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A fast ray trace based simulation software has been developed in order to determine the best layout for the ultrasonic weld seam inspection of large diameter line pipes prior to the production process. An interactive graphical user interface allows the user to adjust the relevant settings. The resulting sound propagation in the pipe wall is directly visualized in a negligible computational time. The program comprises a model to take into account the influence of the ultrasonic sound anisotropy. For the validation of the simulation results, comparisons with semi-analytical calculations were carried out.

NDT use of the concept of ?Probability of Detection? (POD) has been around since about the 1970s. Most recently the concept of ?Probability of Rejection? has been used. A description of its premises and how it is easily adapted from the principles of POD are described here.

AVG (DGS) estimations, immersion tests using focused beams and now more recently phasbed-array examinations all require compensation for the effects of the coupling material on the near field or focal point. Simple equations are used for the approximate positioning of a near field distance or focal point when a single medium is used (e.g. contact testing with a normal beam probe). However, when an intervening material is used (such as a liquid bath for immersion or a delayline or refracting wedge) the position that the focus occurs is modified by the added soundpath in the coupling material. With the readily available ability to alter the focal distance with a phasedarray probe the importance of considering the effects of the coupling path are highlighted.