The effects of shape and plate thickness of a pin connection on its ultimate strength under quasi-static in-plane loading are investigated through a three dimensional finite element idealization. The study utilizes the ABAQUS software to model the geometric and material nonlinearities of the pin connection and the boundary nonlinearity due to the contact between the pin and plate around the hole. The three dimensional idealization provides a better representation of the stress re-distribution, and consequent variation of plate thickness under increasing loads, than the authors" previous work which utilized a plane stress approach. The present results correlate closely with published numerical and experimental results. The effect of padeye shape on its ultimate strength, for a given set of geometric ratios, is found to be insignificant. For a round-ended padeye with certain hole diameter/width ratio and pin size, it is observed that its averaged bearing stress ratio decreases as the plate thickness hole diameter ratio is increased.
Pin connections are commonly used in offshore, civil, mechanical and aerospace structures (Blake, 1985) and are known variously as padeyes, eyebars or lugs. In this paper, the terms pin connection and padeye will be used. interchangeably. The design of padeyes for offshore lift installation of modules, jackets and structures is becoming more critical as the weight of the structures is increasing. The selection of appropriate dimensions and shape of the padeye, to provide the required load transfer, has significant influence on the cost of materials and fabrication, as well as safety during lift installation. Each of the pin-hole connections is a potential source of structural weakness, by overloading or cumulative fatigue damage (Blake, 1985; Kulak et al., 1987). Most of the analytical and experimental work reported on pin connections are on elastic stress distribution.
