Analysis of fatigue cracking of orthotropic steel decks using XFEM. (October 2022)

• Record Type: Journal Article
• Authors: Zeng, Yong; Qu, Yu; Tan, Yujie; Jiang, Yuhang; Gu, Anbang
• Is Part Of: Engineering failure analysis. Volume 140(2022)
• Publication Date: 2022-10
• Subjects: Fatigue -- Bridges -- Steel structures -- Stress analysis; XFEM Extended Finite Element Method -- FE finite element -- FEM finite element method -- FPS the first principal stresses -- IP internal penalty -- LEFM linear elastic fracture mechanics method -- PE perimeter elements -- RHD relative horizontal displacements between deck plate and diaphragm web -- XFEM extended finite element method -- B operator -- d the vector of nodal unknown -- f external force vector -- b body forces -- K the global stiffness matrix -- t¯ applied traction -- N(X) standard FE shape function -- ψI(X) the enrichment function of crack tip -- ϕI(X) the enrichment function for the crack tip -- aI bKI, additional degrees of freedom -- δ the set of nodes in the entire discretization -- δt the set of nodes around the crack tip -- δc the set of nodes associated with elements completely cut by the crack -- f (x) g(x), level set functions -- r θ, polar coordinates -- σhs hot spot stress -- t plate thickness -- Δp axial load range; System failures (Engineering) -- Periodicals; Fracture mechanics -- Periodicals; Reliability (Engineering) -- Periodicals; Pannes -- Périodiques; Rupture, Mécanique de la -- Périodiques; Fiabilité -- Périodiques; Fracture mechanics; Reliability (Engineering); System failures (Engineering); Periodicals; Electronic journals; 620.112
• DOI: 10.1016/j.engfailanal.2022.106536
• Languages: English
• ISSNs: 1350-6307

Abstract

Highlights: A 3D XFEM model simulating experimental results of the longitudinal displacement of U-rib-to-diaphragm connections. DG-XFEM approach is used to analyze crack growth of the inside interior of the floor-beam. Contribution of the out-of-plane displacement to fatigue cracking can result in crack initiation and propagation prior. Abstract: The cutouts of diaphragms and the weld tips of the U-rib-to-diaphragm connections are the very complex structural details in orthotropic steel decks, and are accordingly highly vulnerable to fatigue cracking. The majority of fatigue cracks in these details appear as a result of the stress concentrations and initial weld defects. To determine the reason for the high probability of occurrence of fatigue cracks at these types of fatigue detail categories, a numerical model was established using the extended finite element method (XFEM) to analyze the cracking of diaphragm of an experimental 1:2 scaled deck segment model. This numerical analysis indicated that the cracks that appear at the diaphragm cutouts and near the weld toes of U-rib-to-diaphragm connections are induced by the relative horizontal displacement between the deck plate and diaphragm along the longitudinal axis of the bridge rather than by vertical deflection or moment due to live load. Additionally, stress concentrations play an important role in the initiation and propagation of cracks in these regions. The contribution of the out-of-plane displacement to fatigue cracking may be the most significant, and can frequently result in crack initiation and propagation prior to any cracking caused by vertical deflection or in-plane stresses. The XFEM approach is a useful numerical method for modelling the fatigue cracking of orthotropic steel decks.