The ultimate strength of doubler plate reinforced Y-joints under compression loading

It is common practice in the offshore industry to solve the punching shear problem due to compression by using doubler plate. The finite-element method is a useful tool for studying this problem. The aim of this paper is to study the static strength of doubler plate reinforced Y-joints subjected to compression loading. The finite-element method is adopted in numerical parametric studies. The individual influences of the geometric parameters βand τ _d (doubler plate to chord wall thickness ratio) and l _d /d ₁ (dubler plate length to brace diameter ratio) on the ultimate strength are made clear. The results show the size of plate may have important effects on the strength of reinforced joints. It is found that the ultimate strength of Y-joints reinforced with appropriately proportioned doubler plates can be greatly improved nearly up tothree times to un-reinforced Y-joints. Foundation item: Suppotted by Commission of Science Technology and Industry for National Dofense (NO. 20002781). FENG Qi, born in 1978, is presently a Ph. D candidate in School of Naval Architecture, Ocean and Civil engineering, Shanghai Jiao-Tong University. The main research directions: research of new technology to reinforced tubular joints. TAN Jia-hua, born in 1946, is a professor and doctoral advisor. The main research directions: research and exploitation of new ship model, the technology and equipment of construction at sea and the advanced technology of ship fabrication et al.