Data di Pubblicazione:
2016
Abstract:
The integrity of the wheel is very important for the safety of railway. In this paper a laserultrasonic
diagnostic measurement procedure has been designed for the inspection of the
train wheels with the aid of a FE-model simulating the ultrasound propagation within the
wheel itself.
The laser-ultrasonic method exploits an air-coupled ultrasonic probe that detects the
ultrasonic waves generated by a high-energy pulsed laser. As a result, the measurement
chain is completely non-contact, from generation to detection, this making it possible to
considerably speed up the testing set-up time and make it more flexible. This is an important
advantage with respect to the conventional NDT technologies currently applied to
train component diagnostics, as contact phase array methods. Laser ultrasonics is a complete
remote technique since both the laser source and the receiving probe are installed
in the proximity of the wheel directly on the bogie and therefore it is a more flexible technology
with respect to standard techniques applied for wheel train diagnostics, as phased
array.
The applications of laser-ultrasonic technique available in the state-of-the-art work with
high energy ultrasonic waves to guarantee good signal to noise ratio. Therefore, conventional
laser-ultrasonic systems operates under ablative regime that assures high energy
ultrasonic waves generation. On the other hand, the ablation produces damages on the surface
of the component inspected. In this paper, it has been demonstrated that it is possible
to work with lower energy waves, i.e. in the limit between ablative and thermo-elastic
regime, if the experiment is properly designed on the basis of a numerical model. This
operation regime allowed to guarantee a material removal below the threshold admitted
in rail wheel application. The diagnostic procedure developed has been applied for the
inspection of train wheels provided by the Italian railway company Trenitalia, on which
dominant wheel failure cracks have been expressly created.
diagnostic measurement procedure has been designed for the inspection of the
train wheels with the aid of a FE-model simulating the ultrasound propagation within the
wheel itself.
The laser-ultrasonic method exploits an air-coupled ultrasonic probe that detects the
ultrasonic waves generated by a high-energy pulsed laser. As a result, the measurement
chain is completely non-contact, from generation to detection, this making it possible to
considerably speed up the testing set-up time and make it more flexible. This is an important
advantage with respect to the conventional NDT technologies currently applied to
train component diagnostics, as contact phase array methods. Laser ultrasonics is a complete
remote technique since both the laser source and the receiving probe are installed
in the proximity of the wheel directly on the bogie and therefore it is a more flexible technology
with respect to standard techniques applied for wheel train diagnostics, as phased
array.
The applications of laser-ultrasonic technique available in the state-of-the-art work with
high energy ultrasonic waves to guarantee good signal to noise ratio. Therefore, conventional
laser-ultrasonic systems operates under ablative regime that assures high energy
ultrasonic waves generation. On the other hand, the ablation produces damages on the surface
of the component inspected. In this paper, it has been demonstrated that it is possible
to work with lower energy waves, i.e. in the limit between ablative and thermo-elastic
regime, if the experiment is properly designed on the basis of a numerical model. This
operation regime allowed to guarantee a material removal below the threshold admitted
in rail wheel application. The diagnostic procedure developed has been applied for the
inspection of train wheels provided by the Italian railway company Trenitalia, on which
dominant wheel failure cracks have been expressly created.
Tipologia CRIS:
1.1 Articolo in rivista
Keywords:
Laser-ultrasonics
NDT
Air-coupled ultrasound
Train wheels
FE model
Elenco autori:
Cavuto, A.; Martarelli, Milena; Pandarese, G. .; Revel, G. M.; Tomasini, E. P.
Link alla scheda completa:
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