G. Berry, D. Melodelima, J. Bamber, Yixin Ma, I. Rivens, G. Terhaar
High intensity focused ultrasound (HIFU) has previously been used to destroy tumor tissue near the focus of the ultrasound beam. However, it can be difficult to predict in advance where the lesion associated with a given exposure will form. Furthermore, a means of verifying that the entire tumour mass has been ablated is required. In this study, a new technique was investigated in which the acoustic radiation force that can be generated by running the HIFU transducer for short (10 ms), sub-ablative exposures, was used to generate localised and transient stresses inside the medium. Commercial diagnostic ultrasound scanners and elastographic techniques for displacement tracking and strain estimation were then applied to image both the induced displacement and strain distributions. Each single sub- ablative pulse from the HIFU transducer was found to provide a useful way to help localise the focus of the ultrasound beam (i.e. before any lesions are formed). Multiple sub- ablative pulses on the other hand, where the position of the focus was translated between exposures and, at each focus position, the local induced strain was calculated, were shown to be useful for constructing a composite image of local strain inside the tissue. Such transient strain images show contrast for stiffness, which is considerably increased by thermal coagulation of tissue, and should therefore be helpful post-ablation, in revealing the location and extent of tissue damage. We conclude that elastographic displacement and strain imaging, in which transient acoustic radiation force is generated by the HIFU transducer, has considerable potential to be used in the guidance and monitoring of HIFU treatment.
{"title":"P1C-5 Transient Acoustic Radiation Force Elastography for HIFU Guidance and Monitoring","authors":"G. Berry, D. Melodelima, J. Bamber, Yixin Ma, I. Rivens, G. Terhaar","doi":"10.1109/ULTSYM.2007.338","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.338","url":null,"abstract":"High intensity focused ultrasound (HIFU) has previously been used to destroy tumor tissue near the focus of the ultrasound beam. However, it can be difficult to predict in advance where the lesion associated with a given exposure will form. Furthermore, a means of verifying that the entire tumour mass has been ablated is required. In this study, a new technique was investigated in which the acoustic radiation force that can be generated by running the HIFU transducer for short (10 ms), sub-ablative exposures, was used to generate localised and transient stresses inside the medium. Commercial diagnostic ultrasound scanners and elastographic techniques for displacement tracking and strain estimation were then applied to image both the induced displacement and strain distributions. Each single sub- ablative pulse from the HIFU transducer was found to provide a useful way to help localise the focus of the ultrasound beam (i.e. before any lesions are formed). Multiple sub- ablative pulses on the other hand, where the position of the focus was translated between exposures and, at each focus position, the local induced strain was calculated, were shown to be useful for constructing a composite image of local strain inside the tissue. Such transient strain images show contrast for stiffness, which is considerably increased by thermal coagulation of tissue, and should therefore be helpful post-ablation, in revealing the location and extent of tissue damage. We conclude that elastographic displacement and strain imaging, in which transient acoustic radiation force is generated by the HIFU transducer, has considerable potential to be used in the guidance and monitoring of HIFU treatment.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"83 1","pages":"1345-1348"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83984509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
During the last few years the bulk acoustic wave (BAW) filters have emerged as a viable alternative to surface acoustic wave (SAW) devices. They offer superior performance regarding filtering characteristics, power handling, ESD robustness and size. The first enabling ingredient has been the rapid development in deposition techniques for the thin film piezoelectric layer. Today multiple equipment manufacturers are offering systems for depositing high quality layers with excellent piezoelectric properties. Along with the development in manufacturing issues there has also been important development in understanding the basic device physics of BAW resonators. Like any reactance elements for constructing filters there are three major concerns when designing BAW resonators: sufficient effective coupling coefficient, high Q-values and operation free of spurious modes. These properties enable the fabrication of filters with sufficient band width, low insertion loss, steep transition bands and ripple free characteristics. In this paper developments leading to state-of-the-art BAW resonators are reviewed.
{"title":"3C-1 Review of Wave Propagation in BAW Thin Film Devices - Progress and Prospects","authors":"J. Kaitila","doi":"10.1109/ULTSYM.2007.43","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.43","url":null,"abstract":"During the last few years the bulk acoustic wave (BAW) filters have emerged as a viable alternative to surface acoustic wave (SAW) devices. They offer superior performance regarding filtering characteristics, power handling, ESD robustness and size. The first enabling ingredient has been the rapid development in deposition techniques for the thin film piezoelectric layer. Today multiple equipment manufacturers are offering systems for depositing high quality layers with excellent piezoelectric properties. Along with the development in manufacturing issues there has also been important development in understanding the basic device physics of BAW resonators. Like any reactance elements for constructing filters there are three major concerns when designing BAW resonators: sufficient effective coupling coefficient, high Q-values and operation free of spurious modes. These properties enable the fabrication of filters with sufficient band width, low insertion loss, steep transition bands and ripple free characteristics. In this paper developments leading to state-of-the-art BAW resonators are reviewed.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"122 1","pages":"120-129"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80187920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Packaged commercial 434 MHz quartz SAW resonators were placed at the output of a Colbalt 60 source and exposed to gamma radiation of up to 50 Mrads. Additional devices were positioned in close proximity to the enriched uranium core of a nuclear reactor and exposed to intense neutron radiation of 4.5 x 1012 neutrons/cm2s for up to 40 seconds. The irradiated resonators were then inserted in the feedback loop of a custom oscillator to measure the shift in output frequency as a function of radiation exposure. No clear relationships were observed between the amount of radiation exposure and frequency shift in either case.
封装的商用434 MHz石英SAW谐振器放置在钴60源的输出端，并暴露在高达50毫瓦的伽马辐射中。另外的装置被放置在一个核反应堆的浓缩铀堆芯附近，并暴露在4.5 x 1012中子/厘米秒的强烈中子辐射下长达40秒。然后将辐照谐振器插入定制振荡器的反馈回路中，以测量作为辐射暴露函数的输出频率的移位。在这两种情况下，没有观察到辐射量与频率移动之间的明确关系。
{"title":"P3I-1 Effect of Gamma and Neutron Radiation on Quartz SAW Resonators","authors":"A. Ternawly, R. Kleiman, P.M. Smith","doi":"10.1109/ULTSYM.2007.473","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.473","url":null,"abstract":"Packaged commercial 434 MHz quartz SAW resonators were placed at the output of a Colbalt 60 source and exposed to gamma radiation of up to 50 Mrads. Additional devices were positioned in close proximity to the enriched uranium core of a nuclear reactor and exposed to intense neutron radiation of 4.5 x 1012 neutrons/cm2s for up to 40 seconds. The irradiated resonators were then inserted in the feedback loop of a custom oscillator to measure the shift in output frequency as a function of radiation exposure. No clear relationships were observed between the amount of radiation exposure and frequency shift in either case.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"105 1","pages":"1882-1885"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80692684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Hansen, J. Opretzka, B. Brendel, H. Ermert, M. Engelhardt, C. Brenke, K. Schmieder, S. Hold, K. Hensel, C. Krogias
Ultrasound images of the brain, usually obtained from transcranial scans, are difficult to be interpreted for inexperienced users. We present a newly developed training station, designed to assist physicians at this task. This training station works as a real time anatomic atlas and is an add-on system to a conventional ultrasound scanner. The transducer of the ultrasound system is tracked by a positioning system. In addition to the current ultrasound image of a patient or test person, corresponding images from previously acquired MRI and ultrasound volume data sets are shown.
{"title":"P2C-1 A Training Station to Facilitate Transcranial Ultrasound Imaging","authors":"C. Hansen, J. Opretzka, B. Brendel, H. Ermert, M. Engelhardt, C. Brenke, K. Schmieder, S. Hold, K. Hensel, C. Krogias","doi":"10.1109/ULTSYM.2007.394","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.394","url":null,"abstract":"Ultrasound images of the brain, usually obtained from transcranial scans, are difficult to be interpreted for inexperienced users. We present a newly developed training station, designed to assist physicians at this task. This training station works as a real time anatomic atlas and is an add-on system to a conventional ultrasound scanner. The transducer of the ultrasound system is tracked by a positioning system. In addition to the current ultrasound image of a patient or test person, corresponding images from previously acquired MRI and ultrasound volume data sets are shown.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"12 1","pages":"1567-1570"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83104965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In designing eigen-based clutter filters for color flow imaging, one of the challenges is to develop an accurate way of estimating the eigen-components that represent clutter in slow- time ensembles. To provide new insights on the problem, this paper presents a comparative analysis on how eigen-fllters perform when using eigen-estimation methods that involve multiple ensembles or a single ensemble. The analysis consists of two parts: 1) a comparative review on the principles behind different eigen-estimation methods; 2) an eigen-flltering experiment done with coronary flow imaging data acquired from a porcine during bypass graft operation. For an imaging case containing tissue motion due to myocardial contraction, our analysis showed that the single-ensemble eigen-fllter shared similar performance with a multi-ensemble eigen-fllter that uses small (5times5) ensemble windows (with about 1 dB difference in clutter suppression level). Results also showed that a multi-ensemble eigen-fllter with large (20times20) ensemble windows yielded poorer performance (clutter suppression level was 3 to 6 dB lower).
{"title":"12B-5 Eigen-Based Clutter Filters for Color Flow Imaging: Single-Ensemble vs. Multi-Ensemble Approaches","authors":"A. Yu, L. Løvstakken","doi":"10.1109/ULTSYM.2007.278","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.278","url":null,"abstract":"In designing eigen-based clutter filters for color flow imaging, one of the challenges is to develop an accurate way of estimating the eigen-components that represent clutter in slow- time ensembles. To provide new insights on the problem, this paper presents a comparative analysis on how eigen-fllters perform when using eigen-estimation methods that involve multiple ensembles or a single ensemble. The analysis consists of two parts: 1) a comparative review on the principles behind different eigen-estimation methods; 2) an eigen-flltering experiment done with coronary flow imaging data acquired from a porcine during bypass graft operation. For an imaging case containing tissue motion due to myocardial contraction, our analysis showed that the single-ensemble eigen-fllter shared similar performance with a multi-ensemble eigen-fllter that uses small (5times5) ensemble windows (with about 1 dB difference in clutter suppression level). Results also showed that a multi-ensemble eigen-fllter with large (20times20) ensemble windows yielded poorer performance (clutter suppression level was 3 to 6 dB lower).","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"26 1","pages":"1101-1104"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83283897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents an experimental evidence to correlate the acousto-optic effect of nematic liquid crystals to modal excitations of guided acoustic waves. The optic axes of liquid crystal molecules in a cell can be tilted by ultrasound at oblique incidence. The cell filled with homeotropically aligned liquid crystal material, 5CB, is fully immersed in a water tank situated between two crossed polarizers. Multi-modal guided acoustic waves have been excited in cell by changing the angle of incidence and driving frequency. The liquid crystal material sandwiched between two glass plates is regarded as a Newtonian fluid and modeled to be an isotropic hypothetical solid. The phase velocity dispersion curves and associated modal strains within the liquid crystal cell are determined numerically. Comparison between measured data and prediction reveals that guided acoustic waves have influence on the acousto-optic response of liquid crystals rather than bulk acoustic waves. Simulated results show that homeotropically and homogeneously aligned liquid crystals can be affected by symmetric and antisymmetric modes, respectively.
{"title":"9E-6 Acoustic Realignment of Nematic Liquid Crystals by Guided Waves","authors":"Y. Lee, Wun-Bin Shih, Yu-Wei Su, C. Yin","doi":"10.1109/ULTSYM.2007.213","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.213","url":null,"abstract":"This paper presents an experimental evidence to correlate the acousto-optic effect of nematic liquid crystals to modal excitations of guided acoustic waves. The optic axes of liquid crystal molecules in a cell can be tilted by ultrasound at oblique incidence. The cell filled with homeotropically aligned liquid crystal material, 5CB, is fully immersed in a water tank situated between two crossed polarizers. Multi-modal guided acoustic waves have been excited in cell by changing the angle of incidence and driving frequency. The liquid crystal material sandwiched between two glass plates is regarded as a Newtonian fluid and modeled to be an isotropic hypothetical solid. The phase velocity dispersion curves and associated modal strains within the liquid crystal cell are determined numerically. Comparison between measured data and prediction reveals that guided acoustic waves have influence on the acousto-optic response of liquid crystals rather than bulk acoustic waves. Simulated results show that homeotropically and homogeneously aligned liquid crystals can be affected by symmetric and antisymmetric modes, respectively.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"15 1","pages":"832-835"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83368403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Numerical synthesis of frequency response is discussed for a ladder type filter consisting of ultra-wideband SAW resonators on Cu-grating/15degYX-LiNbO3 structure. For the synthesis, two parameters of each resonator, i.e., the static capacitance and resonant frequency were numerically optimised, while the capacitance ratio and figure of merit were fixed at specific values determined by substrates and grating electrodes employed. First, six-stage SAW ladder type filters having the passband width of 7 to 21% were designed. The result showed that the specified bandwidth is successfully synthesised. Next, a six-stage ladder type filter having the passband width of 8% was fabricated on Cu-grating/15degYX-LiNbO3 structure for experimental discussion. It was shown that the measured frequency response of the filter was in good agreement with the design, where some in-band spurious dips were removed by weighted dummy electrodes. By making analysis on the behaviour of resonant and anti-resonant frequencies of each resonator, it is shown that the method can be extended to the synthesis of filters having sophisticated frequency responses. The result suggested that the proposed method could become one of the powerful design tools for SAW ladder type filters with specified passband width.
{"title":"P6G-2 Synthesis of Frequency Response for Wideband SAW Ladder Type Filters","authors":"T. Omori, Y. Tanaka, K. Hashimoto, M. Yamaguchi","doi":"10.1109/ULTSYM.2007.648","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.648","url":null,"abstract":"Numerical synthesis of frequency response is discussed for a ladder type filter consisting of ultra-wideband SAW resonators on Cu-grating/15degYX-LiNbO3 structure. For the synthesis, two parameters of each resonator, i.e., the static capacitance and resonant frequency were numerically optimised, while the capacitance ratio and figure of merit were fixed at specific values determined by substrates and grating electrodes employed. First, six-stage SAW ladder type filters having the passband width of 7 to 21% were designed. The result showed that the specified bandwidth is successfully synthesised. Next, a six-stage ladder type filter having the passband width of 8% was fabricated on Cu-grating/15degYX-LiNbO3 structure for experimental discussion. It was shown that the measured frequency response of the filter was in good agreement with the design, where some in-band spurious dips were removed by weighted dummy electrodes. By making analysis on the behaviour of resonant and anti-resonant frequencies of each resonator, it is shown that the method can be extended to the synthesis of filters having sophisticated frequency responses. The result suggested that the proposed method could become one of the powerful design tools for SAW ladder type filters with specified passband width.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"7 1","pages":"2574-2577"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82573720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The secular equation for acoustic waves at fluid-solid interfaces yields the common leaky wave and its complement. This complementary wave grows instead of decays with propagation and is time-reversed compared to the leaky wave. Moreover, this growing wave has not yet been observed experimentally, perhaps due to difficulty of its excitation. Experimental observation of this wave was one goal of our work. The second goal was to study mirror reflection of an acoustic beam of special shape when the incident angle is equal to the Rayleigh critical angle. An obliquely incident beam is known to split after reflection into two components: a specular beam and a broad beam generated by the leaky waves. The interference of these two components results in "Schoch displacement" of the reflected beam along the interface and overall beam broadening. Our hypothesis was that by time reversing the reflection at the critical angle, the reflection beam can be made narrower rather than broader.
{"title":"5E-3 Experimental Evidence for a Growing Surface Wave and Acoustic Beam Narrowing upon Reflection from Fluid-Solid Interfaces","authors":"O. Sapozhnikov, A. Karabutov, V. Mozhaev","doi":"10.1109/ULTSYM.2007.107","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.107","url":null,"abstract":"The secular equation for acoustic waves at fluid-solid interfaces yields the common leaky wave and its complement. This complementary wave grows instead of decays with propagation and is time-reversed compared to the leaky wave. Moreover, this growing wave has not yet been observed experimentally, perhaps due to difficulty of its excitation. Experimental observation of this wave was one goal of our work. The second goal was to study mirror reflection of an acoustic beam of special shape when the incident angle is equal to the Rayleigh critical angle. An obliquely incident beam is known to split after reflection into two components: a specular beam and a broad beam generated by the leaky waves. The interference of these two components results in \"Schoch displacement\" of the reflected beam along the interface and overall beam broadening. Our hypothesis was that by time reversing the reflection at the critical angle, the reflection beam can be made narrower rather than broader.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"35 1","pages":"391-394"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82640728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The determination of piezoelectric properties of an aluminium nitride thin film sandwiched between two electrodes, and acoustically coupled to a supporting substrate, is considered. Measuring the properties of such a BAW composite resonator can be used for film characterisation. The resonant spectrum method has been implemented, which consists of analysing the variation in spacing of parallel resonant frequencies for the resonator. The film parameters were derived from experimental measurements of the insertion loss (s11) of aluminium nitride deposited on glass and LiNO3 respectively, with top and bottom electrodes. A one-dimensional model was used to simulate the functional behaviour of the two examples of four-layer aluminium nitride based resonators. The modelling technique for multilayer ultrasonic transducers was based on the solutions to the 1-D wave equation. It was possible to obtain good agreement between the experimental and modelled results. The values of velocity and density agreed within 0.5%. The spacing of parallel resonant frequencies could also be closely matched between the experiment and the simulation. Under these conditions, the value of kt 2 of the piezoelectric film was inferred from the model.
{"title":"P1I-1 Acoustical Parameters Characterisation of Aluminium Nitride Thin Film BAW Resonators Using Resonant Spectrum Approach","authors":"D. Cornez, S. Lapp, S. Cochran, K. Kirk","doi":"10.1109/ULTSYM.2007.361","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.361","url":null,"abstract":"The determination of piezoelectric properties of an aluminium nitride thin film sandwiched between two electrodes, and acoustically coupled to a supporting substrate, is considered. Measuring the properties of such a BAW composite resonator can be used for film characterisation. The resonant spectrum method has been implemented, which consists of analysing the variation in spacing of parallel resonant frequencies for the resonator. The film parameters were derived from experimental measurements of the insertion loss (s11) of aluminium nitride deposited on glass and LiNO3 respectively, with top and bottom electrodes. A one-dimensional model was used to simulate the functional behaviour of the two examples of four-layer aluminium nitride based resonators. The modelling technique for multilayer ultrasonic transducers was based on the solutions to the 1-D wave equation. It was possible to obtain good agreement between the experimental and modelled results. The values of velocity and density agreed within 0.5%. The spacing of parallel resonant frequencies could also be closely matched between the experiment and the simulation. Under these conditions, the value of kt 2 of the piezoelectric film was inferred from the model.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"29 1","pages":"1437-1440"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80854857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Kaltenbacher, B. Kaltenbacher, T. Hegewald, R. Lerch
According to a thermodynamically consistent model, we decompose the physical quantities dielectric displacement and mechanical strain into a reversible and an irreversible part. Therewith, we set the irreversible part of the dielectric displacement equal to the electric polarization. The reversible parts of mechanical strain and dielectric displacement are further described by the linear piezoelectric constitutive law. The irreversible polarization is computed from the history of the driving electric field by a Preisach hysteresis operator. Furthermore, the entries of the piezoelectric modulus tensor are assumed to be a function of the irreversible dielectric polarization. This enhanced model for non-linear piezoelectricity has been recently implemented into our finite element (FE) software environment. We have applied our FE scheme to the numerical computation of the dynamic behavior of a piezoelectric stack actuator. The obtained results compare well to measured data.
{"title":"P2I-5 Enhanced Finite Element Scheme for Non-Linear Piezoelectricity","authors":"M. Kaltenbacher, B. Kaltenbacher, T. Hegewald, R. Lerch","doi":"10.1109/ULTSYM.2007.427","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.427","url":null,"abstract":"According to a thermodynamically consistent model, we decompose the physical quantities dielectric displacement and mechanical strain into a reversible and an irreversible part. Therewith, we set the irreversible part of the dielectric displacement equal to the electric polarization. The reversible parts of mechanical strain and dielectric displacement are further described by the linear piezoelectric constitutive law. The irreversible polarization is computed from the history of the driving electric field by a Preisach hysteresis operator. Furthermore, the entries of the piezoelectric modulus tensor are assumed to be a function of the irreversible dielectric polarization. This enhanced model for non-linear piezoelectricity has been recently implemented into our finite element (FE) software environment. We have applied our FE scheme to the numerical computation of the dynamic behavior of a piezoelectric stack actuator. The obtained results compare well to measured data.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"7 1","pages":"1697-1700"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81163306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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