Outplane angle in padeyes
Outplane angle in padeyes
(OP)
Was wondering how common it is to consider the shackle eccentricity when considering the outplane moment on padeyes.
IOW, instead of considering it acting at the pinhole you consider the sling force acting on the shackle tip.
For larger outplane angles this could be significant. Do you think the 2.0 DAF covers this?
IOW, instead of considering it acting at the pinhole you consider the sling force acting on the shackle tip.
For larger outplane angles this could be significant. Do you think the 2.0 DAF covers this?





RE: Outplane angle in padeyes
In addition there is usually an offlead force applied to cover an out of plane load.
The DAF is not applied to cover errors in the design process.
RE: Outplane angle in padeyes
Instead of talking about an "outplane angle on padeyes" or "shackle eccentricity" consider posting using the terms "lifting lugs" and "eccentric loads".
Word usage makes a big difference on the internet.....
The esteemed seminal US company and leader in the field - Crosby has the best information on out-of-plane loadings...
This was, of course, befor the Chinese copied everything...
My opinion only..
-MJC
RE: Outplane angle in padeyes
In the offshore industry, "padeye" is the norm to describe lifting lugs. I dont think I ever heard someone use the term lifting lug.
Crosby talks about out of plane loading but only in context of the shackle, not in designing a padeye.
RE: Outplane angle in padeyes
All I can tell you is the force applied out of plane to the padeye severly reduces its strength, and as a rule; force should never be applied outplane of the padeye.
RE: Outplane angle in padeyes
As far as the padeye is concerned, if you design your plate and cheekplates (or solid plate) to be 90% of the open width of the jaw, your problem will not be with the padeye. Rather, it will be with the weld that holds the padeye plate to the frame.
As for the original question, it's not unreasonable to apply 5% out-of-plane loading to the padeye, but I believe DNV 2.7-1 states 3 degrees. But you'd have to look it up and verify.
Engineering is not the science behind building. It is the science behind not building.
RE: Outplane angle in padeyes
For the application we are working on there is no way to avoid the outplane angle as there are multiple sling angles as the structure is rotated.
RE: Outplane angle in padeyes
RE: Outplane angle in padeyes
RE: Outplane angle in padeyes
Theman008: I cannot go into that due to policy. Thanks for your feedback though
RE: Outplane angle in padeyes
If you are dealing with rotating an object from horizontal to vertical (or vice-versa), you can do so without loading padeyes out of plane. You will put two padeyes parallel to each other, so that the holes are on the same axis. Then, you lift it with a spreader bar that has the two points of lift exactly the same distance apart as the two eyes on the structure. These two padeyes will be completely separate padeyes from your normal four-part lift.
And on this subject, you should also design a tilting/pivot frame in order to prevent the unit from sliding all over the deck when it's being rotated up or down. If you don't have a frame/cradle or whatever you want to call it, there are a lot of platforms that will require you to use two cranes for the rotation operation.
Engineering is not the science behind building. It is the science behind not building.