from BC Manager and select all the nodes of the rigid body and ensure master node of the rigid body is also selected during the selection.

Altair Forum User

Altair Forum User said:

Hi Roy Duan,

While imposing the initial velocity and gravity to the models, select the nodes option from BC Manager and select all the nodes of the rigid body and ensure master node of the rigid body is also selected during the selection.

Hello  George P,

How did I know whether the master node of the rigid body was selected or not? Is there any method to judge it?

 

Best Wishes

Roy 

Altair Forum User

Hi Roy,

Once all the nodes of the rigid body are selected, the master node will be also selected. You can click on review button and review the loads imposed on the model.

Altair Forum User

Altair Forum User said:

Hi Roy,

Once all the nodes of the rigid body are selected, the master node will be also selected. You can click on review button and review the loads imposed on the model.

Hi George P,

 

Where is the 'review button'? Can you show me a figure about how to judge whether the master node was selected or not?

 

Best Wishes

Roy

Altair Forum User

Hi Roy,

Once the load is created, select the load collector from the BCs Manager menu and you will find the review option.

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gopal_rathore

Hi,

Please find the attached images for it.

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Altair Forum User

Hi,

 

Must the load or boundary conditions be imposed on the master node of a rigid body? Can I define this load or boundary conditions on original component of a rigid body?

 

Best Wishes

Roy

Altair Forum User

Hi Roy,

You can assign imposed loads or boundary conditions to the master node of the rigid body, so that the same will be applied to the slave nodes connected to the rigid body.

But for assigning initial velocity it is always advised to select all the nodes of the rigid body, including the master node of the rigid body.

gopal_rathore

Hi.

For applying imposed boundary conditions, the component needs to have a card image as part if you are applying using part.However, when we assign card image to rbody component as part, it asks to select another option for taking it as rbody/admas .

 Thus rbody component does not take part as card image and thus i think you cannot use it.

 

Altair Forum User

Altair Forum User said:

Hi.

For applying imposed boundary conditions, the component needs to have a card image as part if you are applying using part.However, when we assign card image to rbody component as part, it asks to select another option for taking it as rbody/admas .

 Thus rbody component does not take part as card image and thus i think you cannot use it.

 

Hi gopal_rathore,

As you said, it seems there are two methods to define rigid body.

First Method:  select Rbody/Admas check box for a part component. (see figure 1)

Second Method:  Define a new component with none card image, and create rigid elements by using rigids panel, and select original part component as slave nodes. (see figure 2)

Is there any difference for this two methods in Radioss? How to use it correctly for dropping simulations?

 

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Best Wishes

Roy

 

gopal_rathore

Hi,

You can use any of the options from above . But apply the boundary condition on the master node of the rbody. 

Altair Forum User

Hi all,

 

How to impose Gravity loads to a rigid body? Should the load be imposed on the master node of the rigid body or only slave nodes?

 

Thank you

Roy

Altair Forum User

Hi Roy,

It is better to select the master node of the rigid body. It will reduce the computation time rather than selecting all the nodes.

Altair Forum User

HI !

Please i have a problem with my project ; in fact when  i impose an initial Velocity it calculat but their is no results.

please help us.

 

Unable to find an attachment - read this blog

Simon Križnik

Hi,

 

session file (mvw) is useless without model file, so I am assuming the model is the same as in the other topic.

 

Initial velocity should be applied to the master node of the rigid body.

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