| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 95 === The current study discusses the scattering ultrasound fields by elastic solid scatters in water. The scattering field is significantly affected by the size, geometric shape and material property of the scatter. In this research, the scattering pattern of an elastic scatter is obtained by experimental measurement, numerical simulation, and analytical theory method. A ring-type hydrophone array system with 15 PVDF needle type hydrophones and a PZT transducer are designed for scattering field measurement, the PZT transducer works like a wave transmitter and the PVDF hydrophones positioned on a circle encompassing the scatter are designed as scattering wave receivers. In this work, three different materials, PMMA, aluminum and copper are chosen and designed to form different cylindrical scatter, such as single cylinder and cylindrical compound structure. In this way, the scattering pattern of specific scatters of different material or structure can be obtained and therefore the relations between scatter and scattering pattern can be well established. Experimental results are in good agreement with scattering patterns computed by analytical theory and ANSYS numerical simulation method.
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