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gyngve
Jul 30, 2006, 7:49 PM
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Registered: Dec 28, 2002
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Beal 8.1 mm IceLine:
Impact force: 4.9 kN (factor 1.77 fall w/ mass 55kg)
If clipped twin style, what's the Impact Force on a 1.77 fall w/ mass 80 kg?
(experimental data would be great, otherwise a physics analysis modeling the rope as an elastic spring. any reason why modeling as a linear system would be inaccurate?)
I have my own answer, but I don't want to corrupt anyone else's thought process with mine.
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gyngve
Jul 31, 2006, 8:03 PM
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Registered: Dec 28, 2002
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No one's biting. Fine. I'll post my analysis and see what people think.
Two ropes holding 80kg is like one rope each holding 40 kg.
A rope that has impact force of 4.9 kN on 55 kg should have impact force of 4.2 kN on 40 kg (scaled by sqrt(40/55)).
Two ropes of this adds up to a force of 8.4 kN, which is well within the range of how single ropes perform.
So assuming linear dynamics, clipping this specific rope twin-style is fine for standard rock pro.
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qtm
Jul 31, 2006, 8:48 PM
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Registered: Apr 8, 2004
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There was a thread about this on rec.climbing not long ago.
http://groups.google.com/...ead/52437834632549ce
As usual there's an insightful message from RGOLD. Probably a similar message somewhere here if you do a search.
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