Timestep

Amith Anoop Kumar
Amith Anoop Kumar Altair Community Member
edited March 2021 in Community Q&A

What is exactly timestep for our problem in radioss. How do we set timesteps for a simulation , on what basis do we decide them

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Best Answer

  • Adriano Koga_20259
    Adriano Koga_20259 New Altair Community Member
    edited March 2021 Answer ✓

    Please, take a look at this ebook, as it goes through the aspects of a explicit analysis. Before starting any explicit analysis, you should have this very well understood to avoid misunderstandings.

    https://altairuniversity.com/free-ebooks/free-ebook-crash-analysis-with-radioss-a-study-guide/

     

    Very briefly, timestep is the step used to calculate your solution in an explicit approach.

    The lowr the timestep the longer will take your simulation to run, as it needs more timesteps to conclude the same analysis time. The higher the timestep, the quicker your simulation will finish.

    But, for explicit there's the concept of stability, and essentially you need to keep your timestep below the ideal timestep to make sure your solution will not add too much error along the simulation.

    The timestep is a function of element size and material.

    Take a look at this topic here in the community:

    https://community.altair.com/community?id=community_question&sys_id=22c6c8ba1b2bd0908017dc61ec4bcb48

     

    In HM, you can go to the 'Tools>>check elems' and check the minimum natural timestep for each element type.

    Usually this is a reference value for you to define your timestep (nodal/elemental timestep).

    image

Answers

  • Adriano Koga_20259
    Adriano Koga_20259 New Altair Community Member
    edited March 2021 Answer ✓

    Please, take a look at this ebook, as it goes through the aspects of a explicit analysis. Before starting any explicit analysis, you should have this very well understood to avoid misunderstandings.

    https://altairuniversity.com/free-ebooks/free-ebook-crash-analysis-with-radioss-a-study-guide/

     

    Very briefly, timestep is the step used to calculate your solution in an explicit approach.

    The lowr the timestep the longer will take your simulation to run, as it needs more timesteps to conclude the same analysis time. The higher the timestep, the quicker your simulation will finish.

    But, for explicit there's the concept of stability, and essentially you need to keep your timestep below the ideal timestep to make sure your solution will not add too much error along the simulation.

    The timestep is a function of element size and material.

    Take a look at this topic here in the community:

    https://community.altair.com/community?id=community_question&sys_id=22c6c8ba1b2bd0908017dc61ec4bcb48

     

    In HM, you can go to the 'Tools>>check elems' and check the minimum natural timestep for each element type.

    Usually this is a reference value for you to define your timestep (nodal/elemental timestep).

    image