OK, since there aren't any numbers to quantify this level of abuse I'll chip them in.
Assuming a very conservative 3 meters/story, 7 stories is a 21 meter drop.
Looking up the relevant information
on-line I find the following equation useful, X - Xo = Vot + .5at^2
Assuming that the item is dropped an not thrown we can set Vo=0
If we use the drop height as a zero reference we can also set Xo=0
This simplifies the eqn to X=.5at^2
Assuming that we are coducting this test on earth, not mars, we can use an acceleration, a, due to gravity of 9.81 m/s. X=21 meters from the drop above.
Solving the eqn for 't' yields t=sqrt(X/(.5a)) I'm neglecting the time travel required to make the negative root useful. A quick plug and chug gives ~2.07 seconds.
So how fast is that at impact?
Going back to the web I can pull V = Vo + at from the same page.
Again Vo=0. Plug and chug... V=at=20.3 m/s, or 66.6 fps
So what is the force at impact?
F=ma
m= 15 lbm as stated previously in the thread, or 6.8 kg for my metric calculations.
What about 'a'? Being optimistic, let's assume that the concrete is able to decelerate the item along a constant acceleration profile; it keeps the math simple. Realize that this is a best case scenario.
Pulling another eqn from that page (note: bookmark these kinematic equations, you'll use them over, and over, and over.)
V^2 = Vo^2 + 2a(X - Xo) Simplifing based upon the stuff we set to zero... V^2 = 2aX
Solving for a... a=V^2/(2x)
Now I don't know how much the concrete will compress, x, but since it is not known as a squishy material I'm going to guess, 'not much'. I'll try three values to get a trend. 3mm, 2mm, 1mm i'd guess it is much less than any of those.
So at 3mm of compression we have an acceleration of 68.7 m/s and a force of 467 N or 105 lbf
at 2mm -> 103 m/s -> 700 N or 157 lbf
1mm -> 206 m/s -> 1402 N or 315 lbf
Keep in mind, that load is going into the point on your bot that first contacts the concrete.
Another way to put this in perspective is to look at the energy involved.
The kinetic energy of the bot at impact, KE = .5mV^2
Based upon our previous calculations the energy at impact would then be 1402 Joules. If the impact takes a full second it is like getting wacked by a 1400 Watt device... Power=Energy/Time If it is faster, say 0.1 seconds it is like getting wacked by a
14000 Watt device (18.7 HP).
Now I'm not saying what is appropriate for your testing, but understanding what you are asking is probably useful in interpreting your results. I'd hate to destroy my bot during excessive testing and never get it onto the playing field. I'd also hate to not test it hard enough and get destroyed in it's first match.
I think I've left enough of a trail to create a spreadsheet out of this so that you can modify the assumptions to fit your needs. I can always be PM'd for assistance.