Evaluation of nominal and local stress based approaches for the fatigue assessment of seam welds

In the context of the German joint research project "Applicability of fatigue analysis methods for seam welded components", fatigue tests were performed by five universities and institutes on welded components, welded parts of larger structures as well as component-like samples of weld details. The sheet thickness t was in the range 1 mm t 20 mm. The welding parameters for all test coupons and structures tested were chosen according to the industrial production process. Based on the data acquired, nominal, structural and notch stress approaches were analysed with regard to applicability and quality of assessment. The actual weld geometry except the real notch radii was taken into account within the notch stress approach. For the notch radii various values, the reference radii 0.05, 0.3 and 1 mm, were applied. Experimental and numerical results for welded steel components are presented. Approximately equivalent scatter ranges were obtained when applying the various app roaches based on the current state of the art. It should be noted that both the nominal and the structural stress approaches are limited in their application compared to the notch stress approach. A comparison of the scatter bands obtained for the various approaches is subject to limitations because it was necessary, in each case, to use different test series as the basis for determining the scatter bands

Festigkeitskonzepte für schwingbelastete geschweißte Bauteile

Fatigue Approaches for Welded Structures. In the recent years the local stress approach is gaining importance in comparison to the nominal stress and structural hot spot stress approach the for fatigue assessment of welded structures made from aluminium alloys or steel. Especially while applying application of the local stress approach with a reference radius r(ref) = 0.05 mm on thin sheet structures various influence factors on the design SN curve ca be distinguished. These influences can be explained and quantified by size effects

Ermittlung von ertragbaren Schnittkraeften fuer die betriebsfeste Bemessung von Punktschweissverbindungen im Automobilbau

SIGLETIB Hannover: RN 4481(78) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman