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Post by linkxsc on Feb 13, 2018 20:50:54 GMT
Exactly as the title says.
In any kind of gun you make in the game, one of the limitations of "Beam deflection stress". Which as far as I'm aware, is the stress on a beam supported at 1 or more points, caused by loads across the beam (usually being caused by gravity)
This parameter makes 0 sense to me, in a 0g environment, if only considering the gun. When you bring in the ship accelerating, and turrets turning quickly... I could see it being a relevant statistic, as a long barrel begin whipped around at 20deg/s and brought to a sudden stop... could cause some deflection problems.
But when calculating forces on the gun by itself, there should be no notable forces trying to bend the barrel.
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Post by AdmiralObvious on Feb 14, 2018 1:41:58 GMT
In the case of conventional guns the projectile, depending on the mass could theoretically bend the barrel as it started to reach the end of the barrel, mostly as a result of the propellant potentially burning unevenly.
As for coilguns, they're usually a whole bunch of separate pieces of coil, which can move around as a shot is fired, wether you wanted it to, or not.
Railguns, as far as I'm aware should be much less susceptible to beam deflection. Though, again that would depend on the mass of the projectile fired.
I'm inclined to say "recoil" would be the primary reason of deflection stress, and all guns most likely will recoil of some type as a result of throwing something with enough energy.
You should also factor in uneven forces going along the barrel as the shot continues to move. It's particularly relevant on metals with a low Yield, but a high total Tensile strength.
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Post by n2maniac on Feb 14, 2018 6:09:31 GMT
I was going to say the reaction forces of the projectile causing buckling stresses on the long tube of the barrel, but thinking harder that doesn't make much sense. The barrel is pressurized for conventional guns during firing (and roughly similar for a railgun's magnetic flux) and shouldn't have any tendency to bend (past typical asymmetries of the projectile and barrel). Maybe for coilguns?
Turning would require some strength, but not nearly as much as it requires.
Anyone else aware of what it is?
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Post by coaxjack on Feb 20, 2018 5:30:12 GMT
In a chemical gun, when firing, the barrel suffers from a phenomenon known as Barrel Whip, where the barrel does flex around due to the shockwave from the propellant exploding. In real-world small arms this can be seen at high frame rates, e.g. www.youtube.com/watch?v=_9ULBtsnkR0 There is a fairly well-established science to this, as pressure waves travelling through rigid materials is well understood. See more here: www.shootingsoftware.com/barrel.htmThe limits in the module designer probably describe a failure of the barrel where it permanently deforms due to the stress. An electric or magnetic gun probably has a similar fail state limitation, only the stress on the rails or coil armature are caused by hundreds of teslas of magnetic flux discharging at 2000 rounds/minute.
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Post by AtomHeartDragon on Feb 20, 2018 19:29:34 GMT
Well, a railgun's EM field can't really tell armature from rails either - all that really keeps rails from bending outwards or flying apart like a grotesquely large, electrically powered flak is their own sturdiness and barrel bracing.
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Post by linkxsc on Feb 20, 2018 19:36:34 GMT
In a chemical gun, when firing, the barrel suffers from a phenomenon known as Barrel Whip, where the barrel does flex around due to the shockwave from the propellant exploding. In real-world small arms this can be seen at high frame rates, e.g. www.youtube.com/watch?v=_9ULBtsnkR0 There is a fairly well-established science to this, as pressure waves travelling through rigid materials is well understood. See more here: www.shootingsoftware.com/barrel.htmIf it's caused by whip stress, then why is it not referred to as whip stress? Also, were that the case, why is it that I can't produce several real guns ingame, due to this stress? IRL barrel materials are generally subpar to the VCS we have to work with ingame, but yet the real barrels being significantly thinner than the ones we have ingame? For example try making a very real 7.62x39 gun, .50 cal M2, or a flak 88, or a 5in or 8in US naval gun. With correct powder and shot, you can get real world performance within a few m/s of muzzle velocity. But then you error out on beam deflections stress because your wall thickness isn't high enough? Unless you have a long list of guns with barrel total diameters more than 3x the bore diameter... while being made out of materials with yields in the 400-700MPa range as opposed to 5170MPa VCS.
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Post by coaxjack on Feb 20, 2018 20:05:23 GMT
Real barrels aren't made from monolithic materials, there's no options in-game for different forgings or heat treatment, or work hardening.
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Post by AtomHeartDragon on Feb 20, 2018 20:17:11 GMT
Real barrels aren't made from monolithic materials, there's no options in-game for different forgings or heat treatment, or work hardening. Or taper, or barrel fins, or multibarrel assemblies, or...
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Post by AdmiralObvious on Feb 21, 2018 7:25:42 GMT
Real barrels aren't made from monolithic materials, there's no options in-game for different forgings or heat treatment, or work hardening. You can fix almost all of that with the addition of a few mods. Then it'd be up to you to actually try and balance it out based on the production costs involved.
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Post by n2maniac on Feb 22, 2018 5:26:10 GMT
Real barrels aren't made from monolithic materials, there's no options in-game for different forgings or heat treatment, or work hardening. Modeling it as a uniform hardened steel barrel (say, as VCS steel) is equivalent to just specific parts being hardened by heat treatment as long as the other parts do not exceed their yield strength in real life. The stiffness of the steel does not change with temper, only its yield strength.
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Post by linkxsc on Feb 23, 2018 3:04:06 GMT
Real barrels aren't made from monolithic materials, there's no options in-game for different forgings or heat treatment, or work hardening. Modeling it as a uniform hardened steel barrel (say, as VCS steel) is equivalent to just specific parts being hardened by heat treatment as long as the other parts do not exceed their yield strength in real life. The stiffness of the steel does not change with temper, only its yield strength. And hardness, and toughness. But as we aren't calculating endurance loads (heavens forbid, half the railguns in the game would rent themselves asunder in a short burst of fire if endurance were considered) and barrel wear doesn't exist (Also something that would be a much larger problem for railguns than conventional)... both of those tend to not matter quite so much. And they also don't seem to matter much for penetrating targets either at least as implimented. (Using hard tungsten projectiles doesn't seem to show any notably better performance over soft aluminum shots)
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Post by Brackish on Feb 26, 2018 16:19:47 GMT
And hardness, and toughness. But as we aren't calculating endurance loads (heavens forbid, half the railguns in the game would rent themselves asunder in a short burst of fire if endurance were considered) and barrel wear doesn't exist (Also something that would be a much larger problem for railguns than conventional)... both of those tend to not matter quite so much. And they also don't seem to matter much for penetrating targets either at least as implimented. (Using hard tungsten projectiles doesn't seem to show any notably better performance over soft aluminum shots) At the usual railgun projectile speeds, hardness matters much less than momentum. Chemically powered guns should, of course, make use of armor piercing properties. One more thing for the list! In a chemical gun, when firing, the barrel suffers from a phenomenon known as Barrel Whip, where the barrel does flex around due to the shockwave from the propellant exploding. In real-world small arms this can be seen at high frame rates, e.g. www.youtube.com/watch?v=_9ULBtsnkR0 There is a fairly well-established science to this, as pressure waves travelling through rigid materials is well understood. See more here: www.shootingsoftware.com/barrel.htmIf it's caused by whip stress, then why is it not referred to as whip stress? Also, were that the case, why is it that I can't produce several real guns ingame, due to this stress? IRL barrel materials are generally subpar to the VCS we have to work with ingame, but yet the real barrels being significantly thinner than the ones we have ingame? For example try making a very real 7.62x39 gun, .50 cal M2, or a flak 88, or a 5in or 8in US naval gun. With correct powder and shot, you can get real world performance within a few m/s of muzzle velocity. But then you error out on beam deflections stress because your wall thickness isn't high enough? Unless you have a long list of guns with barrel total diameters more than 3x the bore diameter... while being made out of materials with yields in the 400-700MPa range as opposed to 5170MPa VCS. The barrel thickness issue you speak of is puzzling. Could 1 atm of external air pressure be enough to make up for the additional strength of a thicker barrel? I suspect not, but I'm not a materials expert. Edit: forgot to quote the appropriate post
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Post by AtomHeartDragon on Feb 26, 2018 20:33:55 GMT
And hardness, and toughness. But as we aren't calculating endurance loads (heavens forbid, half the railguns in the game would rent themselves asunder in a short burst of fire if endurance were considered) and barrel wear doesn't exist (Also something that would be a much larger problem for railguns than conventional)... both of those tend to not matter quite so much. And they also don't seem to matter much for penetrating targets either at least as implimented. (Using hard tungsten projectiles doesn't seem to show any notably better performance over soft aluminum shots) At the usual railgun projectile speeds, hardness matters much less than momentum. Chemically powered guns should, of course, make use of armor piercing properties. One more thing for the list! At typical railgun/coilgun velocities the impact details vary between resembling firing a squirt gun into a pool of liquid and firing a nitroglycerin squirt gun into a pool of liquid. Mechanical properties no longer matter.
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Post by linkxsc on Feb 27, 2018 4:15:13 GMT
At the usual railgun projectile speeds, hardness matters much less than momentum. Chemically powered guns should, of course, make use of armor piercing properties. One more thing for the list! At typical railgun/coilgun velocities the impact details vary between resembling firing a squirt gun into a pool of liquid and firing a nitroglycerin squirt gun into a pool of liquid. Mechanical properties no longer matter. Hardness was with regards the to projectile and the rails themselves and barrel wear, not penetration performance. Unless you mean for me to believe that most of the railguns players make regularly would actually work and not... shred themselves after a couple shots due to barrel wear.
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Post by Brackish on Feb 27, 2018 17:29:52 GMT
Your last sentence in the previous post was in reference to armor piercing. Barrel wear is a significant issue in the railgun research I've heard about (though not read), I guess it's just one more thing that's ignored for simplicity here? Or maybe lack of actual published knowledge... Though as I stated earlier, the 3x bore diameter barrel thing is a little puzzling.
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