Local joint flexibility of tubular T/Y-joints retrofitted with GFRP under in-plane bending moment. (May 2021)

• Record Type: Journal Article
• Authors: Nassiraei, Hossein; Rezadoost, Pooya
• Is Part Of: Marine structures. Volume 77(2021)
• Publication Date: 2021-05
• Subjects: T/Y-connections -- Fiber retrofitted polymer (FRP) -- LJF -- ANOVA -- Design formula; Naval architecture -- Periodicals; Offshore structures -- Periodicals; Architecture navale -- Périodiques; Structures offshore -- Périodiques; Naval architecture; Offshore structures; Periodicals; 620.4162
• DOI: 10.1016/j.marstruc.2021.102936
• Languages: English
• ISSNs: 0951-8339

Abstract

Abstract: In the present paper, the Local Joint Flexibility (LJF) of tubular T/Y-joints retrofitted with Glass Fiber Reinforced Polymer (GFRP) under IPB moment is studied and discussed. For this aim, a finite element (FE) model was generated and verified with the results of available experimental data and parametric formulas. Afterward, a set of 158 finite element (FE) models was created to evaluate the efficacy of the FRP sheets (number, length, and orientation), the brace inclination angle ( θ ), and the non-dimensional parameters ( β, τ, and γ ) on the LJF coefficient ( f LJF ) and the f LJF ratio of the retrofitted to the associated un-retrofitted joint. In the FE models, the efficacy of the weld profile and the contact between the FRP and the steel members (chord, weld, and brace) was considered. Also, analysis of variance (ANOVA) is used to identify the most dominant parameters which affect the f LJF ratios. Results showed that in the retrofitted joints, the increment of the FRP sheet number results in the notable drop of the f LJF . But, the efficacy of the FRP sheet orientation on the f LJF can be ignored. Despite the considerable efficacy of the FRP sheets on the behavior of the tubular joints, there was not any study on the LJF in the joints retrofitted with FRP. Hence, after an extensive parametric study, the results were used to derive a parametric equation for determining the f LJF of T/Y-joints retrofitted with FRP. Moreover, the derived equation was checked according to the UK DoE acceptance criteria. Highlights: 139 3-D FE models are generated and analyzed to investigate the Local Joint Flexibility (LJF) of the tubular T/Y-joints reinforced with fiber reinforced polymer (FRP). The effect of the FRP layers (number, length, and orientation), the brace inclination angle ( θ ), and the connection geometry ( θ, β, and γ ) is investigated. A design equation is proposed to determine the f LJF of the T/Y-joints reinforced with FRP.