Learning Forum

[WooMin Jang]

Hi I'm modelling for Debris flow with SPH and Sturcture with Beam element

I used ''CONTACT_AUTOMATIC_NODE_TO_SURFACE && _General'' and SOFT=1 contact

but there's no error occured but no interaction happended between them.

In case i used contact_beams_to_surface, there happens error message 'cannot find element of master segments'

How can i solve it?? and In manual, it seems to be uncertain what can i use for this contact.. 

Please let me know

Thanks in advance

[Ram Gopisetti]

Hi

Have you tried single surface contact ?

Cheers ram. 

 

[WooMin Jang]

Sure but there's nothing changed.. 

I have a question

In LS-DYNA, how beam element's thickness can be considered? 

I think the error message 'cannot find element of master segments ' gives me some hint that 

in the model, beam element have no thickness to be contacted

I double checked 'section_beam' and the thickness is rightly input.

[Andreas Koutras]

It seems the current contacts do not account for node-to-beam contact. An alternative is to wrap the beams with null shells and use the node-to-surface contact between the sph nodes and the null shells.

[WooMin Jang]

I've researched for this few days. 

I understand that this method is used with mat_null and shells,

just for contact and cannot reflect bi-linear behavior of material right?

[Loic Ivaldi]

Hello,

You should try the DEM method instead of SPH. With DEM you have a keyword to allow coupling : *DEFINE_DE_TO_BEAM_COUPLING.

As stated by @Andreas I don't think node-to-beam contact is available.

Best,

Loïc

[WooMin Jang]

Thanks!

But could you let me know the reason why SPH cannot contact with beam but DEM can??

 

[Loic Ivaldi]

Probably a feature not as necessary in SPH as in DEM

SPH is for modeling a continuous medium whereas DEM is intented for granular materials where it's more common to pass through a sieve or grid therefore a coupling between DEM and beam is needed