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searat
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try a trangle, on sky with that deM program they used detcord copper trangle no stand off(small amount per area) and they cased it in rubber(which i
think was used to bounce a shockwave back into the explosive to aid in ignition,and force the copper/plasma to get diercted.)
"Plasma? .. theres no plasma. " are you drunk when a explosive goes off it turns into plasma.
I know you don't think what i said was right but try this.
Timeline
1sec)the explosive is set off.
2sec)the temp rasies to 10,000C,and electrons spreed(like how a ark is greated,just before that)
2.5)electrons engise conductive metals,produceing a magntic feild.
2.6)most of the explosive has decomposed, the copper starts to turn to plasma,losing its field turning into a jet, with the shockwave and replie it
speeds up to high speeds.
2.8)A plasma mass is made, due to the desnity of the metal more plasma per inch. copper is more conductive it easyly excepts electrons, breaking down
quicker
I think heat conductive has some thing to do with it,add to last statment please!
[Edited on 25-2-2005 by searat]
[Edited on 25-2-2005 by searat]
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Bert
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Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
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| Quote: | Originally posted by searat
"Plasma? .. theres no plasma. " are you drunk when a explosive goes off it turns into plasma. |
Axt knows what he's talking about. You don't. Do some more research.
Also learn to spellcheck-
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The_Duke
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| Quote: | Originally posted by searat
Timeline
1sec)the explosive is set off.
2sec)the temp rasies to 10,000C,and electrons spreed(like how a ark is greated,just before that)
2.5)electrons engise conductive metals,produceing a magntic feild.
2.6)most of the explosive has decomposed, the copper starts to turn to plasma,losing its field turning into a jet, with the shockwave and replie it
speeds up to high speeds.
2.8)A plasma mass is made, due to the desnity of the metal more plasma per inch. copper is more conductive it easyly excepts electrons, breaking down
quicker |
So all this happens in 2.8seconds huh? Well I guess you sure learned us then
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WaveFront
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I allways believed that in any conventional flame there was plasma. At least some amount of electrons and positive ions reacting and producing
characteristical spectrum lines. The detector of Gas Chromatograps (TCD or FID) also presume the existence of ions in a flame isn´it?. Well, I
humbly don´t understand how the plasma works in a shaped charge, but there must be plasma.
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Axt
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I apologise in assuming that you were talking about a jet of plasma doing the work, or are you? "the copper starts to turn to plasma, losing its
field turning into a jet"? I can't tell what your talking about, it seems youve made a wrong assumption that you think is common knowledge.
It's a common misconception that plasma is responsible for the cutting effect of shaped charges, when its little more then a solid extrusion of
the liner. Ionised gas is present, yes, in the explosion, not the jet.
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searat
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"the copper starts to turn to plasma, losing its field turning into a jet"? Metals close to a explosive can vaporise(plasma),while the
copper is solid it can produce a magtnic field, when it vaporises it loses its field.
"a solid extrusion of the liner. " does that mean it fires a solid object.
I'am guessing your right about it not being a jet of plamsa, but just think what it would be like if it did,as a plasma cutter can slice through
AL 120mm like butter
"So all this happens in 2.8seconds huh? "
i don't know the timeline, but it would be in milseconds, and as it wasn't bast on fact(that i know of), just my thoery, i could have used
mintes.
[Edited on 26-2-2005 by searat]
[Edited on 26-2-2005 by searat]
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chemoleo
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Am I missing something completely?
What's a magnetic field got to do with a liner, and a shaped charge? Should we be using ferromagnetic compounds or what? What are you on about?
Further, your spelling... where shall I start? Anyone can do a spellcheck and so can YOU!
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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searat
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"What's a magnetic field got to do with a liner, and a shaped charge? Should we be using ferromagnetic compounds or what? What are you on
about? "
if you say a shape charge push the copper through the target, then using ferromagnetic compounds would greatly incease its effectiveness as it would
offer some protection from the plasma.
"liner" does this meaning a shokwave warhead?
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chemoleo
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Oh dear.... I smell a troll...
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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searat
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Whats a troll?.
I'am not going to change my mind, shape chage uses plasma to cut.
"The shape charge is an explosive warhead with its forward face hollowed out into a cone, which is then lined with a thin metal liner. If the
charge is now detonated from its rear end, away from the liner, the effect of the detonation wave passing through the explosive is to deform the
liner, subject it to immense pressure and heat, and turn it into a jet of molten metal and explosive gas moving at speeds in the region of 7-8,000
meters per second. When this jet strikes armour plate it simply forces a hole in the armour due to its combination of heat,mass and high velocity.
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Quince
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That quote doesn't mention plasma. The salient feature of plasma is near complete or complete ionisation. You've failed to argue that the
jet is ionized to any significant extent (not to mention that your own quote says it's not all gas -- "molten metal" rather than
"vaporized metal"!). Moreover, ionization of the fluid has nothing to do with cutting ability; the things that make a difference are listed
by your quote, such as velocity.
You don't know what a troll is? I guess you are an Internet newbie too, not just a chemistry one. Check Wikipedia. Oh, wait, you probably
don't know what that is either. http://en.wikipedia.org/wiki/Internet_troll
_____
Why, yes, I did get up on the wrong side of the bed this morning.
[Edited on 26-2-2005 by Quince]
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Axt
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Heh, I checked the wikipedia entry for "shaped charge", it's been corrected as it used to mention plasma as well.
Anyway enough of this discussion on plasma jets, its simply false. Even your own quote searat contradicts your argument. Its alright to come up with
theories, but you have to base them on facts.
The following info is originally from:
von Holle, W. G, and Trimble, J. J. (1976), "Temperature Measurement of Shocked Copper plates and Shaped Charge Jets by Two-Color IR
Radiometry," J. Appl. Phys. 47(6):2391-2394.
von Holle, W. G, and Trimble, J. J. (1977), "Temperature Measurement of Copper and Eutectic Metal Shaped Charge Jets," Ballistic Research
Laboratory Report.
| Quote: | The temperature of a jet from a 81.3mm diametre, 42° apex angle conical copper liner was measured. The explosive fill was comp B and a four-shot
average of the jet temperature was 432°C with a standard deviation of 76°C.
Also measured the jet temperature of a 60° apex angle, 81.3mm diametre, tin/lead eutectic liner. The liner wall thickness was 2.54mm and the
explosive fill was Comp B. The conical apex was slightly rounded to a 1mm radius. A four shot average revealed a jet temperature of 569°C with a
standard deviation of 34°C. The tin-lead liner had a tip velocity of 6.3 km/s compared to the copper liner jet velocity of nearly 8 km/s (presumably
liners of same dimensions).
It was concluded that the copper jet was solid and the lead-tin jet was liquid in spite of any scatter in the data. |
[Edited on 26-2-2005 by Axt]
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searat
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Damn i hate to be wrong, but thanks for the info. If a shape charge uses the liner as a projectile, how would you incease its depth without useing
more powerfull explosive?
" turn it into a jet of molten metal and ""explosive gas"" moving at speeds in the region of 7-8,000 meters"
That quote doesn't mention plasma?
[Edited on 9-3-2005 by searat]
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Quince
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| Quote: | | Damn i hate to be wrong |
That's not good, because it can affect your judgement of whether you are wrong (and when to consider it). And that equates to stubborness.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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searat
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"whether you are wrong (and when to consider it). "
Yes people can be blind can't they, even internet infomation can be right at times.
Stop blowing the mods/boss's .
GIVE ME THE FACTS WHY I'AM WRONG NOT JUST SOME fm THAT HAS A NICE TITLE.
[Edited on 13-3-2005 by searat]
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pramodattingal
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unconventional shaped charge
hi friends
i have been doing experiments with shaped charge (lead liner ,90 degree cone dia,RDX ,BASED FLSC)for cutting 100 mm diameter steel tube by keeping
FLSC INSIDE.BUT THE RESULT WAS POOR.is the 60 dergee cone angle better.what is the solution for the solving jet divergence during bending.
i had serch various book like fundamental of shaped charge but nothing is said about above things.in some report in net i found out 60 degree is
better.i want to conferm and know the reson also.
please
Edit by chemoleo: Don't double post, and DO search before you post in the first place. This is the thread where you
want to post it.
[Edited on 16-3-2005 by chemoleo]
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Axt
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Two cones joined at the apex, filled with explosive, initiated from the centre. Patent searches would be the best place to look, as this is common
practice in the oil industry.
<center><img src="http://www.sciencemadness.org/scipics/axt/pipecutter.jpg"></center>
[Edited on 7-6-2005 by chemoleo]
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Quince
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Is this better than the configuration where the explosive is outside the pipe, with the two (wraparound) triangles meeting at the cutting line? By
better, I mean using less total amount of explosive needed to succeed cutting a given pipe.
[Edited on 16-3-2005 by Quince]
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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searat
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pic
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searat
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pic
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pramodattingal
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unconventional shaped charge
does the two cone answer was for me.
how can be it assembled inside the pipe
can u make me clear
my question related to 60 and 90 degree is unanswered
[Edited on 17-3-2005 by pramodattingal]
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BASF
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@Axt:
Excuse the simplicity of the question  .....Some very impressive pictures
taken....how did you protect yourself from shrapnel?
[Edited on 17-3-2005 by BASF]
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Axt
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| Quote: | Originally posted by Quince
Is this better than the configuration where the explosive is outside the pipe, with the two (wraparound) triangles meeting at the cutting line?
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I would expect the one above would be more efficient, especially for thicker pipe. Though I expect if given the choice most would attack it from the
outside for simple convenience.
pramodattingal, your lack of fluency in the english language is no excuse for a lack of common sense, obviously its assembled before being slid down
the pipe. 60° will likely be better in a well made charge. In your case I think the angle irrelevant as the precision of the charge is whats going to
determine if it works or not, not the cone angle.
| Quote: | | how did you protect yourself from shrapnel |
I'm not holding the camera. I never watch explosions without something between it and I. I'm about 100m away on the other side of that
stump/rock in the pictures.
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Chris The Great
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You can see him duck down in the distance in the video of the second test. So there is a ditch, large rock and some distance between him and it.
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nitro-genes
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easy coppercones?
Although copper is one of the best liner materials, making a perfectly symmetrical liner out of coppersheet is very hard.
I tried so several times to make one out of multiple layers of 0.15mm sheet always resulting in a jet consisting out of 2 or more "fingers"
I never have this problem with 35 mm steel hemispheres made from.... coffeespoons!  Always making a clean hole through 5 cm of mildsteel! for this I use 2 times diameter standoff with a NM based plastique...
Hopefully not pushing the discusion too much to the practical side, but could it be possible to make a good coppercone by winding and glueing
0.75mm-1mm copperwire over a 60 degree papercone?
Studies revealed that the liner collaps and penetration occur by hydrodynamic flow. So in my theory upon detonation the pieces of wire will collaps
the normal way, plastisize together and form a normal coninuous jet.
Any thoughts?
[Edited on 5-4-2005 by nitro-genes]
[Edited on 5-4-2005 by nitro-genes]
[Edited on 5-4-2005 by nitro-genes]
[Edited on 5-4-2005 by nitro-genes]
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