View source for Padeye

{{Short description|Attachment point on a boat deck}}
{{refimprove|date=September 2013}}
[[File:US Navy 100105-N-6604E-007 Aviation Machinist's Mate Airman John Wagner connects a tiedown chain to a padeye on the flight deck of the aircraft carrier USS Dwight D. Eisenhower (CVN 69).jpg|thumb|300px|An [[Aviation Machinist's Mate]] connecting tiedown chains to padeyes on the flight deck of the aircraft carrier {{USS|Dwight D. Eisenhower|CVN 69}}]]
A '''padeye''' is a device often found on boats or ships that a line runs through or provides an attachment point. It is a kind of [[fairlead]] and often is bolted or welded to the deck or hull.
It is also used in oil and gas projects to assist in the purpose of lifting.
==Detail==
It is made of steel plate with radius at one side. Lifting is done with the help of a D-shackle or sling, which fits into the hole of the padeye. There may be one or more circular plates (cheek plates) welded around the hole.
==Designing==
The following check should be done for the design of padeyes and to keep the stress less than the allowable stresses:
At the hole:
# Bearing stress
# [[Shear stress]]
# Tensile stress
# Hertz bearing stress
At the base
# [[Shear stress]]
# Tensile stress
# Bending stress
# Combined bending stress and tensile stress
# [[Von Mises yield criterion|Von-Mises stress]]<ref>http://e-book.lib.sjtu.edu.cn/otc-2007/pdfs/otc19040.pdf{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
Analysis on a padeye is commonly performed in accordance with the Air Force Stress Analysis Manual<ref>{{Cite web|url=http://www.dtic.mil/dtic/tr/fulltext/u2/759199.pdf|archive-url=https://web.archive.org/web/20161115132504/http://www.dtic.mil/dtic/tr/fulltext/u2/759199.pdf|url-status=dead|archive-date=November 15, 2016|title="Stress Analysis Manual," Air Force Flight Dynamics Laboratory, October 1986.|date=|website=|publisher=|access-date=}}</ref> or ASME BTH-1.<ref>{{Cite web|url=https://www.asme.org/products/codes-standards/bth1-2014-design-belowthehook-lifting-devices|title=ASME BTH-1, "Design of Below-the-Hook Lifting Devices," The American Society of Mechanical Engineers, 2014.|date=|website=|publisher=|access-date=}}</ref> The methodology in ASME BTH-1 only allows for axially loaded lugs, whereas the methodology in the Air Force Stress Analysis Manual allows for axial loading, transverse loading, or oblique (combined) loading.<ref>{{Cite web|url=https://mechanicalc.com/reference/lug-analysis|title=Padeye/Lug Analysis|date=|website=|publisher=|access-date=}}</ref>
== Failure modes ==
Tests have confirmed that there are four potential failure modes for a lug plate:
# Tension failure at the sides of the hole
# Crushing above the lifting pin followed by tearing tension fracture at the plate edge
# Shear failure in the lug plate as the lifting pin attempts to plow its way towards the edge of the free plate
# Dishing (out-of-plane buckling) failure of relatively thin lug plates that are laterally unrestrained
==References==
{{Reflist}}
[[Category:Nautical terminology]]