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Über den Einfluß von Eigenspannungen, Nahtgeometrie und mehrachsigen Spannungszuständen auf die Betriebsfestigkeit geschweißter Konstruktionen aus Baustählen.

About the influence of residual stresses, weld geometry, and multiaxial stress states on the variable amplitude fatigue behaviour of welded constructions from structural steels
 
: Sonsino, C.M.

Verein Deutscher Eisenhüttenleute -VDEh-, Düsseldorf:
Betriebsfestigkeit in Forschung, Lehre und Praxis
Düsseldorf, 1992 (Bericht - Verein Deutscher Eisenhüttenleute ABF 5)
19 S. : Abb.,Lit.
Deutsch
Aufsatz in Buch
Fraunhofer LBF ()
Baustahl; Betriebsfestigkeit; Eigenspannung; Kerbwirkung; Mehrachsigkeit; multiaxial stress-state; notch effect; residual stress; Schweißverbindung; structural fatigue strength; structural steel; welded joint

Abstract
The fatigue behaviour of welded joints depends primarely on the interaction between notch geometry, residual stress and type of loading, i.e. constant and variable amplitude loading. Longitudinal stiffeners respond to a thermal stress relieving with an increase of endurance limit of about 50 %; but in the finite fatigue life region due to plastifications in the sharp weld notch root there is no difference between the as/welded state and the stress relieved state. The plastifications are the reason that also under variable amplitude loading only in the region of high cycles a slight improvement of about 15 % due to the thermal treatment was observed. However, in the case of V-shaped specimens with smooth weld radii a stress relieve results for the whole S-N-curve in an increase of about 56 % and under variable amplitude loading for the whole fatigue life curve in an improvement of 33 %. A TIG-dresesing improves the fatigue strength under variable amplitude loading by a further 53 %. Con cerning multiaxial fatigue, when principal stress directions are constant the von Mises hypothesis can be applied satisfactorily. However, for changing stress directions all conventional hypotheses (von Mises, Tresca, principal stress) severely overestimate the fatigue life. Therefore, a development of strength hypotheses is necessary.

: http://publica.fraunhofer.de/dokumente/PX-37195.html