该文针对超声无损检测与成像功能空气耦合换能器开展了分析计算和研制。为解决压电材料与空气间巨大的阻抗失配问题,进行了多匹配层设计,并基于有限元技术仿真设计了1-3压电复合材料参数。借助复数压电方程,导出考虑损耗的多匹配层压电...该文针对超声无损检测与成像功能空气耦合换能器开展了分析计算和研制。为解决压电材料与空气间巨大的阻抗失配问题,进行了多匹配层设计,并基于有限元技术仿真设计了1-3压电复合材料参数。借助复数压电方程,导出考虑损耗的多匹配层压电复合材料换能器厚度振动等效电路,获得其等效导纳,以此计算电导谱,同时基于有限元技术数值计算相应电导谱,二者有较好的一致性。在此基础上分别设计制作复合压电材料,多匹配层材料以及由此构成的空气耦合超声换能器。换能器的实测电导谱与数值仿真结果一致。进一步的换能器回波信号测试及其谱分析结果表明,所研制的160 k Hz中心频率空气耦合换能器样品有较好灵敏度和带宽。这些结果说明,该文研制的空气耦合超声换能器的初样是成功的。展开更多
Air-coupled ultrasonic transducers are used to generate and receive Lamb waves in quasi-isotropic laminated composite beams for delamination detection. The influence of incident angle on the excited mode is studied. N...Air-coupled ultrasonic transducers are used to generate and receive Lamb waves in quasi-isotropic laminated composite beams for delamination detection. The influence of incident angle on the excited mode is studied. Numerical calculation and experimental results show that a pure Lamb wave mode can be generated if the transmitting transducer is oriented at a specific angle, and the receiving transducer can either be oriented to detect the same mode as that generated by the transmitter or to detect another mode generated by mode conversion at a defect. A three-dimensional finite element model is created to predict the interaction of Lamb waves with delamination, and some unique mechanisms of interaction between A0 mode Lamb waves and delamination are revealed in detail. The experimental results obtained on laminated composite beam using air-coupled ultrasonic transducers are well in accordance with finite element simulation results. Research results show that air-coupled ultrasonic guided waves can be used for delamination damage detection effectively in laminated composite beams.展开更多
文摘该文针对超声无损检测与成像功能空气耦合换能器开展了分析计算和研制。为解决压电材料与空气间巨大的阻抗失配问题,进行了多匹配层设计,并基于有限元技术仿真设计了1-3压电复合材料参数。借助复数压电方程,导出考虑损耗的多匹配层压电复合材料换能器厚度振动等效电路,获得其等效导纳,以此计算电导谱,同时基于有限元技术数值计算相应电导谱,二者有较好的一致性。在此基础上分别设计制作复合压电材料,多匹配层材料以及由此构成的空气耦合超声换能器。换能器的实测电导谱与数值仿真结果一致。进一步的换能器回波信号测试及其谱分析结果表明,所研制的160 k Hz中心频率空气耦合换能器样品有较好灵敏度和带宽。这些结果说明,该文研制的空气耦合超声换能器的初样是成功的。
基金supported by the National Natural Science Foundation of China(Grant Nos. 11272021 and 50975006)Beijing Natural Science Foundation(Grant No. 1122007)+1 种基金the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions(No.CIT&TCD201304048)Beijing Nova Program(Grant No. 2008A015)
文摘Air-coupled ultrasonic transducers are used to generate and receive Lamb waves in quasi-isotropic laminated composite beams for delamination detection. The influence of incident angle on the excited mode is studied. Numerical calculation and experimental results show that a pure Lamb wave mode can be generated if the transmitting transducer is oriented at a specific angle, and the receiving transducer can either be oriented to detect the same mode as that generated by the transmitter or to detect another mode generated by mode conversion at a defect. A three-dimensional finite element model is created to predict the interaction of Lamb waves with delamination, and some unique mechanisms of interaction between A0 mode Lamb waves and delamination are revealed in detail. The experimental results obtained on laminated composite beam using air-coupled ultrasonic transducers are well in accordance with finite element simulation results. Research results show that air-coupled ultrasonic guided waves can be used for delamination damage detection effectively in laminated composite beams.
