# How can my powered armor quickly replace its ceramic plates?

Though ceramic plates are harder than a math exam, and can practically obliterate projectiles, they are one-hit wonders. Self-repairing has been demonstrated for a composite of silicon carbide and aluminum oxide. I guess I should also add that the composite regained full-strength, but needed a minute and 1000 °C. The plate has to be substituted for the duration of the repairing process, but how am I supposed to quickly switch plates, sometimes mid-combat?

I need a way for the armor to:

• quickly
• reliably
• energy-efficiently

replace the plates, the structural components of the mechanism should:

• be sturdy
• lightweight
• and interfere with other activities (shooting and running) as little as possible

The plates are mainly around the torso (front and side) and the legs (front and side), since you only get shot in the back if you face away from combat, or if you let the enemy get behind you.

How should my armor replace its plates?

Note

If first thought of an arm that can reach out for and pick up tiles, then place a new one in the gaps, but Moravec's Paradox blocks the way!

• Why not have a heating array or similar behind the plates to weld them together temporarily. Yes it won't last, but it will hold together long enough to take another shot – nzaman Feb 27 at 17:43
• @nzaman That'd turn the user into a human barbeque, yummy. 1000 degrees Celsius and counting. – Mephistopheles Feb 27 at 17:44
• If I had the recipe for what you are asking I would not post it here, but would start an auction among the world armies, and then retire on a secluded island. – L.Dutch Feb 27 at 17:58
• (a) I'm not sure what you're asking. Are you looking for an automated solution during combat? Are extra plates expected to be towed in a cart behind the soldier? (b) VTC OT:POB because there's no way to choose between "a 9-year-old runs behind him, sliding in new plates" and "new plates are grown from a liquid stored in a tank on his back." (c) Frankly, this question is odd. How is an M1 Abrams supposed to replace its armor in combat? (Answer: it doesn't, a repair bay is required for that). Carrying extra armor is a substantial weakness. – JBH Feb 27 at 18:16
• If the armour is only on the front, your enemy is may choose to invest in razor-sharp poisoned boomerangs. – Chronocidal Feb 28 at 13:03

There are two ways to go with this. The way it SOUNDS like you're asking for is for your powered armor to carry an entire second set of ceramic plates all the time can be swapped in and out while you're fighting. I think this is a Bad Idea and I wouldn't equip MY armored minions this way. You're basically handicapping your troops by adding all that extra weight which basically kills your "interfere with other activities (shooting and running) as little as possible" criteria the moment they put the armor on.

The way that I think makes sense is to have support units embedded with your infantry so that as armor gets too damaged to continue those guys fall back just enough to get out of the heat of battle and have their plates swapped out by a quick-change system, and then go back to fighting.

There's all kinds of ways you can do this depending on how rapidly you want to turn around an individual soldier. The quickest way is to have a 'combat medic' who's embedded with your squad who carries a couple extra sets of plates, so your troops can just fall back just out of the thick of the fighting, have the plates replaced using the medic's special toolkit, and be back in the fray in a few minutes.

A more efficient way if you're envisioning brigade-level rather than squad-level combat would be to swap entire squads in and out of combat. This is a VERY old way of doing things that goes all the way back to Greek warfare where pitched battle was a process of constantly cycling your tired guys at the front of the formation back so they can get a drink of water and rest up for a bit while some fresh troops hold the shieldwall against the Persians or the Gauls or whoever.

In this scenario your squad would fight as a unit till they'd taken sufficient damage that they couldn't maintain anymore and then a fresh squad waiting behind them would move up and the damaged squad would fall back to an APC or something out of range of the thickest fighting and have all their damaged plates replaced at once, along with whatever medical attention was required.

In fact, there's no particular reason you couldn't combine both approaches. That's how I'd do it, if it were MY armored minions.

• As a secondary support you can make the armor plates all standardized so the armor can move plates from low risk areas to high risk areas as the fight goes on and plates are damaged/lost. this makes armor less all or nothing but something that can be replaced just by picking up a package of new plates, just like picking up a bow of ammo. – John Feb 28 at 17:35
• So to avoid downtime of shooting and running by swapping out your own plates you are proposing that the soldier leave the battlefield (practically) completely to find a "medic" to swap the plates out for them? How is that more efficient? – JeffC Feb 28 at 21:32
• @JeffC It's a weight issue. A 10" x12" plate of ceramic the US army issues to its soldiers weighs between 4 and 8 lbs. It's not light. Someone has to carry it. Falling back to drop the plate out and have a new one slipped into place has far less of an impact to the fighting soldier than to carry an additional 20 lbs of ceramic. Ever try running with a brick in your backpack? A brick weighs about 5 lbs. Running, crouching, throwing, jumping, all with a rifle is already tiresome. To have someone else hold onto the extra weight who isnt doing all that keeps your soldiers as effective as possible – Stephan Mar 1 at 14:54
• @JeffC it's more efficient because the only soldiers that are impacted by downtime are the ones who actually got shot, and only for the time it takes for someone else to swap his plates, as opposed to having every single soldier in your unit be less effective 100% of the time. You say 'leaving the battlefield completely', but that's not what I'm describing. I'm not talking about a soldier taking a couple hours to go back to base and get refitted, I'm talking about a soldier taking ~15-20 minutes to fall back a couple hundred yards or get behind some nice solid cover. – Morris The Cat Mar 1 at 14:56

Like sharks replace teeth.
The plates can be put on the armor in an overlapping scale pattern, with one plate visible, and another above it, protected by the overlapping scale. If a scale takes a hit it slides off, and the new scale automatically slides down into place. The broken scale can then be gathered and repaired, then put into the replacement slot.

Depending on the size of the scales you could end up with gaps if someone takes multiple hits in the same area, but if they are small enough then the gaps won't be too big.

• I dunno dragon skin kinda sorta... flopped. – Mephistopheles Feb 27 at 18:02
• @Mephistopheles Similar concept, different execution. Dragon skin was meant to be flexible, and worn by a human. These plats would be attached to a rigid surface, and carried by a powered armor suit. – AndyD273 Feb 27 at 18:10
• @Mephistopheles Also, Dragon Skin flopped (and Pinaccle Arms bankrupted) because of the second shot test, the plates and idea worked great....until high temperatures were involved. At 150C, the glue holding the plates caused adjacent plates to fall off prematurely, leaving large gaps in defense. – Anoplexian Feb 27 at 18:47
• @Anoplexian Take note, would-be-answeres, DON'T use glue to secure the plates! – Mephistopheles Feb 27 at 18:53
• Oh, well, that's good. Mine doesn't involve any glue. – AndyD273 Feb 27 at 19:54

The same way modern soldiers swap their ceramic plates: the plates are all inserted into kevlar pouches in the kevlar vests the soldiers wear. When they get shot, the soldiers pull the broken plate out of the pouch and put a new one in.

• This... is not about powered armor? The question is "How my powered armor do stuff in place of my soldier" not "How my soldier do stuff that he probably hasn't time to". I think you could have the start of an answer if you replaced "soldiers" by "power-armor", but this only adress the overall design, not the replacement mechanism, not the constraints of the question. – Nyakouai Mar 1 at 9:14
• He asked how powered armor can quickly, reliably, and energy-efficiently replace its plates while remaining sturdy, lightweight, and with minimal impairment to the soldier wearing its' mobility, and I gave the solution that modern, non-powered armor systems utilize - if you added a powered mobility exoskeleton to them like the ones the US Military is developing underneath the kevlar and armor plates, you'd have a suit of powered armor that would function in the method that I specified. Sure, it'd be more Call of Duty Advanced Warfare than Warhammer 40k, but it'd still qualify as "power armor". – nick012000 Mar 2 at 10:04

Plate powder.

Your soldiers carry plate powder. Dry, it weighs very little. If a plate breaks, tear a new fabric pocket off of your roll. It has the right amount of powder in it already. Add water, shake and seal, then lay it flat. The new plate sets up in a minute like fast-set cement or plaster of Paris, expanding slightly in the process.

Soldiers will have water with them. Used water, if nothing else.

• That's a bit hard to do in the middle of combat. It could be a good "between engagements" option. – ShadoCat Feb 28 at 1:32
• @Shadocat - If you rigged it so it did not need to be flat to set (for example some sort of fibrous scaffold) you could do it in combat. Discard used plate, add water to new pocket and clip it in wet. – Willk Feb 28 at 1:48
• It would have to be a pretty fast set time to be useful. Though, even with a moderate set time, it would be better than nothing. – ShadoCat Feb 28 at 2:00
• @ShadoCat There's a self-repair mechanism for ceramics, it works under a minute but requires 1000 C° to happen. Link in the question – Mephistopheles Feb 28 at 11:23
• How do you "lay it flat" in the middle of combat? How do you prevent other impurities from getting in there or other factors like humidity, temperature, etc. affecting the process? – JeffC Feb 28 at 21:35

Use a physical, arm mounted, ceramic shield. It can have layers of ceramic plates that are designed to be ejected after taking a hit.

The shield just needs to be thick enough to take the hits needed to get you into attack range. Then you can drop it for greater mobility on your attack.

When not in active combat, the shield can be stored on the back which will make it less cumbersom to carry and protect you from sneak attacks.

Let's take an example from nature - specifically Skin and Nails.

Each Plate consists of several alternating layers of Ceramic (for strength - or perhaps goethite?) and Rubber (for shock-absorption and adhesion)

At the back of the plate is a sheet with lots of holes in. Alternating holes exude 1 of 4 different liquids: 2 of them mix & react to form a Ceramic layer, and 2 mix & react to form a Rubber layer. By pumping the liquid out, you push the existing layers forwards and form a new one behind them.

Cracked ceramic plate layers slough off - you can have microscopic electrodes around the edge that measure the electrical impedance to determine if layers need to be replaced/regenerated on that specific plate.

• Using bio-mimicry, but not quite that specific -- if the plates were chained together such that a broken tile fell out and others slid over, you'd only need to be able to manufacture new plates from a few points (possibly located to to the rear) rather than over the entire surface. – Joe Feb 28 at 16:14

Graft the plates on a carbon nanotube mesh behind it. Given fine enough it would keep the majority of the ceramic plates in place. A bit like gluing linen against a wooden shield. While the wood splinters the fabric holds it together far longer then it would without it.

Holding the plates together makes it easy to remove them as a whole. They could use a magnetic locking system. Easily removing them and slipping a new one in place. This of course isn't automated but down with the help of squad members.

• Automating the release is dead simple, this way. Replacing one could be a simple slide in and snap affair. A retractable scaffold could swing and grab a tile and plug it in or a shuttle could grab a tile and drop down to the proper row and ride along a track built into the tile holder rows to reach the gap. Then it just has to snap it in. (I'd store the spare tiles in neat rank echelon on the back, myself, and replace those with the repaired ones, at least by default. You hopefully won't need a full second set with this scheme, and you'd get some extra armor from the rear this way.) – The Nate Feb 28 at 10:12

How about the plates are aligned in several columns on the body and each can slide down into the place of the plate below it. When plates get to the bottom of the suit, they slide around to the back and go up a chute inside the suit behind the wearer's spine.

If a plate takes a hit, the whole column slides down, around to the back, and up the chute until the damaged plate reaches the "reforger" inside the chute, where it is reforged. All the undamaged plates that pass through just pop out the top of the suit and immediately slide into a column that has room for it (usually the one they just came from).

A column of plates would basically be a chain of armor, and even while it's sliding down it's offering protection everywhere except where the damaged one happens to be at the moment.

• Welcome to the site Jakutz52, please take the tour and read up in our help centre about how we work: help center . Good first answer, +1 – Chickens are not cows Mar 1 at 1:06

Potentially you could have the armour made up of a rows and columns of smaller ceramic plates all around the body (looking almost like an array of pixel on the armour). Each column could be mounted on a rotating belt. As one plate is hit, the row rotates around the body of the wearer, moving the damaged plate to a 'recovery point', where the plate is removed, replaced with a new one and collected for repair.

• Wouldn't the impact destroy the belt if it has no overlapping to spread the force? – Mormacil Feb 27 at 18:05

To go along with the scales idea, since you don't need back plates, make the plates easily attachable to whatever backing fabric is holding the armor. Then you can swap out a dead plate with a new one when it breaks. If you make it so that when scales break, the vast majority of the scale falls off, it's easier and faster to change. Carry the extra plates on your back to swap out, and/or keep a pouch or box around that has backups.

This kind of repair would interfere with movement, but it could also make for some really interesting tense scenarios. It would be like healing in a battle royale game, in the middle of a firefight. Also makes it possible to miss a scale repair and make yourself vulnerable.

Could also make modular armor, with different kinds and sizes of plates that can be hotswapped quickly. If a shield breaks, eject that module and load/attach a new one. This can make it harder to have backups available, but if they use a universal mounting mechanism, you can find all kinds of different modules in the world, depending on the setting.

• There's a size limit on how small a ceramic tile can be before becoming more and more weaker, though, ala Cobham armor. – Mephistopheles Feb 27 at 18:08
• And how do I load? – Mephistopheles Feb 27 at 18:13
• @Mephistopheles Loading would depend entirely on whatever method of attachment you end up going with. If it's like, a ceramic plate attached to a piece of plastic (or carbon fiber or something), you can have it click into place on the backing fabric/harness. Or velcro (not good for longevity), or some other fastening method. When I was imagining it, I was thinking little zipper pouches that you can just slide a new plate into, but that is pretty unwieldy and clunky in the middle of combat. – Jorgomli Feb 27 at 18:36

Temporary patches to cover weak spots and crumble away after an hour or two.

Provides protection while the damaged spot can self repair and patch provides additional protection while still in place after repair in direction of fire. Patches can be bulky and double thickness to be flexible and fit on any armour segment. You only need as many patches as you expect to take hits in any given engagement.

Use back scratcher to slap patches where you cannot reach easily.

You're missing the point of armour, and of soldiers.

### Soldiers die

Basically, that's their job description. Go places, kill other people, and if you're unlucky then get killed yourself.

A soldier does have a money value, of course in terms of the training they've received and perhaps the equipment they're carrying. Which leads onto...

### Armour only needs to be as good as the value of the person it's protecting and the risk they're taking

Back in the days when wars were fought with swords, kings had the best armour. For a long time though, the guys running an army haven't themselves been in the fighting, so they simply haven't needed that kind of personal protection.

Body armour has become cheaper these days, but it's still only practical for some applications, and for use on some areas of the body. It's technically possible to build better body armour, but it would cost more than the value of the soldier wearing it. Unless on average it gives you better fighting ability for the same money, it really isn't happening.

• I might agree with this in a historical context but modern militaries will provide the same armor for those who cost \$44,887 or those who cost \$340,000 and we spend millions on body armor (pg.113-116). In business personnel is a huge cost - in the military personnel is a huge cost and keeping them alive is worth an equally huge investment. So your not wrong - you just have no idea how much a military member is worth – JGreenwell Feb 28 at 0:50
• There's also the PR cost to consider. Harder to recruit or keep your men from going AWOL if there's a 90% death rate. – pipe Feb 28 at 13:22
• JGreenwell Sure, they have a value. But are they worth "perfect" armour? At the moment what they have is more like "good enough for not too much cost". It's easy to spend millions when you have hundreds of thousands of people to equip! – Graham Feb 28 at 22:46

Random idea: like biology repairs broken skin, but faster.

Plates have small reservoirs of liquid epoxy-like goop held under high pressure, this epoxy-like goop is defined as curing at low pressures. Once the outer shell of the armor plate is breached the high pressure reservoir will vent epoxy-like goop, which will then quickly solidify as it escapes into the lower external pressure.

At the end of the battle these armored soldiers would look like crap, literally, but that's of secondary importance and could make for some moments of barracks humor.

I don't see why you would want that. There's plenty of time between battles to repair your armor (replace ceramic plates), and getting hit in the same spot in the same battle is tiny. Taking a headshot is a bigger risk (easier to hit than a degraded part of armor, and more dangerous).

No army uses robotic arms to repair armor in real combat now, and there is a reason for that. If your world doesn't differ from the real one (similar tech level, no magic, etc.) why would you expect a different result?

Is the goal simply healing of the armor?

If so, I agree with @nzaman and say repair, rather than replace. Gluing back together the broken plate is going to be weaker, but if the glue is strong enough, it'll result in the plate breaking in different places the next time. (and it's the breaking that matters -- absorbing energy in the process).

If the plates were in a teflon-lined kevlar pouch, you could have a system that injected an adhesive that could set up and take the shape of the pouch (without sticking to the pouch itself too much). You then just need a pump and a series of tubes and valves to direct the glue to the pouch. (although, I'd run this on the outside of the armor -- it'd suck to have it glue something else together). You might also be able to use something that was two-part to cure, or require a catalyst (heat, UV light, moisture, etc.)

With some better technology, it might be possible to encapsulate a glue so that when the plate breaks, it releases the adhesive automatically in the correct location that it's needed. You might need something to hold the plate together while it curses (as you're not adding volume) but you could use shape-memory metal wires around the pouch that holds the plate snugly while it's curing.

You still have similar mechanics -- there's a limited time window in which a second well-placed shot would be deadly.

I can imagine the ceramic plates being small, likened to a fish scale pattern. The velocity of a bullet will hit a small ceramic plate and the momentum will push it inward (perhaps it's attached to a spring). The damaged plate will come into contact with a hot plate within the armor suit, and will pop out when done and repaired - what are the chances of getting hit in that same exact spot twice in a row?

Or more fancily, it falls back into the suit, but a lever/spring system pushes another plate to fill the gap (like Iron Man style, or there is a system in place that detects light and moves the new armor piece to replace that spot). Alternatively, this system could work using gravity - the extra armor piece sits on top of another piece, and when the damaged piece falls within but out from underneath the extra piece then gravity will pull the new piece of armor downward immediately.

Give your troops the ability the request drop-pods that fall slightly ahead of them that they can step into and has robotic arms that can remove and replace plates that it detects as damaged. Moravec's Paradox should be less of a problem here because you can give them a spot to stand on and each arm has one plate to replace that's right in front of it.

Bonus points for extra cover, replenishing other stuff (Ammo, batteries) and being usable by multiple soldiers.

Bonus bonus points if the pod can also melt-down and reforge plates so it has unlimited stock.

You could also give them thrusters so they can execute a rudimentary "Jump" forward when requested after the troops have advanced past them (Might save your army some budget).

Stick a turret on them to provide some fire support or give them an armory to allow the soldiers to change loadout depending on the battle situation.

They could also hold medical supplies and understand how to cauterize/treat wounds (This gets a bit Moravecian).