Whether the derived contact force is a single contact

shiw
shiw Altair Community Member

Is the data derived from the contact force the force of a sing.le contact at this moment, or the total force of all contacts at this time? I saw that there is a textbook that says that it is a single contact, so I want to verify the following. Thank you.

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Best Answer

  • Stephen Cole
    Stephen Cole
    Altair Employee
    Answer ✓

    Hi,

    Average force in the EDEM screenshot is the average force across multiple Contacts at one point in time, this is different to the average force of a single particle Collision.

    The text book refers to Collisions as well as Contacts. A Collision is something that happens over a set time period, it has a start time, end time, maximum force etc associated with it.

    One Collision can be made up of multiple Contacts, EDEM calculates new contact forces each time-step but these may all be associated with an ongoing collision.

    https://help.altair.com/edem/topics/edem_simulator/track_collision_data_c.htm?

    EDEM stores Contact data by default but not Collision data, I would not recommend using Collisions generally as they are not supported on GPU.

    The query below is set to export the Average contact force between New Particle 2 and Unnamed Section 29.:

    If you have 10 different particles all contacting the same geometry, at each save data point each particle will have a contact force associated with the geometry, and Average will be the average value of these 10 points. If you exported Standard you would get a force for each contact at that specified point in time.

    https://help.altair.com/edem/topics/edem_analyst/exporting_results_data_t.htm

    Regards

    Stephen

Answers

  • PrasadAvilala
    PrasadAvilala
    Altair Employee

    Hi Shiw,

    As per your selection shown in the picture is, its a Average contact normal force between

    New Particle 2 and Unnamed Section 29.

    if you want a specific element normal contact force between New Particle 2 and Unnamed Section 29

    define bin and call that bin in the Selection i.e Currently Selection is All but if you create a bin please call bin so that EDEM extract force between New Particle 2 and Unnamed Section 29 at bin location

    Hope this is clear

    Thanks,

    Prasad A

  • Stephen Cole
    Stephen Cole
    Altair Employee
    Answer ✓

    Hi,

    Average force in the EDEM screenshot is the average force across multiple Contacts at one point in time, this is different to the average force of a single particle Collision.

    The text book refers to Collisions as well as Contacts. A Collision is something that happens over a set time period, it has a start time, end time, maximum force etc associated with it.

    One Collision can be made up of multiple Contacts, EDEM calculates new contact forces each time-step but these may all be associated with an ongoing collision.

    https://help.altair.com/edem/topics/edem_simulator/track_collision_data_c.htm?

    EDEM stores Contact data by default but not Collision data, I would not recommend using Collisions generally as they are not supported on GPU.

    The query below is set to export the Average contact force between New Particle 2 and Unnamed Section 29.:

    If you have 10 different particles all contacting the same geometry, at each save data point each particle will have a contact force associated with the geometry, and Average will be the average value of these 10 points. If you exported Standard you would get a force for each contact at that specified point in time.

    https://help.altair.com/edem/topics/edem_analyst/exporting_results_data_t.htm

    Regards

    Stephen

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