accessory cord break tests

[robinia]

Today I got some splices tested. Mostly out of curiosity and also because I found out there is a lab on campus that can break them for me and I couldn't resist!
I tested several accessory cords and ropes that I have been using and was curious how they would test out in tensile strength. Many of these were made from salvaged rope ends or splices that didn’t turn out. For this reason most of these are NOT properly spliced following standard instruction. Most of these splices DO NOT have the required bury length and several ropes have been disassembled before being spliced. These are only being used for non-critical rigging or other rope tools and are NOT suitable for climbing/ life support.
Some pretty interesting results. The 16 strand especially floored me.

All the test ropes were pre-tensioned to 20 N. Force was applied @ 1cm/second.

The raw data files are available for anyone interested in seeing them.

Cheers!

 

[robinia]

I tested 1/2" 16 strand Yale XTC Fire, 1/4" amsteel, old dirty 3/8" tenex single carrier, Poison Hi-vy cover (no core), Sherrill 5/16 pruner cord, and AllGear HT Loop Line 7/16"
I also pulled on some BranchSaver but it wasn't budging!

 

[evo]

How did you splice the branchsaver? brummell, locked?, buried? and you said that the ropes were pre loaded can you explain this? What was the load limit of the machine? Thanks for sharing, surprising results for sure. If I had more time and $$ for breaking I'd love to experiment with some ideas.

 

[robinia]

The BranchSaver was just spliced with 3 brummels on each end and a 5" bury. When testing it was just too stretchy. The machine only has a 4' stroke and the BS seemed to stretch almost 75% with no sign of breaking. The machine is also only good for 50kN so it probably couldn't break it anyway.
I definitely developed more respect for these things as cables!

 

[robinia]

The tech suggested the pre-tensioning. I guess it's just used as a baseline to measure the elastic elongation before they break.

 

[TreeLogic]

well, the best part about seeing all of those is that they all broke in the middle, and not at the eyes/splices, well except for the pruner cord. which i'm guessing broke at the end that didn't have locking brummels?

 

[TreeLogic]

how did you feel about the avg result robinia?

 

[Tom Dunlap]

Thanks for taking the time in the lab and sharing the results here.

I liked seeing where the ropes broke and what the break looked like.

 

[evo]

Thats good to know! thanks for answering my questions and posting the subject. I just installed some branchsaver and was concerned about doing the recommended 5 brummells so I also added a bury of 12"+ it seemed like a cleaner splice.

 

[bonner1040]

Did Ian do this testing for you Rob? Great data!

 

[RajElectric]

Which campus?

 

[rob.shawlukavsky]

I got this done at my work - university of Guelph, Ontario


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[rob.shawlukavsky]

Anyone have any ideas on how the 16 strand tested so well with such minimal buries?


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[robinia]

Those last two were from me.
Still figuring out Tapatalk...