Primary fragments impacting on concrete

[Cniper]

Does anybody out there know how to determine the impact on concrete from primary fragments, travelling at approx 2-3km/s?

Or a change of formulae to help.

 

[desertfox]

Hi Cniper

Primary fragments of what? What formula are you currently using or is it a secret.

desertfox

 

[Ron]

We need more information in order to offer any constructive advice.

What size particles? What is their shape? How many of them per unit area? What is the impingement angle? What are the particles made of? What type of concrete? What strength concrete?

Formulae don't mean much when dealing with abrasion and durability of concrete. Those are primarily strength and tested parameters.

 

[cloa]

I'd suggest he means the particles produced from an explosion. Its whatever was blown up.

 

[Wrenchbender]

OP asks "..how to determine the impact ...?"
My suggestions:
[a] Measure it by doing a MIL-STD-2105 Fragment Impact Test. (If you are government or a gov't contractor, DOD activities routinely do this. Cost is in 4 digits.)
Estimate it via empirical equations available in open source literature, e.g. google search the words "hertz concrete impact" to find journal papers.
[c] check out textbooks in explosive effects, rock blasting, terminal ballistics, etc.

The specifics will depend on the many variables mentioned in the previous posts.

 

[Cniper]

From the 4 replies you can see my dilema. Concrete of about 1.5m thk, estimate 40 N. Prior to testing etc, just a formula to get me started to give a handle on the outcome. The information onb the initial thread is all I have to work with, ie lots of assumptions which is always the case in Engineering.

Thanks for your comments. Looking at spalling....Trying to determine the imapct from a detonation and although fragments of metal from a casing can be contained the sizes of cracks would be vast for gases to escape.

 

[IRstuff]

There are, available on the web, design and construction handbooks for hardened buildings and facilities. The only unknown that you appear to have is the size and weight of the fragments, which is described in MIL-DTL-46593B.

TTFN

FAQ731-376