Sci-Fi armour

[Roondar]

I've been wondering about something.

See, in modern times armour (for tanks etc) is rarely just one material. Modern tanks have multiple layers of differing materials to enhance their protection, leading to weaponry that could penetrate meters of steel yet not always get through current defenses.

However, most Sci-Fi I've seen suggests that armour is made out of single 'do all' materials - that act out all the functions of armour in one.

I've been wondering about two things really:

1) is such armour always depicted as being good at all things armour is (i.e. does it function like sandwhich style armours of today?)
2) is there Sci-Fi where they actually do use armours more like today's stuff and if so, why?

I know it's an odd thing to wonder about but it really seems to me that most Sci-Fi writers just chalk up armour as unobtanium and be done with it ;)

[Cocytus]

I don't know much about fictional armor outside of Star Trek, really. At least any examples of armor that are well thought out, instead of simply being an uber material.

Modern reactive armor is typically a sandwich of metal and either explosive material or a non-energetic damper material. Ablative armor, typical of combat oriented Starfleet vessels, reacts by sloughing off in response to heat, as in the heat shields on the space shuttle. Ablative armor should be a nonmetal, since metals with high melting points, like tungsten and osmium, are also incredibly dense. Carbon is an ideal material for an ablative armor, having a very high melting point (around 3800K, higher than either tungsten or osmium), as are ceramics and chemical foams.

The drawback of either type of armor is that it is susceptible to the other's intended application. Metallic reactive armors would be more susceptible to directed energy, since metals have lower melting and vaporization points, and nonmetal ablative armors should be more vulnerable to KE penetration due to their brittleness. Ideally, a do-all armor would be a non-metal with a high melting point coupled with a high modulus of elasticity, enabling it to endure greater deformation in response to a kinetic impact without permanently deforming.

I know, as per Quark in "Business as Usual," that reactive armor is certainly still in use. The weapon he was selling, the Breen CRM-114 (a cheeky reference to Stanley Kubrick) was expected to cut through reactive armor in the 6-15cm range, as well as shields up to 4.6 gigajoules. Star Trek reactive armor has apparently come to encompass functions of both reactive and ablative armor. This is probably due to the fact that projectile weapons are much more common for ground battles than for starship combat. As far as I can recall the only projectile type starship weapon was the isokinetic cannon from "Retrospect."

[l33telboi]

2) is there Sci-Fi where they actually do use armours more like today's stuff and if so, why?

Mass Effect does. For the exact same reasons we use composite armor today.

[Jedi Master Spock]

Having read through an enormous stack of WH40k and BTech materials, they also describe layered armor with different substances.

Honestly, I think most of the time we just don't have a very detailed technical description of sci-fi armors. There are usually only a couple "foundational" super-material substances involved, but for all we know, they're being backed/sandwiched with something else.

[Thanatos]

However, most Sci-Fi I've seen suggests that armour is made out of single 'do all' materials - that act out all the functions of armour in one.

Well, for a number of them it could actually be that they are made out of multiple materials and the specific combination is referred to by a single name. You see that IRL with things like Chobham and Dorchestor.

[Roondar]

Well, if all this is true - wouldn't that make yield calculations on armour hits pretty much a no-no?

I mean, proper armour will be optimized for whatever purpose it has. That is to say, armour of ships that mostly spew energy weapons will be optimized to be as sturdy as possible against that, armour of vehicles mostly hit by kinetic weapons will be optimized against that...

Heck, if it's sandwhich style it becomes very hard to determine anything worthwhile - just because the outer layer is kinetic blocking means nothing about the inner layer which happened to be ablative, etc.

[l33telboi]

Well, if all this is true - wouldn't that make yield calculations on armour hits pretty much a no-no?

Most calculations are far too simplistic. Rarely do they distinguish between kinetic and thermal energy (which they definitely should), but even apart from that, things like duration (how fast is the energy delivered?) and surface area are hardly ever mentioned.

[Jedi Master Spock]

Well, if all this is true - wouldn't that make yield calculations on armour hits pretty much a no-no?

Most calculations are far too simplistic. Rarely do they distinguish between kinetic and thermal energy (which they definitely should), but even apart from that, things like duration (how fast is the energy delivered?) and surface area are hardly ever mentioned.

Hey, I talk about surface area all the time. It certainly came up in "Minefield" when we were examining shuttlepod hatch resistance.

Armor calculations in general are something you have to leave a wide margin of error on based on variance in the model, but you can get to general ballparks that way - or rule out figures pretty well if you know what sort of materials are involved.

[l33telboi]

Hey, I talk about surface area all the time. It certainly came up in "Minefield" when we were examining shuttlepod hatch resistance.

I was talking more about my experiences at SB, not here. Yes, you do mention all the things I pointed out in my previous post.