本文選題：陣列式聲場(chǎng)感測(cè) + 超聲聚焦換能器��； 參考：《北京工業(yè)大學(xué)》2014年碩士論文

【摘要】：超聲聚焦換能器作為超聲顯微測(cè)量系統(tǒng)的核心部件，在工業(yè)超聲影像掃描和材料聲學(xué)特性測(cè)量等領(lǐng)域中具有十分重要的作用。隨著工業(yè)加工技術(shù)和材料科學(xué)技術(shù)的發(fā)展，超聲聚焦換能器也向著高頻率、高精度和高分辨率的方向不斷發(fā)展。然而，傳統(tǒng)的超聲聚焦換能器都采用單一的壓電感測(cè)元件，因此得到的信號(hào)是所有反射到其壓電感測(cè)面能量的在感測(cè)面上積分結(jié)果，無法反映反射聲場(chǎng)的空間分布特性。因此，亟待一種陣列化的聲場(chǎng)感測(cè)模式，從多角度感測(cè)聚焦聲場(chǎng)信息，以便更好地還原反射聲場(chǎng)的空間分布。本課題針對(duì)聲場(chǎng)的空間感測(cè)問題展開研究，設(shè)計(jì)制作了陣列解析式超聲聚焦換能器，并進(jìn)行了相應(yīng)理論和實(shí)驗(yàn)的研究，主要研究?jī)?nèi)容如下： (1)針對(duì)傳統(tǒng)超聲聚焦換能器單一感測(cè)元件無法有效還原聲場(chǎng)空間分布特性的問題，結(jié)合聚焦換能器的背向反射聲場(chǎng)的形成機(jī)理，研制了一種新型的超聲聚焦換能器——陣列解析式超聲聚焦換能器，設(shè)計(jì)通過凝膠旋涂、紫外線曝光顯影及微納米電子束蒸鍍等精密加工技術(shù)，實(shí)現(xiàn)了在換能器的大張角聚焦曲面上制作陣列式感測(cè)電極，并利用P(VDF-TrFE)高溫溶膠結(jié)晶技術(shù)來實(shí)現(xiàn)陣列式感測(cè)元件壓電材料的制作，成功實(shí)現(xiàn)了一種激勵(lì)與接收相分離的空間感測(cè)換能器。 (2)搭建了一套基于FPGA技術(shù)的高速超聲檢測(cè)系統(tǒng)，并通過該系統(tǒng)對(duì)陣列解析式超聲聚焦換能器的多個(gè)感測(cè)元件的激勵(lì)響應(yīng)特性進(jìn)行標(biāo)定。結(jié)合無缺陷聚焦模型的有限元仿真結(jié)果，對(duì)各感測(cè)元件的測(cè)試性能進(jìn)行分析，確定了換能器各感測(cè)單元的敏感性修正系數(shù)，最終無缺陷試件的實(shí)際測(cè)量結(jié)果與有限元仿真結(jié)果，，達(dá)到了很好的一致性。 (3)利用新型換能器的陣列感測(cè)元件的空間分布特性，對(duì)多角度聲場(chǎng)感測(cè)信號(hào)進(jìn)行分析和處理，并以垂直邊界高度為測(cè)試對(duì)象開展實(shí)驗(yàn)研究，取得了預(yù)期的測(cè)試效果，解決了傳統(tǒng)超聲成像掃描無法實(shí)現(xiàn)的問題，表明陣列解析式超聲聚焦換能器具有很好的應(yīng)用價(jià)值和學(xué)術(shù)意義。
[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.
【學(xué)位授予單位】：北京工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TB552

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