Issue with defining initial stress using table

Project Support
1

Hello SimScale team,

I want to assign initial stresses \sigma_{xx}, \sigma_{yy}, \sigma_{zz}, \sigma_{xy}, \sigma_{xz}, \sigma_{yz} to the individual mesh node points x, y, z. But some variables are seemingly missing (see the pic attached) in the module option initial condition > stress > table. Am I doing something wrong here? Please let me know.

Here is the public link to the project <link>.

Thank you
Viven

image
image1817×723 17.4 KB

2

Hi @sharm760,

Thanks for posting your question :slight_smile:
Please take a look at this quick tutorial down below and let me know if it helps you.


You can also delete any column if you want. But for now, I hope it helps.

Best,

3

Thanks for the reply,

For defining stress tensor corresponding to a point in 3-D, I need a total of 9 columns there. But there are only 7 columns. How can I add columns to the table?

Viven

4

Hi Viven!

Currently it is not possible to create a table with 3 independent variables (input parameters). Only one independent variable is accepted.

5

Hi,

First, I am still able to select 3 independent variables x, y, z from the drop-down menu. What will that end up doing (see attached pic)?

Second, I am not able to find documentation for your surface friction formulation.

Final, I am still exploring SimScale to see if it will work for my research problem and the free 10 simulation are too less for that. Do you provide free trial version to students for research and academic usage? Please let me know.

By the way the GUI is quite nice. :smiley:

Viven

image
image1035×411 12.8 KB

6

Hi again,

You can select them but you will receive an error message down the line. May I ask, what is your intention with this? What are you trying to model with such a table?

Can you ellaborate about surface friction? Again, what do you need to model here?

For students we have the Academic Program. Please go to this page for details and instructions to apply:

7

Hi,

The research problem I am trying to address is related to stress variations in the solid earth, where the mesh domain size is of the order of ~120 km.

In other words its an elastic solid mechanics problem with very high body forces (gravitational force). If you refer to my stress analysis model, the gravitational acceleration I have taken is 9810 m/s^2, with my mesh domain being in meters.

As initial condition to my model, I need to apply spatially varying gravitational stresses \sigma_{xx}=\sigma_{yy}=\sigma_{zz} = \rho g h, and \sigma_{xy}=\sigma_{xz}=\sigma_{yz}=0. Without these stresses applied as an initial condition, the body forces are too high and the FEM solvers are not able to converge. This is what I am trying to do.

There is an alternative to this. That is to use incompressible elastic body and not use initial stresses. I tried implementing that with SimScale but the results are apparently wrong. I am not sure what the issue is here, but the deviatoric stresses should be higher than those depicted by the results. This refers to the run 2 of my stress analysis model. I need to run more test to see if this could work for which I am requesting the academic license.

Regarding the surface friction formulation, there are other terms also in the Coulomb’s law of friction for example cohesion and pore-fluid pressure. I don’t have to use them in my model but still I wanted to read about the documentation associated with it before using it for my research problem.

I hope this makes things clear from my end. Let me know if you need any other information.

Thank you
Viven