نتایج جستجو برای: tofd
تعداد نتایج: 75 فیلتر نتایج به سال:
Automated ultrasonics is steadily becoming the standard method of inspection of pipeline girth welds throughout the world. In addition, old technology multiprobe systems are rapidly being replaced by newer phased arrays. Olympus NDT developed the first phased array system a decade ago, which proved to be much more flexible and capable than multiprobe systems, particularly for offshore special a...
Several developments in the past have greatly helped to enhance ultrasonic detection and sizing. An important step forward was the introduction of Time of Flight Diffraction (ToFD), making sizing considerably less dependent of defect orientation. Optimized pulse-echo techniques, advances in transducer technology and software support combined with ToFD now enable the relatively high reliability ...
Delayed coke drums are operated under severe conditions of cyclic heating and forced cooling that apply repetitive thermal stresses to the drum walls. It has long been recognized that the ultimate failure mechanism for coke drums is weld cracking due to low cycle fatigue caused by these thermal stresses. It is also known that coke drums distort and bulge in service and that these bulges can be ...
Simulation is helpful for evaluating the performances of inspection techniques and requires the modeling of waves scattering from defects. Two classical flaw scattering models have been previously evaluated and implemented in the CIVA platform developed by CEA/LIST to deal with planar defects: the geometrical theory of diffraction (GTD) and the Kirchhoff approximation (KA). These two approaches...
Ultrasonic NDT techniques based on phased array technology are more and more applied in various industrial contexts, as they provide improved adaptability to different inspection configurations. Such techniques include conventional or advanced inspection modes, as electronic commutation, sectorial scanning, adaptive beam forming, multi-channels data reconstructions... All those features shall b...
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