scholarly journals Parametric Formulae for Elastic Stress Concentration Factor at the Weld Toe of Distorted Butt-Welded Joints

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 169 ◽  
Author(s):  
Yuxiao Luo ◽  
Renle Ma ◽  
Seiichiro Tsutsumi
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Fatigue Test ◽  
Stress Concentration Factor ◽  
Welded Joints ◽  
Concentration Factor ◽  
Angular Distortion ◽  
Large Set ◽  
Finite Element Analyses ◽  
Weld Toe

The evaluation of the stress concentration factor (SCF) at the notches of welds is of importance, especially for butt-welded joints that are widespread in the industry. Some empirical formulae can be found in the literature to estimate the SCF at the weld toes of butt-welded joints, while few solutions are available for the distorted joints under tensile fatigue test conditions. In the present study, the existing SCF formulae for butt-welded joints loaded in tension are examined and discussed. The influence of the weld width on SCF, which is commonly ignored or misestimated by existing solutions, is investigated comprehensively based on a large set of two-dimensional (2D) finite element analyses. Consequently, a new precise parametric formula for the elastic SCF at the weld toe of geometrically symmetric butt-welded joints under tension is proposed, together with a wide application range. Moreover, the analysis is also extended to consider joints with angular distortion. A two-step finite element analysis is employed to simulate the clamping and loading procedures in the fatigue test. Similarly, the parametric formulae for the assessment of clamping-induced stress and SCF caused by angular distortion are carried out as well based on the results from finite element analyses. The formulae proposed by this paper are finally tested and proved to be valid and precise.

Stress Concentration at the Root of Bolt Thread Under Twist With Deformable Flanges

2011 ◽  
Author(s):  
Yasumasa Shoji ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Numerical Methods ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Finite Element Analyses

Bolts and Nuts are required to fasten objects, such as flanges in various types of plants. It is known that stress concentration at the root is relevant for its strength for both static integrity and fatigue. A lot of investigations were carried out to understand the behavior of the bolt using experimental and numerical methods. Recently, finite element analyses have been used to examine the detailed behavior of the bolt root successfully. The authors reported such example in a recent study [13] using submodelling (or so-called zooming) technique that handled only bolt tension with rigid fastened surface; some factors were missing. In this paper, the twist of the bolt was taken into account and the fastened object is replaced by deformable plates. The stress concentration factor has been reconsidered.

scholarly journals New Methods for Stress Concentration Factor Calculation in Butt Welded Joints: A Comparative Study

2020 ◽  
Author(s):  
Miroslav Randic ◽  
Duško Pavletić ◽  
Marko Fabić
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Welded Joints ◽  
Concentration Factor ◽  
Computer Software ◽  
Base Material ◽  
Geometric Parameters ◽  
Stress Concentrations ◽  
Weld Toe ◽  
Toe Angle

Abstract Surface cracks in butt-welded joints usually occur in places with increased stress concentrations. The stress concentration factor (SCF) can be calculated using an empirical equation, with five geometric parameters of a butt-welded joint (thickness of the base material, toe radius, weld toe angle, weld width, and reinforcement height). However, in anindustrial environment, it is impractical and sometimes even impossible to measure all five geometric parameters with sufficient accuracy. In this study, eight experiments on butt-welded joints were performed. All samples were scanned with a 3D scanner, and the geometric sizes of the welded joints were measured using computer software. A modified empirical expression proposed by Ushirokawa and Nakayama was used to calculate the SCF; the expression was adjusted in such a way that the SCF was calculated by knowing only the toe radius. In addition, four new expressions were proposed for the calculation of the SCF by knowing the toe radius in relation to the weld toe angle; the expressions were then compared and analysed. Additionally, the values of the stress concentrations in the butt-welded joints were obtained using afinite element method (FEM). The SCFs calculated using the four methods were compared and further discussed. Our data suggested a new accurate and straightforward approach for calculating the SCF by knowing only the weld toe radius.

Influence of overlays on stresses in fillet-welded joints

1977 ◽  
Vol 12 (1) ◽  
pp. 16-22 ◽  
Author(s):  
T R Gurney
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Coating Thickness ◽  
Welded Joints ◽  
Finite Element Analyses ◽  
Uniform Thickness ◽  
Load Carrying ◽  
Weld Toe ◽  
Low Modulus

Finite-element analyses have been carried out on a specimen with transverse non-load-carrying attachments, to examine the influence of low-modulus overlays consisting either of a layer of uniform thickness over the whole weld or of an infill over the weld toe. The variables studied have included coating thickness and the shape, size and modulus of toe infills. It is shown that substantial reductions in stress concentration can be obtained by such coatings.

scholarly journals Evaluation of the Stress Concentration Factor in Butt Welded Joints: A Comparative Study

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 411
Author(s):  
Miroslav Randić ◽  
Duško Pavletić ◽  
Marko Fabić
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Welded Joints ◽  
Concentration Factor ◽  
Computer Software ◽  
Base Material ◽  
Geometric Parameters ◽  
Stress Concentrations ◽  
Weld Toe ◽  
Toe Angle

Surface cracks in butt-welded joints usually occur in places with increased stress concentrations. The stress concentration factor (SCF) can be calculated using an empirical equation, with five geometric parameters of a butt-welded joint (thickness of the base material, toe radius, weld toe angle, weld width, and reinforcement height). However, in an industrial environment, it is impractical and sometimes even impossible to measure all five geometric parameters with sufficient accuracy. In this study, eight experiments on butt-welded joints were performed. All samples were scanned with a 3D scanner, and the geometric sizes of the welded joints were measured using computer software. A modified empirical expression proposed by Ushirokawa and Nakayama was used to calculate the SCF; the expression was adjusted in such a way that the SCF was calculated by knowing only the toe radius. In addition, four new expressions were proposed for the calculation of the SCF by knowing the toe radius in relation to the weld toe angle; the expressions were then compared and analyzed. Additionally, the values of the stress concentrations in the butt-welded joints were obtained using a finite element method (FEM). The SCFs calculated using the four methods were compared and further discussed. Our data suggested a new accurate and straightforward approach for calculating the SCF by knowing only the weld toe radius.

Fatigue Test Welded Joints Steel S960QL

2012 ◽  
Vol 726 ◽  
pp. 93-99
Author(s):  
Czesław Goss ◽  
Paweł Marecki
Keyword(s):  
Stress Concentration ◽  
Residual Stresses ◽  
Fatigue Test ◽  
Stress Concentration Factor ◽  
Welded Joints ◽  
Concentration Factor ◽  
Test Results ◽  
Butt Joints ◽  
Considerable Research

Test results of residual stresses in welded butt joints were also presented. Finite Elments Methods and Jewdokimow and Lawrance’a methods of stress concentration factor αk calculation were comparative sumarized. Presents results is a part more considerable research attendant bridge MS-20.

Numerical Investigation of Stress Concentration Factor at Irregular Corrosion Pit Under Tension-Torsion Loading

2014 ◽  
Author(s):  
Yuhui Huang ◽  
Chengcheng Wang ◽  
Shan-Tung Tu ◽  
Fu-Zhen Xuan ◽  
Takamoto Itoh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Aspect Ratio ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Three Dimensional ◽  
Element Analysis ◽  
Stress Concentration Factors ◽  
Local Dissolution

Finite element analysis is adopted to study the stress concentration of pit area under tension-torsion loading. The stress concentration factors under regular evolution and irregular evolution of pits are investigated by conducting a series of three-dimensional semi-elliptical pitted models. Based on the finite element analysis, it can be concluded that pit aspect ratio (a/2c) is a significant parameter affecting stress concentration factor (SCF) for regular evolution pits. Pits, having higher aspect ratio, are very dangerous form and can cause significant reduction in the load carrying capacity. When local dissolution occurs in the pitting area, SCF will have a sharp increase, it is more probable for a crack to initiate from these areas compared with pits for regular evolution. Furthermore, local dissolution coefficient is proposed to study effect of local dissolution within the pit on SCF.

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