# Could a non-newtonian armor coupled with a dampening fabric stop bullets but not melee weapons and arrows/bolts? [duplicate]

In a futuristic setting, nations have invented a way to create armor just a bit heavier than cloth. This would be worn like chainmail and would be available widely. I am looking for a way to make this somewhat realistic and avoid deus ex machina as much as possible.

• Would it be plausible if this armor was made of a non-newtonian fluid that reacts well to bullets (up to a certain thershold), coupled with a dampening fabric to absorb most of the impact of the bullet?

• Could melee weapons be effective against such an armor? Wouldn't the dampening fabric defeat mauls, maces or warhammers?

If possible, I want this armor to be effective against bullets, but much less against melee weapons and heavier projectiles like bolts, arrows or darts of any sort.

My hypothesis would be that scientists have a created a non-newtonian fluid or jelly, that "hardens" very well at the energy spectrum of typical bullets. However, it does not "harden" enough for lower energies (melee weapons, arrows, bolts,...) or extremely high energies (railguns, coilguns,..).

Keep in mind, this is the future (we are talking centuries ahead, possibly millennia). Therefore, these melee weapons can be far from primitive (rocket hammers, chainsaw blades,...) but we are focussing on mechanical melee weapons here. There are such weapons like light sabres (based either on plasma or laser technologies).

I have created this separate question in response to this one because conversations tended to go towards the feasibility of the armor instead of towards the main subject. This question is NOT about the feasibility of using melee weapons over ranged, please refer to the linked question for that.

## marked as duplicate by sphennings, HopelessN00b, pluckedkiwi, Rob Watts, SPavelMar 19 '18 at 23:25

• This is already a topic of research and the BBC article linked in the Wikipedia page is nearly a decade old. While this hasn't panned out yet it's entirely plausible that it could. en.wikipedia.org/wiki/Dilatant#Body_armor – Myles Mar 19 '18 at 16:35
• Not a full answer, but in regards to melee weapons, armor (of any kind) stops things piercing you, but doesn't stop the impact force - hence the emergence of maces, clubs and other blunt impact weapons in the middle ages when knights began wearing sword-proof armor. – Skyler Mar 19 '18 at 19:07
• Perhaps in your future world warriors don't try to kill enemy warriors with bullets or melee weapons but try to overpower them and capture them for various purposes. – M. A. Golding Mar 19 '18 at 19:39
• Since you seem hellbent on doing this in spite of the two threads telling you it's not realistically possible, why not just handwave it away? You could do something like the Mass Effect force-fields that handwaved away activating for a (relativistic) bullet, but not sitting down onto a chair, or getting chewed up by a Thresher Maw or whatever. – HopelessN00b Mar 19 '18 at 19:42
• It sounds to me like you may be asking the wrong question, or at least, too specific of one. Is there a specific reason it must be armor? I would think that what you want is any plausible plot device, material or otherwise, that makes firearms impractical. Don't know if you're going post-apocalyptic, but here is my answer for a similar question: worldbuilding.stackexchange.com/a/61674/23150 It's a bit less prone to plot holes, especially baking into the history of the world. If you like it enough to accept/upvote, please tell me so I can adapt to your version of the future. – automaton Mar 19 '18 at 22:27

If possible, I want this armor to be effective against bullets, but much less against melee weapons and heavier projectiles like bolts, arrows or darts of any sort.

Here's your problem: Whether or not it's possible to design armor that can resist bullets but not melee weapons or archaic ranged weapons, bullets that mimic the impact properties of bolts, arrows or darts already exist. For example, saboted darts that can be fired out of standard firearms have been around since the 1960s:

Now, according to this article, a 500 grain (unit of mass) arrow traveling at 220 feet per second is suitable for hunting, and the author states is both heavier and slower than most conventional broadhead arrows. If the objective is for armor to resist light, fast projectiles but not heavy, slow ones, this is probably your perfect weapon. The 10gr dart pictured above is not equivalent.

But let's consider shotguns. A typical shotgun load is 1-1/8oz of buckshot (492 grains) or a 1oz slug (438 grains). So, a typical shotgun load already delivers the same mass as the entire arrow being recommended above, it just has a suboptimal projectile type. The flechette design is not optimal here, since it has very low mass, but a pointed 1oz slug would give weight and cross-sectional area comparable to a broadhead arrow. The main difference would be that instead of a measly 220fps, it flies at around 1800fps.

If the armor has properties such that a heavy, pointed, slow-moving projectile can penetrate it, an equally heavy, equally pointed, much faster moving projectile is going to absolutely ruin your day. And this is something that can be fired out of any off-the-shelf smoothbore shotgun with no redesign needed.

If you want to get more specialized and purpose-built, let me introduce you to the APS Underwater Rifle:

This is, for all intents and purposes, a 20th-century dart thrower.

As far as ballistics are concerned, it doesn't matter whether a projectile is being propelled by a human-powered system or by chemical means. We typically use blunt, lightweight, very fast projectiles in firearms because those are ballistically superior for our common purposes, not because firearms cannot effectively propel pointed, heavy, less-fast ones. If there exists a human-powered system that can pierce a given piece of armor, it's guaranteed that you can design a chemical-powered system that can do the same more effectively and from longer range.

If a spear will work, so will a speargun- so who's going to carry a spear?

• @Hawker65 If the non-Newtonian handwave sets an upper limit on velocity that is right at the speed of an arrow (call it 300fps), well, there's nothing stopping you from loading a shotgun shell to only produce 300fps. It will still be longer-ranged, easier to aim, and considerably more effective than its archaic equivalent. – Catgut Mar 19 '18 at 14:09
• Your first picture got me an idea how one can smuggle caviar. – Alexander Mar 19 '18 at 16:21
• @Hawker65 But where is all that energy going? You're converting an arrow into a hammer. I think a better approach is to look at it as a sweet spot between stopping something from penetrating the armor, and not getting your insides liquefied. – Thebluefish Mar 19 '18 at 17:49
• @Alexander There's a meme floating around about how in America, the trick to sneaking candy into a movie theater is hiding it in the clip of a pistol. – thanby Mar 19 '18 at 18:27
• If a spear will work, so will a speargun- so who's going to carry a spear? Well, people who need ammunition for their spearguns, of course. – HopelessN00b Mar 19 '18 at 19:36

Would it be plausible if this armor was made of a non-newtonian fluid that reacts well to bullets (up to a certain thershold), coupled with a dampening fabric to absorb most of the impact of the bullet?

You can bet that researchers have thought the same thing, and have tried various formulas, and -- given that the impact plates which get put behind Kevlar vests are ceramic instead of a n-N fluid -- have failed to find one that works. (Remember that these vests must be thin enough to allow mobility.)

Wouldn't the dampening fabric defeat mauls, maces or warhammers?

but much less against melee weapons and heavier projectiles like bolts, arrows or darts of any sort.

Pointy objects pierce the Kevlar and whatever is holding the n-N fluid in place.

Remember also that armor-piercing rounds are:

1. small,
2. fast, and
3. pointy.

And bolt- and arrow-tips, and darts are... small, (relatively) fast, and pointy.

Bottom line: your story scientists will have to develop a n-N fluid.

• Yes, that should be what created the armor, the development of a n-N fluid (or jelly) that effectively stop bullets. – Hawker65 Mar 19 '18 at 13:57

Your bigger problem is to come up with a scenario/setting where melee isn't even a consideration, but is able to become a consideration very quickly. Armormakers are going to protect against the threats they see as likely, and unless there's some onus against people being within melee range of each other or lack of appropriate melee armor material, they're going to give the n-n armor a backing to prevent melee stuff.

Enough of the science is there to project that we will be able to produce a fluid that will effectively split and roll an impact around the torso. You just need the proper setting to allow that to be the only consideration.

• Do not worry. This question is related to a video game project and the player will be able to take additional protection in the form of plates to protect himself better against ballistic/plasma/laser threats. – Hawker65 Mar 19 '18 at 15:05

The armour would work in such way that the more force is pushed against it the more it can withstand.

So as in some Sci-Fi - the force field is using projectile force to sustain itself. When you shot plasma and laser the force is working. When you lightly push some small object the field don't have enough force to stop it.

Second melee weapons. You mention blunt ones. Which are not made for penetrating any armour. Just to crush everything that is beneath it. So armour would not be pierced (main purpose of projectiles).

Then you have slash/thrust/pierce melee weapons. Only in thrust/pierce the force is applied 90 degrees against armour. In slashing the force goes over an angle so the weapon would need to be long enough to cut through armour and then go against wearer. Kind of like cutting cheeses with short knife.

BUT - the spear/rapier could have such small point of impact that it would fit between molecules of the armour fluid. So you don't push any stress on the material itself just push it away.

To address any future ideas - yes the bullet would be stopped. Yes, the XVI century cannonball would be stopped too but the amount of force it would apply on the wearer would crush his bones and internal organs.

So to sum up: from .22 to 15 mm bullets would be stopped. anything bigger just crush wearer. Blunt melee weapons would work in similar way - club or hammer would be stopped but anime mace would impose a problem. Sharp melee weapons - would work if PoI is small enough to go through weave. Slashing would work if applied in sharp angle and for time long enough.

• This armour is supposed to stop any small arms fire (anything under 20mm), but the impact could still have some stunning, non-lethal effect. Someone also suggested to coat the melee weapons with a special material that would "decompose" the armor on contact, which would be great for slashing weapons. What do you think of this? – Hawker65 Mar 19 '18 at 13:23
• Creating "acid" melee weapon would lead to wondering why there are no ammo that carry the same load. So instead of hollow point bullet you fill it with this "decompose". Like in modern antitank weapons. – SZCZERZO KŁY Mar 19 '18 at 14:12
• Yes but there is much more exposure time during a melee slash than with a simple bullet impact. – Hawker65 Mar 19 '18 at 14:14
• In time yes. But then you just need to concentrate acid or speed up it's reaction by adding catalysts. Or even better use the armour fluid as catalysts. IMHO adding something that "eat up armour" would end up in question "why not just shoot the hing that eat up armour?" – SZCZERZO KŁY Mar 19 '18 at 14:45
• Because I think you would need dedicated acid rounds and shoot a good amount of them to effectively reduce armor in a given area, then switch to normal bullets hoping you hit the now vulnerable area. – Hawker65 Mar 19 '18 at 14:53

One of the issues with this question is the rather ridiculous overmatch that firearms provide. Similar questions in Worldbuilding reveal that arrows shot by longbows can generate up to 100J of impact energy, and steel crossbows (drawn by some sort of spanning mechanism) can deliver 200J. An Arquebus from the 1400's can deliver 1000J of energy, an order of magnitude difference.

While humans have not become much stronger since the 1400's, firearms technology has advanced by leaps and bounds.

From the Atomic Rockets "Boom Table"(First column =energy in Joules):

Joules          TNT equiv   Ammunition
8.0  × 10^1     0.019 gram  .22 short round
4.75 × 10^02    0.114 gram   9mm Luger Parabellum round
5.2  × 10^02    0.124 gram  .38 Special round
5.4  × 10^02    0.129 gram  .45 ACP round (Colt M1911)
9.4  × 10^02    0.225 gram  .357 Magnum round
1.4  × 10^03    0.335 gram  3.5 g AK-74 bullet fired at 900 m/s
1.56 × 10^03    0.373 gram  .44 Magnum round (AutoMag)
1.82 × 10^03    0.435 gram  5.56mm Remington NATO round
2.05 × 10^03    0.489 gram  7.62mm Soviet AK-47 round
2.56 × 10^03    0.612 gram  .30-30 Winchester round
3.3  × 10^03    0.789 gram  9.33 g NATO rifle cartridge fired at 838 m/s
3.47 × 10^03    0.829 gram  .303 Lee-Enfield round
3.74 × 10^03    0.895 gram  .308 Winchester round (7.62x51 NATO round)


So except for the smallest handguns, the energy is going to be more than a human being can deliver in a hand held melee weapon, and it is being delivered in a smaller point and at a faster impulse time than a human can deliver the energy. To put it another way, you can certainly kill someone by shooting them in the head with a .22, but punching them in the head is far more likely to result in a set of broken knuckles for you.

So the short answer is that any effective armour against small arms is by default protection against virtually any muscle powered or hand held weapon as well. And since the people who make armour are not stupid, if there is a threat of things like stabbing weapons or icepicks being used against the target, they will weave or impregnate or add some sort of stab resistant layer. Even things like "Strike plates" over the most vulnerable part of the body can serve double duty, a metal or ceramic plate proof against the energy of a 7.62 X 51 NATO round can certainly stop a knife blade rather easily.

The only way to get around this is to look at real history. As armour became perfected towards the end of the 1400's ("Proof" armour is proof against gunshots, you can often see the dent in museum pieces where armours "proved" their product with a pistol or arquebus), and fluted or curved pieces deflected strikes by bladed or smashing weapons away from the user; long, narrow stabbing swords were developed to stab through the joints or gaps in armour.

Medieval Armor German Gothic Cuirass with Tasset

If this protection needs unarmored spaces at the joints to allow movement, or is "quilted" to prevent the fluid from leaking or draining to the bottom of the armour, then certain areas may exist where a very thin, extremely stiff, pointed blade might like an "Estoc" might work. (In the real world they evolved into rapiers and short swords)

Estoc. These are actually quite long and heavy

So except for particular situations (like an ambush), or living in a setting where carrying swords is acceptable civilian dress, people in armour are almost certainly going to be protected against both melee weapons and firearms.Modern police riot gear should be a positive demonstration of that.

Come at me bro

And Modern soldiers take this up to "11"

• As I mentioned, melee weapons don't have to be primitive. There are plenty of futuristic upgrades that can be made (jet hammers for example) which would significantly improve the stopping power of melee weapons. Carry all the plates you want, if a hammer hits you harder than a truck, I don't think your plates will be of much use. – Hawker65 Mar 20 '18 at 9:44
• And carrying around something like that is going to be less conspicuous than carrying an Estoc? The first impulse I would have seeing someone carrying that would be to check my firearm, then scan to see where other people are situated before preparing to engage beyond melee weapon range. – Thucydides Mar 21 '18 at 5:16
• This would be a battle weapon. Just like great swords in the Middle Age, this would not be carried around out of battle. – Hawker65 Mar 21 '18 at 8:28