Application of phased array ultrasonic technology for nondestructive testing of railway wheels
A scheme is proposed to realize nondestructive testing (NDT) of railway wheels based on phased array ultrasonic testing technology in order to ensure the safe operation and high-speed of railway transport, and achieve accurate determine the defects of railway wheels. A phased array ultrasonic NDT system for wheels was designed. The system includes four main parts: system management software, probe moving and scanning parts, ultrasonic signal acquisition and imaging. A testing scheme for wheels was designed aiming at the configuration of railroad wheels and the distribution of defects in them. The wheels safety testing experiments were carried out on model wheels with artificial defects. Results of experiments demonstrate that the testing methods are more accurate in examining the depth and the location of defects in the wheels, and this system can obtain the defects status of wheels with higher sensitivity, higher facilitation and less affection by environmental factors.
Applications of Phased Array Techniques to NDT of Industrial Structures
In many industrial areas, such as nuclear, aircraft and oil industry, there is an increasing need for versatile Non Destructive Testing methods, able to ensure the reliab ility of complex structures. Ultrasonic (UPA) phased arrays have been widely studied for several years, sinc e they provide a powerful tool for improved adaptability to a wide range of applications. These phased a rrays rely on transducer splitted into an array of elements individually driven, which allows one to master the ultrasonic beam thanks to delay and amplitude laws. One advantage is the capability of phased array to i ncrease productivity of industrial application. A simple example of a thickness measurement will be developed in order to show how fast phased array can be compared to conventional techniques. One other advantage of pha sed array is their capability to overcome difficult geometrical problems thanks to their adaptability : electronic commutation, beam-steering and focusing in complex geometries. A specific flexible phased ar ray probe will be presented and applied on a nozzle inspection. This phased array is able to conform to a complex component, without degrading the radiated UT beam.
PipING Inspection using A Smart Flexible Phased Array
The inspection of piping in nuclear power plants is mainly performed in contact with ultrasonic wedge transducers. Some areas of circuit pipes have variable geometries (variable radius of curvature, irregular surface conditions) which may limit the efficiency and even the accessibility for wedge transducers. A prototype of smart flexible probe was developed with the support of EDF in order to improve such inspections. The phased array is flexible so as to fit the variable surface. A profilometer, embedded in the transducer, measures the local surface distortion allowing the computation, in realtime, of optimized delay laws and compensate the surface aberration. Those delay laws are transferred to the real-time UT acquisition system, which applies them to the piezoelectric elements. This self-adaptive process preserves, during the scanning, the features of the focused beam (orientation and focal depth) in the specimen. This paper presents results obtained with the prototype on realistic pipes configurations. The inspected configurations were also simulated with the CIVA Software. The good agreement between experimental and simulated results validates the acoustical behavior of the probe and confirms the accurate control of the beam focusing during the tests.