The Gurney Equation

[Garyt]

Anyone had any experience calculation the damage of a high explosive round using the Gurney equation?

I seem to be doing something wrong I think. I'm coming up with numbers that show the damage to me caused be the exploded casing to be far greater than the damage caused be the explosion itself, using kilojoules to measure.

When I say much greater, I mean even with a GP bomb the fragmentation effects are about 10x that of the explosion itself.

 

[Garyt]

I'm taking this as no one has an answer?

 

[VALENGO]

Could you please show the equation and your numbers?, I am curious about it.

 

[bbear]

These pages contain basic material on ballistics, warheads(gurney) and damage estimation.
ES310 Introduction to Naval Weapons Engineering

thanks i'll try to make a 'gurney' based calculation to illustrate the effect of VT fuses on kill rates.

I am a non expert, raw beginner,

 

[Garyt]

I am familiar with the equation - you can find some Gurney calculators online.

I am wondering if I am modeling it properly. AP shells should do lees than HE shells - and I am finding that they generally get better fragmentation results, as to be expected, but the increased HE energy is not enough to compensate for the HE rounds reduced fragmentation, and they wind up coming out somewhat equal.

I am wondering if some the factors should be changed.

I am already reducing fragment velocity to 80% of calculated, this is due to the casing requiring energy to be spent to break it. I am using the "brittle metal" example, though I am not sure if a shell casing really should be categorized as "brittle", though they did not have any other possible categories.

But I am wondering to model damage properly, should frag damage kinetic energy be modelled the same as HE kinetic energy?


BTW - Here is an online gurney calculator, Valengo

http://www.un.org/disarmament/un-saferguard/gurney/

 

[VALENGO]

I have read (Wiki) about unexpected results when applying the equation inside certain range of M/C rate. Wonder if it is not your case.
P.S thanks for the link.

 

[Garyt]

I have read (Wiki) about unexpected results when applying the equation inside certain range of M/C rate.

What do you mean here? I guess I'm not familiar with what the M/C rate means.

 

[VALENGO]

Well, far of being an expert, I was introduced to Gurney equations because of this post. Wiki says C= mass of explosive, M= mass of accelerated shell. As wiki is a public source, I put here the link: Gurney equations - Wikipedia, the free encyclopedia You can read right here about anomalous predictions of the G.E.
Cheers!

 

[Garyt]

Got It Now!

From what I can see, it provides incorrect results if the mass of the shell is 50% or less than the mass of the burster. Even on a 30mm Minengeschoss shell, the shell is 3 times the

weight of the burster, so his should not be an issue.