Altair RISE

You can right click on Model Browser>> Create>> Rigid body. Make sure you go through the Rbody card on OptiStruct help before you create as it gives a fair idea on what is required for Rbody.

Karthic_22061

Hi,

I dont find Rigid body in the create of model browser. I am using HM v14

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

gopal_rathore

Hi,

I think rbody is not available for optistruct solver. You can see it in radioss . Might have come up in 17 version.

Karthic_22061

Thank you Gopal and Prakash,

How to make the part rigid instead of using rb2 ?

I tried giving a high Young's modulus value which results in computation error

A fatal error has occurred

*** ERROR # 277 ***
Jacobi method failed.
Max. off-diagonal term in matrix = 2.74951e+295.

gopal_rathore

Hi,

The methodology seems to be correct for making part rigid i.e provide a high value of E. Are we sure that this error is due to this? I mean is the model running properly if you use rbe2 for making rigid?

Can you share the screenshot for material properties also?

Jacobi method solves equation using a iterative method where it makes the off-diagonal term zero. Thus this might be a convergence issue also.

Altair Forum User

Hi Gopal and Karthik,

There is a RBODY in OptiStruct starting from 2017. Please see the image.

But I think the problem is coming from the flexbody frequencies as the offset is tool large.

Can you try to reduce the mass of the rigid body and check if there is any improvement.

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

Karthic_22061

Thank you,

The model running properly if i assign a realistic value for E and also with rb2.

All i need is Rbody card for the component which i coudn't find in Hm V14.

Altair Forum User

Karthik,

Can you share the modulus value used?

I dont know if there is a better way to define a rigid body.

Karthic_22061

Hi Prakash,

I used 9e150 Mpa

Altair Forum User

Hi karthik,

Can you try with something like 9E20/25?