Simulation run time too high to be realistic

Ashmita Tiwari
Ashmita Tiwari Altair Community Member
edited November 2022 in Community Q&A

I am trying to simulate deformation (and failure) due to a statically applied Force. I am using CLOAD card to apply the force. I read online that I need to ramp up the force in 300 ms. So, I have added a curve to ramp up the force. I am running the simulation for 310 ms (ENG_RUN/Tstop = 310). Per the screenshot below, it will take forever to finish the simulation. So, I have most likely setup something incorrectly.

What should be the appropriate setup to apply a load (increasing from 0 kN to say 4 kN), so that I can identify at what load different connections fail?

Also, the ERR = -99.9% in the screenshot below. I am assuming that this is not acceptable.

image

Any guidance, tips, or suitable examples would help.

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Best Answer

  • PaulAltair
    PaulAltair
    Altair Employee
    edited November 2022 Answer ✓

    it is often better to apply a displacement and measure the force if you can, otherwise, you are guessing the force... and if your connections do fail below the total force requested, then the model will likely blow up, as the only way the requested increasing force can be achieved is to keep accelerating against the inertia of whatever parts are now free!

    if this is in same units as other model you sent, then 1.6e-6 is a factor of a 1000 too small really, likely you need to revise your mesh

    99.9% or -99.9% can be ok in early phase of an applied load model, the energy balance may not have settled down yet. But it sounds like you have other issues beyond that

Answers

  • PaulAltair
    PaulAltair
    Altair Employee
    edited November 2022 Answer ✓

    it is often better to apply a displacement and measure the force if you can, otherwise, you are guessing the force... and if your connections do fail below the total force requested, then the model will likely blow up, as the only way the requested increasing force can be achieved is to keep accelerating against the inertia of whatever parts are now free!

    if this is in same units as other model you sent, then 1.6e-6 is a factor of a 1000 too small really, likely you need to revise your mesh

    99.9% or -99.9% can be ok in early phase of an applied load model, the energy balance may not have settled down yet. But it sounds like you have other issues beyond that

  • Ashmita Tiwari
    Ashmita Tiwari Altair Community Member
    edited November 2022

    Thank you Paul. I have modified the setup to apply displacement load and measure Reaction force.