# Gradation curve of assembly made of clumps

Asked by Ruidong LI

Hello！ I would like to know how to calculate the gradation curve of an assembly consisting of clumps. Many thanks.

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 Revision history for this message Jan Stránský (honzik) said on 2023-05-24: #1

Hello,

please provide a MWE [1]. A few simple clumps and expected result.

Please also state where the actual problem is.
Calculation of gradation curve in general?
Treating of clumps?
...?

Cheers
Jan

 Revision history for this message Ruidong LI (kyle2000) said on 2023-05-24: #2

Hello, Jan.

Actually, what I need is the calculation of the gradation curve in general. I have an assembly of clumps generated based on imported stl files. And I would like to obtain the gradation curve of the assembly. I am new to the numerical simulation. And I don't know how to calculate the size of a clump. More specially, I don't know which length can represent the size of the clump and be used for gradation calculation. The length of the longest axis? I have shared some STL files for your reference [1].

Looking forward to your reply. Many thanks.

Ruidong

 Revision history for this message Jan Stránský (honzik) said on 2023-05-24: #3

> what I need is the calculation of the gradation curve in general

In general it is same as you would do it experimentally.
For a set of defined "passing" sizes, you count particles smaller than that size.
See implementation of psd function [2]

> And I don't know how to calculate the size of a clump. More specially, I don't know which length can represent the size of the clump and be used for gradation calculation. The length of the longest axis?

Depends on your definition.
Calculation then should not be too difficult.

Longest axis is one choice.
For real sieve analysis, probably the longest size is not the most important, as it would pass "perpendicularly" to the longest axis? So maybe the second longest principal axes? Or longest dimension perpendicular to the longest axis? I don't know..
There are more options.

> I have shared some STL files for your reference

An artificial simple example should be enough.

Cheers
Jan

 Revision history for this message Ruidong LI (kyle2000) said on 2023-05-24: #4

Thank you so much. That solved my problem.

 Revision history for this message Afaan Ahsan (apkbgmi) said on 2023-05-26: #5

Hello!

Calculating the gradation curve of an assembly consisting of clumps involves determining the distribution of particle sizes within the clumps and then analyzing the overall particle size distribution. Here are some steps you can follow:
Break down the clumps: Start by breaking down the clumps into individual particles. This can be done manually or using sieving techniques, depending on the size and nature of the clumps.

Obtain particle size data: Measure the size of each individual particle using appropriate techniques such as sieve analysis, laser diffraction, or sedimentation. This will give you a dataset of particle sizes.

Determine the frequency distribution: Organize the particle size data into a frequency distribution table or graph, showing the number or percentage of particles falling within specific size ranges.

Calculate cumulative distribution: Calculate the cumulative distribution by summing up the frequencies or percentages for each size range. This will give you the cumulative percentage of particles smaller than or equal to a particular size.

Plot the gradation curve: Plot the cumulative distribution on a graph, with the particle size on the x-axis (typically on a logarithmic scale) and the cumulative percentage on the y-axis. This curve represents the gradation of the assembly.
It's worth noting that the accuracy and precision of the gradation curve depend on the sample size and the representativeness of the particles obtained from the clumps. Consider using a representative sample and conducting multiple tests for more reliable results. https://apkbgmi.com/

I hope this helps! Let me know if you have any further questions.

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