1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Car bumper crash - deformation

  1. Oct 15, 2007 #1
    1. The problem statement, all variables and given/known data
    hi all,

    Given:
    a car is reversing at 4km/h, weight = 1500kg... n whamps into a lamp post. i'm suppose to calculate the bending of the bumper, which is made of AlZn4,5Mg1 material.

    bumper is 900mm long n fix onto the car body
    dimension : 80x80mm U profile with a 5mm thickness


    2. Relevant equations



    3. The attempt at a solution

    i assume that we should use the kinetic energy formula which is

    E = 1/2mv2

    to get the amount of initial energy.

    According to the law of conservation energy.

    initial energy = final energy
    = deformation energy/potential energy + sound energy(neglegible) + heat (neglegible )

    from my what i've considered here, i guess i need a force F in order to calculate the bending distance of the bumper.

    but from the formulas i have above, how do i go about getting the force F which works on the bumper?

    the area underneath the stress strain diagramme of this material wouldnt help much because i couldnt really calculate (accurately) the area after the elasticity limit right?
     
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you help with the solution or looking for help too?