Sci-Fi Metalurgy and Real World Expectations

[Stravo]

I wartched District 9 over the weekend and one of my favorite sequences is when the protagonist manages to get into a warsuit and fights off the milita forces guarding the camp. Really cool tech sequences here but I do recall there was some criticism of that scene in the movie from folks here about how the warsuit was taken out by man portable weapons and pierced by .50cal sniper fire. The gist was this was advanced alien metal so it should have been harder to take out.

I am not in any way a scientifically minded person in terms of things like metalurgy and penetrating power. So my question to those that are is can we really expect metallurgy to become so advanced that it would be invulnerable to weapons fire from modern or slug throwing weapons? What I mean to say is that absent some unknown X element and all you have to work with is Iron, Steel, etc can there come a point where you can create alloys that would be near invulnerable to that kind of weapons fire?

For example in the last 50-60 years tank armor has had revolutions in design and such so that you have state of the art Chobalm armor on an Abrams. Does that mean that WWII era tanks like the Panther could not penetrate the armor of an Abrams or would it be more like what we saw in District 9 where it would take lots and lots of main gun fire to damage and penetrate the tank? Because if we can do stuff like that in just 50-60 years then I can understand the argument that a society that is space going tech wise could build some truly durable stuff.

Thanks in advance for any observations on this.

[Knife]

Depends. Armor would be developed to counter the weapons designed to defeat it. So, for example, if you're armor develops to fend off bombs and area weapons, it may not be that effective against point weapons. In other words, oblique armor designed to crumple when hit by a blast wave may not do jack and shit against bullets. Armor designed to defeat something like a laser may or may not be effective against kinetic weapons.

Packing crates in ST may adsorb phaser fire but will do little to defend against slug throwers. As far as District 9, I watched the movie and wasn't that enthralled by it, I see little to show that the mech should have been immune to human weapons fire. AFAIK and remember, multiple hits started to cripple various systems in the thing, it died a death of a thousand paper cuts type thing. Seems fair enough to me. An armored compartment for the pilot, but other systems being vulnerable to bullets. Knock out enough secondary systems, or support systems and the thing malfunctions.

[PeZook]

That said, there are hard physical limits on what sort of protection you can pack into a given weight, even if your armor can be built molecule by molecule to your exact specifications and you know all there is to know about material properties and how they are shaped by its composition. There's only so many ways molecules can bind with each other, and a limited amount of things you can do with stacking layers of materials on each other.

Even today, designing body armor is as much about resillience of the materials used as it is about learning and controlling how energy and momentum is dissipated during the impact: hence why Kevlar is actually a fabric, rather than a metal, and why nobody will ever try armoring infantrymen against direct hits from artillery.

All in all, there's nothing wrong with the powered suit being taken out by man-portable weapons like antimaterial rifles (that can pierce side armor of many APCs, remember), especially if it was overoptimized to defeat alien weapons, rather than being a more general-purpose system. Look at how knifeproof vests compare to bulletproof vests - and we know for a fact that alien weapons work on vastly different principles than human ones (Prawn designers might've felt making a soldier not instantly go "pop" when hit with the lightning gun was more important than making him 100% proof against Prawn projectile weapons, for example)

[Sea Skimmer]

The gun on the Panther could not defeat the frontal armor of an M1 tank, even the earliest models, if you placed the muzzle right up against it. Even the side armor would be pretty damn hard to defeat. But a suit is a damn lot different then a tank, because it doesn't have any real margin for volume intensive armors, nor could it weigh all that much before it would risk bogging down while walking (anyone know the ground pressure of an elephant BTW?). Most of the methods by which we have improved the resistance of modern armors over the basic steel of WW2 involve either much denser materials and thus vastly more weight mainly in the form of tungsten or depleted uranium, or else far more volume in the form of composites and controlled deformation armor. A lot of modern 'special' armor also has a limited shelf life and has to be replaced from time to time. Plus even really good armor can suffer from spalling, and a suit that complicated would be very hard to spall line.

I never thought anything was wrong with the whole thing. I mean if it was supposed to be a brand new fully maintained alien battlesuit, I might have questioned it but instead its an old clunker which for all we know might have been highly obsolete at the time it arrived on earth in the first place.

[Zixinus]

Actually I am glad about that sequence. It helps with the narrative (giving the impression that the hero is actually fighting hard rather than just moping the floor), it legitemately empowers the hero, it gives the little kid something useful to do, etc. But most of all, it didn't descend into a wankfest. Anyone insisting that an alien material should have resisted high-calibre bullets meant to destroy vehicles is just looking for an excuse to wank off in someone's face.

Think about it: modern aluminium or carbon composites would be an alien material to a Victorian. He finds the material non-corroding, strong, tough but light. Yet we, knowing the materials first-hand, know that very few types of those materials have any chance of not being penetrated by a an arrow or spear, as they weren't designed for that. Distributing kinetic energy to prevent penetration is not the same as not allowing penetration from a sharp edge. So we would find the Victorian just as silly trying to use a set of aluminium for actual battle, just as it would be silly to expect that a battle-suit could withstand an endless barrage.

Being highly resilient is not the same as invulnerable. Showered with enough bullets, any material can be shattered or penetrated.

Can a Panther defeat an M1's armor? Since I know little about tanks, I am sure that Sea Skimmer is correct that it can't. But what about repeated hits? Surviving one hit is not the same as surviving an entire barrage. I am willing to bet, even if not completely certain, that the M1's superior armor will diminish after several hits.

Besides, it has been suggested that the mech was a retro-fitted working utility vehicle.

[Axiomatic]

I didn't mind it because it was pretty obvious from a previous scene that the suit's armor was never intended to stop projectile weaponry, since it had the weird gravity gun bullet-catcher thing for that. An alien trained in its use would probably never have been stopped because he would have known how to use the armor's defenses properly, but Wikus had no idea.

[Sea Skimmer]

Can a Panther defeat an M1's armor? Since I know little about tanks, I am sure that Sea Skimmer is correct that it can't. But what about repeated hits? Surviving one hit is not the same as surviving an entire barrage. I am willing to bet, even if not completely certain, that the M1's superior armor will diminish after several hits.

The special composite armors break down from repeated hits pretty easily, they are designed to shatter and thus force more mass into the projectiles path, but against the frontal armor of an M1 the Panther's 75mm gun wouldn't even be able to get past the initial shell of steel armor. Even much heavier shells of might fail at all, Iraqi tanks firing 125mm steel sabots (the Soviets would only had out what was basically 1950s ammo) left the sabots sticking out of the armor on M1 tanks. The tanks were repaired by simply sawing off the sabot, grinding it smooth and painting it over.

Breaking down steel armor with repeated hits would very much work... but it'd take all day or at least most of the Panther ammo load. The M1 meanwhile would be able to kill a Panther from any angle at absolutely any range it could hit, even long range indirect fire hits that would not normally occur. But what does one expect anyway, the M1 is a much bigger tank with a much bigger gun, besides its vast technological advantage. Even the tanks of the 1950s were generally far superior to those of the 1940s (just look at a T-54 from 1947 vs. a Panther, the former has a much bigger gun and almost twice max armor thickness already) because of huge improvements in detail design methods and hull and turret shaping. Tanks in WW2 could have been better then they were already, its just very few tanks that saw combat were designed with war experience in mind, and generally only then with early war experience when AT guns were still fairly small.

[Modax]

I had been wondering about that as well. A while ago my friend and I were fooling around in ArmA 2 sending the M1A2 against squadrons of T-34s. The Abrams was destroyed after about 5-6 hits at close range. We were skeptical, even with the game's reputation as a "hardcore sim".

[Steel]

I had been wondering about that as well. A while ago my friend and I were fooling around in ArmA 2 sending the M1A2 against squadrons of T-34s. The Abrams was destroyed after about 5-6 hits at close range. We were skeptical, even with the game's reputation as a "hardcore sim".

The OFP and ArmA series has terrible armour handling. Basically everything just has hitpoints. It doesn't matter at what angle the shell hits, theres no notion of penetration, and if you were to pistol a tank enough, it would eventually explode.

[Sea Skimmer]

They couldn't shift away from hitpoints in Arma2 because otherwise there would be little hope of adapting Arma mods to work with the new game. More then once sacrifice was made to ensure that mods would need only minimal adjustments to work, and they got that much right and as a result Arma2 had hoards of mods out within weeks of release.

[Coalition]

For the District 9 battlesuit, if I remember it correctly he was also trying to escort Christopher (the alien father) to the small shuttle, rather than opening fire immediately. This allowed the mercs to take multiple shots at him, with heavy weapons, before he finally turned around and started shooting.

So while he is running (exposing the weaker side and rear of the suit), he is taking fire, and the smaller items on the suit are getting shot steadily, damaging gears, actuators, etc, plus anti-armor fire from the mercenaries the entire time. Even after that, the suit is still capable of delivering (and receiving) a lot of damage, until it is finally hit by a truck, and run over.

[adam_grif]

The holy grail of real-world material sciences are things like large-scale carbon nanotubes and flawless diamonds. In theory they're fucking insane, in reality they're good but not that good because you can't build flawless structures like that.

Has somebody run the numbers on them? At a cursory glance I don't see any reason why a suit of armor like that couldn't be made nearly impervious to .50 cal rounds except for vulnerable spots.

[Stravo]

I recall reading in the Andromeda Ascendant pages that the ship used some form of theoretical armor known as "Bucky Balls" I didn't look it up to see what the actual definition was but from what I read in the description it seems that the ship's hull was made up of these atomic scale little balls that bend and give but don't break. I could be way off on that because this was years ago. Are Bucky balls something that would be a logical extension of metallurgy or is it something totally unrelated to armor and metal work?

[Steel]

I recall reading in the Andromeda Ascendant pages that the ship used some form of theoretical armor known as "Bucky Balls" I didn't look it up to see what the actual definition was but from what I read in the description it seems that the ship's hull was made up of these atomic scale little balls that bend and give but don't break. I could be way off on that because this was years ago. Are Bucky balls something that would be a logical extension of metallurgy or is it something totally unrelated to armor and metal work?

I'm pretty sure bucky balls would be fuck all use in an armour context.

They're basically little carbon footballs. Genuinely arranged exactly as a football (an actual football, as in a ball kicked by a foot), 60 carbon atoms with an atom at each of the vertices of the hexagon/pentagon arrangement that covers the football.

They're pretty strong on the nanoscale, but I don't see how you would use them as anything other than some bizarre from of ablative armour or something. I think they're pretty much frictionless, so if you had a layer of them on the outside they would just slide off anything. If they were hit by anything then they'd all just be shoved out of the way.

[Starglider]

I'm pretty sure bucky balls would be fuck all use in an armour context. They're basically little carbon footballs.

No, but given arbitrarily advanced nanotechnology you could loop nanotubes into toruses and interlink them like chainmail. I suspect that would have inherently better resistance to penetration than a simple nanotube weave, because the carbon covalent bonds would directly resist sheering forces, rather than relying on functionalisation groups to crosslink the tubes. Certainly it would have crazy high and basically homogeneous tensile strength, and wouldn't have the brittleness problems that diamond has. You'd probably still need a heavy metal filler and matrix to use it as armour, to put more mass in the projectile's path.

I once saw a paper talking about simulations of an even crazier material, which was basically a 3D chainmail-style structure of interlaced benzene rings. Electron cloud effects were supposed to give a sheer strength over ten million times that of armour steel. Highly speculative though, and I can't seem to find the paper online now.

[Admiral Valdemar]

The prawn exosuit is never actually penetrated until the final ramming via the technical, which was after the whole left arm went up from holding on to the caught RPG round (the suit went flying after being rammed when Wikus and Christopher split and suffered no apparent damage or disorientation to the pilot), which obviously didn't react well to the railgun/lightning gun combo in the arm. You see a lot of superficial damage, but up to that point, Wikus is more of the limiting factor, being a green pilot, under intense stress and also, oh yeah, turning into an alien. Even if the suit were in mint condition and piloted by a prawn, it's still one unit versus a whole PMC that was rallying reinforcements. Eventually, even alien tech will fail under constant barrage.

As for carbon armour, the issues are mainly down to simply forming the right structures in a cheap enough and accurate enough manner to allow for such plates to be created. We can make buckminster fullerenes now, for instance, but only at very short lengths, but they're the material most likely for things such as extremely high tensile cabling, provided the manufacturing process can be scaled up from a few millimetres to kilometres of the stuff. There's a new polymer that actually surpasses spider silk pound for pound, which I recall seeing on Bang Goes The Theory which is now being used in mountaineering and the like instead of nylon.

In any case, armour will always fail under enough stress. The prawn exosuit was clearly shown to have active defences too, which Wikus didn't utilise. Today, a tank that relies only on passive armour will be at a disadvantage to one that has an active system as well, which allows for more complex threats to be dealt with without adding too much additional weight in terms of armour, but extra power and sensors may be required. If you can shoot down ATGMs with a laser and leave the armour plate to deal with mines or RPGs and sabot/HEAT rounds, then survivability should be better than just one system or the other.

[Gil Hamilton]

No, but given arbitrarily advanced nanotechnology you could loop nanotubes into toruses and interlink them like chainmail. I suspect that would have inherently better resistance to penetration than a simple nanotube weave, because the carbon covalent bonds would directly resist sheering forces, rather than relying on functionalisation groups to crosslink the tubes. Certainly it would have crazy high and basically homogeneous tensile strength, and wouldn't have the brittleness problems that diamond has. You'd probably still need a heavy metal filler and matrix to use it as armour, to put more mass in the projectile's path.

I once saw a paper talking about simulations of an even crazier material, which was basically a 3D chainmail-style structure of interlaced benzene rings. Electron cloud effects were supposed to give a sheer strength over ten million times that of armour steel. Highly speculative though, and I can't seem to find the paper online now.

I'd strongly question the last simulation. How do you interlace benzene rings without bring the carbons and hydrogen in adjacent rings much closer to each other than they can stably be? They'd break aromaticity and react before they were forced into a potential energy situation that unstable, even if you magicked all the benzene rings into position in the first place. Aromaticity is pretty damn bad ass, but it's not THAT bad ass. I'd like to hear from the study what assumptions they made.

[Admiral Valdemar]

Maybe there was some sort of substrate to hold the benzenes in, rather than just being pure hydrocarbon in composition. It does seem a bit tricky to get that kind of formation in something that isn't crystalline carbon.