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Post by RiftandRend on Mar 8, 2017 22:27:52 GMT
Why is nitrile rubber more mass effective than Polytetrafluoroethylene? PTFE seems far superior on paper. It has a 56% higher melting point, 3.5% higher specific heat while only having a 4% higher thermal conductivity. In addition to this it is twice the density and half the cost.
After some basic tests I have determined that 10 cm of PTFE lasts ~34 seconds compared to ~25 seconds for 10cm of Nitrile rubber. Nitrile lasts 24% longer with an equivalent mass which is bizarre considering how much better PTFE looks on paper. I was testing with the stock 100 MW laser against a 20 meter diameter flat target if you want to repeat my tests.
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Post by David367th on Mar 8, 2017 22:32:44 GMT
Why is nitrile rubber the standard cost effective anti-laser armor? Polytetrafluoroethylene seems far superior. It has a 56% higher melting point, 3.5% higher specific heat while only having a 4% higher thermal conductivity. In addition to this it is twice the density and half the cost. Through field studies rather than technical data. PTFE if I recall has no resistance to lase damage.I recalled incorrectly, Nitrile Rubber and PTFE have similar drill times for equal mass.
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Post by RiftandRend on Mar 8, 2017 22:50:38 GMT
Why is nitrile rubber the standard cost effective anti-laser armor? Polytetrafluoroethylene seems far superior. It has a 56% higher melting point, 3.5% higher specific heat while only having a 4% higher thermal conductivity. In addition to this it is twice the density and half the cost. Through field studies rather than technical data. PTFE if I recall has no resistance to lase damage.I recalled incorrectly, Nitrile Rubber and PTFE have similar drill times for equal mass. For equal thickness 10 cm of PTFE lasts ~74 ~34 seconds compared to ~25 seconds for 10cm of Nitrile rubber. Nitrile lasts 24% longer with an equivalent mass which is bizarre considering how much better PTFE looks on paper. I was testing with the stock 100 MW laser against a 20 meter diameter flat target if you want to repeat my tests.
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Post by Enderminion on Mar 8, 2017 23:41:27 GMT
I got 30 seconds for 10cm PTFE, 26 seconds for Nitrile Rubber, and more then 50 seconds for aramid fiber (I invalidated the test at 50 seconds) all ten CM with stock 100MW lasers
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Post by n2maniac on Mar 9, 2017 6:14:28 GMT
I don't really know.
I tried reasoning through it before, made hypotheses, tested them, and summarily dismissed my hypotheses. I just go on empirical data now.
I will point out that nitrile rubber will melt before it cracks whereas PTFE will crack first (based on ingame material properties). Aramid fiber and basalt fiber composite also melt before cracking (to a much larger degree I will note!), yet aramid is good and basalt is pretty meh. Graphite aerogel is one of the kings of this property, yet doesn't really do much (though arguably the thermal conductivity does it in).
*shrug*
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Post by The Astronomer on Mar 9, 2017 6:16:46 GMT
Remember the square law, if you use different size of objects the outcome would be different.
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Post by Rocket Witch on Mar 9, 2017 16:27:37 GMT
I think the styrene-acrylonitrile refraction index may be bugged like the silica aerogel one before it, after my expanded polystyrene lasted indefinitely under laser fire before I changed it. Rubber also produces unusual deep red sparks.
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Post by ross128 on Mar 9, 2017 16:37:23 GMT
I'm just going to go ahead and guess density. Because it looks like first you compare them at the same thickness, and there PTFE is better centimeter-for-centimeter, but when you match weights rubber is better gram-for-gram.
Well, I'd say the most obvious explanation is that the latter has a lower density, so 1cm of rubber just weighs less than 1cm of PTFE.
Which is also the same reason Silica Aerogel was the undisputed king of anti-laser armor back when it was bugged. Even back then, aramid fiber was better for the same thickness. But silica aerogel was far less dense, so you could take a much thicker layer at a lower weight and cost. It was able to make up the difference in volume.
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Post by vegetal on Mar 9, 2017 16:42:21 GMT
I still use SiGel on my missiles and they seem almost invulnerable to laser fire. Am I missing something here? Is rubber better in any way?
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Post by David367th on Mar 9, 2017 17:09:06 GMT
I still use SiGel on my missiles and they seem almost invulnerable to laser fire. Am I missing something here? Is rubber better in any way? For the same mass Rubber and SiGel are almost identical in burn time but Rubber is cheaper. However Aramid fiber being more expensive than both, has almost double their burn times. SiGel @ 100cm - Average burn about 55 seconds. Rubber @ 9.21cm - Average burn around 50 seconds. Aramid @ 7.295cm - Average at 90 seconds. Measured with a 95MW Ti:Sa UV Laser with all masses 1.31kt on a cone looking target, burning on the central axis. I actually found the threads where I showed off the data. Ok so really quickly got a couple tests done with Aramid Fiber v Silica Aerogel. Using an armor test bed similar to Jason's laser challenge. 100cm of SA was used as the mass baseline which when converted to Aramid was 7.295cm both sitting at 1.31kt, 717m/s dV, 51.3mg. The laser used was a 95MW stock revamp from the 100MW Violet laser used on the Laser Frigate, fitted on a revamped Solar Lance. Around the standard location for the sandbox, Herculina, the test bed was set to aggressive to fly into the Lance. Both initial and final velocities were recorded. The laser was focused on the central axis engine of the test bed, and ablated away, starting at 50km, while time between orange armor tiles to black armor tiles were recorded. Silica Aerogel1.31kt
113Mc
717m/s dv
51.3mg a Times Trial # | Vi | Time to black | Vf | 1 | 225m/s | 44.05s | 170m/s | 2 | 147m/s | 58.75s | 163m/s | 3 | 56m/s | 42.25s | 66.8m/s | 4 | 117m/s | 56.01s | 134m/s | 5 | 74.9m/s | 1:19.68s | 95.6m/s |
Aramid Fiber1.31kt 292Mc 717m/s dv 51.3mg a Times Trial # | Vi | Time to black | Vf | 1 | 51.4m/s | 1:54.18 | 86.5m/s | 2 | 103m/s | 1:08.24 | 120m/s | 3 | 62.6m/s | 1:51.93 | 93m/s | 4 | 130m/s | 1:42.44 | 151m/s | 5 | 150m/s | 1:19.17 | 171m/s |
Fancy imgur album of ships and lasers.Excellent data! Have you tried this with rubber yet? I've not yet tested nitrile rubber as a monolithic layer, only as part of a composite. Nitrile Rubber 9.21cm 1.31kt 45.1Mc 717m/s dv 51.3mg a Times Trial # | Vi | Time to black | Vf | 1 | 188m/s | 54.13 | 203m/s | 2 | 128m/s | 1:02.05 | 145m/s | 3 | 201m/s | 48.76 | 214m/s | 4 | 57.3m/s | 45.62 | 69.6m/s | 5 | 50.8m/s | 46.15 | 65.9m/s |
Looks as if it's slightly worse or roughly the same, whichever way you look at it, than Silica Aerogel for half the cost.
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Post by vegetal on Mar 9, 2017 17:15:51 GMT
Test object number 1 is going to receive a rubber coating soon. Gonna have to see this in action.
I know about aramid, but only use it on the tip of my biggest missile, it's way too expensive for that role. My capital's whipple shield is aramid though. It's pretty even...
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Post by vegetal on Mar 9, 2017 17:56:26 GMT
Current test conclusions: The AI is way too retarded in this game. I'm having to redesign my test laser ship in order to overcome the AI's dumbness.
It tumbles around in a random fashion in a futile attempt to dodge my missiles, up to the point the onboard laser cannot fire anymore because the missiles are outside it's firing arc. So it doesn't dodge, doesn't fire, and doesn't allow me to conduct a simple test. Giving it an MPD next to avoid this kind of bullshit.
But the nitrile rubber seems to be holding up. Test Object 3 is identical to my standard missile, just the outer layer changed. It has less than a single milimeter of rubber, and it looks like it's working. Which is kind of bizarre in my opinion.
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Post by targetx on Mar 10, 2017 1:29:32 GMT
Perhaps PTFE melts and flows away easier, whereas rubber chars, and thus isn't cleared away as fast as the PTFE
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Post by RiftandRend on Mar 10, 2017 4:34:14 GMT
I'm just going to go ahead and guess density. Because it looks like first you compare them at the same thickness, and there PTFE is better centimeter-for-centimeter, but when you match weights rubber is better gram-for-gram. Well, I'd say the most obvious explanation is that the latter has a lower density, so 1cm of rubber just weighs less than 1cm of PTFE. Which is also the same reason Silica Aerogel was the undisputed king of anti-laser armor back when it was bugged. Even back then, aramid fiber was better for the same thickness. But silica aerogel was far less dense, so you could take a much thicker layer at a lower weight and cost. It was able to make up the difference in volume. What I am wondering is why rubber is better per mass. It should be far worse unless melting point means nothing.
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Post by AdmiralObvious on Mar 10, 2017 5:00:26 GMT
Technically, a higher thermal conductivity would mean that the heat disperses over the surface area slightly quicker.
My rudimentary understanding of how that works says that even though the point of impact might melt, it disperses and reduces the temperature faster for anything not being directly hit by the lasing.
Depending on how thick the layer you have, it could lead to something more resistant to a total melt through than something with less thermal conductivity.
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