Experimental results and fatigue life evaluation of magnesium laserbeam‐welded joints under proportional and non‐proportional multiaxial fatigue loading with variable amplitudes: Experimentelle Ergebnisse und Lebensdauerberechnung für laserstrahlgeschweißte Verbindungen aus Magnesium unter proportionalen und nichtproportionalen mehrachsigen zyklischen Belastungen mit variablen Amplituden. Issue 2 (17th February 2017)

• Record Type: Journal Article
• Authors: Bolchoun, A.; Sonsino, C. M.; Kaufmann, H.; Melz, T.
• Is Part Of: Materialwissenschaft und Werkstofftechnik. Volume 48:Issue 2(2017:Feb.)
• Page Start: 88
• Page End: 100
• Publication Date: 2017-02-17
• Subjects: Magnesium -- dünnwandige Schweißverbindungen -- spannungsbasierte Hypothesen -- nichtproportionale Belastung -- Nichtproportionalitätsfaktor; Magnesium -- thin‐walled welded joints -- stress‐based hypothesis -- out‐of‐phase loading -- non‐proportionality factor; Materials -- Periodicals; Materials -- Testing -- Periodicals; 620.1
• DOI: 10.1002/mawe.201600558
• Languages: English
• ISSNs: 0933-5137

Abstract

Abstract : Fatigue life of magnesium laserbeam‐welds (AZ31 and AZ61 alloys) was assessed experimentally under variable amplitude loadings. The specimens were subjected to load‐controlled cyclic loadings. The tests were carried out using a Gauss‐distributed amplitude sequence of length LS = 5 · 10 4 cycles and loading ratio R = –1 under pure axial, pure torsion as well as in‐phase and out‐of‐phase combined loadings. The notch stresses were obtained from a linear‐elastic FE‐model using the reference radius approach with rref = 0.05 mm. The stress‐based hypotheses were applied: Effective equivalent stress hypothesis (EESH), shear stress intensity hypothesis (SIH), Findley, and modified Gough‐Pollard. A non‐proportionality factor is introduced and steps required for computing are presented in order to improve fatigue life assessment under non‐proportional loadings.