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RE: bullet proof concrete?
- To: seaint(--nospam--at)seaint.org
- Subject: RE: bullet proof concrete?
- From: G Vishwanath <gvshwnth(--nospam--at)yahoo.com>
- Date: Mon, 26 May 2008 02:00:17 -0700 (PDT)
About 22 years ago, when I was a productive and active structural engineer, I had the opportunity to study and design some explosion proof armor rooms designed to resist blast pressures from exploding cylinders stored inside the room.
These cylinders were pressurized upto 500 atmospheres and the rooms were intended to serve as safety rooms whose function was to contain the damage inside the room if the cylinders exploded by any chance.
The walls of the armor room were also to resist penetration from fragments hitting the walls at ballistic speeds. The cylinders were made of titanium alloy and the walls of the rooms were double walled armor steel plates with a 12" spacing filed with concrete.
I remember to have sought academic help from scientists working for a reputed research labroratory that dealt with explosives and safety measures. (Indian Nobel Basic
Resarch Institute at Bangalore)
The scientists were most helpful and one useful reference in particular which came to our immediate aid was an article published in the ASCE journal of the structural division authored by Dr A. K Kar.
The article was titled (if my memory serves me right) "Projectile penetration into concrete". There were two more articles titled "Projectile penetration into steel" and "Projectile penetration into earth".
I remember that this article had summarised experimental results of field studies conducted in this area and had listed a long empirically arrived formula which would yield the distance that a projectile would penetrate into concrete/steel/earth as applicable.
The inputs were the mass of the projectile, speed at which it hits the wall, some relevant material properties of both the projectile and the wall, angle
at which the projectile strikes the wall and some shape factors which defined sharpness of the projectile.
I used this formula with success in my project. We made juidicious assumptions for input data.
The original calcs are not with me and since the project was a defense related project, I cold not keep any material with me for my personal reference. However, if I do some rummaging in my old dusty files kept in some attic, I may be able to locate a photocopy of the article that I am referring to. I dont remember the date of the article but it was published some time in the late seventies of early eighties. I am sure of the name of the author viz Dr. A. K Kar. The journal was most definitely the ASCE journal of the structural division.
If you wish, I will try to locate this article and scan it for you.If you are lucky, I may be able to find it and convince my wife that
keeping them all these years was indeed worth it.
Let me know.