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So I'm writing a story (set well into the future and on a different, but similar to Earth planet colonised by humans) and as part of it I am including specs and designs for the armour that the military stationed there uses.

I want the story to be at least vaguely based on reality (this makes it easier to make the designs) so I have been thinking of a material that would be suited to the enviroment/warfare of that time.

My plan is that the soldier wears a lightweight but nearly-bulletproof suit (similar to kevlar but lighter and more flexible), and on top of that some sort of titanium x ceramic compound plating.

The armour preferably needs to be able to cope with: 1. High-temperature blasts (plasma rifles exist in this universe). 2. High-impact projectiles (gauss/rail cannons have been developed and made viable for use in the military).

It does not need to be knife proof (although I doubt it wouldn't be) as the suit underneath sorts that out.

Is it possible to combine or mix a metal such as titanium and ceramic or would it be layered? Also would this substance likely meet the basic requirements and sort of lightweight? (If not I can have my soldiers wearing exosuits).

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  • $\begingroup$ en.wikipedia.org/wiki/Eddy_current_brake I somehow need to implement them into nanites, but then, PROFIT. $\endgroup$ – Mephistopheles Aug 14 '17 at 18:39
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    $\begingroup$ @RedactedRedacted Pardon? Sorry, I fail to see how this is relevant to the question asked... $\endgroup$ – HyperdriveMacGee Aug 14 '17 at 18:46
  • $\begingroup$ Brakes stop objects. $\endgroup$ – Mephistopheles Aug 14 '17 at 18:48
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    $\begingroup$ Consider these real-world places to start your project: en.wikipedia.org/wiki/Aluminium_oxynitride or here: science.howstuffworks.com/transparent-aluminum-armor.htm $\endgroup$ – Joe Aug 14 '17 at 19:57
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    $\begingroup$ The muzzle energy of a .50 BMG round fired from a M82 is about 15000 Joules. Deposited on a 100 kg person around center mass, that's enough to accelerate their ~50kg torso to about 24 meters/sec, which is like free falling 30 meters onto ONLY your chest This is a real weapon, with no futurism required, and you probably have smaller weapons that hit harder. Stopping that bullet is not enough. $\endgroup$ – Sean Boddy Aug 15 '17 at 4:25
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OK, my first revision of this answer was remarkably negative. I'm afraid some of that is unavoidable. Asking to produce a reasonably-physics-real armor to stop the actually-relatively-known problems of rail guns and plasma weapons is kinda asking for magic — and I suggest you approach it from that perspective.

Consider the way the armor in the game Halo is described. Its description focuses almost entirely on what it does, not how it's made, with enough techy-sounding words thrown in to help readers/players to suspend their disbelief. That's because when you start looking closely at the physics and practicality of the armor, you quickly realize it's nearly impossible to build and nearly worthless to use.

Our world has been slowly moving away from ridid armor for centuries because it seriously limits the infantry's ability to do anything. Climbing hills, slipping through doorways, getting into a Yugo. The more rigid armor you plate onto a person, the less they can do. Video games and movies wave their hands at the fact that inertia, bulk, limited articulation, weight, and everything else can't actually be ignored. I love the movie Edge of Tomorrow, but it only takes a moment to realize that even with the world's best gyroscopes, the first time you swing around to blast something, you're on your back, unable to get up.

Therefore, I would take the Star Wars way out. In the movies you never hear anything about how the stormtrooper suits are made. You only know they're effective (well, considering Han Solo dropped troopers like flies without even getting grazed... they're more like optical magnets... but that's another answer). I'd focus on what the suits look like, considering how the infantry must use them in the field, rather than worrying about how they're manufactured.


Potentially Unecessary Background

Rail guns (and here) produce unimaginable velocities. The stuff the U.S. Navy is testing right now is capable of penetrating full ship armor at the horizon. (Gasping in awe is now appropriate.) This is a long and fancy way of saying, even if you reduce the size of the rail gun from naval battery size to carbine-sized, there frankly isn't likely to be anything an individual can wear that could stop the shot. And even if we have something that stops the shot, the force behind a rail gun shell would kill the bearer of said armor simply from the concussive shock. Your body might be intact, but your heart would be jelly. The energy needs to go someplace. (Well... what if you created a piezzo-electric something or other that converted the concussive wave into electricity and stored it... Or some kind of jelly that converts kinetics to heat, and then dissipates the heat. You'd be really easy to see in a thermal scope, but... Hmm....)

Add to this that the armor must handle plasma-grade heat. This isn't a bit-o-armor anymore, now it's an enclosed suit with independent oxygen and conditioning that could handle all but the most heated of furnances. And hope like crazy its integrity isn't broken by the rail gun....

Can you see why the Halo description pretty much ignores the physics?

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  • $\begingroup$ This is a great answer, not sure why it got a downvote. (+1) $\endgroup$ – Charles Aug 15 '17 at 4:33
  • $\begingroup$ Nor I. The hard science behind stopping a rail gun shell via personal armor doesn't exist. It certainly doesn't exist for a nonexistent plasma weapon. But, every once in a while reviewers get tied up in the specifics and forget that helping people write a story is more important than meeting bureaucratic rules. $\endgroup$ – JBH Aug 15 '17 at 5:35
  • $\begingroup$ Lol, even in Halo, the railgun is a one-hit kill ;) $\endgroup$ – Pyrotrain Aug 16 '17 at 4:04
  • $\begingroup$ Awesome answer man thanks much. That idea about the piezo-electric resonance absorber has given me a fantastic idea that may be used in more than just the armour, thanks a ton. $\endgroup$ – HyperdriveMacGee Aug 24 '17 at 13:15
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I shall make the following assumptions of your world.

  • Graphene and its production are mature in your world. This allows for readily-available super capacitors and large, stable sheets of graphene layered as much as 1 mm.
  • Plasma weapons utilize a form of "cold plasma" and rely mostly on the concussive force of high-velocity gas particles, and less on raw heat distribution. These plasmas therefore are in the thousands of K in temperature.
  • The soldiers in this case will wear armor equivalent in thickness to a level IV vest, at 20mm thick.

Keeping those things in mind, we shall construct your armor.

Sheer-thickening fluids

Modern bullet-proof vests are being designed in part around non-Newtonian fluids. Oobleck is an example of one such fluid. If you hit it hard and fast, the "fluid" hardens and deflects the pressure of the impact over the entire area of the fluid, thereby stopping your hand and not allowing you to penetrate it.

Taking a modern example, such as the Moratex Institute of Security Technologies liquid armor, into consideration, the technology currently boasts being able to stop an object traveling at 450 m/s when fitted in a vest.

This isn't protection for our cases, bit we want this material for its impact-distribution over a much larger area than most other materials.

Graphene

Graphene is a material made up of only carbon atoms in a single layer. It has tons of useful properties, among which is great strength and impact resistance. Research groups at Rice University and the University of Massachusetts carried out an experiment using between 10 and 100 layers of graphene and high-velocity objects. They "shot" tiny gold fragments at the layers at up to 3000 m/s. These layers survived these impacts and showed twice the stopping power of kevlar.

100 layers of graphene is only 100 nanometers thick. A million layers of graphene is 1 mm thick. We have 20 mm to work with here.

Ceramics

Ceramics are very good at turning impact energy into breaking energy. When something hits a ceramic and it shatters, a lot of that impact is deflected into the shattering process.

However, ceramics also have awful capacity for heat transfer. This is good for us. When getting hit with relatively high-temperature plasmas, the ceramic layer will keep the the human on the other side of at least somewhat safe.

Armor

Lets add up our pieces: high-strength graphene, impact displacing sheer-force fluids, and heat-resistant ceramics.

Theoretically, if you take the fluid and wrap it in a couple millimeters of graphene you have a very strong vest that can take high-velocity impacts into the several-thousands of meters per second before failing. Not only does it absorb those impacts, it deflects them across the volume of the liquid in the vest.

Whatever impact force makes it too deep into the vest proper can be further deflected by ceramic plates placed in pouches in the vest. Using multiple plates ensures multiple potential chances for survival. If the vest is hit with high-temperature plasma, the ceramics give the wearer a chance to make it away with burns as opposed to molten bones. Lastly, the liquid in the vest will have water content, which will provide for a layer of high-heat-capacity material as well.

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You could construct the armour out of novel (to us) metamaterials that channelled energy around the armour, to be emitted on the far side of it (or directed out in a particular direction).

For projectiles, the armour could stiffen to shatter the projectile and convert the kinetic energy into heat or sound (or both) and radiate it away.

For plasma, charged radiation or photonic weapons, the armour could channel it around itself (in the same way as some nanomaterials can be used to cloak objects to radiation by channeling them around it).

Of course, it means that every railgun projectile impact results in the target emitting an explosion of energy (and scattering hypersonic projectile fragments), with energy weapon beams passing around the target to strike whatever is behind it, but that's a design compromise. It's possible to tune the metamaterials to do whatever you need them to do; for far future materials, it's as much magic as science. To quote the immortal Arthur C. Clarke: "Any sufficiently advanced technology is indistinguishable from magic."

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If you haven't read William Gibson's "The Peripheral," a major plot point hinges on the use of a fibrous textile armor described as looking like greenish-purple cotton candy, which stiffens at the impact of a projectile, causing the bullet to fragment. The armor is incorporated into jackets that look like street wear. Several research groups are working on similar concepts, some of which are based on particulates suspended in gel and others that resemble Gibson's description.

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    $\begingroup$ This would be a suggestion on the undersuit, however this does not answer the question I asked, are you sure you read the whole thing? Thanks for the suggestion anyway, I'll keep it in mind. $\endgroup$ – HyperdriveMacGee Aug 14 '17 at 18:49
  • $\begingroup$ Well, like I said, it'd be resistant to high-velocity projectiles, and many shear-thickening materials could also be resistant to high temp. I directly addressed your question, not sure why you think I didn't. $\endgroup$ – Snark218 Aug 16 '17 at 22:16
  • $\begingroup$ No idea why this got a downvote, I don't think it is an unreasonable answer, it could be quite useful in minimising the rigid armour on the unit, maximising mobility. After reading some other answers I realised this could be more useful than I originally thought, as it could be used for undercover agents and such. Thanks! $\endgroup$ – HyperdriveMacGee Aug 24 '17 at 13:28

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