Inflation of 3 tryton balloon

[pradeepburla]

Hi Guys,

I generated Tryton balloon geometry and meshed them with shell elements.
I am using Abaqus/Explicit to inflate the balloon. I am applying uniform pressure to the internal walls of the balloon with a linear amplitude curve from 0-1.
E=920 MPA
Poisson Ratio=0.4
I see a recoiling behavior, which can also be interpreted from Kinetic Energy values after each increment.I am attaching a series of images,in the increasing order of step time.
Link
Is it because of the fact that i am applying pressure in an impulsive way?I tried to do the same simulation for a step size of 10, the recoiling effect was dampened but the balloon was still recoiling.
I would like to know what can be the potential reasons for this.

Any suggestion or idea would help

 

[IceBreakerSours]

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[Dave442]

Hi,

Given the limited info you provided I would suggest the following:

1) Use membrane (M3D4R) elements instead of shell elements.
2) If you are trying to perform a quasi-static analysis, remove any damping or mass-scaling and adjust your loading rate so that kinetic energy remains <5% of internal energy for the duration of the analysis. Internal/kinetic energy are reported as history outputs by default for explicit analyses.
3) Use a smooth step amplitude for your pressure load.
4) Check your units - your equivalent stress values look very low.
5) If you just intend to model a balloon, use standard/implicit.

Good luck,
Dave