阵列解析式超声聚焦换能器的研制

发布时间：2018-04-30 21:32

本文选题：阵列式声场感测 + 超声聚焦换能器　；参考：《北京工业大学》2014年硕士论文

【摘要】：超声聚焦换能器作为超声显微测量系统的核心部件，在工业超声影像扫描和材料声学特性测量等领域中具有十分重要的作用。随着工业加工技术和材料科学技术的发展，超声聚焦换能器也向着高频率、高精度和高分辨率的方向不断发展。然而，传统的超声聚焦换能器都采用单一的压电感测元件，因此得到的信号是所有反射到其压电感测面能量的在感测面上积分结果，无法反映反射声场的空间分布特性。因此，亟待一种阵列化的声场感测模式，从多角度感测聚焦声场信息，以便更好地还原反射声场的空间分布。本课题针对声场的空间感测问题展开研究，设计制作了阵列解析式超声聚焦换能器，并进行了相应理论和实验的研究，主要研究内容如下： (1)针对传统超声聚焦换能器单一感测元件无法有效还原声场空间分布特性的问题，结合聚焦换能器的背向反射声场的形成机理，研制了一种新型的超声聚焦换能器——阵列解析式超声聚焦换能器，设计通过凝胶旋涂、紫外线曝光显影及微纳米电子束蒸镀等精密加工技术，实现了在换能器的大张角聚焦曲面上制作阵列式感测电极，并利用P(VDF-TrFE)高温溶胶结晶技术来实现阵列式感测元件压电材料的制作，成功实现了一种激励与接收相分离的空间感测换能器。 (2)搭建了一套基于FPGA技术的高速超声检测系统，并通过该系统对阵列解析式超声聚焦换能器的多个感测元件的激励响应特性进行标定。结合无缺陷聚焦模型的有限元仿真结果，对各感测元件的测试性能进行分析，确定了换能器各感测单元的敏感性修正系数，最终无缺陷试件的实际测量结果与有限元仿真结果，，达到了很好的一致性。 (3)利用新型换能器的阵列感测元件的空间分布特性，对多角度声场感测信号进行分析和处理，并以垂直边界高度为测试对象开展实验研究，取得了预期的测试效果，解决了传统超声成像扫描无法实现的问题，表明阵列解析式超声聚焦换能器具有很好的应用价值和学术意义。
[Abstract]:As the core component of ultrasonic microscopic measurement system, ultrasonic focused transducer plays an important role in the field of industrial ultrasonic image scanning and measurement of material acoustic characteristics. With the development of industrial processing technology and material science and technology, ultrasonic focused transducer is developing towards high frequency, high precision and high resolution. However, the traditional ultrasonic focusing transducer uses a single piezoelectric sensor, so the signal obtained is the integral result of all the energy reflected to its piezoelectric sensor surface, which can not reflect the spatial distribution of the reflected sound field. Therefore, an array sound field sensing mode is urgently needed to detect the focused sound field information from multiple angles in order to better restore the spatial distribution of the reflected sound field. In this paper, the space sensing problem of sound field is studied, the array analytical ultrasonic focusing transducer is designed and fabricated, and the corresponding theoretical and experimental research is carried out. The main research contents are as follows: 1) aiming at the problem that the single sensing element of traditional ultrasonic focusing transducer can not effectively reduce the spatial distribution of sound field, combining with the formation mechanism of the sound field reflected in the back direction of the focused transducer, A new type of ultrasonic focusing transducer, array analytical ultrasonic focusing transducer, was developed. The precise processing technology was designed through gel spin coating, ultraviolet exposure development and micro-nano electron beam evaporation, etc. The array sensing electrode is fabricated on the large angle focusing surface of transducer, and the piezoelectric material of array sensing element is fabricated by using the high temperature sol crystallization technology of PvDF-TrFE. A space sensing transducer which separates excitation from receiving phase is successfully realized. (2) A high speed ultrasonic detection system based on FPGA technology is set up, and the excitation response characteristics of several sensing elements of the array analytical ultrasonic focusing transducer are calibrated by the system. Combined with the finite element simulation results of the non-defect focusing model, the testing performance of each sensing element is analyzed, and the sensitivity correction coefficient of each sensing element of the transducer is determined, and the actual measurement results and the finite element simulation results of the non-defect specimen are determined. Good consistency has been achieved. 3) using the spatial distribution characteristics of the array sensor of the new transducer, the multi-angle acoustic field sensing signal is analyzed and processed, and the experimental research is carried out with the vertical boundary height as the test object, and the expected test results are obtained. It solves the problem that the traditional ultrasonic imaging scanning can not be realized, and shows that the array analytical ultrasonic focusing transducer has good application value and academic significance.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB552

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