Learning Forum

[Aliyu]

Hi ANSYS Community, Thanks to Mobiusprime, I have progressed a bit in the understanding of spring attachments to simulate foundation stiffness but would kindly appreciate any further help with the questions below: 1. Most literature I have seen assume the pile as a beam element and as such only apply a horizontal single spring(p-y) to a level. I however assume that in 3-D this should be applied to every node on the circumference of a chosen ground level along with the vertical springs representing t-z (I'd like your opinion please). 2. How do I input the p-y, t-z and q-z values in workbench? Any useful materials or even screenshots would help greatly.

I'm sorry these seem like a lot of questions but I'm afraid they have been bothering me for sometime now and I'm glad to find that this community can help.

Thanks, everyone.

Aliyu

[Sandeep Medikonda]

Hi, I am not sure what p-y, t-z and q-z refer to? can you explain?

I wanted to point to these 2 resources:

Resource 1

Resource 2

[Aliyu]

Hi Sandeep
Thanks for your reply.I'm modelling a wind turbine consisting of a tower and a monopile foundation making contact with the soil and thus, need to consider the soil structure interaction (SSI) using Winkler non linear Spring Models (p-y, t-z and q-z data representing the lateral stiffness, skin friction and end bearing respectively). These are calculated using the soil properties but my question actually takes off from after obtaining these values so you may not bother yourself with these, sir.

In other softwares, I'm aware that once these values are inputed, it gives the foundation stiffnesses in the X and y directions but not sure how this works in Ansys workbench. Also, I want to know if this should apply to every node (as foundation stiffness is usually defined for a level on the pile, say per meter) and if so, how?
Some people have mentioned combin39 as the right element type to accommodate these, I just havent found a good enough guide on how this should be done yet.

I hope this gives a fair idea of what I'm looking for Sir. An example of the use of Winkler springs in workbench would greatly help. Thanks so much for your help and time and have a lovely day

[Sandeep Medikonda]

Aliyu,

It should work the same way in ANSYS too. i.e., you may define foundation stiffness in X & Y direction. The discussions I linked to above discuss how to specify this.

Read this Article. It recommends using INTER195 elements to model soil support.

COMBIN40 might give you more options than COMBIN39. Peter had a couple of good discussions on the Community about this:

Discussion 1

Discussion 2

Refer to the Element Reference in the manual.

I came across this Master's Thesis from Delft University (by Brénousky J.S. Breeveld) where they have shown 3 methods of doing this:

So, From what I understand you can either place non-linear springs for the entire based nodes (COMBINE39 or COMBINE40) or just model the soil as a foundation using INTER195 elements.

Regards,
Sandeep
Guidelines on the Student Community

[Aliyu]

Thanks so much Sandeep. Your explanations are very helpful but a little too technical.
Seeing that I am new to the use of Ansys, I got lost. Is it possible to have a numerical example that spells out the steps to achieve soil stiffness simulation say on a 40m hollow pile at two levels?
I'm sorry this seems quite demanding but an example appears the best way to learn since it can easily be replicated.

Regards
Aliyu

[Shobhitgupta13]

Hi Aliyu, Hope you are doing good. I too have a similar doubt. I have modeled a OWT with a tower & monopile in spaceclaim and now i need to make the contact of inner plug+monopile & also monopile with the outer surrounding soil. In many literatures I have found the usage of spring elements to establish the connection but unfortunately I am not aware how to proceed with it. As you have gone through the same issue so i wonder if you could help me out.

Thanks in advance. 

[SimonG]

Hello Aliyu,nHello Shobhitgupta13,nI run into the very same problem. Did you resolve the issue? I would highly appreciate your support. Thank you.nRegards,nSimonn