Trouble creating Rigid Body Radioss

Altair Forum User

Hi, 

 

I'm new using RADIOSS. 
I want to compute a basic droping test, using a plate in composite and a rigid impactor.

I tried to applied a Rigid property to the impactor but it doesn't worked. I also tried to create a new component, without card, but it also doesn't work.

 

As you can see on the screen, my impactor is deformed.

 

Could you help me dealing this ?

 

Thanks, 

 

Best regards, 

Raphael 

 

PS : sorry for my english, I'm French

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Altair Forum User

Hi Raphael,

Create a separate component collector for rigids without any card image and no material or porperty. Now go to 1D panel, select rigids >>select calculate node option >> select comps option and select this impactor. Now the rigid elements are created on this impactor thereby making the imapctor a non-deformable body. 
 

<?xml version="1.0" encoding="UTF-8"?>

 

If you still have doubts let us know so that we can create a short video also showing these steps.

 

 

Altair Forum User

Hi Georges, 

 

Thanks for your answer. I already tried this, but it doesn't work with my model.

 

I defined my impactor as Part, Property P1_SHELL, and Material M1_ELAST. Then, the rigid is defined using nodes of this impactor. After running RADIOSS, nothing is moving. 

Do I have to set my velocity BC on the impactor or on the rigid ? 

 

Thank you, 

 

Raphael 

Altair Forum User

Hi Raphael,

While defining initial velocity select all the nodes of the impactor including the rigid body master node and run the analysis.

Altair Forum User

Thanks Georges, I'll try this.

 

I've an other issue. My plate is in composite, using 2 differents composite. There isn't core, it's just a laminate using 2 differents composites. 

I created both materials, the differents plies, then I realized the laminate. A new component appears. The question is, which material should be assigned to this new component ? I run 2 identical models changing the assigned material, and I calculated a 12% error...

 

Thank you

 

Raphael

Altair Forum User

Hi Raphael,

In the latest HyperWorks update (2017.2) this realization option is removed. We use normally this for the visualization of layers and fiber direction purpose.

Can you try without using this realize option?.

Altair Forum User

Hi Georges, 

 

I'll try this then  I'll come back to you. 

 

Thanks 

Altair Forum User

Hi George P Johnson, 

 

As you said yesterday, I tried without the 'realize' option, and sadly it doesn't work. I've some errors to run the model.

 

What do you want to say by this sentence ?

Altair Forum User said:

We use normally this for the visualization of layers and fiber direction purpose.

 

If I want to keep using this function, is it okay for the model ? If yes, how can I choose between both materials created ?

 

Thank you, 

 

Best regards, 

Raphael

Altair Forum User

Hi Raphel,

If using a recent version of RADIOSS, it should not matter too much, this is used only for contact stiffness with the element. 

In older versions this was used to calculate timestep for the part then you could get very different results between models. Also let us know are the laminates in contact? And also, are these 2 materials very different in stiffness?.

Altair Forum User

Hi Georges, 

 

I'm using HyperWorks 2017.2, and I don't see the 'realize' function as you said yesterday. By the way, I always have to choose between both materials.

 

It's a monolithic composite, so there are 2 plies of A and 16 plies of B. The plies of B are between the A layers. The specifications are on the Table below.

 

Thank you for your help

 

Best regards, 

Raphael 

Altair Forum User

Hi Raphael,

It seems like these material parameters difference for both the laminates is causing this results difference in your model and also they are in contact. As I told before it should not matter too much, as it is used only for contact stiffness with the element. 

pohan

Hi @Raphael_Mtl I have the same problem as yours. I created a rigid body and them imposed a certain velocity but nothing moves. Did you solve your problems?

Simon Križnik

Hi

 

initial velocity and gravity should include all slave nodes of a rigid body as well as its master node. Other boundary conditions require only the master node. 

pohan

Hi @Hyperman 

Do you know how to get the number of master node when using 'calculate node'?

Tks

Simon Križnik

I prefer Utility>Radioss Tools>RBODY manager where all rigid elements are listed with their related master nodes. There are other ways to get master node ID:

https://community.altair.com/community?id=community_question&sys_id=4c5644b61b2bd0908017dc61ec4bcbbc