Calculating the force applied by a seat belt on a person at point of accident

[Elite Engineer]

I'm trying to illustrate the importance of wearing a seat belt properly, specifically when people wear seat belts over their mid stomach,

instead of their pelvic girdle.  In figuring out the force applied to a passengers abdomen when the car hits an object and the person's inertia

drives them into the seat belt, is it necessary to the factor in the area of the seat belt? I'd think it would be important because of P = F/A. 

Hence the seat belt is maybe 2 inches in width, so it's going to produce way more damage that if it were 20 inches in width. 

 

Also, how would you calculate the force of the person moving forward? Just a standard momentum calculation?

 

~ee

 

 

 

[fiveworlds]

You could use a crash test dummy with sensors all over it and send the data back to yourself to have a look at.

The modern crash test dummy(https://en.wikipedia.org/wiki/Hybrid_III) is calibrated to specific regulations but you could make a simple one yourself.

Edited December 4, 2017 by fiveworlds

[Elite Engineer]

What about a simple physics diagram, with vectors, mass, velocity?

Won't be the EXACT data, but can get close I imagine.

[fiveworlds]

Quote

What about a simple physics diagram, with vectors, mass, velocity?

There is way too many variables. You'd need to know everything about the vehicle.

[swansont]

The average force is the momentum change divided by the impact time. Final momentum is zero, so F = p/t

[Elite Engineer]

3 hours ago, fiveworlds said:

There is way too many variables. You'd need to know everything about the vehicle.

Give me a handful of variables. I'm not trying to test the effectiveness of a seat belt. Just trying to get a "close" average of the forces applied to the passenger 

[swansont]

m, v, and t are the variables

[fiveworlds]

 

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Just trying to get a "close" average of the forces applied to the passenger  

Could you not just use the software that does that? http://www.altairhyperworks.com/solution/Crash-Safety-Impact

 

[Elite Engineer]

Now that I know it exists, yes. Thanks