# Internal stress in a wall at object impact

1. Jan 29, 2012

### Aragorn49

1. The problem statement, all variables and given/known data
In the past months I've been working on a work calculating the behavior of a wall at an object impacting into it. I thought I have made it by knowing the impact force and the pressure it makes but then I realized that to fully complete my work I have to somehow calculate the internal stress in the wall. So to sumarize it, I know the impact force of the object hitting the wall and I also know the dimensions of both the wall and the object. What I'm trying to find out is what form of stress does occur inside the wall after object impact. Is it shear stress or maybe shear stress + another stress? How can I calculate this stress?

2. Relevant equations
When studying about the individual stresses I found that there is always the equation of the stress being equal to F/A. I know F but I don't know what the A is. i know the dimensions of the wall but I don't know how to characterize what is the A and what isn't.

3. The attempt at a solution
Well, I have studied the info I could find about the individual stresses but I still don't understand which stress to apply and what to consider the area (A) or cross section of the impact. I became pretty much confident that at least partially the stress is shear but there could be more stresses. I also don't know how to calculate a possible combined stress.

Thank you for reading my question
Aragorn49