Air Pillow Event Simulation

[Anonymous]

Hello,

I am trying to simulate a drop test of an 3 kg payload that has an air pillow on the bottom for shock absorption (the air pillow has compressed air), Is there anyway to simulate/model this on Fusion? 

Kind regards,

Aadam

[John_Holtz]

Hi Aadam,

I would say that the answer is no.

• Air is a gas, so the pressure throughout the gas is essentially equal. (At least as equal as the pressure waves moving through it allow it to equalize.) The analysis can only simulate solids. The pressure wave passing through the solid behaves much differently.
• I would assume that the "pillow" is a thin membrane. That would be best analyzed with a membrane element. Fusion only has solid elements which will not give accurate results for anything that is really thin.

[Anonymous]

Hi John, 

Hope you are keeping well and safe. Thank you very much for your reply! Could you please tell me more about using membrane element analysis ? Is there a paper for me to read or a video perhaps ?

Thank you very much for your help! 

Kind regards,

Aadam

[John_Holtz]

A membrane cannot resist bending. Think of fabric (clothing) or the thin material in a car air bag. It will bend or fold with a very small load -- essentially, it has no stiffness in bending. It resists the applied loads only by creating forces/stress in the plane of the material; that is, it creates membrane stresses.

I do not have any particular references, but you can use your favorite search engine to find lots of hits for "FEA membrane element".