Does testing rope strength weaken it?

[Woodwork]

Thanks for your reply, JeffGu. I was hoping you would weigh in on this since you were so helpful on my "Roof Job" thread. I ended up making four roof anchors like those you mentioned in that thread...would like to figure out a way to leave them up there for future work, in fact...

 

[Bart_]

To the original title/question: loading a rope to its breaking strength constitutes the one cycle to failure data point. Running 10 or 20x less than that load turns the rope into "huge number of cycles before any possibility of failure". So depending on the rope's history, you are dipping into its unknown durability reservoir by doing the test. Per an earlier post, a sort of statistical sample can occur by break testing a sample off perhaps one end of the rope. So, short answer, yes, strength testing the rope does cause damage by using up some of the cycles to failure, worsened by how hard you test the rope.

take care

 

[Woodwork]

Thank you, Bart. Exactly what I was looking for.
(Unfortunately, the parts of the rope I'm concerned about are in the middle, rather than the ends, so I'd probably need to cut the rope in half, then cut the end off one of those halves for testing.)
Jeff

 

[JeffGu]

Jeff Gu returns from the hinterlands...

Thanks bro. Lots going on. I've been short on time and long on headaches.

 

[oldoakman]

Thanks bro. Lots going on. I've been short on time and long on headaches.

I understand.