Simulation and applications of NDT ultrasonic array techniques

More and more, phased arrays play an increasing role in ultrasonic non destructive testing, as they provide improved versatility, adaptability to complex configurations and efficiency compared to conventional techniques. The possibilities offered by arrays are numerous, involving electronic commutation, applications of electronic delays in the aim of beam forming, signal processing, etc... Besides the most standard techniques based on 2D beam steering and focusing, more sophisticated techniques are emerging involving matrix arrays and 3D beam forming. Flexible arrays are now available which allow to overcome problems due to complex and varying geometries of the inspected part (elbow, nozzles, butt weld...). The conception and optimization of the techniques, the design of the arrays, as well as the imaging and interpretation of the data requires dedicated simulation tools. Such tools based on an accurate modelling of ultrasound propagation in the part and dedicated to the conception and optimization of the techniques, the design of the arrays, as well as the imaging and interpretation of the data have been developed and implemented in the CIVA software plat-form. They allow to fully exploit electronic commutation over linear or matrix arrays, to compute adapted delay laws which take into account the whole complexity of the inspection, to predict transmitted beams in the part as well as echoes arising for prescribed flaws. In this communication the efficiency of array techniques and the capabilities of related simulation are illustrated on various complex applications such as nozzles, welds, and pipes inspection.