Numerical Analysis of Fatigue Behavior of Welded CFCHS T-Joints

Abstract

Fatigue life assessment of welded joints made of circular hollow sections (CHS) with concrete filled (CF) chord member subject to vehicle load is vital in designing of CFCHS arch truss bridge. A key issue in fatigue life assessment of such joints is how to accurately estimate the stress intensity factor. This paper describes a methodology for calculating the stress intensity factor of the hot spot region in the welded CFCHS T-joints based on a finite element analysis which considers weld modeling, crack modeling and nonlinear interface element between steel and concrete. A procedure for fatigue life estimation of welded CFCHS T-joints is also established. Discussions are made on the effect of the initial crack size and concrete strength on fatigue life and hot spot stresses. The majority of crack propagation life is found to be associated with the shallow crack stage. The proposed method gives reasonable estimation of fatigue life of welded CFCHS T-joints.

Investigating Fatigue Mechanisms and Crack Growth in 20mntib Steel High-Strength Bolts: An Experimental and Simulation Study

“…Fang et al [20] simulated crack propagation direction and path in a perforated plate using Abaqus, with results closely aligning with experimental data. In another study, Gu et al [21] calculated the stress intensity factor (SIF) of cold-formed, circular, hollow-section (CFCHS), T-type, welded joints using Ansys software and developed a method for assessing the fatigue life of such joints. The extended finite element method (XFEM) is the most prevalent technique for investigating fatigue crack propagation issues.…”

New Experimental Results of the Research on Reinforced Node in Space Truss

“…It is possible to observe in reference [5] the design of welded tubular connections. Fatigue is an important issue in designing welded joints [6]. That paper presented a fracture mechanics approach to assess the fatigue life of CFCHS T-joints, which involves the determination of initial crack location and size, stress intensity factor and proper crack growth model (Figure 2).…”

“…That paper presented a fracture mechanics approach to assess the fatigue life of CFCHS T-joints, which involves the determination of initial crack location and size, stress intensity factor and proper crack growth model (Figure 2). In [6], numerical and experimental analyses on welded joints were presented. Figure 2.…”

“…Figure 2. Fatigue Study in Welded Joints [6] There are systems without a special nodal piece ( Figure 3). In this case, the chord bars have flattened ends and can be continuous or not.…”

Static and Fatigue Behavior of CFRP-Strengthened Rc Bridge Girders Subjected to Vehicle Overloading

“…Sun et al [3] monitored the structural behavior of a 25 m span simply-supported RC girder bridge in China on basis of the in-situ traffic survey data and found that the maximum stress in the longitudinal reinforcement may reach up to about 85% of its yield strength. Usually the vehicle overloading does not cause an RC bridge to collapse instantly, but the high stress amplitude caused by overloading will definitely accelerate the damage accumulation and the structural performance degradation in critical details [4]. In both USA and China, Hersi [5], Ji and Fu [6] found that vehicle overloading has become a major factor leading to the failure of bridge structures (Figure1 and Figure 2).…”