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Old 02-05-2017, 08:08 PM
mmartin798 mmartin798 is offline
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Join Date: Feb 2014
Location: Michigan
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Quote:
Originally Posted by nuke11 View Post
Very nice and helpful! I hope you plan on releasing the excel formula at some point.

For the specs of the Armbrust, I had to dig really deep into the archives, but the projectile is 0.99 kg and the filler is 0.16 kg of RDX (MP RE of 1.20) (it could also be some what closer to 0.19 kg) and it can penetrate 300 mm of rha.
I do most of my work at home on my MacBook Pro using Numbers. However, I did export my master as an Excel spreadsheet. There are two sheets. The Explosives Data sheet and the Whole Body Damage sheet. I will explain the assumptions made and the formula used so people can understand where everything came from. If you just want the calculations, you can download the spreadsheet, goto the Explosive Data sheet, enter the weight of the explosive filler in Kg into cell B3, enter the explosive damage number from the game into cell B5 and then goto the Whole Body Damage sheet to see the results.

If you are still reading, I assume you want the math and such behind the sheet. I make two major assumptions in these calculations. The first is that the damage drops off exponentially with distance. The second, the point at which the Department of the Army Pamphlet 385-63 assumes a less than 1% chance of a ruptured eardrum from the over pressure generated by an explosive device, the minimum stand-off distance, is equal to 1 DPW. Using these assumptions, we have two known points with which to solve for the constants a and b in the general exponential function: f(x) = a(b)^x, where f(x) gives the damage at range x from the explosion. The values a and b are calculated on the Explosive Data sheet. When x=0, f(0)=a(b)^0. The term (b)^0 = 1, therefore at range 0 the value of a can be determined to be the full force of the explosion, Ex. To solve for b, we need our second known point. From our assumptions, we know at at the minimum stand-off distance (Msd), damage equals one. The Msd is given by D=23.4*(mass of explosive filler in Kg)^1/3. Therefore, F(Msd)=1. Substituting values we have, 1=Ex(b)^Msd. Dividing both sides by Ex and then taking the Msd-th root of both sides, we end up with b=(1/Ex)^(1/Msd). So our exponential equation is, f(x)=Ex*((1/Ex)^(1/Msd))^x. Easy peasy!

If there are any error in the math or questions about the assumptions, let me know.
Attached Files
File Type: xlsx Whole Body Damage Master.xlsx (484.0 KB, 26 views)

Last edited by mmartin798; 02-05-2017 at 08:39 PM.
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