Finding the Volume or Relative density(RD) of a solid model

General Questions
1

I have successfully done analysis in prepomax. Now, I want to find out the volume of the lattice structure or the relative density for a given thickness. I am only able to view min surface area of the model. Can anyone please help how can I find volume for any structure.

2

You can request the EVOL (volume) variable as history output.

To calculate the relative density, you will have to divide the volume of the solid material of the lattice structure (without voids) by the total volume of the unit cell (with voids - as if the unit cell was fully occupied by the solid material).

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3

I have tried that way. But EVOL displaying the volume of each element instead of the volume of the lattice structure. Is there any way to directly find out the entire volume of the body.

4

You have to manually sum the values. Or calculate the volume of the structure in CAD software.

5

You can use the setting Totals: Yes or Only to get the summed-up values. But I think CacluliX computes the undeformed volume.

image

6

I forgot that Totals=yes works for EVOL too.

I just checked it and you are right - it’s undeformed volume unlike in Abaqus (but at least accounts for model change):

abq
abq1238×736 67.1 KB

ppm
ppm1353×696 52.8 KB

As a workaround, I suggest exporting the deformed mesh, importing it to FreeCAD, converting to solid and checking the volume there.

7

Is this undeformed volume a bug or a feature? Comparing it to Abaqus, it seems to be a bug.

8

The deformed mesh can also be read back into PrePoMax, and a dummy step without loads can be used to get the EVOL again.

9

Or a limitation as it’s often the case in CalculiX. But I also think that it might be a bug. Unfortunately, the documentation doesn’t explain the expected behavior. But I can create a GitHub issue about this and ask Guido at the earliest opportunity.

Right, that’s yet another way.

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10

Thank you Matej. So we can find both deformed and undeformed volume of any structure?

11

okay, but I want to calculate the undeformed volume of a complex structure.

12

Then you should use total EVOL in PrePoMax or calculate the volume in CAD software like FreeCAD.