Modeling and fatigue assessment of weld start‐end locations based on the effective notch stress approach

Abstract

The present paper contains a methodology for modeling and life assessment of fatigue loaded welded components providing distinct weld start and end locations. The proposed methodology follows the IIW recommendation regarding modeling and finite element meshing of weld toe and root by means of an effective notch radius and uses the corresponding Wöhler curve (FAT class) to assess the durability. Geometrical singularities and, therewith, numerical discontinuities, can be overcome especially when 3D weld root problems are treated. The fatigue life assessment is performed on the basis of normal stresses acting at the failure-critical weld toe and root locations. Comprehensive experimental database containing stress and fatigue life results derived from motor truck's hypoid rear axles providing complex 3D welds subject to vertical, longitudinal, and torsional loading is used to verify the calculation accuracy of the proposed methodology. The agreement between experimentally determined and calculated fatigue results is satisfactory.

An extrapolation method to determine the effective notch stress in welded joints

“…Recent experimental investigations on small‐scale and large‐scale specimens have verified the accuracy of the effective notch stress S–N curve for various welded steel joints. Other research activities have also extended ENSC for fatigue assessment of joints with pronounced weld termination region, at which the critical notch stress normally locates.…”

“…Other research activities [11][12][13][14][15][16] have also extended ENSC for fatigue assessment of joints with pronounced weld termination region, at which the critical notch stress normally locates. As described in engineering guidelines, [2][3][4] the effective notch stress derives from a numerical analysis of welded joints modeled with a prescribed notch radius at the weld toe or at the weld root, as illustrated in Fig.…”

Fatigue assessment of thin‐welded joints with pronounced terminations

“…It provides an elevated accuracy in return of a bearable consumption of computational resources and time. Recently, Kaffenberger and Vormwald and Malikoutsakis and Savaidis proposed procedures to extend its applicability to 3D structures with pronounced weld terminations and complex geometry. Specific instructions concerning design and FE meshing of these regions are suggested and validated through respective experimental investigations on thick and thin‐welded components.…”

Notch stress and fracture mechanics based assessment of fatigue of seam weld ends under shear loading

“…Interested readers may find thorough description of the experimental investigation in Refs. . These components are considered as thick welded joints, because they present a sheet thickness of t = 9.5 mm in the area near the weld detail in question, a throat thickness of a w = 6.8 mm.…”