Abstract

The paper is concerned with the problem of stress concentration in cruciform fillet welded joints subjected to axial and bending load. Extended numerical analyses were carried out with the help of the finite element method. It made it possible to estimate stress concentration factors Kt for a variety of geometrical parameters defining the geometry of cruciform welded joints. It has been found that approximate Kt formulas, available in the literature, have two disadvantages, i.e. an unknown accuracy and small range of application with respect to geometrical parameters defining the weld shape. For these reasons, more general and accurate new formulas for stress concentration factors Kt have been derived. Even though the present approach is applicable to all types of welded joints, the analysis presented below has been conducted for a cruciform joint with the weld flank angle of θ = 45°. Final solutions have been given in the form of polynomial expressions, and they can be easily used in computer-aided design procedures.

Highlights

  • The linear elastic stress concentration factor Kt is one of the most important parameters used in predicting fatigue life of structural components with various types of stress raisers like holes, notches, grooves, and stiffeners

  • The damage process usually initiates at the weld toe [8, 9], especially in the case of cruciform joints without the lack of penetration [10] or when the fillet weld size is sufficiently large [11]

  • It appears that the approximate formulas have two important disadvantages: undetermined accuracy and narrow range of application with respect to geometrical parameters defining the weld geometry

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Summary

Introduction

The linear elastic stress concentration factor Kt is one of the most important parameters used in predicting fatigue life of structural components with various types of stress raisers like holes, notches, grooves, and stiffeners. It is generally accepted [12, 13] that the overall load applied to the main plate of thickness t may be regarded as the superposition of the axial and bending load. For this reason, the maximum stress, appearing at critical locations, shown in Fig. 1 as circles, depends on both the axial and bending load magnitude, and it is described by two stress concentration factors Ktt and Ktb, respectively. Various approximate formulas of Kt are used

Available stress concentration factor formulas for cruciform joints
General assumptions
The numerical model and boundary conditions
Accuracy of approximate Kt formulas
The weld toe radius effect
The plate thickness effect
Conclusions drawn from finite element method solutions
General form of the analytical stress concentration factor formula
The sharp corner configuration as the limiting case of the weld toe radius
Validation of approximating formulas
Findings
Conclusions
Full Text
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