Sciencemadness Discussion Board

Sympathetic boosting of VoD?

OneEyedPyro - 12-9-2023 at 22:45

Would it be possible to use a core of a very high VOD explosive inside of a very energy dense but lower VoD to overdrive it? If so, how fast would the effect attenuate back to normal.
For example, would a core of high density HMX within a shell consisting of high density AN/Al artificially boost the performance of the outer charge?

Sorry if this is already a well established thing but I've never heard anyone talk about it on here.

Microtek - 13-9-2023 at 01:58

Well, I've heard of the inverse design - a shell of high VOD explosive over a core of slower HE. IIRC I read a patent that claimed 40 GPa in a TNT core with a shell made up of a HMX based PBX. I think you would need a larger charge than I want to experiment with, so I never tried it.

You can read about the principle in this patent:


[Edited on 13-9-2023 by Microtek]

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EF2000 - 13-9-2023 at 01:58

Don't know about VoD boost, but if surrounding mixture is rich in fuel, than you're describing annular thermobaric charge. High velocity core surrounded by oxidizer+fuel, basically. Not used widely yet, except in TB variant of Hellfire (AGM-114N) and in Bulgarian A-TBX composition.
Most of current TBXs are homogeneous, but annular ones have some advantages: more complete burning and zero issues with compatability between exploding and burning parts.
Update: added article about A-TBX and patents (Bulgarian original and translation by DeepL)

[Edited on 13-9-2023 by EF2000]

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[Edited on 13-9-2023 by EF2000]

Etanol - 13-9-2023 at 09:49

Yes. This takes place.
But this effect weakens to normal detonation through 1-3 core radius.
It is more important that a massive high-speed core allows you to get normal detonation. With ordinary detonators, ammonia nitrate mixtures often do not reach normal detonation.

[Edited on 13-9-2023 by Etanol]

OneEyedPyro - 13-9-2023 at 10:18

Quote: Originally posted by Etanol  
Yes. This takes place.
But this effect weakens to normal detonation through 1-3 core radius.
It is more important that a massive high-speed core allows you to get normal detonation. With ordinary detonators, ammonia nitrate mixtures often do not reach normal detonation.

[Edited on 13-9-2023 by Etanol]

I was really wondering about the possibility of driving a more energy dense explosive to a much higher than normal VoD perhaps artificially driving the output performance beyond that of the booster core itself or as Microtek suggested an outer shell with a higher VoD. Perhaps even use layers at appropriately spaced intervals to maintain the effect.

I used AN/Al as an example because even at a stoichiometric ratio it has an impressive energy density at reasonably achievable densities but has a relatively low VoD. If you were boost AN/Al to detonate at 8,000 m/s even for a short period the power would be dramatically increased.

Etanol - 13-9-2023 at 10:47

Quote: Originally posted by OneEyedPyro  
If you were boost AN/Al to detonate at 8,000 m/s even for a short period the power would be dramatically increased.

AN/Al has a low speed of real and normal detonation due to the small volume of gases also.
AN/Al shell with a high-speed core will not be stronger than a whole high-speed charge, if you are about it.

OneEyedPyro - 13-9-2023 at 11:25

Quote: Originally posted by Etanol  
Quote: Originally posted by OneEyedPyro  
If you were boost AN/Al to detonate at 8,000 m/s even for a short period the power would be dramatically increased.

AN/Al has a low speed of real and normal detonation due to the small volume of gases also.
AN/Al shell with a high-speed core will not be stronger than a whole high-speed charge, if you are about it.

As I understand it, AN/Al despite its lower VoD and gas production has an effective blast radius per volume of explosive rivaling that of enhanced blast mixtures like Composition H6 but with much less brisance. If nothing else it could reduce the cost of a charge while maintaining a similar level of performance.

Etanol - 13-9-2023 at 12:44

Quote: Originally posted by OneEyedPyro  

As I understand it, AN/Al despite its lower VoD and gas production has an effective blast radius per volume of explosive rivaling that of enhanced blast mixtures like Composition H6 but with much less brisance. If nothing else it could reduce the cost of a charge while maintaining a similar level of performance.

On the fugas action, yes.
High-VoD substance is more expensive than AN/Al.
It is profitable, when the all AN/Al mass works in normal detonation mode from the core of a large mass, but core mass is much less than AN/Al mass.