# Why would a suit of armour need power to provide protection to its wearer? [closed]

Why would electricity be needed to provide protection to the user of a suit of power armour? I'm not referring to the movement or any other systems in the armour. I mean, if the user gets shot, stabbed or otherwise physically attacked power is used & needed by the armour to protect from this attack. Why would this be the case? There is near future technology. It can't just be energy shields.

• VTC:Needs-Details. We need to convert this from an off-topic infinite list of things to an on-topic finite list of things. As written, there's no way to judge wither "because you need headlights" is better or worse than "you need electromagnetic shielding!" Please remember that fishing-for-ideas questions don't work well here. If you think about it, this is also a classic off-topic high concept question. Oct 13 at 16:37
• Specifically, I would appreciate some details about what kind of soldiers would be using the armour and under what circumstances. Oct 13 at 18:20

Your armour functions like ERA In Space

ERA usually stands for explosive reactive armour, a subtype of reactive armour. Currently seen on tanks, ERA comprises of explosive blocks that detonates outwards to counteract the impact of a weapon. In the case of ERA, the energy is already pre-stored in the explosives. However, your power armour could function as electric reactive armour instead, as described in the Wikipedia article linked. The external layers of your armour would be constantly electrically charged, and require a power supply as a result. Your suit of armour could also use a directed energy solution like lasers or a cutting torch directed outwards as a form of active protection system to intercept incoming attacks. Naturally, those would also require power to function.

Just as importantly, behind the aforementioned defensive systems, there are computers running software that govern their function and are necessary for their operation. Unsurprisingly those also require power.

• But of course. So lame to wait in space like a lame duck for the incoming to hit you and only then engage in a momentum transfer transaction. Why, now you can be reactive like a rocket! Oct 13 at 12:45
• So something like this: en.wikipedia.org/wiki/Trophy_(countermeasure) Oct 13 at 22:03

Electroshapable material

Electroshapable material is material that can be shaped when an electric current is flowing through, while rigit otherwise. The inverse of this also possible, but I can't find the correct word for it. It is experimental and not for use in body armour, but with near future technology it might be possible.

The idea is simple. You want your soldiers to have as little obstruction in manipulation. Soldiers need to manipulate the environment, like moving from one wall to another, aiming or pulling the trigger, to be effective soldiers. Enter the inverse electroshapable material. It's flexible when there's no current through it, giving maximum mobility to your soldiers. But on impact this can change. The impact of a bullet will start pushing the material. If the pressure is high enough a circuit will be completed, making the material rigit. All further energy of the bullet bill is canceled by the electricity.

Power armour might be more like bulky big suits of metal. Yet here it can still apply. It might look big and intimidating, but good inverse electroshapable material can seriously reduce weight and increase flexibility. Your armour is essentially electricity, though some wear and tear of the material is certainly to be expected.

• The word is piezoelectricity. It works both ways: bending the material produces electricity, while adding electricity makes the stuff rigid. Your answer is the same as mine :) Oct 13 at 12:09
• I just can't wait to try my GAU-8 pellet gun on them, I'll even load it with 30mm depleted uranium pellets. I'm sure the instant rigidity of the armor will play as nice as those trust inspiring rigid chassis of the cars before they invented the lame crumple zones. ;) Oct 13 at 12:38
• @AdrianColomitchi what's your point? Incredibly big weapons against people in power armour is effective? All armour can fail. In addition, the electricity can be ramped up with pressure, meaning you have a scale of rigidity as well as less or no effect if too little pressure is applied. Otherwise the armour would lock up with every movement. Oct 13 at 13:25
• @Trioxidane my point is that rigidity is a suboptimal choice, gradual deceleration is better. AK47 - muzzle velocity 700m/s, 7.62x51 - mass of 25.4g. Deceleration over 20mm by bullet deformation (rigid armor)=>311150N. Deceleration over 50mm=>124460N (say, hardening "ballistic gel" 50mm thick). In both cases, the body receiving it ain't going to stay put, it will be throw back by a "punch" of 6kJ. And AK47 is not what one would call a "big weapon". Oct 13 at 14:55
• @Nosajimiki because the question asks for electricity and in this future fantasy it works much better than non-Newtonian fluids. Thinner, lighter, stronger, easier to work into a suit of armour. Oct 14 at 2:38

The suit is made of hard stuff over softer padding, all mundane materials that do not need electricity because the same design has been in use since Ancient Greece. But it covers the body entirely, without any gaps or weak points. That means that it quickly gets hot inside. A vein system of coolant runs through the lower layer, just like modern space suits, but that system of course needs power to function.

You could wear it with an empty battery and be protected, but unless you are in Siberia, you would quickly suffer a heat stroke while doing so.

The armour is made of a revolutionary but not unthinkable substance that's soft like jelly for most of the time. It is barely a centimetre thick and fits over the wearer like a second skin, allowing for the same flexibility and range of movement as if the wearer had been in their birthday suit. It is covered in sensors that transmit sensations of touch, hot and cold to the skin underneath.

However, when an impact is registred by those sensors, an electric pulse is sent out and the jelly temporarily solidifies in a large region around the point of contact. This distributes the force over a large portion of the body, in a nigh-flawless manner. Once the impact has impacted, it liquifies again and regular movement can continue.

When the battery is empty, there's no current to harden the suit. Climate control would also fail without electricity. So without a full battery, the suit is generally useless.

• May I like the militarized version of P-5000 better, please? I mean, if I am to carry a battery, then let it be a BFB and power a lot more useful tools. Oct 13 at 12:15
• Why use piezoelectricity when you can get the same effect passively out of non-Newtonian fluids? Oct 13 at 21:57
• @Nosajimiki for reference youtube.com/watch?v=L5Ts9lYZIDk Oct 13 at 23:11

Air bags.

A problem with armoring a body against an impact is that the kinetic energy of the impactor is still transferred to the target. Frangible armor plates can absorb the impact but are then destroyed. Reactive armor meets the impactor with an outward explosion and is also then destroyed.

Car air bags deal with kinetic energy in a way similar to reactive armor - an explosion inflates a bag of gas which is compressed, absorbing the kinetic energy. Auto air bags are also one use defenses and must be replaced after use.

Your armor contains electric air bags. On impact by a hard surface (bullet, club) or shock wave (explosion), powered sensors deploy small air bags between the hard armor and the body beneath. These bags are inflated pneumatically and receive the energy of impact as compression, then deflate again. The compressed air charge held ready for inflation is renewed by electrical power but more importantly the detectors are electrical and without them the bags will not deploy.

The armor will still work as a barrier when unpowered. Without power, the person wearing the armor will still not get cut by an edge or penetrated by a bullet. But that person will get bruised, and will have little protection against shock waves.

• Better than what I've seen so far. But "air bag inflation" needs to be really explosive to deploy in the available time. That's gonna break some ribs anyway. Oct 13 at 15:01

The armor protects the wearer from damages by astonishingly quickly repairing the damages it has taken, so that, by all means, acts like a brand new armor at any moment. This thanks to the patented NoMoDa$$^{TM}$$ (No More Damage)

Of course, in order for this to happen, energy has to be supplied to the armor. Without energy it will quickly break and fail to fulfill its scope.

• I'd so much better like an armor that stops the bullet first than one that quickly repairs the hole left after the bullet passed through it. ;) Oct 13 at 12:08
• @AdrianColomitchi its fine. The armor has a hard time differentiating from itself and its wearer! it'll patch you up in no time flat (as long as its powered). Just don't think about the Ship of Theseus too hard. also, try not to scream as it will give away your position! Oct 13 at 12:20

## Polarized Armor Plating

In the near future, escalation in material science either made ballistic armor so good that militaries have to switch to energy weapons or energy weapons got so good that they rendered kinetic weapons obsolete.

To protect you from this new trend in high energy weapons, you need to magnetize your armor which would create a form fitting magnetic field around the user that will trap and redirect electrons, ions, and/or plasma around the user instead of hitting him.

Covering a solider in always-on magnets would pose all sorts of complications; so, instead the armor uses electromagnets to only polarize itself as needed.

While this may sound like just a variation of "energy shields" it is an actual technology that more or less exists today, we just don't have many practical applications for it since it is useless against kinetic weapons which is 99% of what we now face on the battlefield.

I don't know what exactly you consider 'near future technology,' but an armour could have its plates made out of a relatively flexible, ferrous material held in shape by electromagnets. Any dents or impacts are immediately counteracted by the magnetic force actively straightening the armour plate back out, requiring varying amounts of power. Alternatively, there's also an option of a material that gets deformed normally, but is able to form itself back into a predetermined shape and 'heal' when electric current is applied.