# Autodyn impulse

Centurion_2020
Member

Hello,

I 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?

## Comments

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?

You need to subtract atmospheric pressure from the pressure calculated before calculating the impulse

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?

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.

Thanks man, this was very helpful.

I 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?I am uploading an image of one example.