题　目：Multi-element air-coupled capacitive ultrasonic transducer with dynamic focusing for NDT of materials - Modeling, numerical simulations and experiments
报告人：张迪 博士（法国波尔多第一大学）
时　间：12月17日（周二），下午4:00-5:00
地　点：声学馆102 会议室
报告摘要：
This presentation focuses on the development of a Multi-Element Air-coupled Capacitive Ultrasonic Transducer (MEACUT) and its use in the field of ultrasonic Non-Destructive Testing (NDT) of materials. An analytical Kirchhoff integration model (KIM) is developed and used to simulate the circular or annular transducers, and to optimize the dimension in order to obtain required acoustic field profile. An optimized annular MEACUT is then built and experimentally characterized to quantify its frequency response and dynamic focusing performance. It turns out to be a broad frequency bandwidth with the capability of dynamic focusing. This prototype is then used for the inspection of damage caused by impact in a composite plate. It is clearly found that the spatial resolution of the inspection process employed (C-scan) is greatly improved due to the local focusing performance of MEACUT. Finally, a 3D hybrid model composed with Kirchhoff-FE-Rayleigh models is developed to simulate quickly and fully, the process of NDT. The good agreement obtained between numerical predictions and experimental measurements suggests that this simulation tool can be used to simulate and develop other NDT experiments, which may in turn exploit the performance of MEACUT.