压电材料全矩阵材料常数超声谐振谱反演技术中的变温模式识别  

Mode identification via temperature variation in resonant ultrasonic spectroscopy technique for piezoelectric material

作　　者：汤立国[1] Tang Li-Guo(Key Laboratory of Underwater Acoustic Communication and Marine Information Technology, Ministry of Education Xiamen University, Xiamen 361102, China)

机构地区：[1]厦门大学水声通信与海洋信息技术教育部重点实验室,厦门361102

出　　处：《物理学报》2017年第2期330-337,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11374245;11674270)资助的课题~~

摘　　要：利用传统的超声脉冲-回波与电谐振技术定征压电材料全矩阵材料参数,必须采用多块尺寸差异显著的样品,故很可能导致定征结果不自洽.超声谐振谱(RUS)技术仅需一块样品即可对压电材料全矩阵材料参数进行定征,故可确保定征结果的自洽.由于实际测量谐振谱中模式混叠与遗漏现象不可避免,使得谐振谱中谐振模式的准确识别成为RUS技术顺利实施的最大难点.本文提出一种谐振模式的变温识别技术.温度变化可导致压电体材料参数发生变化,材料参数的改变可影响各谐振模式的振动频率,且对不同谐振模式影响不一致,因此改变测量环境温度,有可能使得所测量超声谐振谱中某些原本混叠的模式分开或使得某些原本遗漏的模式出现.压电陶瓷(PZT-8)的实验结果表明,该技术可有效提高谐振谱中谐振模式识别准确率,从而保证了RUS反演的可靠性.The full matrix material constants of piezoelectric materials should be characterized first before they have been used to make actuators or sensors.Up to now,they are usually determined by the ultrasonic pulse-echo and electric impedance resonance techniques through using multiple samples with drastically different sizes.However,the constants determined by the aforementioned techniques are probably inconsistent because the sample-to-sample variation cannot be eliminated.The technique of resonant ultrasonic spectroscopy（RUS） only needs one sample to determine the full matrix constants of piezoelectric material.Therefore,the consistency of the constants is guaranteed.During the implementation of the RUS technique,the elastic stiffness cijE and piezoelectric constants eij can be determined from the resonance modes identified from the resonant ultrasonic spectrum.The free and clamped dielectric constants cannot be determined by the RUS technique because they have very weak influence on resonance frequency.However,they can be directly measured from the same sample by using an impedance analyzer.To ensure the reliable inversion of material constants,enough resonance modes should be identified from the measured resonant ultrasonic spectrum.However,there are many missing and overlapped modes in the spectrum,which makes mode identification become a biggest obstacle to the implementation of the RUS technique.The adjacent modes may overlap if the resonance frequencies corresponding to them have a very small difference.In addition,the lower the mechanical quality factor QM,the more likely to overlap the adjacent modes are.During the RUS measurement,the rectangular parallelepiped sample is placed between the transmitting and receiving transducers with contacts only at the opposite corners of the sample.Resonance modes would not be detected if the receiving point,i.e.,one corner of the sample,is the node of these modes.Therefore,there are missing modes in the resonant ultrasonic spectrum.To overcome the difficulty in ident

关 键 词：压电材料 材料常数 超声谐振谱 变温模式识别 

分 类 号：TB34[一般工业技术—材料科学与工程]