How to apply initial uniform temperature in explicit simulation

HaiquanHaiquan Member Posts: 22

Hello

I am performing explicit simulation using Johnson cook model. As I know, the properties of JC model is dependent of temperature. One of my parts(not all the parts) has initial high temperature, but temperature load can not be applied directly in explicit, how can I take into account the initial temperature condition? Thank you in advance!

Answers

  • HaiquanHaiquan Member Posts: 22

    @cxquan @peteroznewman @akhemka Any comment on my question?

    I tried to do a thermal steady and link to the explicit, but the link is not allowed between thermal steady and explicit.

    I also found similar question in Customer Portal as shown below, how to map temperature in Explicit?



  • akhemkaakhemka Forum Coordinator Posts: 676
  • cxquancxquan Berkeley, CAForum Coordinator Posts: 79

    Yes, it is true that material property data of Johnson-Cook model is temperature-dependent. If you are modeling a material in an elevated temperature (i, e., higher than the room temperature), you need to manually adjust the property data by treating the elevated temperature as the new room temperature.

    Thus, the initial Yield Stress should be reduced and equal to the yield stress at the elevated temperature (thermal softening). The melting temperature also needs to be reduced because the new room temperature is higher than the original room temperature where the melting temperature was derived.

  • cxquancxquan Berkeley, CAForum Coordinator Posts: 79

    Thermal Analysis system won't work with Explicit Dynamics system. Static Structural system can transfer the stress/displacement to Explicit Dynamics system as Initial Conditions.

    This is because only stress/displacement, not temperature, can be transferred to Explicit Dynamics system.

  • HaiquanHaiquan Member Posts: 22

    @cxquan @akhemka Thank you so much for your comments! It is helpfull. For JC strength, all I have to do is to reduce the initial yield and melting temperature.

    I still have other questions:

    1/ For JC failure, how to modify the D1 to D5 ? I am not quite sure what exactly these parameters means.

    2/ We know that higher temperature, lower Young's modulus. My material model introduce the shock EOS linear, is this EOS related to linear elastic material propertise(Young's modulus)? If yes, how to modify the them? Can I input the temperature-dependent linear elastic properties instead of EOS?

    3/ My simulation is metal cutting, but cutting procedure is very slow, duration is about 1s. Is JC material model a correct selection?

    Thank you in advance!

  • cxquancxquan Berkeley, CAForum Coordinator Posts: 79

    D1 to D5 are obtained from experiment studies. Please refer to the original paper of the model before making any changes on these parameters.

    Shock EOS linear means that relationship between the shock wave velocity and the partical velocity is linear. It's not the Linear Elastic EOS.

    If the strain rate is high, JC model applies.

  • HaiquanHaiquan Member Posts: 22

    @cxquan Thank you so much for your feedback. I am trying to refer to some papers about JC model.

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