How strong would chitin armor really be?

[Jub]

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Reading your post, my mind jumped to making composite bone armor out of five layers. Maybe something like:

wood --> tightly knit cloth --> bone --> tightly knit cloth --> wood

The cloth would be soaked in glue and used to bind the wood to the bone. Then the innermost layer of wood could have cloth or fur padding, or the user could wear a gambeson underneath their armor. In a nation with very poor quality metal, but skilled smiths, one might also rivet an outer layer of copper over the outermost layer of wood.

This would end up being fairly bulky, but it would probably beat pure bone as or very poor quality copper as an armor material.

[Sea Skimmer]

This would end up being fairly bulky, but it would probably beat pure bone as or very poor quality copper as an armor material.

You are thinking the right way about this.

I think you'd only want the cloth on the inside for a weight economical approach though, because its not goign to be effective in thin layers and two thick layers of it seems excessive.

Key thing is, many systems will work for armor, the goal is of course to get the lightest and cheapest one for the amount of protection provided. But that doesn't mean another system won't work, or indeed work well. And about all of this was and is determined by chance and experimentation with informed ideas (computer modeling is still... lame... at this sort of thing)

We discovered ceramic armor because someone in WW1 shot steel plates that happened to be painted in ceramic paint, and on the scale of 8mm rifle bullets that made a real different to penetration. But modern ceramics are rather different! Also this means dinner plates are realistically useful as armor.

Another option to think about. Bone-Wood-Bone, all bonded together. The outer bone slows down the hit, the wood spreads the impact while absorbing more energy, and then hopefully the inner bone is now able to outright stop the hit without cracking at all.

[Jub]

This would end up being fairly bulky, but it would probably beat pure bone as or very poor quality copper as an armor material.

You are thinking the right way about this.

I think you'd only want the cloth on the inside for a weight economical approach though, because its not goign to be effective in thin layers and two thick layers of it seems excessive.

My thinking with two layers of cloth is that it would hold things together after an impact hard enough to break your layers of wood and bone. It might turn out to add extra bulk for very little effect, but I'd certainly test both if I was ever to test this idea.

[Sea Skimmer]

It'd depend on how good of glue you really had I suppose. Thing is if you glue all the fabric together tightly it won't perform as well, the fibers won't move to absorb more energy over length. They'll behave more like a solid and cleave through. Fiber armor is generally quilted together rather then solidly bonded. Hard plates are then bonded only to the surface of this fiber matrix. We need some pretty advanced glue to make that work. Ye olden times had some impressive glue, compound bows are amazing, but I'm not sure you could use that to make a glue that will strongly bond, but not penetrate into the fabrics.

[Jub]

We're rapidly hitting the limits of my knowledge in this area, but my best idea would be to dip your cloth in wax and then scrape away small sections in a pattern. That way, hopefully, the glue will stick to some areas while leaving the rest of your cloth supple and free to move. If that doesn't work I have no idea what would get the desired effect.

[Sea Skimmer]

Well one other approach would be to integrate those soft layers into an overall inner and outer shell of fabric joined around the bottom edge of he helmet, and sew all the hard plates into one sort of tight fully wrapped bag. That would have environmental and durability issues to solve concerning getting it wet, but its not out of the question.

[Jub]

You could probably deal with the wet by tarring over the soft layers with pitch or sap. It would be sticky and a pain to carry, but if you used a liner between your head and the inner layer of cloth it could be made wearable. Like all these ideas it's not the most practical, but if it was all you had...?

[Sea Skimmer]

I think a worth its own post is what is the criteria for making armor effective?

Maybe that isn't a shocking idea to anyone, but its worth thinking about to make the thread more useful. I have mentioned that protection is probabilistic. While I have also mentioned certain armor pieces may behave as if they have 'hit points' just ignore that. Its seldom true of overall armor systems on a specific person or vehicle in a realistic context of one battle. The enemy shouldn't be able to hammer on one spot over and over again to exploit this problem without the armor user killing them in turn. More or less, the armor system should be engineered such that the hit points don't matter.

It's context in the span of campaign meanwhile such accumulated damage can be merged into the probabilistic rating. The probability that armor was already damaged vs. any single hit simply modifies the probability that the armor mattered at all. Tough shit for the people who die, but welcome to war.

Gaps meanwhile simply always exist. The probability of one being hit doesn't change, against a given weapon. If you have a lot of gaps the maximum value of the armor is always strongly reduced. Very small gaps may have no relevance as no enemy weapon can fully enter the gap, but that's a tall order for technology like sewn together bone. Arrowheads are small things.

Armor will always end up with certain weak points, if only at say the joints and face (as was obtained with ultimate metal armor suits). The quest of the armor designer is not to fully eliminate them with a goal of making the user act like a videogame character with an armor rating, but to minimize them to the point that the enemy cannot specifically target them, or at least has a very hard time doing so. That can be enhanced by the user knowing his weak spots and more strongly protecting them. You want the weakness to be something the user can manage, not dread.

Swords evolved heavily in Europe as part of this quest, reacting to changes in armor, generally evolving into finer points and more thrusting styles. Less probability of a hit (stab vs slash) but increased chance of effect given a hit.

Near the end of the sword the shift was radically towards big swords that could combat pike weapons, as the pike became so important defensively that the swordsman couldn't get at the armor at all. That kind of design spiral is where you expect a weapon to die out.

Since both user ability to carry armor and user ability to carry weapon are finite one can seek ultimate standards on this for a given tech level, but they will not be ones of total resistance or totally effective offense. Vulnerability and countermeasures are always going to exist. The armor designer wants to force the enemy into countermeasures which are tactical and training, rather then simply issuing a better weapon to negate the armor completely. Tactical and training skulls are more variable, less reliable, easier to counter with your own training and tactics in the field.

Probabilistic protection for an army also means sometimes more armor isn't good. For example if we could double our mass of armor for 30% more protection, defined as the probability a successful enemy hit does not cause a incapacitating wound or death, but that doubled mass of armor means the enemy can score 50% more hits (because our guys move slower, get tired faster) then we have actually lost effective protection. Simple, but frankly I see this idea utterly ignored all the time. It isn't easy to quantify for random scenarios so people don't want to think about it in interweb debates. Yet without such considerations nothing makes any damn sense. It also points to certain truths. Such as full suits of European armor and European swords simply could not be excessively cumbersome. It doesn't matter what numbers you put on it, because its just a reality that if they were no army using them could survive combat. The test of long term combat is proof enough of this.

So the reality should be that the excessive armor argument should never matter, because nobody should be dumb enough to try it more then once. Humans are very good at judging risk based on observation. The trick is not to die before you can do so.

So as far as bone or whatever armor goes what this means is that the armor will be useful, until it isn't. But as far as I can tell on history the trend has been that even crappy armor is just about always useful compared to no armor. Even bad armor will probably eliminate a lot of enemy ranged and area attack weapons, and on a less quantifiable level it encourages troops to take more effective offensive actions, which further reduce losses compared to hesitation in the enemy field of fire (melee is all the same on this even if your field of 'fire' is a five foot sword swipe). You have to get pretty damn bad before your armor is actually going to cause you to take losses above the baseline; though inclement weather and long distances can modify this.

We did see an era in Europe when armor was barely being used in the late gunpowder era. But even there the reality really was more economic then armor sucks. Basically armies got bigger and bigger, rapidly, and this made the cost of armor with limited value much harder to afford for such large armies. So armor was totally dropped in favor of moving faster and arming more total troops. But that doesn't necessarily mean armor wouldn't have still been useful. Look at how much bayonet fighting went on if nothing else.

So how effective is the armor? Well who are you fighting and where? What is the other option? And that is where durability concerns come into play too because if your defending a small Greek Kingdom you can put up with a lot less durable gear then if you follow Alexander the Great to Persia. If you are rich you can put up with less durability then if you are poor. That hasn't gone away either Modern kevlar type vests usually only have a warranty period of about four years. The fibers DO degrade. This is why so many armies still don't issue body armor, and of those that do many use less then the best possible fibers. Zylon armor was completely removed from the market because it proved to have lower then projected durability. This was no small loss since at the time (2005) it had more then 50% greater strength then armor grade Kevlar (the stuff used for say canoes is about the same chemically, but spun into bigger yarns and with more flaws) and was superior to any other product available.

[Sea Skimmer]

You could probably deal with the wet by tarring over the soft layers with pitch or sap. It would be sticky and a pain to carry, but if you used a liner between your head and the inner layer of cloth it could be made wearable. Like all these ideas it's not the most practical, but if it was all you had...?

Probably be wearable yeah. Just a nightmare to dry out if it got wet. An outer layer of well oiled leather might solve the problem, though leather that does get wet will shrink, which might crush the helmet.

Rule of thumb though is humans don't much mind helmet weights up to about 3.5lb, and find over 5-6lb to be unbearable for long periods. So you don't have a lot of mass to work with for a five layer helmet. Modern military helmets are about 3.5lb but they also have to support the weight of night vision gear. Football helmets are a very similar weight.

[Jub]

Probably be wearable yeah. Just a nightmare to dry out if it got wet. An outer layer of well oiled leather might solve the problem, though leather that does get wet will shrink, which might crush the helmet.

Rule of thumb though is humans don't much mind helmet weights up to about 3.5lb, and find over 5-6lb to be unbearable for long periods. So you don't have a lot of mass to work with for a five layer helmet. Modern military helmets are about 3.5lb but they also have to support the weight of night vision gear. Football helmets are a very similar weight.

The entire idea of trying to make a workable composite helmet using things like wood, bone, and cloth feels like a nightmare already compared to just banging out some steel plates.

The leather idea might work, you'd make an oversized leather case for your helmet that cinches closed before the helmet is worn. If your helmets gets wet and starts to dry during a battle there isn't much you can do, but if you can make it to the end of the battle you loosen the case and solve the issue.

[LaCroix]

A slight addition to your pretty good analysis, it's not bone, but tusk - Boar tusks are VERY dense and hard, and in no way compareable to bone.

http://gems.minsoc.ru/eng/articles/ivory/

IVORY, BONE

IVORY (Elfenbein—Ivoire—Кость слоновая), BONE (Knochen—Os—Кость) There is also description of following types of bone, used in jewelry – dentinal ivory and bones of vertebrates.

Composition & Properties. This is a biomineral formation of the group of the corneous materials. Calcium hydroxyl phosphate in the composition with an organic substance. Amorphous. Hardness 2-3, for tusks of mammoth and mastodon – up to 5. Density 1.7-2.0; for tusks of mammoth and mastodon – up to 3.0. Dull luster. Non-transparent. Dentinal ivory: 1) Tusks – elephant’s tusks, mammoth tusks, mastodon’s tusks, wild boar’s tusks, bear’s tusks, dog’s tusks, hippopotamus’s tusks, narwhal’s tusks, tiger’s tusks, walrus’s tusks, wolf ’s tusks; 2) Teeth – white bear’s teeth, cachalot’s teeth, sea cow’s teeth, crocodile’s teeth, elephant’s teeth, hippopotamus’s teeth, horse teeth, mammoth teeth, shark’s teeth, and others.

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Wild boar’s tusks can reach 24 cm. long. For adornments they use bear’s tusks up to 5 cm. long, too. On Alaska polar bear’s tusks served as cash; on New Guinea they used dog’s tusks for the same purpose; and on islands of Southern seas – wild boar’s tusks. Hippopotamus’s tusks are known among bone carvers under the name of sea horse ivory. Their length is 12-15 cm., their weight reaches 1-3 kg. In Japan there are popular trinkets, which came from China; they are called netsuke, from “ne” – root and “tske” – to attach. They are intricately cut figures from ivory, horns of the deer, buffalo horns, wild boar’s tusks, as well as bear’s tusks, wolf ’s tusks and tiger’s tusks and other dentinal ivory . After a while, the assortment of materials for netsuke got wider.

Boar dusks are amongst the most dense teeth known, so they certainly rank with elephant - Hardness up to 5, density ~3. This makes it quite effective against bronze age weaponry (Hardness 2-3) - after all, it was used for 700 years.