Has element birth and death been implemented in Aster nowadays (2021)?

rodrigofarias

Hi!

Regarding welding simulations, following the original question from the link below:

code-aster.org/forum2/viewtopic.php?id=20166

Has there been any progress regarding the use of the element birth and death technique (element activation, quiet element, or inactive element) in Aster?

It still needs to be implemented the old way, creating 2 materials, one with physical properties with values close to zero, and changing the material as the heat source advances?

In the article below apparently a mesh is created for each timestep, and the simulation is used with the projection technique, but it seems to me that a large number of mesh files will be necessary.

Thermo-mechanical simulation of overlaid layers made with wire arc additive manufacturing and GMAW-cold metal transfer

DOI: doi.org/10.1007/s40194-020-00951-x

Is there a better way?

Thanks!

AsterO'dactyle

Hello,

The current strategy is to use a variable MODEL on a fixed MESH

rodrigofarias

AsterO'dactyle wrote:
Hello,

The current strategy is to use a variable MODEL on a fixed MESH

Thanks for a quick reply AsterO'dactyle.

Could you clarify a bit this approach?

Thanks!

Musuuu

Really interested in this topic too

Maggoo

Dear colleagues,

I tried something that may be of your interest.

Changing the thermal properties of the materials assigned to arc, seam and void groups it is possible to cause the void region to not participate in the model, keeping it constant throughout the running.

The attached file contains the model, very simple, indeed, with a figure that shows how the smearing of temperature ahead of the arc position is absent when the appropriate properties are applied. 'VOID' and 'FULL' refers to the space ahead of the arc being treated as empty or solid.

Phase transformation and other temperature dependent characteristics will have to be added.

The 'dent' behind the arc, I believe, is the result of insufficient discretization in time and space.

I hope this will help.

Best regards.

PS: the solution is quite similar to the one @rodrigofarias proposed in another thread, of which I was unaware of.

Attached file:
WeldSurf.zip, 356618kb

Samubri

Hi everyone !

For those who are interested in this subject, I have implemented a simulation of an additive manufacturing process that implies element activation on code_aster.

To simulate that, the model is updated at every instant so that newly activated elements can be considered for the calculation of the next step.

I uploaded the simulation to a public repository in gitlab where I explain all the details, feel free to check if you are interested !

gitlab repository -> https://gitlab.com/codeaster-additive-examples/codeaster-element-activation

AsterO'dactyle

WAOUH

That's magnificent! What a great job!

That's exactly the kind of strategy we use at EDF in additive manufacturing and multi-pass welding!

simvia-max

Hello,

Thank you very much for sharing this very interesting approach with the community. For your information, we are looking to compile these types of examples in the user network’s GitLab repository (AsterLab - https://asterlab.tech/). Please let us know if you’d like to contribute; the repository is: https://gitlab.com/asterlab1/examples

Maxime