RBE3 in combination with ADMAS and GRAV

Marion_20756 · October 2020

Dear all,

I made a small test model in to check the load distribution in an RBE3 element in Radioss. The model consists of a square tube (2D shell) and an ADMAS (100 kg) which is connected to all nodes of the top side of the tube using an RBE3 element. Weighing factor is 1 for all master nodes of the RBE3. ADMAS is exactly above the center of the top plane of the tube. Gravity of 9810 mm/s^2 is applied in negative Z-direction to all nodes of the model. All the nodes of the bottom plane are constrained in all directions. See figure below.

The figure below shows the results of the external forces in Z-direction (forces in X- and Y-direction are zero). Note that these values are completely different for all nodes. I would expect them to be equal. Why is the distribution this way? I don’t understand what is happening using the RBE3 element in Radioss.

Yuhao He_20868 · November 2020

Can you share your test model?

Are you using Radioss explicit? If so, do you apply any method to stabilize the model and reach steady state before checking the force?

Dhanasharee Jadhav_20562 · December 2020

Yuhao He_20868 said:
Can you share your test model?

Are you using Radioss explicit? If so, do you apply any method to stabilize the model and reach steady state before checking the force?

Hi,

You can refer to these videos -

A detailed video on Impact / Quasi-Static Analysis setup.

https://www.youtube.com/watch?v=CxM52wP3_ew&list=PLQ7KUGFuVz4u5y3SvIEIU07427-gATaG6

Short Videos

1-Impact analysis Set-up for RADIOSS in 20mins

https://www.youtube.com/watch?v=aDeNhQFvqjE&index=1&list=PLQ7KUGFuVz4uyfru1mekcmyqb783jA862

2-Guidelines to create Engine file for RADIOSS

https://www.youtube.com/watch?v=PZXiybZ8Fds&index=2&list=PLQ7KUGFuVz4uyfru1mekcmyqb783jA862

3-Initial Run checks for RADIOSS

https://www.youtube.com/watch?v=OFQUW-yzbVs&list=PLQ7KUGFuVz4uyfru1mekcmyqb783jA862&index=3

4-Procedure for Mass_Scaling in RADIOSS