Inflatable Seatbelt Help: Calculations & Optimum Pressure

[sdawkins]

howdy,
I am making a project on inflatable seat belt ()

I need some help with calculations
I will be working with a air cylinder with compressed air in it, a solenoid valve (electro pneumatic), and seatbelt made out of airbag fabric.

how do i determine how much pressure i need in air cylinder( previously I've built the same project with 85psi but did not take care of specifics and performance, and 85 was just an arbitrary value which i could attain max that time ,and i don't have access to that project anymore)

how how do i calculate optimum pressure required,aslo what kind of valve should be used on the cylinder before the solenoid valve is attached, as this time i need things to be more specific

if more data is required please ask me, am badly in need of help

 

[Stephen Tashi]

how do i calculate optimum pressure required

You'd have to say what you mean by "optimum" first and this may not be simple. What is being optimized?

It may be a compromise between several objectives. Is the objective to inflate the belt as quickly as possible to some given pressure in the belt? Is this belt reusable after it inflates? Must the cylinder hold enough pressurized air for several uses? - or is it for a single use, like an air bag ?

 

[sdawkins]

You'd have to say what you mean by "optimum" It may be a compromise between several objectives. Is the objective to inflate the belt as quickly as possible to some given pressure in the belt? Is this belt reusable after it inflates? Must the cylinder hold enough pressurized air for several uses? - or is it for a single use, like an air bag ?

By optimum i mean what minimum pressure is sufficient to inflate it quickly(as i said previously i kept pressure 85psi,is 85 psi really required)

And yes it needs to inflate real quick and if required two cylinders and valves may be used

And yes it should hold pressure in bag but not for long as soon as it inflates it also starts to deflate as in airbag

Yes it can be reused unlike airbag, and a container should contain air for more than 1 inflation(but that's not mandatory)

 

[DEvens]

By "real quick" I assume you mean 37 days. This is "real quick" for purposes of getting a document back from the government.

What? It needs to be faster than that? Ok, you need to send me the cash to pay my Mind Reading Bill. Or you need to put in a number for how quick is "real quick."

As to "what sort of valve" you need, I'm guessing "real quick." You could Google up some valve makers and their products, and see what opening characteristics they have.

 

[berkeman]

@sdawkins -- can you tell us how a regular airbag inflates/deflates? What is used? And how is your design going to differ from that?

 

[sdawkins]

By "real quick" I assume you mean 37 days. This is "real quick" for purposes of getting a document back from the government.
.

Ford claims its system works in 40milliseconds
So that is the desired result but for me i can go upto 80milliseconds

@sdawkins -- can you tell us how a regular airbag inflates/deflates? What is used? And how is your design going to differ from that?

A regular airbag inflates using chemical reactions,generating gases required for inflation.as soon as the air bag inflates the gases starts to escape from small pores of the airbags.

In my project cold compressed gas is used for inflation, for ease of calculation deflation may be ignored