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Dynamic pendulum fall
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Lutze


Nov 6, 2013, 4:35 AM
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Dynamic pendulum fall
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My question is how the impact force is affected by a dynamic pendulum fall with slack, i.e how much force is transfered to the radial force.

Simple sketch:


I've checked the forum on previous articles related to this subject. But they just seem to go off-track after awhile. So I appreciate all input.


USnavy


Nov 6, 2013, 9:43 PM
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Re: [Lutze] Dynamic pendulum fall [In reply to]
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Lutze wrote:
My question is how the impact force is affected by a dynamic pendulum fall with slack, i.e how much force is transfered to the radial force.

Simple sketch:
[image]http://img13.imageshack.us/img13/2715/7kvm.png[/image]

I've checked the forum on previous articles related to this subject. But they just seem to go off-track after awhile. So I appreciate all input.
I am sure someone will come in and try to throw down some math and give you an answer, but the reality is there are too many variables in the real world to be able to accurately calculate it. The best option would be to test directly the question in the field with a load cell and find out.

If you are nearly on-axis, the pendulum obviously wont affect the load too much, whereas if you are completely horizontal with your pro, the pendulum will have a much larger effect on limiting the load.


juiced442


Nov 7, 2013, 12:11 AM
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Re: [Lutze] Dynamic pendulum fall [In reply to]
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just jump it and find out.Wink should hold


Lutze


Nov 7, 2013, 6:39 AM
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Re: [juiced442] Dynamic pendulum fall [In reply to]
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USnavy wrote:
I am sure someone will come in and try to throw down some math and give you an answer, but the reality is there are too many variables in the real world to be able to accurately calculate it. The best option would be to test directly the question in the field with a load cell and find out.

I was hoping there was a way to get a rough estimate. By using the kinetic energy, the angle when the line gets under tension, and energy absortion from the rope. Tried looking into viscoelastic theory for ropes, but I might aswell have tried speaking penguin.

Thanks for your input.

juiced442 wrote:
just jump it and find out.Wink should hold

Already done, calculated for the worst case scenario, but it's more fun to know things I guess:)


(This post was edited by Lutze on Nov 7, 2013, 6:45 AM)


amarius


Nov 7, 2013, 7:03 AM
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Re: [Lutze] Dynamic pendulum fall [In reply to]
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I'll try to put math together over the weekend.
UIAA published article "Behaviour of a mountaineering
rope under stretching during a climber's fall"
, it might give you some ideas

Say, here is an article intriguingly named "Viscoelastic Theory of Climbing Ropes"


(This post was edited by amarius on Nov 7, 2013, 7:09 AM)


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