TY  - JOUR
A1  - Stegemann, Robert
A1  - Cabeza, Sandra
A1  - Pelkner, Matthias
A1  - Lyamkin, Viktor
A1  - Pittner, Andreas
A1  - Werner, Daniel
A1  - Wimpory, Robert
A1  - Boin, Mirko
A1  - Kreutzbruck, Marc
A1  - Bruno, Giovanni
T1  - Influence of the microstructure on magnetic stray fields of low-carbon steel welds
JF  - Journal of Nondestructive Evaluation
N2  - This study examines the relationship between the magnetic mesostructure with the microstructure of low carbon steel tungsten inert gas welds. Optical microscopy revealed variation in the microstructure of the parent material, in the heat affected and fusion zones, correlating with distinctive changes in the local magnetic stray fields measured with high spatial resolution giant magneto resistance sensors. In the vicinity of the heat affected zone high residual stresses were found using neutron diffraction. Notably, the gradients of von Mises stress and triaxial magnetic stray field modulus follow the same tendency transverse to the weld. In contrast, micro-X-ray fluorescence characterization indicated that local changes in element composition had no independent effect on magnetic stray fields.
KW  - TIG-welding
KW  - GMR sensors
KW  - Magnetic stray field
KW  - Neutron diffraction
KW  - Residual stress
KW  - Microstructure
KW  - Low carbon steel
Y1  - 2018
U6  - https://doi.org/10.1007/s10921-018-0522-0
SN  - 0195-9298
SN  - 1573-4862
VL  - 37
IS  - 3
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Daschewski, Maxim
A1  - Kreutzbruck, Marc
A1  - Prager, Jens
A1  - Dohse, Elmar
A1  - Gaal, Mate
A1  - Harrer, Andrea
T1  - Resonance-free measuring and excitation of ultrasound
JF  - Technisches Messen : tm ; Plattform für Methoden, Systeme und Anwendungen der Messtechnik
N2  - In this contribution we present innovative methods for broadband and resonance-free sensing and emitting of ultrasound. The sensing method uses a polyethylene foil and a laser vibrometer as a broadband and resonance-free sound receiver. In general, this method enables absolute measurement of sound particle velocity and sound pressure in arbitrary, laser beam transparent liquids and gases with known density and sound velocity. The resonance-free emitting method is based on the electro-thermo-acoustic principle and enables, contrary to conventional ultrasound transducers, generation of arbitrary shaped acoustic signals without resonances and post-oscillations.
KW  - Ultrasound
KW  - transfer function
KW  - characterization of ultrasonic measurement systems
KW  - thermo-acoustic ultrasound emitter
Y1  - 2015
U6  - https://doi.org/10.1515/teme-2014-0020
SN  - 0171-8096
VL  - 82
IS  - 3
SP  - 156
EP  - 166
PB  - De Gruyter
CY  - Berlin
ER  -