# Air Bag Inflation Rate

#### faiz513

I am designing an exhaust powered vehicle car jack air bag. I have calculated the mass flow rate and velocity of the exhaust gases leaving the vehicles exhaust pipe. I need to calculate the amount of time it will take to inflate an air bag of a particular size. What equations do I need to be using in order to calcualte the rate of inflation? Also I need to calcuate the stresses the air bag will have to withstand in order to lift the vehicle. I have taken fluid mechanics but I am having trouble figuring out which equations to use.

Thanks for the help......

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#### dipstik

turn mass flow into volume flow, i would think. if its a cylindar, then you need to consider the walls of the inflated material as the weakest point (or the seams, or the intake). there should be some mechanics of materials equations for a pressureized cylinlar, then superpose a force on the cylindar from the car load at a sidewall position (say r=R or x=r,y=0.z=0.5h or something). then you need to do all the principle stuff with the design

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