TY - JOUR A1 - Sonntag, Nadja A1 - Skrotzki, Birgit A1 - Stegemann, Robert A1 - Löwe, Peter A1 - Kreutzbruck, M. T1 - The role of surface topography on deformation-induced magnetization under inhomogeneous elastic-plastic deformation JF - Materials N2 - It is widely accepted that the magnetic state of a ferromagnetic material may be irreversibly altered by mechanical loading due to magnetoelastic effects. A novel standardized nondestructive testing (NDT) technique uses weak magnetic stray fields, which are assumed to arise from inhomogeneous deformation, for structural health monitoring (i.e., for detection and assessment of damage). However, the mechanical and microstructural complexity of damage has hitherto only been insufficiently considered. The aim of this study is to discuss the phenomenon of inhomogeneous “self-magnetization” of a polycrystalline ferromagnetic material under inhomogeneous deformation experimentally and with stronger material-mechanical focus. To this end, notched specimens were elastically and plastically deformed. Surface magnetic states were measured by a three-axis giant magnetoresistant (GMR) sensor and were compared with strain field (digital image correlation) and optical topography measurements. It is demonstrated that the stray fields do not solely form due to magnetoelastic effects. Instead, inhomogeneous plastic deformation causes topography, which is one of the main origins for the magnetic stray field formation. Additionally, if not considered, topography may falsify the magnetic signals due to variable lift-off values. The correlation of magnetic vector components with mechanical tensors, particularly for multiaxial stress/strain states and inhomogeneous elastic-plastic deformations remains an issue. KW - Magnetic stray fields KW - Magnetomechanical effect KW - Damage KW - Topography KW - Multiaxial deformation KW - Notch KW - Plastic deformation KW - Metal magnetic memory KW - Digital image correlation KW - Structural steel PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457878 DO - https://doi.org/10.3390/ma11091518 SN - 1996-1944 VL - 11 IS - 9 SP - 1518, 1 EP - 26 PB - MDPI CY - Basel, Switzerland AN - OPUS4-45787 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schöne, Dieter A1 - Bork, Claus-Peter ED - Klingbeil, D. ED - Vormwald, M. ED - Eulitz, K.-G. T1 - Fatigue investigations of damaged railway rails of UIC 60 profile T2 - 18th European conference on fracture (ECF 18) - Fracture of materials and structures from micro to macro scale (Proceedings) N2 - The development of procedures to calculate the service life of railway rails requires test results which describe the damage of rails thus affording their validation. Within the DEUFRAKO integrated project NOVUM, ten rail specimens were tested under constant and variable amplitude loads to investigate the propagation of lateral cracks and to ascertain the service life. The test conditions were based on real rail loading and were used in the 3-point-bending test frame under alternating stress. An eccentric notch was applied as pre-arranged damage in the 60 E1 (260) rail specimens. The notched rails showed a similar behaviour like rails with strong head checks damaged by rolling contact fatigue. T2 - 18th European conference on fracture (ECF 18) - Fracture of materials and structures from micro to macro scale CY - Dresden, Germany DA - 2010-08-30 KW - Railway rail KW - Notch KW - Service loading fatigue KW - Crack propagation KW - Bending KW - Damage PY - 2010 SN - 978-3-00-031802-3 IS - Paper 88 SP - 1 EP - 8 AN - OPUS4-22328 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hünecke, Joachim A1 - Schöne, Dieter A1 - Klingbeil, Dietmar A1 - Bork, Claus-Peter T1 - Advanced life prediction by microstructural simulation of short cracks in a low carbon steel JF - International Journal of Fatigue N2 - This paper deals with life prediction by observation and simulation of short fatigue cracks in cyclically loaded smooth and notched specimens made of 0.15 wt-% carbon steel SAE1017. The measured crack behaviour was simulated in a microstructural environment. Reference tests under constant amplitude loading allowed to determine model parameters and hence a reasonable life prediction by simulation resulted even for service loading. Short crack behaviour was a measurable property for damage also to compare smooth and notched specimens. KW - Short cracks KW - Life prediction KW - Simulation KW - Fatigue KW - Microstructure KW - Service loading KW - Notch KW - Kurze Risse KW - Gefüge KW - Ermüdung KW - Lebensdauer PY - 2006 DO - https://doi.org/10.1016/j.ijfatigue.2005.07.049 SN - 0142-1123 VL - 28 IS - 9 SP - 993 EP - 1000 PB - Elsevier CY - Oxford AN - OPUS4-12559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -