Sideloading climbing rings

Discussion in 'Climber's Talk' started by robinia, Oct 30, 2017.

  1. monkeylove

    monkeylove Well-Known Member

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    I am also not a scientist lol. But Tony correct my thinking if it is wrong but in the redirect picture I think that the forces on the biner into the ring are only about 1/6th of the natural rope forces. Assumption is that almost 180 degrees give you 6 times the force and we are using that same logic in reverse. @Tony

    [​IMG]
     
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  2. New2trees

    New2trees Member

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    One thing that bothers me (from the little I know) is seeing the Aluminum rings that have failed without deformation. I think it would be a good idea if rings either steel or aluminum were spec-d of material with more toughness rather than strictly a maximum strength material, so that if you were subjecting them to excess stress you would generally see deformation before failure.

    Maybe someone in the field can chime in (as I may be wrong on the standards) but if the rating is strictly a strength before failure, then it would tempt manufacturers to use material with insufficient toughness to achieve a higher KN rating on a given part.

    I know this same thing holds true in racing car parts (this is where my background is) some brands of aluminum connecting rods [BRC] will bend at the beam before fracture where others [GRP] are more likely to simply fracture...The brands that deform tend to be favored by the blower cars as if you miss your tune-up you can often bend a rod on the first 4 second pass and find your problem...with the stronger rods it will not bend on the first pass but may fail catastrophically on pass 2 or 3 taking out the entire engine.
     
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  3. Tom Dunlap

    Tom Dunlap Longest registered member

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    New.

    Please elaborate on the tings that you've seen fail

    Brand
    Application for failure
    Pictures
     
  4. robinia

    robinia Well-Known Member

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    Tony,
    In your experience are these configurations totally untested, industry-wide??
     
  5. moss

    moss Well-Known Member

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    Everything I've seen, for example where an aluminum alloy carabiner is hammered to sideloading failure with the bottom of the biner in a vice, the aluminum bent quite a bit before the gate popped and finally longitudinal fractures started appearing in the biner. Point being a piece of hardware like a biner or ring needs a lever, fulcrum, and force to actuate enough bend to create failure. I'm not seeing all the elements required to do that in photos posted above. I suspect the fact that quality alloy carabiners and rings are forged creates favorable metallurgic qualities that resist a "snapping/breaking" failure as opposed to a fair amount of bend before side-loading failure. A poster above mentioned seeing a ring break, we all remember the Kong ring failures, this is a manufacturing quality control issue. Assuming you've researched and trust the manufacturer of your life support gear I just don't see the elements (lever/fulcrum/force) in the photos above to create side loading failure. The comments above are excellent, certainly there should be questions to manufacturers and focused testing on the anchor configurations we're using.
    -AJ
     
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  6. TheTreeSpyder

    TheTreeSpyder Well-Known Member

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    In many scenarios might not be as bad as seems.
    The ring itself will seek to find minimal loading position/angle;
    >> seen more when ring, then by extension any part of system is left to be free ranging in the soft connections.
    .
    Trapping to wood so can't self adjust to minimal loading, then tourquing would be worst i think
    .
    Force only builds, where it is resisted.
    Still good topic for 'metal magicians' (whisperers)!
     
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  7. New2trees

    New2trees Member

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    Hey my mistake. The tests I saw were on a bad batch of rings, not representative of rated rings in the industry. I looked for the thread but it seems the entire thread has been taken down, perhaps to protect the company that was accidently distributing them not knowing they were defective.
     
  8. Tom Dunlap

    Tom Dunlap Longest registered member

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    Are you referencing the Kong ring debacle?

    If so it seems to be a bit of a stretch to connect it to this thread
     
  9. hatchetation

    hatchetation Member

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    Last year I went down a nasty rabbit hole of researching aluminum rings- meant to share, but didn't really come to any satisfying conclusions so it went on the back burner. Might as well get it all out now, I guess.

    First - here's a mostly-complete list of Aluminum Rings on the market, with as many details as I could find. (There are a lot of weird Taiwanese rings on there, mostly because I was trying to nail down the OEM for a few brands.)

    Don @ SMC was more than happy to pull back the kimono and talk details from the point of view of a manufacturer.

    Yes, some products are made intentionally to deform before they break as a specific design feature (vs an intrinsic property of the material). Hollow aluminum rappel rings are meant to be semi-disposable and will intentionally oval after being exposed to a high load.

    SMC's 32kN aluminum rings are a bit of an outlier - they're machined out of 6061 sheet stock instead of being forged like most of the others. (DMM rings are also machined, but are 7075-T6 which is more typical.) I'm a bit foggy, but seem to remember him mentioning the stock being full T6 temper without a heat treat post machining. Personally, I like the idea of 6061 rings. Not an engineer, but 7075 seems a bit spookier with embrittlement and the possibility of faulty heat-treatments.

    Regarding direction of loading, this came up when I asked him about proof testing. Their rings are not individually proof tested, and he cited not knowing the ultimate loading configuration as one of the reasons. So, the manufacturers seem to know that people will be doing weird things with them.

    The best numbers I've seen on three-way loading of anything aluminum comes from Richard Delaney at RopeLab - sadly it's a members-only report behind a paywall: Three -way loading of carabiners.

    To summarize, "In November 2014, 34 aluminium carabiners of differing shape were placed in varying configurations on a slow-pull hydraulic test bed and pulled to destruction. ... Specifically, all of the tests with sling angles of 60° or less maintained 80% of the published MBS. ... these tests would suggest that it is appropriate to apply a de-rating of 20% to the MBS of aluminium carabiners for uses with sling angles up to 60°."
    I would be really shocked if aluminum rings did worse than carabiners, given their shape. Someone with slightly more experience could probably run the tri-loading numbers by hand assuming simple hoop stress.

    Wesspur was kind enough to pull a few rings apart for me, mostly because the manufacturer I bought them from seemed really dodgy, couldn't even report their basic specs consistently (25kN? 32kN?), I was hoping for embarrassing failure, and they were willing to help. 3 rings from 2 brands - all broke well above the MBS, and showed significant deformation. The failures look nothing like any of the failed ring pictures I've ever seen online. (If there's interest I'll upload em.)

    I wish there was a complete post-mortem from those old terrible rings. My money is on a total failure of heat treat or similar + abysmal QC, assuming the manufacturer even knew they were making something intended for climbing - I don't think anything more specific was ever released, at least not publicly.

    Last point - just a reminder in case anyone is tempted to buy the cheap stuff - there are no real safety standards for aluminum rings, only a few standards they might fall under depending on the application. They don't fall under EN 362 (because they don't open, so they're never going to be a connector), and in anchoring applications things are apparently pretty murky too. Gotta trust the manufacturer to trust the ring I think.

    Fortunately, the market seems to have really expanded. I count at least a half-dozen reputable brands selling rings these days, get the impression it wasn't that way before.
     
  10. moss

    moss Well-Known Member

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    Awesome info Hatchetation!

    Good to know DMM machines (as opposed to forging) their rings. Also good that you pointed out that rap rings are hollow, don't think any arborist climber would attempt to use a rap ring as an anchor component but good reminder that they exist.

    Tree climbers are amazingly resourceful and innovative, we're going to push the limits on every piece of gear we use or re-imagine. That pursuit requires experience, solid knowledge and some kind of intuitive physics mixed with a healthy dose of self-preservation. As a result many of us are going to be smartly skeptical and at the same time respectful of aspects of safety standards. That doesn't go over well with many in arboriculture who have to do the battle to raise the safety bar. It's a tension that will always exist.
    -AJ
     
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  11. adaycj

    adaycj Member

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    First I want to say that I love these conversations. I think we can evolve as a group involved in a risky endeavor if we share our thoughts and info. Thank you for sharing Hatchetation.

    People will often flock to the highest MBS, or some property or claim such as a the numbering of the material (ie 6061), or one type of test as the reason one product is better than another. In every case I have ever seen, and I've looked at as many as I can find, those things had nothing to do with a failure. The only failed rings I have seen or heard verifiable stories about were either obviously severely worn, or seriously deformed already. The one outlier being the poorly handled Kong mess. All of this despite the fact that there are many hundreds of vendors selling likely untested, unmarked, "unrated" rings. Many of those vendors likely don't even know the manufacture of their product.

    I agree with your statement "Gotta trust the manufacturer to trust the ring I think.". With single point of failure = death type of stuff I try to hedge my bets as much as I can. I buy from a known vendor I "trust". I buy a brand name that is known and I trust. I don't know what else to do because I can't test these things myself. At least a known vendor with a known product has a financial stake in the quality. As an example DMM knows it will cost them if their rings start popping a low loads and killing people, as do the other major players.

    For myself, I'd never buy a Kong branded product. It's not only because they had a failure of a simple product that shouldn't have failed. It is because of the way the problem originated and was handled. Years later we are all still wondering about the real facts.
     
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  12. robinia

    robinia Well-Known Member

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    This is great dialogue. I'm really happy with the info being shared here.

    Now that TCIA is done- did anyone get to hear the info Tony presented??
     
  13. Tony

    Tony Well-Known Member

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    Sorry for the delay. Travel and all. Give me a day or three, I’ll post some of what we delivered.

    Tony
     
  14. Tony

    Tony Well-Known Member

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    DISCLAIMER: THESE ARE NOT SCIENTIFIC TESTS! BEWARE OF DRAWING TOO MANY CONCLUSIONS BASED ON SUCH A LIMITED SAMPLE SIZE AND THE VARIABLE CONDITIONS this is simply tree guys and gals asking questions and having the opportunity to break stuff

    Here are a few of the configurations that were failed.

    All in all the numbers exceed acceptable limits. The idea was to see where the failure happened There was roughly a 30% decrease in anchor strength when hardware was introduced into the system. The knot slipped through the two ring friction save at a very low load. If you do this make sure you put a carabiner in the loop. One ring and ring configuration slipped at a very low load (not included in video)

    Conclusions: adding hardware generally decreases strength. The choice of knot is important. Relying on published knot strengths is not valid if they are loaded in different ways/directions. Use good judgement.

    Tony
     
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  15. Ty Ratfield

    Ty Ratfield New Member

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    I was doing a lot of digging around about aluminum rings at one point. What I found said that (can't remember if it was milled rings or milled and forged) they will deform way before they fail. You'd pretty much have to keep using a jacked up one to get it to fail. Unless you are purposely trying to break them I'd imagine.
     
  16. Tony

    Tony Well-Known Member

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    Rated hardware will always outlast the cordage. It is not the individual components that are of concern, it is how they are configured into the system/anchor.

    Tony
     

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