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Author: Subject: SM EM Research Project - Calling for EM Research Junkies
Praxichys
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[*] posted on 13-4-2015 at 10:50
SM EM Research Project - Calling for EM Research Junkies


I am in the process of gathering referenced data (preferably in .pdf format) to create a comprehensive chart of "explosive power.*" In an attempt to classify explosives by their relative "power", I have designed an arbitrary method to classify them using equal weighting on density, measured or chapman-jouguet calculated detonation velocity, and chapman-jouguet calculated detonation pressure, as they stand relative to TNT - correlation to TNT - or CTNT.

I found a chart I made a few years ago, but I have forgotten many of the abbreviations and I am having a difficult time finding the references used. My goal is to compile every reference we can find for every explosive we can think of, and compile them into a giant infographic using the three data values discussed above.

Here is a preview of the old plot:

Performance.png - 27kB


*Note that explosive effectiveness varies by application. This project aims to find one way to rank explosives using several performance factors, to make an interesting chart. It creates a fun way to look at who can make/has made the most powerful EM, as an eventual contest of sorts. It could eventually lead to a score chart of username vs CTNT

So, if you have a reference to a compound which contains those three data values, post a link to it here or attach it to your post. I will make a public-access infographic chart including a .zip file containing every reference we find, in full, as .pdf. I will list all of the contributing members somewhere on the chart as well.




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Rosco Bodine
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[*] posted on 13-4-2015 at 12:26


The scaling is misleading with regards to "explosive power" being a kind of vague term as unclear about "power to do what kind of work" with amount of work done being relative "power" or TNT percentile equivalency. There are different measures and criteria for brisance and bubble energy or heaving power.

An example would be foot pounds per pound, but another practical aspect important about explosives is the energy density, energy per unit volume available without regard to the weight of the material. Bulk energy is I think a term used for that quality. "Most powerful" is an abstract term, most powerful by weight, or "most powerful" for the size of the charge by volume, and "most powerful" in terms of what measure of work done, the smallest mesh for fragments of rock or steel produced, or the bulk amount of earth that can be heaved, or the distance to which a mass can be thrown by an explosion?

So there are different tests. Lead block compression, lead block expansion, ballistic pendulum, ect. And those can be done on a comparison weight basis, or comparative volume basis.

The scaling you propose is misleading WRT "power values" for nitromethane and ANFO and NG compared with TNT. Nitromethane is slightly greater RE than TNT and ANFO would go in about the 70% RE (or more) and picric acid and styphnic acid would be a little better RE than TNT also but are missing.

A more useful scaling is going to show a much steeper gradient for relative "explosive power".

I think if you compare the modeling with some real test data there will be a discrepancy.

[Edited on 13-4-2015 by Rosco Bodine]
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[*] posted on 13-4-2015 at 22:03


I agree with what Rosco says, you need a quite precise metric for comparing explosives. IIRC I read an article some years back that advocated using Pcj as a central metric for comparing explosives. I think I read another one though, that argued that by comparing many different materials over several different metrics PETN seemed to be one of the most highly performing explosives (of the ones they compared, which included RDX and HMX IIRC).
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Rosco Bodine
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[*] posted on 14-4-2015 at 04:53


I think the closest sort of comparison figure might be a translation of the rocket fuel value that is "specific impulse", because really with an explosive you have a translation of that linear quantity into a distributed spherical bubble quantity, as force applied to an area. The operation of an explosive also interacts with the atmosphere, or if underwater the water becomes a medium for energy transfer, so there is a proximity effect and a compression wave that varies with distance and the gas volume produced by the explosive. In a vacuum environment, this could have bearing on what is the "explosive power" delivered to a target varying greatly by distance, since there is no force coupling other than from the
expanding gas from the explosive itself. What may be a powerful explosive in contact with a target may have very little effect at a distance, while a "less powerful" explosive in contact may have greater power at a distance simply for having greater gas volume to do work across a gap.

There are gap tests and ballistic mortar tests also used to measure the effects of explosives, in addition to the lead block compression and lead block expansion and ballistic pendulum tests, and there are fragmentation tests also. There is a portfolio of tests that give particular explosives a general ranking of "explosive power" to rate their ability to do specific types of work. It becomes a specialized kind of task matching where compositions are custom formulated for the purpose, thermobaric type of explosives, fuel - air explosives, ditching explosives, quarrying explosives, steel cutting explosives, ect.
where the composition most optimized for the task is then found to be the "most powerful" ....if that makes sense :D

The "most powerful explosive" for an aerial bomb meant to flatten buildings may not be the "most powerful explosive" for a torpedo meant to sink a ship. The energetic materials are task specific.

[Edited on 14-4-2015 by Rosco Bodine]
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[*] posted on 14-4-2015 at 05:41


I agree, for instance high velocity explosives are needed to efficiently cut steel and while they do also show higher performance than low velocity explosives for moving stumps and earth, there is not nearly as great a difference in performance as there is against a hard target such as steel. When making comparisons, make sure to compare apples to apples and oranges to oranges.



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[*] posted on 14-4-2015 at 06:12


I think it is best to make a table of all the following parameters; and then allow the observator to choose the parameters to plot and set in order sequence:

-d (and max d)
-VOD (@ d and max d at infinite diameter) (effective VOD)
-VODcj (theorical VOD)
-Pcj (theorical pressure of detonation - kbar)
-Molar mass (g/mol)
-Volume of detonation gases (L/kg)
-Oxygen Balance (%)
-Lead block test/10g (weight performance - ccm/10g)
-Lead block test for 5 ccm (volumic performance - ccm/5ccm)
-Heat of formation/kg (kJ/kg) (kJ/mol)
-Heat of explosion/kg (kJ/kg) (kJ/mol)
-Melting point (°C)
-Explosion temperature (°C)
-Sand crushed / weight (weight brisance) (g/g)
-Sand crushed / volume (volumic brisance) (g/ccm)
-Impact sensitivity (Nm)
-Friction sensitivity (N)
-Heat sensitivity (temperature of detonation/explosion) (°C)
-Temperature of decomposition (°C)
-Critical diameter of detonation (mm)

[Edited on 14-4-2015 by PHILOU Zrealone]




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Praxichys
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[*] posted on 14-4-2015 at 07:50
Collab Folder/Spreadsheet!


Quote: Originally posted by Microtek  
... IIRC I read an article some years back that advocated using Pcj as a central metric for comparing explosives. ...
This seems like a good idea. If pressure is a function of VoD, gas produced, enthalpy, and density, then why not use this as a ranking factor?

Regardless of our classification method (which is still up for debate) the first step is to gather as much information as possible. If anything, we should start to assemble a comprehensive table of calculated and measured explosive properties which we can use to find useful ranking metrics.

Here is a link to a public Google Drive folder for depositing references:
https://drive.google.com/folderview?id=0B_16NzkNoL75fmZhcXU5...

And here is the beginning of the master spreadsheet:
https://docs.google.com/spreadsheets/d/1TQY7iMx2YpJO3GC4nTKY...

I have dropped 51 reference papers into the "unmined references" folder. The data will need to be mined from these papers and added to the sheet. I will work on this in my spare time, but anyone is welcome to help. Just make sure to cite that paper on the sheet if you transfer any data.

Feel free to dump your references. This could be a good repository of EM papers if everyone copies their EM folder into this drive. Don't be afraid to make folders or whatever you feel necessary to maintain some method to the madness. If we exceed 3GB I will happily pay Google to expand my drive space to 100GB and host this library of information.

Together, we can make a large, organized library of EM properties and syntheses, as well as provide various performance charts using several classification methods.

@ PHILOU Zrealone - I agree. I will set up the sheet.

[Edited on 14-4-2015 by Praxichys]

[Edited on 14-4-2015 by Praxichys]




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Praxichys
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[*] posted on 15-4-2015 at 09:22


Quick update:

The table is coming along rather well, with comprehensive and referenced data on 58 compounds, including 33 whose VoD(cj) exceeds 9000m/s. There are six whose Vcj exceed 10km/s, and several with Pcj values around 500kbar.

There are a total of 151 unique explosive compounds listed so far, and research is well underway to establish reputable data for these as well.

I owe a big thanks to Dornier 335A for all the help yesterday evening. If anyone else is interested in helping, the table is located here. Feel free to add anything we may have missed, or donate some time running %N calculations, finding formulas and references, etc.

Soon we will have a database like the Topical Compendium of EM... except the scope will be all of modern chemistry rather than just SM. It will be a great launch point and reference library for amateur research and synthesis.

Thanks!




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[*] posted on 16-4-2015 at 12:35


WoW! Great work!!
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Praxichys
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[*] posted on 16-4-2015 at 13:03


Thanks!

We are now up to 175 individual compounds with over 1550 pieces of data, and growing every day.

We also now feature some handy calculators which can simulate detonation parameters using the Kamlet-Jacobs and Keshavarz equation sets, with some thermodynamic simulation on the way as the project develops.

If anyone knows anything about explosives, feel free to help out with our collaboration project by adding referenced data to the table, thinking of compounds we missed, or simply enjoying the volumes of data that are being assembled.




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[*] posted on 16-4-2015 at 22:18


I'd like to offer a little constructive criticism: I think it is very nice that you include both VOD, Pcj and TMD for the compounds; this makes it quite easy to get a feel for the ranking of these energetics if you know your scenario. However, some of the data are a little questionable, eg. ONC which is rated as having a VOD of 10100 m/s and Pcj 500 kbar. Unless I'm mistaken, this value is based on the assumption that there exists an undiscovered high density polymorph, and the results so far cannot live up to those calculated values. Maybe you could use a color scheme to indicate whether a value is experimental or simulated?

Another thing is the references, which would benefit from a more search friendly format (including journal/book title and author name(s)).

Other than this, I would like to say that it is very interesting for someone, like myself, who has an interest in new high-performance energetics to see something like this. I have already seen a few that I hadn't been aware of before.
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Praxichys
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[*] posted on 17-4-2015 at 04:54


Aha! This is exactly why the project is collaborative. We need people like yourself to spot these issues and help us fix them. Many of these references come from older books and papers, which are often inaccurate, misinterpreted, or use older methods of calculation. Feel free to add new columns, upload and cite references, overwrite/update data, add comments, or whatever you feel is necessary to make this table true to the best of your knowledge.

So far, this table is mostly "plug-and-chug" copy/paste work. We rely on the fact that many people on this forum are quite knowledgeable about a few energetic compounds, and can pitch in a few minutes to provide correct and properly referenced data about them. We operate like Wikipedia - the more collaborators we have, the better we can corroborate the data.

I have also noticed that the calculated value column for VoD and Pcj may not necessarily use the C-J method to arrive at that value. Perhaps we need to change the title of the columns to "calculated VoD" rather than "Dcj"?

EDIT: I should also mention that many of these new compounds are still being researched, bringing newer and more accurate data into the spotlight but often only for those with access to journals. Dany has been helping a lot with this but we could use more collaborators with research paper access.

[Edited on 17-4-2015 by Praxichys]




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[*] posted on 17-4-2015 at 07:40


You can change "Measured VoD at measured density (m/s)" by "Measured DCJ at measured or predicted density (m/s)". I will also change "Measured density (g/cc)" by "Predicted or Measured density (g/cc)". The reason for these changes is that today few investigators measure detonation velocity of new EM compound and this for several reasons: Detonation velocity measurements need hundreds of grams of the explosive which may not be available due to the cost of explosive, danger in handling multi-grams of sensitive explosive, high cost of apparatus needed to measure VoD, etc. Most of investigators uses Thermochemical code (e.g., EXPLO 5) in order to obtain detonation velocity, pressure and specific impulse. Nearly all detonation performance of EM synthesized by Prof. KLAPOTKE were obtained via thermochemical code. Although most EM densities are the actual observed one some authors report the calculated or predicted crystal density especially in the case of theoretical molecules like Tetrazino-tetrazine-tetraoxide (TTTO).

Another important thing about Tetrazino-tetrazine-tetraoxide. In order to obtain the detonation performance and other physical and chemical properties of TTTO, Dornier 335 cited the theoretical paper published by a Chinese group (Song X., Li J., Hou H., Wang B., Extensive Theoretical Studies of a New Energetic Material: Tetrazino-tetrazine-tetraoxide (TTTO), J. Comput. Chem., 2009, 30,1816-1820). However, the group has made some mistakes in using the computational method which leads to erroneous heat of formation value. The corrections for this paper has been published in 2012 (see, JORGENSEN, K. R. & WILSON, A. K. 2012. Comment on the paper “Extensive Theoretical Studies of a New Energetic Material: Tetrazino-Tetrazine-Tetraoxide (TTTO)” by Xinli Song, Jicun Li, Hua Hou, and Baoshan Wang. J. Comput. Chem., 33, 1967-1968).

TTTO has been studied recently by Politzer et al. (Computational Characterization of Two Di-1,2,3,4- tetrazine Tetraoxides, DTTO and iso-DTTO, as Potential Energetic Compounds CEJEM Materials, 2013, 10(1), 37-52). Politzer uses the name iso-DTTO instead of TTTO and the new calculated properties are shown in Table.3 of the above references which stated (for iso-DTTO) a 9700 m/s and 431 kbar for Dcj and Pcj at a calculated density of 1.90 g/cm3. For this reason I changed the old results by Politzer findings.

Dany.


[Edited on 17-4-2015 by Dany]
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[*] posted on 18-4-2015 at 01:21


Waaay outside my field and so I have no useful information to add.
But... this growing database is extremely impressive to behold. And the collaborative manner in which it is being produced is really exciting science. Consider me highly impressed.
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[*] posted on 20-4-2015 at 12:20


Thanks for the suggestions, Dany. I have updated some of the columns to better reflect the points you made, something I had not thought about.

We now have nearly 2000 data points on 176 compounds spanning many tens of references. We also feature three detonation parameter calculators for predictions like developed pressure and detonation velocity using several different methods.

We are continuing to expand and update data. Feel free to add or amend anything we have missed, add references, or simply check it out! The sheet can be found here.

And thanks, j_sum1. We appreciate the feedback!




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