FEM based design of experiment for train wheelset diagnostics by laser ultrasonics.

Laser-Ultrasonics Testing (LUT) is a Non-Destructive Technique (NDT) with good potential for application in the railway sector, nevertheless this technique is not yet used in practice because there are some practical difficulties to overcome. The possibility of measuring on a complete wheelset by bypassing the keying of the wheel will allow drastically reducing the inspection time but it has not yet been demonstrated. In fact, the attenuation of the signal in the path makes complex the interpretation of the generated waves.

Laser ultrasonics for bulk-density distribution measurement on green ceramic tiles.

In this paper a Laser Ultrasonics (LUT) system is developed and applied to measure bulk density distribution of green ceramic tiles, which are porous materials with low heat conductivity. Bulk density of green ceramic bodies is a fundamental parameter to be kept under control in the industrial production of ceramic tiles. The LUT system proposed is based on a Nd:YAG pulsed laser for excitation and an air-coupled electro-capacitive transducer for detection.

Experimental investigation by laser ultrasonics for high speed train axle diagnostics.

The present paper demonstrates the applicability of a laser-ultrasonic procedure to improve the performances of train axle ultrasonic inspection. The method exploits an air-coupled ultrasonic probe that detects the ultrasonic waves generated by a high-power pulsed laser. As a result, the measurement chain is completely non-contact, from generation to detection, this making it possible to considerably speed up inspection time and make the set-up more flexible.

The development of a shock-tube based characterization technique for air-coupled ultrasonic probes.

The present paper proposes a new characterization technique for air-coupled ultrasound probes. The technique is based on a shock tube to generate a controlled pressure wave to calibrate transducers within their operating frequency range. The aim is to generate a high frequency pressure wave (at least up to 200 kHz) with the low energy levels typical of commonly used air-coupled ultrasound probes.