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Abstract

Flange-tube joints from fine-grained steel Fe E 460 with as-welded and machined welds were investigated under biaxial constant and variable amplitude loading (bending and torsion). In-phase loading can be treated fairly well using the conventional hypotheses (von Mises or Tresca) on a basis of nominal, structural or local strains or stresses. But the influence of out-of-phase loading on fatigue life is severely overestimated if conventional hypotheses are used. However, the introduced hypothesis of the effective equivalent stress (EESH) leads to fairly accurate predictions. For this the knowledge of local stresses and strains is necessary.


Damage accumulation under a Gaussian spectrum can be assessed for In- and out-of-phase combined bending and torsion using an allowable damage sum of 0.35 for weldments in the aswelded state and 0.16 for joints with machined weldments with a lower notch factor of the critical area.

As an interim design approach, the present and relevant published results indicate that Eurocode 3/IIW S-N curve FAT80/3 (negative inverse slope of 3) is suitable for combined nominal normal and nominal shear stresses acting in-phase, and possibly out-of-phase bending and shear. However, lower curve FAT56/5 is necessary for out-of-phase torsion and bending or tension. Both curves are used in conjunction with the normal maximum principal stress range occurring during the loading cycle.cle.

Additional information

Authors: RAZMJOO G R, The Welding Institute, Cambridge (GB);MADDOX S J, The Welding Institute, Cambridge (GB);GÄTH N, Fraunhofer Institut für Betriebsfestigkeit LBF, Darmstadt (DE);KÜPPERS M, Fraunhofer Institut für Betriebsfestigkeit LBF, Darmstadt (DE);SORSINO C M, Fraunhofer Institut für Betriebsfestigkeit LBF, Darmstadt (DE);GATH N, Fraunhofer Institut fur Betriebsfestigkeit LBF, Darmstadt (DE);KUPPERS M, Fraunhofer Institut fur Betriebsfestigkeit LBF, Darmstadt (DE)
Bibliographic Reference: EUR 20050 EN (2001), pp.105. Euro:16.00
Availability: Available from EUR-OP sales agents. URL: http://eur-op.eu
ISBN: ISBN:92-894-2067-7
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