Export particles' positions to a new EDEM project, to apply new material data

MQ

Hi Everyone,

Is there any way to export particles (sizes and positions, once they have dropped and settled) to a new EDEM project, in order to study them with the different material properties?

The idea is that I need exact same arrangment of particles (could be in large numbers), subject them to same conditions, but with different material properties. However, changing the properties (e.g., density) midway through the simulation does not work, as discussed in one of the previous posts (Link here!)

Thank you.

Best regards,

MQ

 

Stefan Pantaleev_21979

Hi MQ,

 

All the particle material property changes are applied to the existing particles with the exception of the particle mass, volume and moments of inertia. As Richard says you might disrupt the equilibrium in a static bed by chanigng those and therefore might need to simulate more time to arrive at a new static state. If you want to change the particle mass, volume and moments of inertia you can download free HDFview from https://www.hdfgroup.org/downloads/hdfview/ and open the 0.h5 file in the  [EDEM_deck_name]_data folder of the exoported EDEM deck. Then you can navigate to the particle types you want to modify and edit their attributes as per below. Make sure to edit them in the TimestepData and the CreatorData both. Do not forget to change both the particle inertia and mass together. This will work but keep in mind that changes like these are not officially supported or recommended by us.

Renan

Hi MQ,

 

You can run a set up simulation in which you just create the particles and let them settle. Once that simulation is done you can go in the Analyst and export a simulation deck (screenshot below). This way you can make sure that all your particles will have the same initial position, regardless of their properties.

 

 

Best regards,

Renan

MQ

Renan Calmon_20325 said:

Hi MQ,

 

You can run a set up simulation in which you just create the particles and let them settle. Once that simulation is done you can go in the Analyst and export a simulation deck (screenshot below). This way you can make sure that all your particles will have the same initial position, regardless of their properties.

 

 

Best regards,

Renan

Hi Renan,

Thank you for your response.

I have tried this method, but I noticed that still older material properties are being read. I have a custom contact model that exports the particle density and mass into a text file. The new density is correctly being output but the mass still corresponds to the density from previous EDEM project (from which this export was done). This is a bit strange!

Any work around in your mind?

Best regards,

MQ

Renan

MQ said:

Hi Renan,

Thank you for your response.

I have tried this method, but I noticed that still older material properties are being read. I have a custom contact model that exports the particle density and mass into a text file. The new density is correctly being output but the mass still corresponds to the density from previous EDEM project (from which this export was done). This is a bit strange!

Any work around in your mind?

Best regards,

MQ

Hi MQ,

In this case, the only thing I can think of is to manually modify the h5 file. However, this is highly risky and not advisable because if make make any mistake you'll have an unusable file. You could have python script (or any other programming language) read the h5 file and then overwrite the values of the properties you want change. So I'd recommend creating a backup of your simulation and only try this if you know what you're doing.

Best regards,

Renan

 

RWood

Renan Calmon_20325 said:

Hi MQ,

In this case, the only thing I can think of is to manually modify the h5 file. However, this is highly risky and not advisable because if make make any mistake you'll have an unusable file. You could have python script (or any other programming language) read the h5 file and then overwrite the values of the properties you want change. So I'd recommend creating a backup of your simulation and only try this if you know what you're doing.

Best regards,

Renan

 

Something to bear in mind is that if you're interested in changing the properties of a settled system, the whole reason they are settled is because the forces are in equilibrium. If you go change the particle density, or any other material property, the forces will no longer be in equilibrium.

Richard

Stefan Pantaleev_21979

Hi MQ,

 

All the particle material property changes are applied to the existing particles with the exception of the particle mass, volume and moments of inertia. As Richard says you might disrupt the equilibrium in a static bed by chanigng those and therefore might need to simulate more time to arrive at a new static state. If you want to change the particle mass, volume and moments of inertia you can download free HDFview from https://www.hdfgroup.org/downloads/hdfview/ and open the 0.h5 file in the  [EDEM_deck_name]_data folder of the exoported EDEM deck. Then you can navigate to the particle types you want to modify and edit their attributes as per below. Make sure to edit them in the TimestepData and the CreatorData both. Do not forget to change both the particle inertia and mass together. This will work but keep in mind that changes like these are not officially supported or recommended by us.