On Tue, 12 Jul 2005, Dennis Crawley wrote:

> Mike Hord, just mention the rope.
>
> I'm trying to figured out a mathemathic model of the rope when a climber
> falls.
>
> I have the mass, the spring, and I feel aplying Hooke and Newton laws I can
> solved but I have a lot of little obstacles like spring constant when the
> rope has a dynamic elongation of 33,1%, like "bluewater accelerator 10.5
> rope".
>
> Well,... I'm working on that, any help on math is well come.
>
> Dennis Crawley.
> ps: I've download "Rope System Analysis" by Stephen Attaway,... looks good
> but he doesn't state the system in Transfer words. (In/Out)

I think that you will find that the rope absorbs a lot of energy as it 
elongates. Using just Hooke's law and energy will not get you anywhere. 
Get a sample of the rope and put a weight on it and see what damping 
coefficient it has (probably very large). Then I heard that some ropes 
have a different damping depending on whether they are elongated fast or 
slow. Besides bungee jumping and parachute related devices I cannot 
think of other uses for this, so maybe those communities (parachute, 
bungee) have the info you need. I also remember to have read that both 
modulus and elongation depend on whether the rope is wet.

Peter
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