A garage door opener was set up to rappel back and forth a thousand times to see how ropes are affected by rappelling. (Result: the rope is less robust, but the single pull to failure did not break either the rappel rope or the control).
Drop tests were conducted on screamers to see if they limit the force on the rope. The simple answer is "not much." Initially the force is limited to that of the energy absorbing system's (EAS) deployment force, but the energy absorbed by the screamer is about the same as the additional kinetic energy introduced into the system as the screamer opens up. The resulting force is similar to the force produced by the control drop (no EAS present) and is highly dependent on the mass of the falling climber and other characteristics of the belay & fall. EAS are capable of reducing loads for short falls that occur near the belay. For the ice climbing community, the ability of the EAS to increase the duration of the impact and thus reduce the load rate is perhaps of greater importance than any small reduction in the load applied to the top anchor.
Students subjected cams in a steel crack to drop tests. Result: Cams placed in parallel steel cracks don't reliably hold falls (not enough friction). This project eventually lead to:
An Elastic Model of the Holding Power of Spring Loaded Camming Devices Used as Rock Climbing Anchors
Once there was a conspiracy with folks at Marlborough College in Vermont to construct a UIAA drop test facility to test climbing ropes. But this has stalled for lack of physics majors at Marlborough College.
More recently, work has been done in conjunction with the MIT Center for Sports Innovation.
Jon Graham and Marianne Okal fatigue cycled carabiners. Their work is available in Sports Engineering (2005) 8, 107-113.
Julio Payan built a rope modulus tester; it was never instrumented and no testing was done.
Steph and Warren tortured ice screws. A 16.621 proposal and a 16.622 report are available courtesy of the Open Courseware folks. The peer reviewed article has appeared in the proceedings of the ISEA/ASME 5th Conference of Sport.
Spiral back to Dave's home page.