Development of Focus-type Ultrasonic Spectroscopy System Using Polymeric Piezoelectric Films

本项目的目标是开发能够研究各种材料的局部声学特性的超声频谱系统，并将该系统应用于非探伤检测。通过这两年的研究，取得了良好的效果。1)利用聚合物压电薄膜，结合单脉冲和快速傅立叶变换方法，我们成功地构建了超声光谱系统，该系统可以在很大的自由范围内快速测量超声波的速度和吸收。2)除了脉冲电机驱动的X-Y-Z样品台外，还使用了聚合物超声换能器或凹形声透镜，使三维超声光谱测量成为可能。3)该系统成功地用于观察NYLOM-6和聚合物液晶等各种聚合物的力学行为，4)将该系统应用于玻璃/聚合物复合材料，得到了玻璃微珠的直径和分散度信息。5)提出了该系统能够提供传统超声测量无法获得的关于金属、复合材料和生物材料的内部结构和力学特性的有价值的信息的能力，并正在考虑该仪器的一个实用版本。

Objectives of this project are to develop the ultrasonic spectroscopy system capable to investigate local acoustic characteristics of various materials and to apply the system for nondestractive testings. By performing the research in these two years, the foolowing good results have been obtained.1) By utilizing polymeric piezoelectric films and combining the single pulse and fast Fourie transformation method, we succeeded in constructing the ultrasonic spectroscopy system, which can perform rapidly measurements of ultrasonic velocity and absorption in a wide freauency range.2) By using a polymeric ultrasonic transducer or an acoustic lens with a concabe shape in addition to the X-Y-Z sample stage driven with a pulse motor, three-dimensional ultrasonic spectroscopy mesurements have become possible.3) The system was successfully applied to observe mechanical ralaxations in various polymers such as Nylom-6 and polymer liquid crystals, revealing the frequency dependent natures.4) The application of the system to glass/polymer composites gave the information of diameters and dispersity of the included glass beads.5) The capability that this system provides valuable information, which can not be obtained by conventional ultrasonic measurements, on the internal structure and mechanical cararcteristics of metals, composites, and biomaterials is suggested, and a practical version of this instrument is now considered.