Ola Guys

I'm doing a bit of research for what is currently a wild dio idea and I still have not really figured out how to do it. But I think it is possible. And it will be my very first modern project.

I'm looking for a bit of info of which I hope some of the people who served in Iraq and Afghanistan can shed some light on. Basically the question is... How powerfull is the shockwave coming from an IED? Now I realise the explosion from an IED depends on what explosive it was based on. I'm looking for an IED that fits inside a cardboard box. I heard somewhere it is the shockwave that does the damage not so much the explosion itself. Would the shockwave of an IED in a cardboard box be powerfull enough to splinter wooden planks? Shatter glasspanes, Dent metal? Could it disrupt a wall (In this case the IED would be placed against the wall.) And it probably will throw stuff around. But how big and how far?

Looking forward to your experiences
Hopefully it gives me enough information to get on with my dio.

With friendly greetz

Robert Blokker

The actual shape of the charge has alot to do with it. The blast emanates from the explosive perpendicular to the surface. Two things happen in milliseconds. The initial detonation causes a vacuum, and you get a "in and out" effect.

The blast radiates out ward mostly up and away. It can and will "bounce" off anything in it's way to a certain extent. A wall will tend to deflect the blast out away from it. It might be penetrated, yet it will act as a buffer.

Now put the charge against the wall, pile sandbags over it, detonate, and the blast will be focused, for that brief instant, back on the wall. Anything and everything becomes "shrapnel".

I could go on and on, I was a bomb tech for the PD back in the day, but that's the basics.

Remember, milliseconds with high order explosives.

G

Ola Wayne

Thanks for your reply.
Just to make sure I understood your story correctly I made a little drawing which I think translates what you say


I think I got that more or less right. If the explosive is blocked by heavy stuff like sandbags it will direct all it's force to the other direction. In this case the wall and blowing it away.

And in Figure one it has no obstructions and it simply balloons out.

For my dio idea I am leaning towards figure 1. It works visually better. But will the shockwave in the first few meters from the explosion be able to shatter stuff that is in the way. I have seen footage of a heavy IED explosion which blew forward a layer of sand. Will it be able to shatter wood, glass, push stones forward? From what I saw in footage it seemed that eventually a shockwave looses it's force. How strong is it at detonation point?

With friendly greetz

Robert Blokker

At the point of detonation overpressure could get as high as 7000 pounds per square inch depending on the type of explosive used. This dissipates rapidly in the atmosphere, but anything close by will be, well effected. Also remember, at the point of detonation you can have temps as high as 3000 degrees F.

Those diagrams are spot on.

A lot depends on where the device is when detonation occurs. A partially buried, or completely covered, device will move a substantial amount of earth.

When you consider shock waves, think of dropping a pebble in a lake. The ripples radiate outward until they dissipate. Shockwaves are like that but in 3 dimension.

G

Depends on what the IED was made from. Most of the IEDs my unit encountered in Baghdad '03-'04 were wired artillery or mortar rounds. From what the EOD guys told me, the one that hit me was an arty round. I'll take their word for it. As far as the blast/shockwave goes, it was enough to bounce me into the windshield (I was in the driver's seat) of my uparmor hmmwv, I know that much. I will try to post pictures tomorrow of the blast site, but it basically tore the guard rail and blew out a chunk of the concrete on the side of the highway.

Kenny the guys you faced seem to have an inexhaustable supply of arty and mortar rounds. Are most Com block or what?

In my day we feared our own handgrenades. That's what got me. Mr Charles put one in a c-rat can. Our own grenades in our own trash. Sheesh......

G

@ Wayne
Thanks for confirming that I was correct with my drawings. And thanks for the additional information. I more and more get the feeling that I have something that I can make work. If all is well I have my kit (AFV Clubs Talon EOD Robot) in tomorrow and I can do some experimenting then
And about your own grenades being used against you.. How did that work... Was it in training or something? And how did you find it out that the grenade was there? Must have been some scary moments.

@ Kenny
Talking of scary moments. You actually have been in an IED explosion.. That is some heavy stuff. And no serious injuries? I know it sounds odd but I would like to see the pics of that.. Not for the excitement of it but it helps me visualise the forces at work.

The general way was to take the grenade and remove the safety clip. Then it was placed in a can, which held the spoon.

You strung the thing up in such a way as to invert and drop the grenade when someone walked into the trigger. The last thing was to pull the pin.
Once it fell from the can, the spoon popped off igniting the fuse.

There are three safeties, a spoon, or handle which when held keeps the fuse from igniting, the pin/ring which holds the spoon in place, and a wire clip that also holds the spoon in shipment.

We heard the rattle, and pop of the fuse igniting so we had time to flop. Trouble was I held my left leg just a bit to high off the ground. Ouch. Not bad though.

It got me a free trip outta there and to the Phillipines for a bit!

G

@ Wayne
Damn you actually was hit with shrapnell.. That is also pretty heavy. was this during a conflict? In that case one of your own grenades used against you by the enemy or was it a forgotten boobytrap?

sorry about the delay, hopefully I posted the images correctly.

Kenny
Thanks for posting those pictures. You posted the thumbs but I found them in your Gallery. Hope you don't mind that i post the full size pics here



That is some heavy devastation. How close by were you when the thing went off? Looking at it you can tell that there was a lot of force unleashed as it takes a lot of work to damage one of those guardrails let alone rip it apart.
This is information that I can use very good.. Seeing those pictures it kinda gives me an idea of what the explosion and shockwave are capable off.

On another note... I saw the Mythbusters episode where they tested if it had made a difference with the bombing attempt on Hitler if the meeting was held in the concrete bunker as was the real plan instead of the Wooden building they ended up using instead. They also showed the shockwave in a fluid and how it would behave in a closed off space and a space with windows. But what most struck me is the amount of devastation it created. And that was done with a bomb that was considered small. Plus the fact that he was not able to arm the second explosive. And pretty much the most of the damage there will probably be attributed to the shockwave. The area I am going to try to portray will be even a smaller area then what the Meeting Room at the Wolfsschanze was so I think I have a lot of possibilities

No problemo. I may have well driven over it. We were pretty close as the hmmwv absorbed all of the damage, which was very good news for my gunner in the hatch. If we had been further away he probably wouldn't be here today. That was our first night out with the new uparmored hmmwvs.

Amazing isn't it? Being on top of it helped save lives, as did the Hummer itself.

Robert it could may have well been a booby trap forgotten by everyone!

G

the tv show mythbusters did a great episode on explosive blast and how close or far away you could be. the showed several different hiding places and set them off to see if you would be hurt or killed and if the structure you was behind would with stand. i suggest you check it out it was very good.
RICK

Sounds to be a great dio Robert and with the research you're doing it should be right on the money. I'll be watching for this one and please keep us posted.


Cheers, Ski.

Here are some u tube videos showing the blast:

http://www.youtube.com/watch?v=b4GRIbhWgiI&feature=related
http://www.youtube.com/watch?v=rSLyBlLw2Lo


You can see tons of them on there.

Your second diagram is a very good representation of "tamping" the charge. I mentioned it briefly in this thread a few months ago:

https://armorama.kitmaker.net/forums/174481#1465308

Speaking from experience, a suicide bomber hit a small building next to our COP in Iraq. We never ascertained how much explosive he used, but it was an amount concealed underneath his clothing. The force blew three out of four concrete walls out from under the concrete roof. It killed two others including the bomber, but surprisingly, the two soldiers sitting directly across from him survived. (although one had his face peeled back from the front of his skull) So much for the Mythbusters episode. Explosives do strange things.

Wayne mentions higher order explosives. They fracture objects more readily than lower order explosives, which tend to push objects.

As for your question about denting metal, it depends on several factors, but generally speaking, in your cardboard box scenario, probably not.

I have taken out many a metal door with an improvised water impulse charge - simply three six inch pieces of det cord taped tightly between two IV bags, and placed directly against the door. It needs to be constructed in this manner to insure enough focus of the blast into the door. It puts a huge dent in the door, causing all of the locking mechanisms to be pulled from the doorframe. And you get a nice cooling mist right before you enter the house.

Your IED in a box might very well be HME, made from animal urine, which was very prevalent where I was. It'll certainly put a dent in a wall if placed correctly.

One last note: Don't try this at home.

@ Kenny
Pfeew thanks for modern science aye. It's amazing how sturdy those vehicles are to protect the people inside. But it must have been a hairy experience. Glad you all came out ok.

@ Wayne.
Whatever it was I'm sure it was also a pretty hairy experience. Also to you glad you came out ok.

@ Rick
Funny you mentioned that... The episode aired here in Holland this evening and I have watched it. Even though some things were in my mind a bit questionable it sure was interesting to see what kind of damage explosions inflict. Even with the charge a meter up in the airwith no way of directing it's force to a special direction.

@ Steven
Thanks for the confidence... I still have a long way to go (for such a small vignette) But with all the info I get here I already am kinda visualising it in my mind. And I think it is doable. And of course I will update all you guys here by opening a topic once I start building it.

@ Robert
That is also some pretty good information. I don't know the difference between High order explosives and Low Order explosives but I guess it has to do with the contents and the speed and force with which it explodes. I have read somewhere that in mining they use an explosive that explodes "slower"And with that creating huge forces on the rockface.
I think I have also seen that method of blasting doors you explained. The water works pretty well in directing the force and if I have paid attention to the program it means you can use a smaller charge too.

I still have some things that are not totally clear to me therefore I think I'm going to turn the question around. Since there are quite a a few persons here who know much about the subject. As there are quite a lot of variables at work I'm going to explain precisely what the dio will be. And I made a diagram to go with it... I just love Diagrams. Ok here goes... First the diagram


Basically the idea is Bomb Disposal gone horribly wrong. But I am lookinbg to try to create the moment a few 1000th of a second just after detonation. Basically the Shockwave has travelled 1 to 2 meter. But the problem is that you normally can't see a shockwave. So I have to make it visible by the damage it creates. So basically I'm looking for a scenario in which the explosive is strong enough to push the more solid stuff away, to obliterate wood, toss away lighter stuff and generally creating a lot of mayhem and chaos. Also the wall at the back where the charge is placed against is one of those segmented walls where you slide panes of concrete between slotted poles. You find them anywhere in the world and should be light enough to be at least damaged.

I actually like the charges hidden in a thing like a lawnmower like in the picture... But my main question is... what kind of scenario do I need to make this work? I hope you guys can help me on this.

With friendly greetz

Robert Blokker