# sphere packing

Asked by Othman Sh on 2019-12-21

Hello,

I know that the stress-strain curve of a cylinder made of spheres in Yade depends on the packing of aggregates. I have tried making cylinders with different packing using makeCloud function with seed=1, 2, 3 and then compress the particles to a specific porosity. Although all cylinders have same porosity and approximately same number of particles, for each cylinder the stress-strain curve is drastically different.

My question is, is there a function, equation or a method to quantify the packing arrangement of spheres to explain the effect of packing on the mechanical properties of a cylinder made of particles?

From a previous question [1] I learned that I can show the network of interactions and hide the spheres for different packing arrangements, but it would be great if there is a parameter or an equation that differentiate different packing arrangements.

I hope my question is clear and I appreciate any suggestions or thoughts in this regard.

Thank you,
Othman

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Robert Caulk
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2020-01-28
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2020-01-28
2019-12-22
 Robert Caulk (rcaulk) said on 2019-12-22: #1

>drastically different

Can you quantify "drastic"?

> if there is a parameter or an equation that differentiate different packing arrangements

I guess the most descriptive information you can give is the size distribution (uniform? gaussian? PSD?) and associated properties (min, max, mean). You can also use the coordination number [1].

 Othman Sh (othman-sh) said on 2019-12-22: #2

Hi Robert,

>Can you quantify "drastic"?

For example, the maximum stress for packing 1 is 1000 psi but for packing 2 is 1800 psi. Same porosity and PSD but the seed value is different.

Thanks for suggesting the coordination number and size distribution. If anyone have any other suggestions or can share a link for previous publication on this topic, that will be very helpful.

Thank you
Othman

 Othman Sh (othman-sh) said on 2020-01-28: #3

Thanks Robert Caulk, that solved my question.