Suspension dynamics question

To stave off boredom I'm developing an independent, pushrod suspension for a trailer.  Figure it will give me a good starting place to move to actual car stuff later on.

I've got the static part pretty much figured out I think, I also have a rough FBD and equation from a vibrations standpoint, but how do you figure out the force from a bump in the road?

If the trailer, loaded and everything, is 900-1000lbs, and hits a pothole that is 1" deep, what is that force?  Is the force when it tries to climb out of the pothole worse?

In reply to Mr_Asa :

For every action there's a reaction. Same force up as same force down. Unless, you have a shock absorber keeping the shock from "boinging" back as hard. 

The forces on the back side of a pothole are worse, because you have the mass of trailer accelerating downward as you encounter the back face. The front of the pot hole is basically going off a cliff. Use a factor of safety of 1.5 for most anything you come up with load wise since we cant all figure out every situation.

My initial thought on a worst case loading would be something like a 4x4 in the road that the trailer encounters. Anything bigger and you probably have other issues.

In reply to _ :

Sorry, yes, I am planning on having a shock in the system.

This is a much more complicated than your typical plug & chug equation based solution. You have sprung mass, unsprung mass, tire stiffness, damper rates, friction.... Too much interaction and reactions happening to really crunch it out. What I have done, all the way back to my FSAE days, is assume full vehicle mass on that corner at a 1.5g bump. So for your 1000lb trailer, assume 1500lb into your FBD and then size components from there. Go up in size on hardware for critical joints that take load in multiple directions.