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Author Topic: Seat-belt stuff.  (Read 522 times)

w3526602

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Seat-belt stuff.
« on: November 19, 2021, 07:58:54 AM »

Hi,

I came across this while looking for something else about fitting seat belts.

https://www.nmisafety.com/about-us/technical-area/

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w3526602

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Re: Seat-belt stuff.
« Reply #1 on: November 19, 2021, 08:09:09 AM »

Hi again,

A quick extract from the above ....

One of the main tests is the Dynamic sled test. The seat must be tested front and rear facing and must withstand a force of 20G. Sled tests now include two loose blocks impacting the rear of the seats to simulate loose luggage or boxes hitting the seat during a crash.

20G? For me? that's about 2000kgs.

Probably an unfair (and incorrect physics) question, but would you want to dangle a complete S2 by one roof mounted seat belt point?

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Nanuq

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Re: Seat-belt stuff.
« Reply #2 on: November 19, 2021, 08:24:44 AM »

That 20G is an impulse, not an extended amount of force.  From simple physics,

The derivative of speed with time is the acceleration (the slope of the line), and
The derivative of acceleration with time is the impulse (again the slope of the line).

The integral of the impulse over time is the acceleration (the area under the curve), and
The integral of the acceleration over time is the speed (again the area under the curve).

So you can have a very narrow, very tall impulse wave with very little area beneath its curve, and the total acceleration won't kill you.
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diffwhine

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Re: Seat-belt stuff.
« Reply #3 on: November 19, 2021, 09:05:18 AM »

Can we have that again in English please? Google translate can't cope - nor can my brain...
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1965 88" Station Wagon
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