Explosive Fragmentation

[KingTempest]

Nothing needs to be changed, but potentially implemented.

I found this link (yes it's a wordpress, but bare with me) that found another method of destruction.

Explosive Fragmentation.​

I quote the owner of the page

Explosive Fragmentation

Fragmentation merely breaks the rock into a bunch of pieces, but what about when the rock goes flying around?

Which is... pretty new and interesting to me.

It linked this source where I found a table with the values of the specific energy for explosive fragmentation for rock.

Could this be used for a new potential method of destruction?

 

[DemonGodMitchAubin]

Interesting, really interesting

 

[KLOL506]

I would've said it looks good, but...

Holy **** why does limestone have an explosive frag energy of 1430 j/cc.

Also it seems that to be able to use this chart we're gonna first have to prove that the debris actually flies at that speed, so...

The speed part is gonna be really tough to prove.

 

[XSOULOFCINDERX]

Huh. I'm not a CGM but this is intriguing.

 

[Migue79]

I’ll be watching this…

This is interesting to say the least.

 

[KingTempest]

I would've said it looks good, but...

Holy **** why does limestone have an explosive frag energy of 1430 j/cc.

Bro I don't know

Also it seems that to be able to use this chart we're gonna first have to prove that the debris actually flies at that speed, so...

The speed part is gonna be really tough to prove.

I'll check the references

 

[KLOL506]

Yeah, this table specifically which you linked.

Some of those speeds are like, inching near re-entry speeds.

 

[Epsilon_R]

 

[DontTalkDT]

Is the full source available somewhere for context?

 

[Psychomaster35]

This feels interesting

Isnt this like the same method we use for planets exploding?

 

[KLOL506]

This feels interesting

Isnt this like the same method we use for planets exploding?

As far as I recall, no, we just use normal KE based on assumed timeframes (If it is a still image) or cinematic timeframe or any stated timeframe that the planet exploded and disappeared in x seconds or any other unit of time.

 

[M3X_2.0]

Good. Wank material.

 

[Migue79]

I am assuming this would apply to anything that fragments from an explosion in the case that we do accept it, yes?

 

[KLOL506]

I am assuming this would apply to anything that fragments from an explosion in the case that we do accept it, yes?

Probably, assuming there is also evidence that the debris is hurled that fast. 2800 m/s is no joke, that's ablation speed.

 

[Shadyboi0]

DBZ will skyrocket

 

[DontTalkDT]

Probably, assuming there is also evidence that the debris is hurled that fast. 2800 m/s is no joke, that's ablation speed.

I think 2800 m/s isn't the speed of the debris, but of the projectile hitting the stone? The source is about hypervelocity impacts, after all.

 

[DontTalkDT]

Btw. have I ever mentioned that the UN has some cool explosion calculators?
If you want to estimate the strength of a (chemical) explosion by the speed of the debris there is this. Has its limits, though.
Still, good old United Nations. Always there for you when you want to blow stuff up.

 

[M3X_2.0]

Define a "chemical" explosion, please

 

[DontTalkDT]

Explosions caused by a chemical explosive. TNT, C4 etc. At least, that's what the calculator is designed for. One can debate in which limits that can be applied to other fictional explosions.

 

[KLOL506]

I think 2800 m/s isn't the speed of the debris, but of the projectile hitting the stone? The source is about hypervelocity impacts, after all.

Oh.

 

[KLOL506]

Btw. have I ever mentioned that the UN has some cool explosion calculators?
If you want to estimate the strength of a (chemical) explosion by the speed of the debris there is this. Has its limits, though.
Still, good old United Nations. Always there for you when you want to blow stuff up.

Convenient and sus at the same time for a peacekeeping organization that does little to stave off mass conflict in the poorly-developed regions.

I'll stop now.

 

[KingTempest]

Ok

So from what I found (the math dudes obviously know this) is that they found specific energy based on the KE of a projectile into a certain material, used the KE divided by the crater's volume in cc and found the specific energy (the value we multiply the volume by).

gm = gram
m/sec = velocity
joules = energy
cc = volume

In the many damn references which make it hard to find anything, I found the concept of "high impact velocity" and "shaped charge jets".

I found the section on Wikipedia that talks about Hypervelocity, where it says this

For structural metals, hypervelocity is generally considered to be over 2,500 m/s

And this

Hypervelocity is very high velocity, approximately over 3,000 meters per second

The speeds used in the table range from 2.8km/s to 10.7km/s

I think 2800 m/s isn't the speed of the debris, but of the projectile hitting the stone? The source is about hypervelocity impacts, after all.

Pretty much this

They're shooting a material at a certain speed and finding it's KE

The material leaves a crater, and they divide the KE by the volume of the crater to find the specific energy

 

[DontTalkDT]

So... in order for this to work, one would need to figure out the speed of the thing (projectile) that hits the rock in order to confirm that it is the appropriate velocity?
That would probably make it redundant, as, knowing the speed, one can just do a KE calc.

 

[KingTempest]

So... in order for this to work, one would need to figure out the speed of the thing (projectile) that hits the rock in order to confirm that it is the appropriate velocity?
That would probably make it redundant, as, knowing the speed, one can just do a KE calc.

That's for materials we know the mass for.

This is using that KE against a certain material to find the specific energy required to destroy that material.

If someone makes the same sized crater with an energy blast, can't do KE for it

 

[KingTempest]

Bump

 

[KLOL506]

If someone makes the same sized crater with an energy blast, can't do KE for it

Kinna limiting form of destruction then don'cha think?

 

[KingTempest]

Kinna limiting form of destruction then don'cha think?

Not really
If something gets destroyed and fragments fly around, then it's explosive frag. Can be done w/ anything.

I was referring to KE using an energy blast, since you can't calc energy's mass most of the time

 

[KLOL506]

Not really
If something gets destroyed and fragments fly around, then it's explosive frag. Can be done w/ anything.

I was referring to KE using an energy blast, since you can't calc energy's mass most of the time

Oh. Okay then.

Still, kinna weird to see limestone explosive frag be potentially as high as depleted uranium normal frag energy.

 

[LIFE_OF_KING]

What is the conclusion?

 

[FinePoint]

Wait, did the wiki just ignore the fact that it takes energy to give the fragments momentum before this?

 

[Arceus0x]

Wait, did the wiki just ignore the fact that it takes energy to give the fragments momentum before this?

Kinda, they didn't ignore it for planets

 

[FinePoint]

Kinda, they didn't ignore it for planets

That seems like a massive oversight to me.
Though, I understand that finding speeds would usually be difficult.

 

[KLOL506]

Bump. This never got concluded. But someone else made a thread on this exact topic here LOL

 

[KingTempest]

Welp, guess the discussion is here (damn near a year later)

 

[Shmeatywerbenmanjenson]

We need to figure out a solid way to actually find a materials Explosive fragmentation value.
As of right now that means we need to decide on a minimum velocity to use as a base.