Austere Emancipator
Feb 26 2004, 11:36 PM
Just read an
article (.PDF) that says:
QUOTE |
Protection against blast injury is very difficult to achieve. Research has shown that conventional personnel protection (bulletproof vests) might even increase injury, enhancing blast effects by increasing target surface area and changing the effective loading function on the thorax. |
It also mentions that research is underway to find ways to protect personnel against blasts. It mentions resources, but those are almost impossible for me to hunt down, and Google is of very limited use in such a specialized issue. Does anyone here have relevant knowledge?
If it is true that conventional body armor is useless against blasts, then weapons which are based on blast damage (offensive/concussion grenades for one) should probably ignore body armor, or at least work against 1/4 or 1/2 Impact.
This would also allow for clearer differentiation between explosives that derive most of their damaging potential from fragmentation (ie extreme majority of conventional explosive weapons, regardless of what SR3 tries to tell you about HE and AP munitions) and explosives which depend on blast.
For example:
Fragmentation-based weapons would have far greater damaging radii, up to ~20 meters for a standard defensive hand grenade, while allowing the target full protection from Impact armor. Blast-based weapons would have extremely limited damaging radii, only 3-4 meters for standard offensive hand grenades in the open, and work against 1/2 or less Impact.
Certainly not perfect, because simplicity demands that fragmentation and blast damages are still rolled into one with all explosions. But might be fun.
BTW, the article has a nice scientific
![proof.gif](http://invision.dumpshock.com/html/emoticons/proof.gif)
for the Chunky Salsa Effect.
Raygun
Feb 27 2004, 01:00 AM
I wouldn't say that conventional body armor would be useless against a blast. The sheer mass of it has to offer at least some protection against concussion. I don't really see how wearing body armor could really make it any worse. The kind of blast that would cause that kind of effects that they're talking about is probably going to kill you, the car you're in, and whatever you land on anyway. I don't think a small explosion like a grenade or claymore is going to give this kind of effect.
Siege
Feb 27 2004, 01:29 AM
Body armor was never designed to repel firepower of that magnitude. (we really need a geek smilie)
It was initially designed to stop projectiles and shrapnel -- which it does with varying degrees of effectiveness.
Defensive grenades -- IRL are high-frag grenades, should actually work against Ballistic in SR because fundamentally, that's what shrapnel is.
Although I'd like to see how well hard armor stands up to shock waves.
-Siege
Modesitt
Feb 27 2004, 08:18 AM
Just to provide another viewpoint, a brief conversation from another forum:
QUOTE ("Soldier") |
you probably haven't served or if yoiu have never went to the gulf but as a veteran of GW1 I can tell you my body armor was worn not once while I was there. We all turned it in still wrapped in plastic. The reason is it isnt what cops wear its designed for grenade shrapnel at best. Body armor like the military has wont stop an AK round much less a medium machinegun round so its extra weight.
Yeah you see the guys on TV wearing it but keep in mind a lot of the scenes you see on TV are just that. Scenes for TV so worried folks wont worry. Much of the force there will rarely wear the stuff as it not practicle from a heat/weaight standpoint. |
hobgoblin
Feb 27 2004, 08:30 AM
hmm, that reminds me of storys from vietnam. troops down there was issued armor but most used them to sit on rather then wearing them as they where hot, heavy and directly unconfortable.
as far back as ww2 bomber personell where issued flack jackets, designed to stop (obviusly) flak fragments as well as diffrent caliber machine gun rounds.
Austere Emancipator
Feb 27 2004, 09:13 AM
QUOTE (Raygun) |
I don't think a small explosion like a grenade or claymore is going to give this kind of effect. |
While the article itself is indeed about explosive devices quite a lot bigger than that, I don't think the sources are. "Cloth ballistic vest alters response to blast" from "Journal of Trauma" doesn't sound like it only has to do with huge-ass bombs, nor does "Effect of clothing on thoracic response".
Note that I would consider claymores frag-based anyway, and as such they would work against full Impact. The only (hand) grenade sized munitions that would work against lowered armor ratings would be the defensive grenades, which are pretty much just 200-300g lumps of high explosive.
It seems logical to me that less powerful shock waves work mostly with the same principles as the extremely powerful shock waves.
QUOTE (Siege) |
Defensive grenades -- IRL are high-frag grenades, should actually work against Ballistic in SR because fundamentally, that's what shrapnel is. |
I sort of agree. If there was an easy way to distinguish between fragment, blast and thermal damage, then the fragment damage should definitely work against Ballistic. But frag grenades do cause wounds with the 2 other ways as well. Further away from the grenade these are insignificant, but close to the grenade they might be powerful enough to kill/disable on their own.
QUOTE |
Although I'd like to see how well hard armor stands up to shock waves. |
It's quite probable that they'd do better than soft armor. Less/no deformation, and it also provides "layers of materials with different densities". It seems that even in SR canon hard armor has higher Impact armor ratings than soft armor, and certainly this is true in my games, so using 1/2 Impact would take this into account. Sort of.
QUOTE (Modesitt) |
QUOTE (Soldier) | The reason is it isnt what cops wear its designed for grenade shrapnel at best. Body armor like the military has wont stop an AK round much less a medium machinegun round so its extra weight. |
|
Cops do wear that, don't they? At least the
National Institute of Justice tries to tell them to. Body armor most certainly stops bullets, modern soft armor stops anything up to and including 9mmP +P FMJs from SMG-length barrels and any expanding pistol-caliber bullets. With the SAPI plates, they
do stop AK rounds, and, if the plates provided by the DoD are up to the NIJ standards, they also
do stop MMG rounds.
The basic level III protection, which even PASGT with plates should be, must be capable of stopping 7.62x51mm NATO FMJs at point blank range with minimal backing material deformation.
That stuff is really heavy, that's for sure, and it only protects part of your torso. But that doesn't change the fact that it
does stop bullets.
QUOTE (hobgoblin) |
as far back as ww2 bomber personell where issued flack jackets, designed to stop (obviusly) flak fragments as well as diffrent caliber machine gun rounds. |
I'm pretty sure back then there was no kind of body armor capable of stopping any kind of machine gun rounds at most ranges. Maybe they thought that if the bullet has already traveled several hundred meters from the machine guns to the aircraft, and then pierced the airframe, they might be slow enough for the flak jacket to stop. *Shrug*
Siege
Feb 27 2004, 09:44 AM
I smell a houserule set on grenades.
Your point on ways grenades impact their target is well made. I suppose I should have specified "the primary fashion in which a defensive grenade operates" etc.
If a character is X meters or less from point of detonation, they must apply armor Ballistic Armor versus shrapnel, 1/2 Impact against Heat and 1/2 Impact against Explosion.
If a character is beyond x meters, apply Ballistic Shrapnel damage.
It would certainly see a proliferation in characters with the "Throw" skill and an amazing reduction in the number of grenades being carried.
![grinbig.gif](http://invision.dumpshock.com/html/emoticons/grinbig.gif)
If you want to get really technical, double "hard" armors against grenade damage -- sec and mil-spec armors.
-Siege
toturi
Feb 27 2004, 10:08 AM
QUOTE (Austere Emancipator @ Feb 27 2004, 07:36 AM) |
Just read an article (.PDF) that says:QUOTE | Protection against blast injury is very difficult to achieve. Research has shown that conventional personnel protection (bulletproof vests) might even increase injury, enhancing blast effects by increasing target surface area and changing the effective loading function on the thorax. |
It also mentions that research is underway to find ways to protect personnel against blasts. It mentions resources, but those are almost impossible for me to hunt down, and Google is of very limited use in such a specialized issue. Does anyone here have relevant knowledge?
|
I read some articles on the subject but I think they were all classified for some reason. But yes, Kevlar and ceramic armour sucks at soaking large area high amplitude dynamic stress waves. Basically the best things that should against concussive shock waves are useless against projectiles, so you can't have both, at least with today's technology.
hobgoblin
Feb 27 2004, 10:09 AM
never underestimate the ability of metal strips inside lather armor
![smile.gif](http://invision.dumpshock.com/html/emoticons/smile.gif)
ok so machinegun rounds was a bit wrong, im going by memory here...
Arethusa
Feb 27 2004, 10:11 AM
QUOTE (Austere Emancipator) |
I'm pretty sure back then there was no kind of body armor capable of stopping any kind of machine gun rounds at most ranges. Maybe they thought that if the bullet has already traveled several hundred meters from the machine guns to the aircraft, and then pierced the airframe, they might be slow enough for the flak jacket to stop. *Shrug* |
You are correct. Flak jackets were only intended to stop just that: flak. They were large, bulky, and entirely unsuited for any sort of mobile combat, and while they did a decent job of protecting against flak and low velocity shrapnel, if they stopped a bullet, it was a combination of pure luck and extreme distance. Chances are that one of those flak jackets would get shredded by a modern M67, much less a .30-06, 8mm Mauser, or .50 BMG round, which is what those airmen would've been seeing at the time.
Austere Emancipator
Feb 27 2004, 10:11 AM
QUOTE (Siege) |
I suppose I should have specified "the primary fashion in which a defensive grenade operates" etc. |
I understood, I just got carried away. Sorry. You're absolutely correct, and what I really meant to say is that, a lot of the time, fragmentation is by far the main source of damage with those. Shadowrun might see slightly more blast and thermal injuries from defensive grenades than normal because of the prevalence of indoor fighting, but fragments would still cause the massive majority of casualties.
QUOTE |
If a character is X meters or less from point of detonation, they must apply armor Ballistic Armor versus shrapnel, 1/2 Impact against Heat and 1/2 Impact against Explosion. |
If you were to separate fragment damage from blast and thermal damage, I think it might still be reasonable to roll blast and thermal into one and call that blast. Ballistic against fragments, 1/2 Impact against blast. Allow half of thermal insulation be used against blast. Not a very pleasant compromise, but I rather not have three figures to play around with. The threat radii of the two are pretty similar, and Impact armor already provides some protection against other sorts of heat threats. (I think?)
A defensive hand grenade might break down to 10S frag, -1/2m + 5S blast, -2/m. An offensive hand grenade could be 10S blast, -2/m.
It's always going to be more complicated if you separate them, because you'll have to consider two different Damage Codes, two radii, two armor ratings, etc. But that's about as simple and reasonable as it can be done, if you wish to go that route.
For the time being, though, I'm just advocating the use of 1/2 Impact against defensive grenades and other weapons based on blast first and foremost, not really the separation of fragment and blast/thermal damage.
QUOTE |
If you want to get really technical, double "hard" armors against grenade damage -- sec and mil-spec armors. |
I'm not sure if that's really called for. Might allow them to use their full Impact rating, but double Impact is too much IMO. After all, even if the armor itself remains rigid and doesn't crush your thorax itself, much of the pressure wave would propagate through it to crush your thorax within. Plus I don't think protecting against the blast should be easier than protecting against the fragments in any case, because fragments are so very, very easy to stop with body armor with minimal blunt trauma.
toturi
Feb 27 2004, 10:15 AM
QUOTE (Siege) |
IIf you want to get really technical, double "hard" armors against grenade damage -- sec and mil-spec armors.
-Siege |
I would increase grenade concussive effect on anyone in a sec/milspec amour at close range. The high freq energies of a dynamic wave are changed into a lower freq and being trapped in a sealed enironment. If you do not understand, it is kind of like the kinetic equivalent of global warming, energy gets in and can't get out.
Austere Emancipator
Feb 27 2004, 11:56 AM
QUOTE (toturi) |
The high freq energies of a dynamic wave are changed into a lower freq and being trapped in a sealed enironment. |
I must admit this sounds a bit like the ".22s bounce around in the chest cavity" stuff that gets thrown around every now and then. Not saying it's necessarily not true, but it doesn't sound like a perfect explanation either.
I don't personally know squat about how pressure waves propagate through different mediums, but, to someone uneducated like me, it seems that if the suit of armor reflects the wave back to the wearer, it would reflect it away from the armor in the first place. So if it happens that some of the wave is reflected back and forth inside the suit, then it is at least partly offset by some of the wave being reflected away at first.
Funny you should mention global warming.
toturi
Feb 27 2004, 12:37 PM
The lower freqs are reflected away,yes. But when the higher freq waves pass through certain materials that causes the wave to change freqs into a lower freq, that's when you have the chunky salsa effect in the armour.
A friend of mine did an experiment on lab mice, using a Hopkinson bar. A mice was strapped into a ceramic/steel reinforced nylon harness(funny looking mice, yes) and subjected to shock waves simulating a bomb blast. Poor things died, no visible physical wounds.
Don't sue me, I didn't hurt those mice.
Siege
Feb 27 2004, 05:40 PM
QUOTE (toturi) |
The lower freqs are reflected away,yes. But when the higher freq waves pass through certain materials that causes the wave to change freqs into a lower freq, that's when you have the chunky salsa effect in the armour.
A friend of mine did an experiment on lab mice, using a Hopkinson bar. A mice was strapped into a ceramic/steel reinforced nylon harness(funny looking mice, yes) and subjected to shock waves simulating a bomb blast. Poor things died, no visible physical wounds.
Don't sue me, I didn't hurt those mice. |
I think it's called the "angel" effect from suicide bombers -- being caught close to the blast and the concussion wave turns your lungs to soup.
Aust: I wasn't upset, just clarifying my point to better suit the current audience.
![grinbig.gif](http://invision.dumpshock.com/html/emoticons/grinbig.gif)
As complicated house rules go, very true. Although it might be fun to implement them in a game once and see how the mortality rate goes.
Tot: I'll take your word for it -- I'm not a scientist and I haven't had the misfortune of suffering a grenade hit at close range while in sec or mil-spec armors.
![grinbig.gif](http://invision.dumpshock.com/html/emoticons/grinbig.gif)
-Siege
lodestar
Feb 28 2004, 02:09 AM
While conventional body armor does in most cases help protect against fragments, it unlikely that it does much to protect against the damage actually caused by the force of the blast aside from pad them from whatever they might get knocked down or into. The usual problem that most victims suffer is what the doctors call the "white butterfly" (what the x-ray looks like) where most internal organs are essentially pulped even though exterior damage is minimal. This shows up most often in car bomb trauma scenes, unfortuantely not much can be done for the victim.
In game terms this could be represented by the high damage codes for being in close proximity to demolition blasts or similar explosions. Where fragments are the primary damage cause the standard gernade rules might apply.
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