Learning Forum

[Ben_Ben]

Hello LS-Dyna forum,

 

I have a successful simulation as seen below. However, when I try and transfer it to another model so I can do the second step of my solution, I get an error of "Error updating cell solution in system LS-DYNA.". I am using Ansys Workbench 2022 R2.

 

Here is model tree showing successful solution.

Here is the view of model from project schematic.

Here are the properties of the Model and Solution cells.

 

Here is me inputting second model.

 

Here is me connecting the solution cell of successful model to the model cell of the new model.

Here is the error I get when updating solution component.

Here is the error in the messages tab.

 

 

I would greatly appreciate some input on this as I have been struggling with this problem for a while. I thought it might be a problem with my download of 2022 R1 so I updated to R2 but I am still facing this issue.

 

Thanks in advance,

Ben

[Ram Gopisetti]

Hi, are you writing the dynain file using the write file for flexable parts option in the settings of the lsdyna system?, what you are trying to transfer, deformed geo or dispalcement or stress. 

cheers, Ram 

[Ben_Ben]

Hi Ram, 

Thanks for the reply. Here are my settings:  

I can't see a write file for flexible parts option. Please could you advise on where to find it. I would like to transfer deformed geometry. 

[Ben_Ben]

I see the stress file for flexible parts now. Will put to yes and see if it makes a difference.

 

[Ben_Ben]

I changed my output controls to: And I still recieved the same errors:

 

[Ram Gopisetti]

Hi you need to first map the materials into second system and then transmitt the deformed shape. 

Cheers Ram 

[Ben_Ben]

Hi Ram, 

This time I mapped enineering data across and then did solution to model after and I still got the error. 

Cheers, 

Ben

 

[Ram Gopisetti]

hi can you check for dynain file in the file directory of this project, can you be able to laod it via external model then plug it to lsdyna system !

[Ram Gopisetti]

something as above.

[Ben_Ben]

Hey Ram, 

That worked. Thanks for your advice! Really appreciate it.

[Ben_Ben]

Hi Ram, 

I think on reflection I need to transfer the stress. As I would like to return the geometry to it's original shape by applying on the inside face. Please could you advise me on how to transfer the stress? 

Thanks, 

Ben

[Ben_Ben]

Ram for context,

- In the first step I am deforming a cylinder with rigid bodies

- In the second step I want to apply a pressure on the inside of the cyclinder to return it to the original shape

[Ram Gopisetti]

HI, What version of LSDYNA-WB are you using, in newer version you can work with dynain file to map stress on to the body via stress solid card 

Cheers, Ram 

[Ben_Ben]

I am using R2 2022.

How do I map the stress on? 

 

[Ben_Ben]

 

 

Hi Ram, 

I am using the method above to perform sequential simulations with beams. I have a structure that is composed of 60 beams and is slightly deformed in the first simulation and then in the second it is compressed. However, when I apply any BCs in the second simulation I get general errors due to out of range velocities. I am using Workbench LS-Dyna 2022 R2, here is the break down of my problem:

When I use this method for beams it combines 60 beam bodies into 1 beam body:

->

This would be fine as I can still select lines and nodes to apply BCs. 

However, when I apply BCs I get exponential kinetic energies. 

For example, if I apply a displacement to the top edges in the picture below and use a fixed support on the bottom edges. I get error due to runaway velocities:

If I apply those BCs to the geometry in the first simulation (the one that doesn’t take geometry from dynain), I can compress the structure without exponential Kinetic energies. 

Do you have any advice for using beams in sequential simulations with dynain?

Thanks in advance, 

Ben

 

 

 

[Ben_Ben]

I decided to start a new issue for my problem, see: /forum/forums/topic/runaway-velocity-error-using-dynain-file-for-sequential-simulations-with-beams/