AIR-COUPLED TRANSDUCER WITH A HOLLOW GLASS MICROSPHERES FILLED EPOXY RESIN MATCHING LAYER
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- 英文论文题名：AIR-COUPLED TRANSDUCER WITH A HOLLOW GLASS MICROSPHERES FILLED EPOXY RESIN MATCHING LAYER
- 论文作者：Qiao WU ; Qiu-ying CHEN ; Guo-xuan LIAN ; Xiao-min WANG
- 英文论文作者：Qiao WU ; Qiu-ying CHEN ; Guo-xuan LIAN ; Xiao-min WANG ; State Key Laboratory of Acoustics ; Institute of Acoustics ; Chinese Academy of Sciences
- 年：2016
- 作者机构：State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences;
- 英文论文关键词：Hollow glass microspheres filled epoxy resin ; Air-coupled transducer ; Matching layer
- 会议召开时间：2016-10-21
- 会议录名称：2016年全国压电和声波理论及器件应用研讨会论文摘要集
- 英文会议录名称：Abstract Book of 2016 Symposium on Piezoelectricity, Acoustic Waves and Device Applications
- 语种：英文
- 分类号：TB552
- 学会代码：AGLU
- 会议名称：2016年全国压电和声波理论及器件应用研讨会
- 会议地点：中国陕西西安
- 主办单位：中国力学学会、中国声学学会、IEEE UFFC分会
- 学会名称：中国力学学会
- 页数：2
- 文件大小：93k
- 原文格式：D
- 会议级别：全国
摘要
Background, Motivation and Objective Air-coupled ultrasonic transducer is a kind of non-contact ultrasonic testing transducer. The main problem among the developing of the thickness mode piezoelectric air-coupled ultrasonic transducer is the acoustic impedance mismatch between piezoelectric plate and air. This will lead to a low acoustic energy radiation efficiency and low receiving voltage sensitivity. Some low acoustic impedance materials are introduced as matching layers to solve this problem. Porous materials like porous polypropylene, polyurethane, silicon rubber or silicon aerogel are reported as commonly used matching layers. These materials have the properties of high porosity and low acoustic impedance. Hollow glass microspheres filled epoxy resin can produce a low density porous composite material which is now used as a solid buoyancy material. Such porous light material is simple to manufacture and has flexibility on density and acoustic impedance by controlling the proportion of hollow glass microspheres. Besides, the close-cell structure makes it able to use conventional transducers to do some acoustic material measurement, which reduces the measuring difficulty. It also allows the use of epoxy glue on the adhesion of matching layer. The aim of this article is to manufacture a thickness mode air-coupled piezoelectric transducer with hollow glass microspheres filled epoxy resin matching layer. Statement of Contribution/Methods The longitudinal wave velocity of the material is measured by a conventional 700 k Hz transducer connecting to a 5800 ultrasonic analyzer in the pulse echo mode. The time difference between the first and second bottom echo is used to measure the longitudinal wave velocity. The attenuation coefficient is measured by a spectral analysis method referring to Nondestructive Testing Handbook and Thomas E Gomez Alvarez-Arenas' work. A pair of conventional transducers is used to obtain a transfer function related to the attenuation coefficient of the sample. The central frequency and Q value can be obtained through spectrum analysis. On this basis, attenuation coefficient α can be obtained. The sample is cut into quarter wavelength wafers according to the velocity measured above, with 1mm thickness and 30 mm diameter. A pair of 700 k Hz air-coupled transducers is then manufactured using these wafers as single matching layers. The time domain receiving signal and frequency spectrum is measured by a 5800 ultrasonic analyzer in the transmitting receiving mode and compared to those with no matching layers. Some theoretical calculations are provided. Considering the normal incidence longitude wave, the sound wave goes into the matching layer and goes into air directly or after multiple reflection. Since the matching layer is quarter wavelength and there is a phase shift on the interface between the piezoelectric plate and matching layer, the direct and reflected wave is cophasal. The total transmitting coefficient T is calculated. Comparing to the transmitting coefficient without matching layers, the insertion sensitivity uplifting can be calculated. Results The density, sound velocity and attenuation coefficient of the hollow glass microspheres filled epoxy resin composite material sample is measured by several experiments. The measured density is 665kg/m3, longitudinal velocity is 2862m/s, and the attenuation coefficient of the material is 1245Np/m. A pair of air-coupled transducers with the hollow glass microspheres filled epoxy resin matching layer are manufactured. They are tested by a 5800 ultrasonic analyzer under transmitting receiving mode, setting coaxial 40 mm apart against each other. The experimental result shows a 29.6d B uplifting of receiving signal voltage peak-to-peak value, which is very close to the theoretical calculation result 31.5d B. Discussion and Conclusions The sound velocity and attenuation coefficient of the hollow glass microspheres filled epoxy resin composite material is measured. A pair of 700 k Hz air-coupled transducers with hollow glass microspheres filled epoxy resin matching layer are manufactured. The insertion of the matching layer brings a 29.6d B uplifting of the receiving voltage peak to peak value tested by a transmitting receiving system. The result is confirmed by theoretical calculations. Considering the classical quarter wavelength matching layer design theories like Chebyshev, Desilets and Souquet theories, the impedance of this material is still a bit higher than we want. The next step of work concerns double matching layer air-coupled transducers manufacturing to siege more uplifting of sensitivity.
Background, Motivation and Objective Air-coupled ultrasonic transducer is a kind of non-contact ultrasonic testing transducer. The main problem among the developing of the thickness mode piezoelectric air-coupled ultrasonic transducer is the acoustic impedance mismatch between piezoelectric plate and air. This will lead to a low acoustic energy radiation efficiency and low receiving voltage sensitivity. Some low acoustic impedance materials are introduced as matching layers to solve this problem. Porous materials like porous polypropylene, polyurethane, silicon rubber or silicon aerogel are reported as commonly used matching layers. These materials have the properties of high porosity and low acoustic impedance. Hollow glass microspheres filled epoxy resin can produce a low density porous composite material which is now used as a solid buoyancy material. Such porous light material is simple to manufacture and has flexibility on density and acoustic impedance by controlling the proportion of hollow glass microspheres. Besides, the close-cell structure makes it able to use conventional transducers to do some acoustic material measurement, which reduces the measuring difficulty. It also allows the use of epoxy glue on the adhesion of matching layer. The aim of this article is to manufacture a thickness mode air-coupled piezoelectric transducer with hollow glass microspheres filled epoxy resin matching layer. Statement of Contribution/Methods The longitudinal wave velocity of the material is measured by a conventional 700 k Hz transducer connecting to a 5800 ultrasonic analyzer in the pulse echo mode. The time difference between the first and second bottom echo is used to measure the longitudinal wave velocity. The attenuation coefficient is measured by a spectral analysis method referring to Nondestructive Testing Handbook and Thomas E Gomez Alvarez-Arenas' work. A pair of conventional transducers is used to obtain a transfer function related to the attenuation coefficient of the sample. The central frequency and Q value can be obtained through spectrum analysis. On this basis, attenuation coefficient α can be obtained. The sample is cut into quarter wavelength wafers according to the velocity measured above, with 1mm thickness and 30 mm diameter. A pair of 700 k Hz air-coupled transducers is then manufactured using these wafers as single matching layers. The time domain receiving signal and frequency spectrum is measured by a 5800 ultrasonic analyzer in the transmitting receiving mode and compared to those with no matching layers. Some theoretical calculations are provided. Considering the normal incidence longitude wave, the sound wave goes into the matching layer and goes into air directly or after multiple reflection. Since the matching layer is quarter wavelength and there is a phase shift on the interface between the piezoelectric plate and matching layer, the direct and reflected wave is cophasal. The total transmitting coefficient T is calculated. Comparing to the transmitting coefficient without matching layers, the insertion sensitivity uplifting can be calculated. Results The density, sound velocity and attenuation coefficient of the hollow glass microspheres filled epoxy resin composite material sample is measured by several experiments. The measured density is 665kg/m3, longitudinal velocity is 2862m/s, and the attenuation coefficient of the material is 1245Np/m. A pair of air-coupled transducers with the hollow glass microspheres filled epoxy resin matching layer are manufactured. They are tested by a 5800 ultrasonic analyzer under transmitting receiving mode, setting coaxial 40 mm apart against each other. The experimental result shows a 29.6d B uplifting of receiving signal voltage peak-to-peak value, which is very close to the theoretical calculation result 31.5d B. Discussion and Conclusions The sound velocity and attenuation coefficient of the hollow glass microspheres filled epoxy resin composite material is measured. A pair of 700 k Hz air-coupled transducers with hollow glass microspheres filled epoxy resin matching layer are manufactured. The insertion of the matching layer brings a 29.6d B uplifting of the receiving voltage peak to peak value tested by a transmitting receiving system. The result is confirmed by theoretical calculations. Considering the classical quarter wavelength matching layer design theories like Chebyshev, Desilets and Souquet theories, the impedance of this material is still a bit higher than we want. The next step of work concerns double matching layer air-coupled transducers manufacturing to siege more uplifting of sensitivity.
Background, Motivation and Objective Air-coupled ultrasonic transducer is a kind of non-contact ultrasonic testing transducer. The main problem among the developing of the thickness mode piezoelectric air-coupled ultrasonic transducer is the acoustic impedance mismatch between piezoelectric plate and air. This will lead to a low acoustic energy radiation efficiency and low receiving voltage sensitivity. Some low acoustic impedance materials are introduced as matching layers to solve this problem. Porous materials like porous polypropylene, polyurethane, silicon rubber or silicon aerogel are reported as commonly used matching layers. These materials have the properties of high porosity and low acoustic impedance. Hollow glass microspheres filled epoxy resin can produce a low density porous composite material which is now used as a solid buoyancy material. Such porous light material is simple to manufacture and has flexibility on density and acoustic impedance by controlling the proportion of hollow glass microspheres. Besides, the close-cell structure makes it able to use conventional transducers to do some acoustic material measurement, which reduces the measuring difficulty. It also allows the use of epoxy glue on the adhesion of matching layer. The aim of this article is to manufacture a thickness mode air-coupled piezoelectric transducer with hollow glass microspheres filled epoxy resin matching layer. Statement of Contribution/Methods The longitudinal wave velocity of the material is measured by a conventional 700 k Hz transducer connecting to a 5800 ultrasonic analyzer in the pulse echo mode. The time difference between the first and second bottom echo is used to measure the longitudinal wave velocity. The attenuation coefficient is measured by a spectral analysis method referring to Nondestructive Testing Handbook and Thomas E Gomez Alvarez-Arenas' work. A pair of conventional transducers is used to obtain a transfer function related to the attenuation coefficient of the sample. The central frequency and Q value can be obtained through spectrum analysis. On this basis, attenuation coefficient α can be obtained. The sample is cut into quarter wavelength wafers according to the velocity measured above, with 1mm thickness and 30 mm diameter. A pair of 700 k Hz air-coupled transducers is then manufactured using these wafers as single matching layers. The time domain receiving signal and frequency spectrum is measured by a 5800 ultrasonic analyzer in the transmitting receiving mode and compared to those with no matching layers. Some theoretical calculations are provided. Considering the normal incidence longitude wave, the sound wave goes into the matching layer and goes into air directly or after multiple reflection. Since the matching layer is quarter wavelength and there is a phase shift on the interface between the piezoelectric plate and matching layer, the direct and reflected wave is cophasal. The total transmitting coefficient T is calculated. Comparing to the transmitting coefficient without matching layers, the insertion sensitivity uplifting can be calculated. Results The density, sound velocity and attenuation coefficient of the hollow glass microspheres filled epoxy resin composite material sample is measured by several experiments. The measured density is 665kg/m3, longitudinal velocity is 2862m/s, and the attenuation coefficient of the material is 1245Np/m. A pair of air-coupled transducers with the hollow glass microspheres filled epoxy resin matching layer are manufactured. They are tested by a 5800 ultrasonic analyzer under transmitting receiving mode, setting coaxial 40 mm apart against each other. The experimental result shows a 29.6d B uplifting of receiving signal voltage peak-to-peak value, which is very close to the theoretical calculation result 31.5d B. Discussion and Conclusions The sound velocity and attenuation coefficient of the hollow glass microspheres filled epoxy resin composite material is measured. A pair of 700 k Hz air-coupled transducers with hollow glass microspheres filled epoxy resin matching layer are manufactured. The insertion of the matching layer brings a 29.6d B uplifting of the receiving voltage peak to peak value tested by a transmitting receiving system. The result is confirmed by theoretical calculations. Considering the classical quarter wavelength matching layer design theories like Chebyshev, Desilets and Souquet theories, the impedance of this material is still a bit higher than we want. The next step of work concerns double matching layer air-coupled transducers manufacturing to siege more uplifting of sensitivity.
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