TY - JOUR
T1 - Mid- and High-Cycle Fatigue of Welded Joints in Steel Marine Structures
T2 - Effective Notch Stress and Total Stress Concept Evaluations
AU - Qin, Yanxin
AU - den Besten, Henk
AU - Palkar, Saloni
AU - Kaminski, Miroslaw Lech
PY - 2021
Y1 - 2021
N2 - The characteristic far field response spectrum of welded joints – the governing fatigue sensitive locations in steel marine structures – is predominantly linear elastic, meaning mid- and high-cycle fatigue (MCF and HCF) is most important for design. Using the effective notch stress- and the total stress concept, involving respectively Se and ST as intact- and cracked geometry fatigue strength criterion, one MCF-HCF resistance curve has been obtained for all welded joints. A generalised random fatigue limit model explicitly incorporating the MCF life time and HCF strength limit scatter provides statistically the most accurate fatigue strength and fatigue life time estimates. Similar MCF performance is obtained for Se and ST. Although crack growth dominates the MCF damage process, the results for an initiation related criterion like Se and natural crack growth related criterion like ST are similar. Adopting Se rather than ST as fatigue strength criterion naturally related to the crack initiation dominated HCF region showing the largest data scatter may explain the better effective notch stress concept HCF performance. Since the HCF resistance scatter is relatively large, the MCF-HCF generalised random fatigue limit model design curves show approximately 1-slope behaviour. meaning that for design purposes a linear Basquin model approximation rather than a piecewise continuous bi-linear MCF-HCF formulation according to guidelines, standards and classification notes should be adopted.
AB - The characteristic far field response spectrum of welded joints – the governing fatigue sensitive locations in steel marine structures – is predominantly linear elastic, meaning mid- and high-cycle fatigue (MCF and HCF) is most important for design. Using the effective notch stress- and the total stress concept, involving respectively Se and ST as intact- and cracked geometry fatigue strength criterion, one MCF-HCF resistance curve has been obtained for all welded joints. A generalised random fatigue limit model explicitly incorporating the MCF life time and HCF strength limit scatter provides statistically the most accurate fatigue strength and fatigue life time estimates. Similar MCF performance is obtained for Se and ST. Although crack growth dominates the MCF damage process, the results for an initiation related criterion like Se and natural crack growth related criterion like ST are similar. Adopting Se rather than ST as fatigue strength criterion naturally related to the crack initiation dominated HCF region showing the largest data scatter may explain the better effective notch stress concept HCF performance. Since the HCF resistance scatter is relatively large, the MCF-HCF generalised random fatigue limit model design curves show approximately 1-slope behaviour. meaning that for design purposes a linear Basquin model approximation rather than a piecewise continuous bi-linear MCF-HCF formulation according to guidelines, standards and classification notes should be adopted.
KW - Effective notch stress
KW - Mid- and high-cycle fatigue
KW - Steel marine structures
KW - Total stress
KW - Welded joints
UR - http://www.scopus.com/inward/record.url?scp=85089940637&partnerID=8YFLogxK
U2 - 10.1016/j.ijfatigue.2020.105822
DO - 10.1016/j.ijfatigue.2020.105822
M3 - Article
AN - SCOPUS:85089940637
SN - 0142-1123
VL - 142
JO - International Journal of Fatigue
JF - International Journal of Fatigue
M1 - 105822
ER -