New weld toe magnification factors for semi-elliptical cracks in double-sided T-butt joints and cruciform X-joints

This study considers the effect of bending loading and the symmetry of joints on the fatigue strength of transverse non‐load carrying attachments. Conventionally, the fatigue strength of a welded joint has been determined without taking these factors into account. Experimental and finite element analyses were carried out and both methods showed that both loading type and symmetry have an influence on the fatigue resistance of a welded joint. Under tensile loading, the fatigue strength of asymmetric T‐joints was higher than that of symmetric X‐joints. Respectively, the fatigue resistance of tested joints improved explicitly when the external loading was bending. The finite element analysis was in good agreement with the test results in the joints subjected to tension but gave very conservative results in the joints subjected to bending.

Section: Introductionmentioning

confidence: 99%

Effect of loading type on the fatigue strength of asymmetric and symmetric transverse non‐load carrying attachments

Ahola

Nykänen

Björk

2016

“…This section is divided into two subsections. The first subsection gives a comparison of M k values between butt welds with single T‐butt welds and X‐joints . And the second one covers the influence of the four parameters ( a / T , a / c , L / T and θ ) on M k values.…”

Section: Resultsmentioning

confidence: 99%

“…Butt welds are subjected to both axial and bending loadings. For axial loading cases, one end of the main plate parallel to crack face is restrained, and a uniform stress is applied at the other end of the main plate . Bending loading is achieved through pure bending .…”

Section: Parametric Studymentioning

confidence: 99%

“…An extensive parametric study on M k of single T-butt joints was conducted by Bowness and Lee, 11 which covered the most commonly used weld profiles found in practice and has been incorporated in the British Standard BS7910. 12 On the basis of the work carried out by Bowness and Lee, 11 Lie et al 13 subsequently established the M k equations for semi-elliptical cracks in doublesided T-butt joints and cruciform X-joints. Until now, M k equations for T-butt geometry with one-sided weld, 11 T-butt geometry with double-sided weld and non-load carrying cruciform X-joints 13 have been established.…”

mentioning

confidence: 99%

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New weld toe magnification factors for semi‐elliptical cracks in plate‐to‐plate butt‐welded joints

Lie

Zhao

Vipin

2016

A B S T R A C T British Standard 7910:2013 includes a single set of equations for estimating the weld toe magnification factor (M k ) of different types of welded joints with a semi-elliptical surface crack. In this study, extensive finite element analyses are performed to determine the M k of plate-to-plate butt-welded joints subjected to axial and bending loading. The M k values at the crack deepest points and the crack ends are determined. It is found that the M k results of butt welds are different with those of single T-butt joints with percentage difference in values being as high as 63.8% and 97.4% for axial and bending loading cases, respectively. Percentage differences of 60.4% and 358.2% for axial and bending loading cases are observed between butt welds and X-joints. New M k equations for butt welds are proposed using multiple regression analyses.Keywords butt welds; finite element analysis; regression analysis; surface crack; weld toe magnification factor. N O M E N C L A T U R Ea = crack depth B = plate width c = crack half length K = stress intensity factor L = weld length for butt welds, = attachment footprint width for single T-butt joints and X-joints M k = weld toe magnification factor R = radius of weld profile T = main plate thickness θ = weld angle SUBSCRIPTS a = deepest point b = bending loading c = crack ends m = axial loading

“…5 In practice, semielliptical surface cracks usually observed at the weld toe cannot be accurately represented by the 2D approximation because of the 3D nature of the geometry. 7,9 Recently, Lie et al 10,11 observed the differences between the M k solutions for the abovementioned 3 types of joint and the T-butt joint with one side weld and proposed new M k equations based on multiple regression analyses. 5,6 The sets of equations they developed have been incorporated in the British Standard BS7910 7 and are used with the plain plate solutions of Newman and Raju 8 to estimate the SIFs.…”

Section: Introductionmentioning

confidence: 99%

Stress distribution and fatigue crack propagation analyses in welded joints

Dong

Soares

2018

An approach is presented, based on the weight function method to calculate the stress intensity factors of semielliptical surface cracks originating from the notch root of welded joints. The stress distribution along the potential crack plane required in the weight function method is constructed on the basis of the notch stress intensity factor approach in the highly stressed zone and of the equivalent linearized stress distribution and is compared with those determined by the finite element method and existing predictions. The stress intensity factors determined by the proposed approach are compared with available solutions. These comparisons show that the results determined by the proposed approach generally agree well with the existing solutions. For the cases where the agreement is poor, the reasons are identified. One important feature of the proposed approach is that the stress singularity at sharp notch tip can be considered, which cannot be appropriately simulated by the finite element method. Finally, to demonstrate the applicability of the proposed approach, the fatigue life and the fatigue crack shape evolution of welded joints are predicted and they are compared with experimental results.