Proceedings of the Fourth (1994) Internationai Offshore and Polar Engineering ConferenceOsaka, Japan, April 10-15, 1994Copyright 1994 by The International Society of Offshore and Polar EngineersISBN 1-880653-10-9 (Set); ISBN 1-880653-11-7 (VoL I)

A Comparative Study on Theoretical and Experimental Strengthsof Padeyes Under In-Plane Loads

Y.S. Choo, K.C. Choi and K.B. LeeNational University of Singapore

Singapore

Padeyes and pin-eonnections are commonly used as lifting

components in onshore and offshore installation. Despite of their apparent

geometric simplicity, the nonlinear elasto-plastic behaviour of padeyes under

increasing loading is complex. Present design approaches normally limit the

maximum elastic stresses calculated from simplified equations to within

allowable stress limits and are very stringent on the pin-hole tolerance.

This paper presents parametric results for padeyes subjected to in-plane

quasi-static loads using nonlinear finite element analyses and a simple

graphical plot which facilitates the evaluation of padeye strength in relation

to its geometric ratios. The current results are shown to correlate closely

with published experimental results and provide better correlation than some

standard design equations. The effect of different padeye shapes, for the

parametric range investigated, is found to have marginal influence on

strength. The reduction in ultimate strength of padeyes with large pinlhole

tolerance is significantly lower than predicted by elastic theory due to stress

redistribution within the padeye plate.

KEYWORDs: Padeyes, pin-eonnections, strength comparison, nonlinear

behaviour, finite element analysis, design codes

NOMENCLATUREa "Loaded-edge" distance along the line of load P referenced from the

hole centre-line = L (see Fig. 1)a' "Loaded-edge" distance along the line of load P, measured from

edge of hole (see Fig 1)be "Unloaded-edge" distance, measured from the side of hole to the

edge of padeye (see Fig. 1)C, Strength reduction ratio = p / P'"