Interface elements

[ennioc]

Good morning,
I am a new member of the forum.
Please, I would like understand how it is possible add contact interface element between two 3D bodies using STKO.
In particular, I have to understand the 3D sliding behaviour between dam and rock.
Thanks for your help

[STKO Team]

Dear User,
Here you can find a simple file that you can use to understand how contact elements work in OpenSees.

Contact.zip

(121.59 KiB) Downloaded 372 times

The basic steps are:

• create a new interaction
• select the master faces (in this case the top face of the bottom solid)
• select the slave faces (in this case the bottom face of the top solid)
• In OpenSees the zeroLengthContact3D elements can ony be oriented in X Y or Z global directions (in this case the Z)
• the master face's normal direction should point along the +Z axis, that's why I chose the bottom solid as the master and the top as the slave
• create a zeroLengthContact3D element and assign it to the interaction

Keep in mind that we are developing a new contact element that converges much better then the current ones, and can be arbitrarily oriented in space. It will be available soon in OpenSees.

In the meantime you can test this one, and if you have any doubt on how I created the example file, just write here

[ennioc]

Thank you very much!

Have a nice day.

[jandre]

Dear STKO Team,

Hello. I also need to activate contact, in my case between two shell surfaces.
I understand I have to create an Interaction for each group of surfaces in contact and then assign a contact element to it.
I have some questions which I kindly ask you please to give me a feedback:
1- Does opensees can handle contact between surfaces which are not initially in contact, but will eventually be during the simulation? If yes are there any particularities to include this type of contact wrt to contact between surfaces which are initially in contact?
2- Does opensees consider the thickness of a shell element in the contact? Or do we have to specify an initial closure distance to inform opensees to ignore the initial gap between shell surfaces?
3- Which contact element do you recommend to simulate contact in the normal and tangential directions between 2 shell surfaces?
4- Can I select all master/slave surfaces that will be/are in contact in interaction or I need to define/select pair by pair?
Thank you very much for your attention.
Kind regards,
João

[STKO Team]

It can be done, but it requires some knowledge.
We explained contact in our previous webinar.
In the next webinar, we will repeat the previous webinar, but we a new (more performant) contact element.

[jandre]

Dear STKO Team,

Thank you very much.
I will watch your past webinar and the upcoming one!
Kind regards,
Joao

[STKO Team]

You are welcome!

[BuuNguyen]

The basic steps are:

• create a new interaction
• select the master faces (in this case the top face of the bottom solid)
• select the slave faces (in this case the bottom face of the top solid)
• In OpenSees the zeroLengthContact3D elements can ony be oriented in X Y or Z global directions (in this case the Z)
• the master face's normal direction should point along the +Z axis, that's why I chose the bottom solid as the master and the top as the slave
• create a zeroLengthContact3D element and assign it to the interaction

Hi STKO team, can you suggest some tips or rules to select the master and slave parts for the interfaces?
For example: soil-pile, soil-soil, soil-wall, soil-foundation.
I have read some documents for ABAQUS, they suggested that: master portion should be: larger surfaces, stiffer body, coarser mesh.

Thank you for your support.
Buu

[Lucy2012]

Dear Buu,
Abaqus provides the most comprehensive documentation there is around.
Also for STKO opensees the rule is the same, the master should be larger surfaces, stiffer body, coarser mesh.