Forums: Climbing Information: The Lab:
Dynamic pendulum fall
RSS FeedRSS Feeds for The Lab

Premier Sponsor:

 
 


Lutze


Nov 6, 2013, 12:35 PM
Post #1 of 5 (7582 views)
Shortcut

Registered: Oct 19, 2013
Posts: 4

Dynamic pendulum fall
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

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 7, 2013, 5:43 AM
Post #2 of 5 (7437 views)
Shortcut

Registered: Nov 6, 2007
Posts: 2667

Re: [Lutze] Dynamic pendulum fall [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (1 rating)  
Can't Post

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, 8:11 AM
Post #3 of 5 (7411 views)
Shortcut

Registered: Nov 1, 2008
Posts: 11

Re: [Lutze] Dynamic pendulum fall [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

just jump it and find out.Wink should hold


Lutze


Nov 7, 2013, 2:39 PM
Post #4 of 5 (7370 views)
Shortcut

Registered: Oct 19, 2013
Posts: 4

Re: [juiced442] Dynamic pendulum fall [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

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, 2:45 PM)


amarius


Nov 7, 2013, 3:03 PM
Post #5 of 5 (7360 views)
Shortcut

Registered: Feb 23, 2012
Posts: 122

Re: [Lutze] Dynamic pendulum fall [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

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, 3:09 PM)

 

Forums : Climbing Information : The Lab

 


Search for (options)

Log In:

Username:
Password: Remember me:

Go Register
Go Lost Password?



Follow us on Twiter Become a Fan on Facebook