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Identification of local cyclic stress‐strain curves at material inhomogeneities on the basis of digital image correlation
Author(s) -
Lang E.
Publication year - 2016
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.201600623
Subject(s) - digital image correlation , welding , materials science , low cycle fatigue , stress (linguistics) , finite element method , structural engineering , amplitude , residual stress , strain (injury) , basis (linear algebra) , mechanics , composite material , mathematics , geometry , engineering , physics , optics , medicine , philosophy , linguistics
Low‐cycle fatigue (LCF) tests on butt‐welded joints revealed that material inhomogeneities become decisive for the fatigue behavior at elastic‐plastic strain amplitudes and the geometrical notch is no longer the failure location – as observed in high‐cycle fatigue (HCF) regime. Digital image correlation techniques enable the measurement of local strains at the surface of the welded region. A new method is proposed that is able to calculate related local stresses and identifies local cyclic material properties in structures of inhomogeneous material and geometry. This method combines strain measurements and Finite Element simulations. It is a fast iteration procedure that is able to perform the identification within less than ten iterative steps at several hundred local points. Transient material behavior is easy to capture and an application at high temperatures is anticipated due to the method is based on materials mechanics.