Detail investigation on un-stiffened T/Y tubular joints behavior under axial compressive loads

This paper presents the failure pattern, ultimate static strength and detailed behavior of un-stiffened T and Y tubular joints under axial brace compressive loading using finite element method performed by ABAQUS software package. Properties of the un-stiffened tubular joints were extracted from the available experimental-based tubular joint database. Utilizing the Modified Riks Method in numerical analyses led to an accurate simulation of joint behavior and also helped to investigate its correct failure pattern. The modes of failure observed throughout the numerical analysis were local bending of the chord member, ovalization and plastic failure of the chord. The results obtained from the numerical modeling revealed the critical areas on the joint surface with respect to ovalization, deflections and stresses. Also, the ultimate strength predicted by the numerical analysis was compared and validated with available experiment results. Despite the fact that much research has been conducted on tubular joints which have mostly focused on the estimation of ultimate strength or stress concentration factors rather than detail study of joint behavior, the present detail investigation has provided a thorough understanding of joint behavior under axial compressive loads. Such an in-depth and detail tubular joint investigation has been rarely reported in the open literature.

► The critical zone on the chord circumference was from the saddle point to 3√DT.
► The critical zone for the crown line stretched from crown point to 6√DT.
► Longitudinal reinforcement up to 6√DT was proposed for strength enhancement.
► Circumferential reinforcement up to 3√DT was proposed for strength enhancement.
► Tubular joint behavior with polymeric composite reinforcement to be investigated.