[thejavarma9]

Dear FOAM users,


I'm doing stress analysis for a geometry using elastic solid foam. My problem is the geometry consists of different materials. I would like to know if there is a way to assign different material properties to the geometry??


with regards,
Theja

[amuzeshi]

Originally Posted by thejavarma9

Dear FOAM users,


I'm doing stress analysis for a geometry using elastic solid foam. My problem is the geometry consists of different materials. I would like to know if there is a way to assign different material properties to the geometry??


with regards,
Theja

Hi
I think this tutorial is appropriate for your need:
tutorials/solidMechanics/elasticSolidFoam/bimaterialPlate
In constant/rheologyProperties you can assign different properties for different materials. First, the geometry is generated by for example blockMesh. Then setFields will be treated 'material' dictionary in '0' directory as one part or another is made of a different material.
Ali

[thejavarma9]

Originally Posted by amuzeshi

Hi
I think this tutorial is appropriate for your need:
tutorials/solidMechanics/elasticSolidFoam/bimaterialPlate
In constant/rheologyProperties you can assign different properties for different materials. First, the geometry is generated by for example blockMesh. Then setFields will be treated 'material' dictionary in '0' directory as one part or another is made of a different material.
Ali

Hi

Thank you for your reply! I'm working on it. I would like to know if we can add 4 different materials using the same solver??


Theja

[amuzeshi]

Originally Posted by thejavarma9

Hi

Thank you for your reply! I'm working on it. I would like to know if we can add 4 different materials using the same solver??


Theja

Yes, you can.
You only need to define 4 regions in setFieldsDict and then specify their properties in rheologyProperties.

[thejavarma9]

Originally Posted by amuzeshi

Yes, you can.
You only need to define 4 regions in setFieldsDict and then specify their properties in rheologyProperties.

Hi!
Thanks again for your reply! Can you help in clarifying how to know which block corresponds to which material? for example; in material properties i defined steel, aluminium in material properties then after executing the setFields,

defaultFieldValues
(
volScalarFieldValue materials 0
volVectorFieldValue U (0 0 0)
);

regions
(
boxToCell
{
box (0 0 0) (1 0.5 1);
fieldValues
(
volScalarFieldValue materials 1
);
}
);

we get








From this, how can we know block 1 belongs to the aluminium and remaining block is steel?

[bigphil]

Hi,

In elasticSolidFoam, the order in which the materials are given in rheologyProperties defines the index of the material i.e. the first material in "material 0", the second is "material 1", etc.

The material index for each cell (i.e. defining what material it is) is specified in 0/materials and can be set with setFields.

By the way, the solids4foam toolbox has removed this material index field and instead uses cellZones to specify different materials.

Philip

[thejavarma9]

Originally Posted by bigphil

Hi,

In elasticSolidFoam, the order in which the materials are given in rheologyProperties defines the index of the material i.e. the first material in "material 0", the second is "material 1", etc.

The material index for each cell (i.e. defining what material it is) is specified in 0/materials and can be set with setFields.

By the way, the solids4foam toolbox has removed this material index field and instead uses cellZones to specify different materials.

Philip

Hi,


Thanks for clarification.


Theja

[thejavarma9]

Hi,


My task is compute the stresses developed on a cylinder consisting of different materials. so I performed the simulation by adding one by one material using setFields. But the problem is "when I'm assigning a rubber material" to one of the component I'm getting floating point exception. Instead of rubber when I'm using different material (like aluminium) I'm getting results. But I need for rubber. I don't know where I'm deviating and I would like to know!!



Attached are the case b.c's.




with regards,
Theja

[amuzeshi]

Originally Posted by thejavarma9

Hi,


My task is compute the stresses developed on a cylinder consisting of different materials. so I performed the simulation by adding one by one material using setFields. But the problem is "when I'm assigning a rubber material" to one of the component I'm getting floating point exception. Instead of rubber when I'm using different material (like aluminium) I'm getting results. But I need for rubber. I don't know where I'm deviating and I would like to know!!



Attached are the case b.c's.




with regards,
Theja

I think it would be better to share your case folder in order to I can cross-check your settings and run-time errors.
Ali

[thejavarma9]

Originally Posted by amuzeshi

I think it would be better to share your case folder in order to I can cross-check your settings and run-time errors.
Ali

Hi! Ali,


Thank you for your reply! I have attached link of my case file.


https://drive.google.com/open?id=1-W...HPO3FX7FCHeGQh

[amuzeshi]

Originally Posted by thejavarma9

Hi! Ali,


Thank you for your reply! I have attached link of my case file.


https://drive.google.com/open?id=1-W...HPO3FX7FCHeGQh

I downloaded and executed this case by:

setFields
elasticSolidFoam

It returned no error! [BTW, I did not wait for 10E04 nCorrectors to complete.]
By the way, Are you sure that this is correct[0/U]:

    inside
    {
        type            solidTraction;
        traction        uniform ( 1 1 1 );
        pressure        uniform 3000000;
        value           uniform (0 0 0);
    }

Does ' (1 1 1) ' mean radial direction?

Ali

[thejavarma9]

[QUOTE=amuzeshi;742180]I downloaded and executed this case by:

setFields
elasticSolidFoam

It returned no error! [BTW, I did not wait for 10E04 nCorrectors to complete.]
By the way, Are you sure that this is correct[0/U]:

    inside
    {
        type            solidTraction;
        traction        uniform ( 1 1 1 );
        pressure        uniform 3000000;
        value           uniform (0 0 0);
    }

Does ' (1 1 1) ' mean radial direction?

Ali[/QUOTE



Thank you for your reply and executing the case.

Yeah, It means that it was acting radially. correct me if I was wrong!

I again re-executed it and got converged but that was not the solution I was expecting. I think there is still more I need to know before executing. I would like to know is there a way to extract a certain number of cell sets from a selected cells?



From the figure, the geometry consists of 2 materials. using the setFields I assigned different material to one end of the pipe (orange color) by using 'boxToCell'. But I wouldn't want the bolts which are passing inside end of the flange to be of the different materials. The entire bolt should be the same material (blue color). so I would like to exclude the 'holes' region for the end pipe. How can I do that?
can you suggest me any other ways?


Theja

[amuzeshi]

Thank you for your reply and executing the case.

Yeah, It means that it was acting radially. correct me if I was wrong!

I again re-executed it and got converged but that was not the solution I was expecting. I think there is still more I need to know before executing. I would like to know is there a way to extract a certain number of cell sets from a selected cells?



From the figure, the geometry consists of 2 materials. using the setFields I assigned different material to one end of the pipe (orange color) by using 'boxToCell'. But I wouldn't want the bolts which are passing inside end of the flange to be of the different materials. The entire bolt should be the same material (blue color). so I would like to exclude the 'holes' region for the end pipe. How can I do that?
can you suggest me any other ways?


Theja

Quick answer:
1- Prepare a STL file of the end pipe surface (containing holes). Then use surfaceToCell rather than boxToCell in setFieldsDict:

    surfaceToCell
    {
        file           "geometry.stl";
        outsidePoints  ( (0 0 0) );
        includeCut     no;
        includeInside  yes;
        includeOutside no;
        nearDistance   0;
        curvature      0;
        fieldValues
        (
            volScalarFieldValue material 1
            volVectorFieldValue U (1 0 0)
        );
    }

(You may revise these settings for your own face.)

2- About radial direction, I should investigate more; To the best of my knowledge however, current setting is not correct.

Ali

[thejavarma9]

Originally Posted by amuzeshi

Quick answer:
1- Prepare a STL file of the end pipe surface (containing holes). Then use surfaceToCell rather than boxToCell in setFieldsDict:

    surfaceToCell
    {
        file           "geometry.stl";
        outsidePoints  ( (0 0 0) );
        includeCut     no;
        includeInside  yes;
        includeOutside no;
        nearDistance   0;
        curvature      0;
        fieldValues
        (
            volScalarFieldValue material 1
            volVectorFieldValue U (1 0 0)
        );
    }

(You may revise these settings for your own face.)

2- About radial direction, I should investigate more; To the best of my knowledge however, current setting is not correct.

Ali

Thank you for your help!




Theja

[bigphil]

Originally Posted by amuzeshi

    inside
    {
        type            solidTraction;
        traction        uniform ( 1 1 1 );
        pressure        uniform 3000000;
        value           uniform (0 0 0);
    }

Does ' (1 1 1) ' mean radial direction?

Ali

Hi Ali,

'(1 1 1)' means to apply a traction of 1 Pa in the X direction, 1 Pa in the Y direction and 1 Pa in the Z direction, whereas the pressure of 3000000 is automatically applied in the normal direction.

The traction and pressure entries are summed together and applied as a total traction.

Presumably, in this case the traction entry should be set to (0 0 0).

Philip

[thejavarma9]

Originally Posted by amuzeshi

Quick answer:
1- Prepare a STL file of the end pipe surface (containing holes). Then use surfaceToCell rather than boxToCell in setFieldsDict:

    surfaceToCell
    {
        file           "geometry.stl";
        outsidePoints  ( (0 0 0) );
        includeCut     no;
        includeInside  yes;
        includeOutside no;
        nearDistance   0;
        curvature      0;
        fieldValues
        (
            volScalarFieldValue material 1
            volVectorFieldValue U (1 0 0)
        );
    }

(You may revise these settings for your own face.)

2- About radial direction, I should investigate more; To the best of my knowledge however, current setting is not correct.

Ali

Hi! Ali
I tried the 'surfaceToCell' using the .stl file. But the problem was when I'm specifying the outside points, I'm getting an error 'outside point is not inside the cell'.

The .stl domain ranges from (-0.142 -0.142 -0.022) to (0.142 0.142 0).
And for solid structures do we specify as

{
...

includeInside no;
includeOutside yes;
...
}


and vice-versa for pipe flows..!!


And I would like to know What's the major difference in specifying the 'volVectorFieldValue U (1 0 0)' instead of U (0 0 0)..!!


Or is there a way to execute using 'setSet' (creating a zone and assigning the material properties to that zone)?




And in the tutorial of biMaterial case (elasticSolidFoam), 'setFieldDict' was defined as:


regions
(
boxToCell
{
box (0 0 0) (1 0.5 1);
fieldValues
..
)


But the mesh domain ranges from 0 to 0.1 in z-direction. so how could the box be constructed from 0 to 1 in z-direction.




Theja

[bigphil]

Hi,

Just to comment on the following points:

1.

Originally Posted by thejavarma9

Or is there a way to execute using 'setSet' (creating a zone and assigning the material properties to that zone)?

If you like, you can try solids4foam, where cellZones are used for the different materials regions (the "materials" index field is no longer used).

2.

Originally Posted by thejavarma9

And in the tutorial of biMaterial case (elasticSolidFoam), 'setFieldDict' was defined as:

regions
(
boxToCell
{
box (0 0 0) (1 0.5 1);
fieldValues
..
)

But the mesh domain ranges from 0 to 0.1 in z-direction. so how could the box be constructed from 0 to 1 in z-direction.

setFields will select all cells within this region/box so it is not a problem that the region/box is larger than the cell region to be selected.

Philip

[amuzeshi]

Originally Posted by thejavarma9

Hi! Ali
I tried the 'surfaceToCell' using the .stl file. But the problem was when I'm specifying the outside points, I'm getting an error 'outside point is not inside the cell'.

The .stl domain ranges from (-0.142 -0.142 -0.022) to (0.142 0.142 0).
And for solid structures do we specify as

{
...

includeInside no;
includeOutside yes;
...
}


and vice-versa for pipe flows..!!

Hi Theja,
I can cross-check what u mentioned if you upload your STL file.

Originally Posted by thejavarma9

And I would like to know What's the major difference in specifying the 'volVectorFieldValue U (1 0 0)' instead of U (0 0 0)..!!

There is no difference, It is only an initialization for numerical scheme. Bad initialization may end with diverging of the solution.

[thejavarma9]

Originally Posted by amuzeshi

Hi Theja,
I can cross-check what u mentioned if you upload your STL file.



There is no difference, It is only an initialization for numerical scheme. Bad initialization may end with diverging of the solution.

Hi!,


Thank you for your reply!


I have attached link of my stl file.


https://drive.google.com/open?id=1_V...elUbHfrP_eaSWf


Theja

[amuzeshi]

Originally Posted by thejavarma9

Hi!,


Thank you for your reply!


I have attached link of my stl file.


https://drive.google.com/open?id=1_V...elUbHfrP_eaSWf


Theja

This surface is not oriented and positioned exactly as the left end of your whole geometry; It must be so in order to do cell operations.