Liebherr Orion crane failure under 5500t load test
Liebherr Orion crane failure under 5500t load test
(OP)
https://www.youtube.com/watch?v=tkdxhqGbGSI&fe...
supposedly the hook failed and boom slingshot over the top.
supposedly the hook failed and boom slingshot over the top.
RE: Liebherr Orion crane failure under 5500t load test
Apparently the hook block failed and what you see on the video is the crane jib flicking over backwards and given it wasn't designed for it collapsing at the mid point.
This photo shows it before and you can see the lack of rear flip capacity of the top half of the boom.
from here https://www.khl.com/international-cranes-and-speci...
The 5000 tonne capacity is clearly at minimum boom angle, but if it snaps then the whip back can't be avoided for high angle operation.
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RE: Liebherr Orion crane failure under 5500t load test
https://www.youtube.com/watch?v=6BJTLRfWocM&fe...
RE: Liebherr Orion crane failure under 5500t load test
Edit:
1. Equipment owned by Cosco. Not good timing considering the mass of inventory they probably want to move in a short time.
2. Amazing that the 4 point hook just snapped off. It is hard to tell how it was secured to the shaft. Perhaps some weldment failed or someone forgot shear pins.
3. I'm wondering if the hook assembly had some type of fuseable link designed to prevent overloading. Even so I'd think it would have a safety factor of at least 2 or 5.
4. Sorry, one more comment. The uncertainty of the load has to be a prime concern for a ship mounted crane to avoid capsizing. How could they not consider the reaction due to loss of load?
RE: Liebherr Orion crane failure under 5500t load test
One part is pivoted from a fixed member, in the illustration midway on the top of the machinery housing, and the other part is pivoted to the boom.
The two back stops look like hydraulic cylinders.
They may stop wind events but given the violence of this event they would not have helped.
The tower or gantry would have acted as a back stop, but the upward reaction was so powerful that it bent the boom over the tower.
Conventional telescopic stops low on the boom would have been much less effective.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Liebherr Orion crane failure under 5500t load test
A strut was pivoted near the pivot between the main boom and the jib and swung below the pivot.
Slack cables ran from a point on the main boom through the end of the strut and to the jib.
The cables came tight when the jib reached the maximum allowable upward position.
These systems seem to have fallen out of favour.
On a large crane they may do more damage to the jib than they prevent.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
Apparently this crane has no counterweights and uses water pumped into ballast tanks. There must be a huge amount of energy stored in the loaded system due to cables elongation, jib deflection, ship rotation, and the sudden out-of-balance condition of the ballast tanks. It seems like a sudden loss of load is simply a catastrophic, unrecoverable event.
RE: Liebherr Orion crane failure under 5500t load test
Fred
RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
Same thing, different names?
I wonder if some of the injuries were self inflicted when diving for cover?
I made more than one frantic run or dive working as a logger out west.
Finally sanity prevailed over the adrenaline rush and I quit and went back to school.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Liebherr Orion crane failure under 5500t load test
Dik
RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
Whoever drew the failure plane seems to think the center pin snapped.
RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
What I was trying to point out is the tension member which the boom is resting on, has taken the shape of the boom. In the first picture provided by Eufalconimorph, the member is straight. Once a large box section is bent it is usually less expensive to discard it and start over.
Well that is not a Din 15402-c Quad Forged Hooks. The red line is not correct. In this photo (screenshot from Eufalconimorph's set
) The bottom of the taper the cylindrical section, which is threaded is still attached to the shank.
Possibilities -
1) The nut cracked and the inside diameter increased until the threads no longer engaged each other.
2) Threads stripped.
I am out of guesses
Fred
RE: Liebherr Orion crane failure under 5500t load test
Granted, the following overlay of images from the quoted link is very crude, I would agree with the assesment that the failure was in the pin, at or above the seat of the nut. With this failure occurring at less than half the design load, it will be interesting to learn what metallurgical flaws were present and why they weren't discovered earlier in the fab process.
RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
The bearing areas on the nut from the hook block don't look very big to me.
And the hook looks like it is able to swivel around.
Any difference in hook load or rigging would seem to put a large bending moment on that thick, but reducing diameter shaft.
To break in what looks like pure tension is difficult to understand.
I'd love to see more drawings of the hook assembly though.
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RE: Liebherr Orion crane failure under 5500t load test
I'm still trying to convince myself that it was loaded in pure tension. Looking at the rigging, the mooring lines would need to have been looped around to opposite sides of the hook in order to ensure uniform loading. Was this done? If not, it would be difficult to avoid putting a large moment on the shaft. I wonder what is the load rating if only one or two adjacent hooks are loaded?
Edit:
From this second view I'm gonna say there was almost no hope of ensuring a uniform load.
RE: Liebherr Orion crane failure under 5500t load test
Added: To break in pure tension, implies necking, which would be visible.
RE: Liebherr Orion crane failure under 5500t load test
It looks like such a clean break that there must be some massive inclusion.
I hope the design didn't mix up lbs weight with kg....
But for five thousand tonnes that shaft looks mightily small to me. I reckon you would need a 1m diam shaft. Not easy to make in high strength steel.
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RE: Liebherr Orion crane failure under 5500t load test
If the hook is free to rotate on that bearing, then the tapered area above the bearing is just a guide and not an interference fit, as I first assumed. I would look for fretting damage from rubbing on that area for crack initiation. We have seen this sort of failure in large piston rods in reciprocating compressors.
How is this area lubricated?
Johnny Pellin
RE: Liebherr Orion crane failure under 5500t load test
[img https://lh3.googleusercontent.com/LlIFK1K7gb13MQNN...]
RE: Liebherr Orion crane failure under 5500t load test
But it's the design of the shaft and hook attachment I just don't get.
Why is it tapered?
How does that bearing work?
What are the strange tapping holes?
What's the plate on the bottom?
Nothing looks right.
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RE: Liebherr Orion crane failure under 5500t load test
A.
RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
Johnny Pellin
RE: Liebherr Orion crane failure under 5500t load test
It appears that the lifting points are canted longitudinally but not rotated towards the center of lift. This of course leaves all of the inside lines vulnerable to slipping off. I see some cinching cables, highlighted below,
but I struggle to understand this system.
Added: I see it now, when the hook is at the determined height, the canted planes pass through the center of lift.
RE: Liebherr Orion crane failure under 5500t load test
https://renews.biz/60152/orion-hook-designer-cites...
Brad Waybright
It's all okay as long as it's okay.
RE: Liebherr Orion crane failure under 5500t load test
https://www.youtube.com/watch?v=3m5qxZm_JqM
RE: Liebherr Orion crane failure under 5500t load test
Rules should require a pre-test in a safe working environment, step-by-step increase of load, thorough check for cracks prior and after.
But I don't know whether this is perhaps already the case with load hooks?
I don't know whether the enquiry (at least the technical part) shall be public, or being made public. But I'd very much like it to be made public, in all detail.
Such sudden death of a big size forging is quite unique to my professional experience. The more with the certificates and checking that must have undergone this particular one.
I have seen once a cluster of forgings that had been heat treated incorrectly, they just fell apart during transport, due to internal stress state.
Does anyone know whether there's a requirement to have a material sample going with the main hook components during heat treatment, in order to do a metallographical analysis?
Roland Heilmann
RE: Liebherr Orion crane failure under 5500t load test
https://www.linkedin.com/posts/tamlynlingham-a197b...
RE: Liebherr Orion crane failure under 5500t load test
The hook falls off and the block doesn't move for several seconds.
It's the fact the vessel is ballasted on the side that causes the large motion and movement of the crane arm backwards.
Seems like a bit of a design flaw to me. If the load had to be suddenly lowered in operation then the ship clearly can't ballast level fast enough to prevent large motion of the vessel and crane arm.
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RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
John R. Baker, P.E. (ret)
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RE: Liebherr Orion crane failure under 5500t load test
It's clear that is the motion of the vessel which causes the crane jib to flex back until it goes beyond the vertical.
If the job wasn't as vertical as it was it might have survived. I do wonder though if this scenario ( loosing the load very suddenly) had been properly analysed.
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RE: Liebherr Orion crane failure under 5500t load test
TTFN (ta ta for now)
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RE: Liebherr Orion crane failure under 5500t load test
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: Liebherr Orion crane failure under 5500t load test
I suggest you think that out a little bit more. You are probably thinking about suction effects that may occur when trying to pull something out of mud, but that too is not relevant here.
RE: Liebherr Orion crane failure under 5500t load test
In the first clip on this video, it looks like the crane turned over rearwards due to load release, but it's hard to tell for sure what was happening with it:
https://www.youtube.com/watch?v=3q8ylgL0Fy0
In this clip, there's a pretty signifcant load release and you can see the boom (and crane) bouncing around pretty good, but not flipping over backwards, either:
https://www.youtube.com/watch?v=YJq-RuJxA-A
RE: Liebherr Orion crane failure under 5500t load test
https://res.cloudinary.com/engineering-com/video/upload/v1589138202/tips/orion_linked_in_failure_video_furjwm.mp4
Edit:
I don't think that they ever intended for the barge to come clear of the water. Those lifting points seem too close together for such a long load. At any rate, the real-time load would be metered/monitored by the crane.
RE: Liebherr Orion crane failure under 5500t load test
In this case in addition to the obvious situation with the hook, there is (to me) a question hull stability design.
So on a barge or ship mounted cranes is the backwards boom stability with maximum dynamic hull rotation in a loss of load event a required consideration when designing the load chart?
RE: Liebherr Orion crane failure under 5500t load test
Well I think it will be now!
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Liebherr Orion crane failure under 5500t load test
850 tons was the max I knew of 20 years ago.
They used to test the offshore cranes in Aberdeen harbour with a similar setup but a lot smaller barge. They were though the recertification checks.
I think this will be covered by DNV who were always pretty hot on logging of heat treatment and NDT.
RE: Liebherr Orion crane failure under 5500t load test
Brad Waybright
It's all okay as long as it's okay.
RE: Liebherr Orion crane failure under 5500t load test
But once that boom went past vertical then the result was not in doubt.
I guess there were very good reasons why the crane is on one side of the vessel, but the ballasting arrangement to allow any load to be moved on or off the vessel would be significant and involve a lot of water movement between ballast tanks. Fundamentally this is the key to this failure.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Liebherr Orion crane failure under 5500t load test
Its not the first time its been used and it won't be the last time either.
They don't lift off the actual deck they lift off barges and then position. The ones I have seen so far building off shore windfarms have all used jack up rigs next to the work site.
But they are wanting now to have one vessel putting foundations and piles in then build the complete mast plus turbine and blades on the shore or maybe on the deck then lift the whole lot into position in one lift. Before it would be piles then mast, then turbine on top then fit the blades. And fitting the blades apparently was extremely weather dependant.
RE: Liebherr Orion crane failure under 5500t load test
In the US, smaller lifting hardware typically uses a factor of safety of 5 or so. They may lower that in a case like that, especially if they can analyze the heck out of it. But still, it had to have failed at just a fraction of its intended strength.
I'll bet barge has a pretty good ding in the deck now.
RE: Liebherr Orion crane failure under 5500t load test
Is that certain at this point? Firstly, the crane is only good for the rated load under narrow constraints which surely include restrictions on uniform loading of the hooks. Secondly, I understand that safety factors might be as low as 1.3 for these heavy lift systems. Thirdly, the rigging system doesn't give much confidence of a uniform load application. I can see a rather large moment being applied to the hook which might quickly put you well past the stresses expected at the 50% load reported by the crane sensors. Finally, I can't really see them getting this far in the process without testing and certification of the hook prior to installation.
RE: Liebherr Orion crane failure under 5500t load test
You're right in that of all of the component parts of the crane, the hook would probably have been one of the easiest to conduct a static load as a separate part. In fact, I guess we don't really know whether such a test wasn't performed prior to shipping. We also don't yet know the failure mode, so it's possible that it might have passed in a different configuration. Ropeblock might be having similar thoughts in hindsight as I'm sure their liability is probably into seven figures.
BTW, from reading the press releases It seems to me that Liebherr was quick to note that the hook came from a 3rd party vendor and I get the feeling they're trying to throw them under the bus. I would say that unless that equipment was purchased/provided by somebody else like the customer, then it's part of Liebherr's equipment it and it's theirs to own. Ropeblock makes a similar notation that the failed part comes from an outside supplier, but they seem to defend that supplier's design, construction, materials, etc. a little more than Liebherr.
Brad Waybright
It's all okay as long as it's okay.
RE: Liebherr Orion crane failure under 5500t load test
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
RE: Liebherr Orion crane failure under 5500t load test
Thanks for the MP4 heads up...
Dik