# Impulse and Impact time of a collision

1. Apr 13, 2010

### frostie

Hi there,

For my Final Year Project at University I am analysing Road Restraint Systems/Safety Barriers in a Finite Element Analysis package.

My problem is calculating the force exerted onto the barrier by a vehicle during a collision, more specifically the time over which this impact occurs.

Using d (this distance over which the impact occurs) isn't an option as this is an unknown that is calculated during the analysis.

What I've got so far...

E=1/2mv2
Momentum = mv=2E/v
Momentum = F. delta t = 2E/v

Therefore, F = 2E/v.delta t

What I really need is an assumed value of delta t from past numerical or field tests. I've searched for journals with such information with no luck. Failing that a method or idea how else to calculate the force exerted on the barrier from a vehicle.

Any help would be greatly appreciated.

Regards,

Frostie

2. Apr 13, 2010

### frostie

Sorry...Looking at the sub-forum descriptions and the general topics of the posts in this forum...I think I may have posted this in the wrong section. I saw PhD help and posted...but I think this is probably more for help on choosing a PhD?

Could a moderator possibly move this to a more appropriate place.

Thanks,

Frostie