5 replies to this topic

[Healey]

Hi all 

 

I'm currently studying for an engineering doctorate, and I'm researching ceramic body armour. I've come up against a sticking point lately; I'm looking at the different ways ceramics fragment when hit by a bullet, and it's possible to see some differences in the patterns the ejected fragments (ejecta) make. Some fly out in a vertical-ish plume, some go out at odd angles, etc. 

 

What I'm trying to do is put numbers next to these differences, and I was wondering if there's such a system in pyrotechnics? Can we quantify the difference in shape between explosions caused by different fireworks/pyrotechnics? 

 

To give you an idea of what I'm working with, I'm trying to quantify differences between these two...

 

 

 

Any help would be greatly appreciated.

[cooperman435]

I have no idea myself if there already exists a process for this but Ive never even heard of one.

 

If I were to try and think of a method then I can suggest a few. I imagine breaking down the differing charecteristics may be a starting point

 

ANGLE of material projection maybe (Ie 30deg from vertical)

Range of material projection angles (Ie 0-5deg 3%, 5-10deg 5%, 10-15deg 8%) 

Size of hole compared to projectile maybe on a graph plotted with projectile speed too?

Distribution of material after coming to rest?

 

Not an easy one certainly

Edited by cooperman435, 13 February 2015 - 09:33 PM.

[Pyromancer]

I'm guessing that your doing your doctorate at Cranfield's Shrivenham campus (I'm doing a masters there), If you are and you want to meet up sometime PM me.

 

I don't know of any explosion mapping that has been done with pyrotechnics, but I do know that quite a bit of mapping work has been done on sparks produced by different materials.  The last time I saw this is was in the Journal of Pyrotechnics (JPyro.com I think) or in the Pyrotechnic Chemistry publications by Ken and Bonnie Kosanke.

 

Hope this helps.

 

Steve

[Healey]

I have no idea myself if there already exists a process for this but Ive never even heard of one.

 

If I were to try and think of a method then I can suggest a few. I imagine breaking down the differing charecteristics may be a starting point

 

ANGLE of material projection maybe (Ie 30deg from vertical)

Range of material projection angles (Ie 0-5deg 3%, 5-10deg 5%, 10-15deg 8%) 

Size of hole compared to projectile maybe on a graph plotted with projectile speed too?

Distribution of material after coming to rest?

 

Not an easy one certainly

 

Hi cooperman, thanks for the reply,

 

Aye, I've started some work down those lines; using some computer programs like MATLAB could speed that process up. For that last suggestion there's a lot of literature on debris distribution in planetary science (meteorite impacts, etc. - pretty interesting).

 

I'm guessing that your doing your doctorate at Cranfield's Shrivenham campus (I'm doing a masters there), If you are and you want to meet up sometime PM me.

 

I don't know of any explosion mapping that has been done with pyrotechnics, but I do know that quite a bit of mapping work has been done on sparks produced by different materials.  The last time I saw this is was in the Journal of Pyrotechnics (JPyro.com I think) or in the Pyrotechnic Chemistry publications by Ken and Bonnie Kosanke.

 

Hope this helps.

 

Steve

 

Hi Pyromancer Steve,

 

Good guess, but my EngD is with the University of Surrey (although Cranfield does a lot of relevant courses I might be on in the near future). Thanks for the heads-up on the article, I'll have a look at it.

 

Cheers for the help guys!

[Crazy Cat]

Hi all 
 
I'm currently studying for an engineering doctorate, and I'm researching ceramic body armour. I've come up against a sticking point lately; I'm looking at the different ways ceramics fragment when hit by a bullet, and it's possible to see some differences in the patterns the ejected fragments (ejecta) make. Some fly out in a vertical-ish plume, some go out at odd angles, etc. 
 

See the attached PDF files and these links.

Missile Impact Craters. http://pubs.usgs.gov...812b/report.pdf

http://web.gps.calte...Seismo_1314.pdf
http://www.currentsc...107/05/0824.pdf
http://www.lpi.usra....13/pdf/1054.pdf

Attached Files

•  Material Ejection of Granite Blocks- Hogan.pdf   1.1MB   365 downloads
•  ADA579865.pdf   4.04MB   1766 downloads

[Healey]

You have an excellent eye for literature, Crazy Cat. Ah, Hogan, we meet again...

 

Thanks very much for the info, will give these a read