LS Dyna

LS Dyna

Autodyn impulse

    • Centurion_2020
      Subscriber
      Hello,nI was trying to model explosion and obtained P(t) curve via Gauge point. Now, I would like to get impulse result for that P(t) curve. In the History menu when you make P(t) curve there is an option INTEGRATE bellow. I guess it is here for impulse calculation, but I usually get bad results. How to get accurate reading of impulse for particular P(t) curve since when I do INTEGRATE, I get another curve?n
    • Centurion_2020
      Subscriber
      n
    • Missy Ji
      Ansys Employee
       You can create the pressure impulse by clicking on the box Integrate after plotting the time history of pressure at a gauge point. What do you mean bad results?n
    • Chris Quan
      Ansys Employee
      You need to subtract atmospheric pressure from the pressure calculated before calculating the impulsen
    • Centurion_2020
      Subscriber
      mji, please look at the upper two images. Lower image is integrated curve of the P(t). What exactly is impulse values on this curve, how can I read it exactly?.cxquan, how can I subtract atmospheric pressure in Autodyn on P(t) curve before calculating the impulse?.n
    • Chris Quan
      Ansys Employee
      To get over-pressure by subtracting atmospheric pressure from the calculated pressure, you can either add atmospheric pressure to P-shift in the EOS or click on Write Text Output to export the data to Excel. Then in Excel to subtract the atm.n
    • Centurion_2020
      Subscriber
      Thanks man, this was very helpful. nI was wondering if you know why there is a second peak behind initial peak over-pressure in autodyn? I am running free air-burst simulation, no reflection of any kind. Can this be solved by some initial setup before running simulation?nI am uploading an image of one example.nn
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