Abstract An efficient numerical analysis procedure based on FEM was implemented for evaluating the effect of welding residual stress (WRS) on mixed-mode stress intensity factors (MM-SIFs) for a non-planar surface-cracked tubular T-joint with a rounded weld toe. A multi-pass welding simulation was carried out using real welding conditions by means of an effective in-house welding simulation code. A fully compatible 3D finite element mesh generation system was implemented to model non-planar perpendicular surface-cracked tubular T-joints with rounded weld toes. The adequacy of the mesh generation system was verified with the reference solutions. A fully automated mapping code was developed to assign the six components of the simulated WRS to each element face over the crack surface. A developed fracture approach was employed to accurately compute MM-SIFs resulting from WRS in which normal and shear components of WRS were considered. MM-SIFs were calculated carefully for several surface cracks with different shapes under different loading conditions. The behavior of MM-SIF solutions resulting from the combination of external load and WRS was influenced significantly by the behavior of those produced due to WRS only. In addition, the value of the computed SIFs resulting from the combination of external load and WRS was almost doubled for mode-I SIF compared to those obtained by external load only and WRS only especially near the crack end locations. The behavior of the calculated fracture parameters was also discussed.
Abstract Welded steel tubular structures are easily exposed to impact loading which may cause devastated damage firstly to their connecting joints. The critical joints determine the dynamic mechanical performance of the structures in those unexpected catastrophes. This paper describes an experimental and numerical impact investigation on dynamic behavior of CHS-SHS tubular T-joints, made up of a circular hollow section (CHS) brace and a square hollow section (SHS) chord. Seven CHS-SHS tubular T-...
The results of a fatigue finite element analysis (FEA) based on the continuum damage mechanics of welding tubular members are presented. The effects of welding joint type on fatigue life and crack location were investigated. The initial mechanical state of a welded tubular member was simulated to identify initial welding imperfections such as welding residual stress and welding deformation using three-dimensional (3D) thermal elasto-plastic large-deformation FEA. The temperature history, which w...
Last. Chentai Wu(Southwest Jiaotong University)H-Index: 1
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Abstract Specimen testing of concrete-filled steel-tube (CFST) joints and the fatigue assessment approaches for such joints were investigated and summarized to understand comprehensively the fatigue behavior of CFST trusses. The main factors that influence the fatigue resistance of CFST joints were discussed. Nominal stress- and hot-spot stress (HSS)-based methods were compared based on available experimental results, and the current state and development direction of fatigue assessment of CFST ...
Abstract This paper investigates the influence of the change in welding heat input (HI) and welding residual stress (RS) on the behavior of stress intensity factor (SIF) and fatigue crack propagation (FCP) by means of finite element method. Three welding HI cases were examined using a bead-on-plate FE model. One of the applied welding HI cases represents welding conditions used in experiments. Furthermore, for the sake of comparison, a stress-relieved case that does not consider the influence of...
Abstract This paper accurately evaluates mixed-mode SIFs (MM-SIFs) for cracks in welding residual stress (WRS) fields using a novel approach based on finite element method (FEM). For this reason, the interaction integral method (IIM) available in WARP3D, an open source code, was developed to include normal and shear stress components in MM-SIF solutions. The effectiveness of the developed WARP3D-IIM was verified based on the superposition method and by means of well-established analytical and nu...
Abstract Overlapped K-joints arise in truss type structures when one diagonal (overlap brace) intersects the other diagonal (through brace). In such joints, part of the through brace is hidden within the overlap brace, and the hidden toe of the through brace may or may not be welded to the chord. This study investigates the hysteretic behaviour of partially overlapped circular hollow section K-joints, with and without hidden welds, under cyclic loading. This study involved nine full-scale specim...
Abstract Welded tubular joints are widely used for the mast arm pole connection in signal support structures. In order to study the fatigue behavior of such welded tubular joints, static loading and fatigue tests were carried out on several full-scale experiments. In order to understand the local behavior and perform parametric study of critical factors such as initial crack location, finite element (FE) models are subsequently built and the numerical simulation results are validated with the ex...
Abstract Tubular arch bridges are susceptible to fatigue problems due to stress concentrations, welding imperfections and tensile residual weld stresses. These bridges are composed of circular hollow section profiles welded together in tubular joints. This paper describes the determination of residual weld stresses in T-joints with the incremental hole-drilling method. The residual stress distribution can be used to determine fatigue crack behavior and fatigue lifetime more precisely. The increm...
Abstract A software system to perform SCC crack propagation analyses for complex and realistically shaped structures consisting of dissimilar materials, such as weld metal, base metal, etc., under weld residual stresses is presented in this paper. The system consists of programs to perform automatic generation of the finite element mesh, weld residual stress mapping to the finite element model with weld residual stresses to carry out fracture analysis and finite element analysis, and evaluating ...
#2H.Th. Beier(Technische Universität Darmstadt)H-Index: 8
Last. Michael Vormwald(Technische Universität Darmstadt)H-Index: 25
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Abstract The aim of the present investigation is to calculate the fatigue life of cruciform welded joints by taking into account both the effect of residual stresses and the influence of the weld toe geometry. Two and three dimensional finite element models, with cracks as initial defects, will be constructed for this purpose. Fatigue crack growth analyses are performed by using the node release technique, together with the finite element program ABAQUS. The welding residual stresses, as well as...
#2Chao Hou(Southern University of Science and Technology)H-Index: 14
Last. Luming Shen(USYD: University of Sydney)H-Index: 24
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Abstract null null The residual stress and the dimensional distortion due to rapid temperature variation during the welding process are often crucial for the life-cycle behavior of structures, especially for key connection regions in offshore and marine applications. This paper evaluates the detailed welding effects on the strength and stiffness of concrete-filled steel tubular (CFST) Y- and K-joints using advanced finite element modeling (FEM), and the results are then validated and compared wi...
Last. Ramy Gadallah(OPU: Osaka Prefecture University)H-Index: 5
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Fatigue crack propagation (FCP) is the most threatening failure to welded joints due to high local stress concentration and the effect of welding residual stress (WRS). Therefore, fatigue life assessment of welded joints considering residual stress distribution is an important procedure in designing and maintaining of welded structures. In this study, fatigue life of welded structures is evaluated using the fracture mechanics approach. The WRS is predicted by using the thermal elastic–plastic-fi...
Last. Menglan Duan(China University of Petroleum)H-Index: 18
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ABSTRACT At present, the research on the cavity formed by spudcan penetration is based on two-dimensional axisymmetric analysis of circular spudcans, and it is doubtful whether the results could be applicable to rectangular spudcans. In this paper, centrifuge experiments and finite element analysis are combined to study the penetration process of large scale rectangular spudcans in the clay with undrained shear strength varying with depth. Soil back-flow is found to occur preferentially from the...
Abstract The buckling and collapse behaviors of a cracked thin steel panel subjected to sequential tensile and compressive loading were investigated. An experimental apparatus was developed. Three different test specimens were employed, i.e., an intact panel and cracked panels with different crack lengths. The load-displacement curve and crack opening displacement (COD) were measured during the loading. The experimental results were examined via finite element (FE) computation. The results revea...
Abstract This paper proposes an interaction integral retardation (IIR) model to predict fatigue life accurately for components subjected to multi-step loading (MSL) conditions. The IIR model is based on the cyclic interaction integral that considers the effect of elasticity and plasticity simultaneously at the crack tip. Elasto-plastic numerical simulations were carried out based on FEM to compute the cyclic interaction integral. The IIR model was verified against the experiments under different...
