Pub Date : 2019-11-01DOI: 10.1109/SPAWDA48812.2019.9019320
Guang-ying Yang, Minghua Zhang, J. Lou, Meng-kai Lu, Ji Wang, Jianke Du
We investigate theoretically the band structures of one-dimensional phononic crystal plates with a ferroelectric inversion layer. The phononic crystal structure in the form of rectangular-like periodic grooves made on both surfaces of LiNbO3 crystal plate. The effects of the inversion layer on the dispersion curves are demonstrated using the analysis of the band structures which can be calculated by the finite element method. It is found that the width and position of Lamb wave shift prominently with variation of thickness of the inversion layer. The results obtained may provide theoretical guidance for the design of high-performance acoustic devices made of phononic crystal.
{"title":"Bandgaps in One-Dimensional Phononic Crystal Plate with A Ferroelectric Inversion Layer","authors":"Guang-ying Yang, Minghua Zhang, J. Lou, Meng-kai Lu, Ji Wang, Jianke Du","doi":"10.1109/SPAWDA48812.2019.9019320","DOIUrl":"https://doi.org/10.1109/SPAWDA48812.2019.9019320","url":null,"abstract":"We investigate theoretically the band structures of one-dimensional phononic crystal plates with a ferroelectric inversion layer. The phononic crystal structure in the form of rectangular-like periodic grooves made on both surfaces of LiNbO3 crystal plate. The effects of the inversion layer on the dispersion curves are demonstrated using the analysis of the band structures which can be calculated by the finite element method. It is found that the width and position of Lamb wave shift prominently with variation of thickness of the inversion layer. The results obtained may provide theoretical guidance for the design of high-performance acoustic devices made of phononic crystal.","PeriodicalId":208819,"journal":{"name":"2019 14th Symposium on Piezoelectrcity, Acoustic Waves and Device Applications (SPAWDA)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132418630","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}
Pub Date : 2019-11-01DOI: 10.1109/SPAWDA48812.2019.9019296
Hanxun Qiu, M. Fan, Dan Wang, H. Tzou
Flexoelectric is a kind of smart materials, which has a special effect called flexoelectricity. The converse flexoelectric effect can be utilized to actuate and control flexible structure. This paper focus on the precision actuation and control effectiveness of conical shells. A flexoelectric patch is attached to a truncated conical shell. Applying a control voltage to the line-electrode on the external surface of the flexoelectric patch, coupled with the bottom surface electrode layer, an inhomogeneous electric field can be generated, and consequently induce internal actuation stresses. The stress-induced membrane control forces and bending control moments regulate the vibrations of conical shell, its longitudinal, circumferential and transverse control actions are evaluated in this paper. The relationships between the actuation effects and various design parameters, such as the thickness of flexoelectric patch, radius of line-electrode, etc., are also studied.
{"title":"Flexoelectric Actuation and Control of Conical Shells","authors":"Hanxun Qiu, M. Fan, Dan Wang, H. Tzou","doi":"10.1109/SPAWDA48812.2019.9019296","DOIUrl":"https://doi.org/10.1109/SPAWDA48812.2019.9019296","url":null,"abstract":"Flexoelectric is a kind of smart materials, which has a special effect called flexoelectricity. The converse flexoelectric effect can be utilized to actuate and control flexible structure. This paper focus on the precision actuation and control effectiveness of conical shells. A flexoelectric patch is attached to a truncated conical shell. Applying a control voltage to the line-electrode on the external surface of the flexoelectric patch, coupled with the bottom surface electrode layer, an inhomogeneous electric field can be generated, and consequently induce internal actuation stresses. The stress-induced membrane control forces and bending control moments regulate the vibrations of conical shell, its longitudinal, circumferential and transverse control actions are evaluated in this paper. The relationships between the actuation effects and various design parameters, such as the thickness of flexoelectric patch, radius of line-electrode, etc., are also studied.","PeriodicalId":208819,"journal":{"name":"2019 14th Symposium on Piezoelectrcity, Acoustic Waves and Device Applications (SPAWDA)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132307751","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}
Pub Date : 2019-11-01DOI: 10.1109/SPAWDA48812.2019.9019261
Mingyue Shao, Jiajuan Qing, Jing Wang, Jimei Wu, Y. Wang, Dingqiang Liu
Geometrically nonlinear vibration characteristics of large deflection of a printing membrane under a linear tension distribution and external excitation are analyzed. The mathematical model of the printing membrane under nonuniform tension is established. Based on the D'Alembert principle and von Karman nonlinear plate theory, the forced nonlinear partial differential equations of the printing membrane under nonuniform tension are deduced. The Galerkin method is applied for discretizing the governing equations, and the method of multiple scales is employed to determine the solution of the ordinary differential equations. The influence of the aspect ratio and the tension ratio on the system stability is highlighted. The results show that nonlinear vibration of the printing membrane can be suppressed by increasing the aspect ratio and reducing the tension ratio in the actual production process.
{"title":"Transverse Forced Nonlinear Vibration of the Printing Membrane under a Linear Tension Distribution","authors":"Mingyue Shao, Jiajuan Qing, Jing Wang, Jimei Wu, Y. Wang, Dingqiang Liu","doi":"10.1109/SPAWDA48812.2019.9019261","DOIUrl":"https://doi.org/10.1109/SPAWDA48812.2019.9019261","url":null,"abstract":"Geometrically nonlinear vibration characteristics of large deflection of a printing membrane under a linear tension distribution and external excitation are analyzed. The mathematical model of the printing membrane under nonuniform tension is established. Based on the D'Alembert principle and von Karman nonlinear plate theory, the forced nonlinear partial differential equations of the printing membrane under nonuniform tension are deduced. The Galerkin method is applied for discretizing the governing equations, and the method of multiple scales is employed to determine the solution of the ordinary differential equations. The influence of the aspect ratio and the tension ratio on the system stability is highlighted. The results show that nonlinear vibration of the printing membrane can be suppressed by increasing the aspect ratio and reducing the tension ratio in the actual production process.","PeriodicalId":208819,"journal":{"name":"2019 14th Symposium on Piezoelectrcity, Acoustic Waves and Device Applications (SPAWDA)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131029205","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}
Pub Date : 2019-11-01DOI: 10.1109/SPAWDA48812.2019.9019279
B. Liu, Qian Wei, Cheng-xuan Che, Jian-sheng Cong
High temperature properties of 1-3 piezoelectric composite material sample were studied for borehole ultrasonic imaging logging. The pulse echo waveforms were measured from room temperature to 240°C. The curves of echo peak values, the central frequency and bandwidth extracted from the corresponding frequency spectrum, with changing temperature were obtained. The results showed that the material can work steadily and continuously under 210°C. This work will provide experimental data and basis for the development of high temperature ultrasonic transducers and borehole ultrasonic imaging logging tools.
{"title":"Study on High-Temperature Properties of 1-3 Piezoelectric Composites","authors":"B. Liu, Qian Wei, Cheng-xuan Che, Jian-sheng Cong","doi":"10.1109/SPAWDA48812.2019.9019279","DOIUrl":"https://doi.org/10.1109/SPAWDA48812.2019.9019279","url":null,"abstract":"High temperature properties of 1-3 piezoelectric composite material sample were studied for borehole ultrasonic imaging logging. The pulse echo waveforms were measured from room temperature to 240°C. The curves of echo peak values, the central frequency and bandwidth extracted from the corresponding frequency spectrum, with changing temperature were obtained. The results showed that the material can work steadily and continuously under 210°C. This work will provide experimental data and basis for the development of high temperature ultrasonic transducers and borehole ultrasonic imaging logging tools.","PeriodicalId":208819,"journal":{"name":"2019 14th Symposium on Piezoelectrcity, Acoustic Waves and Device Applications (SPAWDA)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114212057","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}
Pub Date : 2019-11-01DOI: 10.1109/SPAWDA48812.2019.9019283
Yan Guo, Bin Huang, Ji Wang
We present a stress function based bending stress analysis method for piezoelectric nanoplate under inhomogeneous electric fields considering both piezoelectric effect and flexoelectric effect in this work. A Ritz type solution procedure is developed by means of the quasi-three dimensional stress functions with the initial assumption of out-of-plane stress functions. A standard eigenvalue problem is constructed to obtain the general solutions of governing equations which are obtained by the principle of complementary virtual work. For the numerical analysis, we investigate the bending stresses in laminated piezoelectric nanoplate with or without flexoelectricity and the size-dependent effect on the bending stress distributions. Two kinds of inhomogeneous electric fields are considered for discussion. With the proper assumption of flexoelectric coefficients, the bending stresses are presented which are contributed by both flexoelectric effect and piezoelectric effect. The size effect on bending stresses is also investigated in this work and the size-dependent stress distributions are presented as demonstration.
{"title":"Inhomogeneous Electric Field Induced Bending Stresses in Piezoelectric Medium with Flexoelectricity","authors":"Yan Guo, Bin Huang, Ji Wang","doi":"10.1109/SPAWDA48812.2019.9019283","DOIUrl":"https://doi.org/10.1109/SPAWDA48812.2019.9019283","url":null,"abstract":"We present a stress function based bending stress analysis method for piezoelectric nanoplate under inhomogeneous electric fields considering both piezoelectric effect and flexoelectric effect in this work. A Ritz type solution procedure is developed by means of the quasi-three dimensional stress functions with the initial assumption of out-of-plane stress functions. A standard eigenvalue problem is constructed to obtain the general solutions of governing equations which are obtained by the principle of complementary virtual work. For the numerical analysis, we investigate the bending stresses in laminated piezoelectric nanoplate with or without flexoelectricity and the size-dependent effect on the bending stress distributions. Two kinds of inhomogeneous electric fields are considered for discussion. With the proper assumption of flexoelectric coefficients, the bending stresses are presented which are contributed by both flexoelectric effect and piezoelectric effect. The size effect on bending stresses is also investigated in this work and the size-dependent stress distributions are presented as demonstration.","PeriodicalId":208819,"journal":{"name":"2019 14th Symposium on Piezoelectrcity, Acoustic Waves and Device Applications (SPAWDA)","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117338487","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}
Pub Date : 2019-11-01DOI: 10.1109/SPAWDA48812.2019.9019281
Xue Ding, Jianying Hu, Guangyong Li, Lichen Hua, Wan-li Zuo, Ji Wang, Ben-jie Ding, Jianke Du
This paper studies the relationship between the various vibration modes of the magnetoelectric composite structure and the biased magnetic field. Matlab is used to calculate three nonlinear parameters of Terfenol-D, then the nonlinear relation between the characteristic frequencies of the four vibration modes of the magnetoelectric composite structure and the external magnetic field is obtained by finite element method (FEM). Finally, the magnetoelectric composite structure specimen is prepared, and the correctness of the finite element method is verified by the experimental method. In addition, the vibration frequency of the magnetoelectric composite structure specimen in the magnetic field is measured by the laser vibrometer. The experimental data agree well with the results of FEM, which provides a new method for magnetic field measure.
{"title":"Multiple Vibration Modal Analysis of Magnetoelectric Composite Structures under the Magnetic Fields","authors":"Xue Ding, Jianying Hu, Guangyong Li, Lichen Hua, Wan-li Zuo, Ji Wang, Ben-jie Ding, Jianke Du","doi":"10.1109/SPAWDA48812.2019.9019281","DOIUrl":"https://doi.org/10.1109/SPAWDA48812.2019.9019281","url":null,"abstract":"This paper studies the relationship between the various vibration modes of the magnetoelectric composite structure and the biased magnetic field. Matlab is used to calculate three nonlinear parameters of Terfenol-D, then the nonlinear relation between the characteristic frequencies of the four vibration modes of the magnetoelectric composite structure and the external magnetic field is obtained by finite element method (FEM). Finally, the magnetoelectric composite structure specimen is prepared, and the correctness of the finite element method is verified by the experimental method. In addition, the vibration frequency of the magnetoelectric composite structure specimen in the magnetic field is measured by the laser vibrometer. The experimental data agree well with the results of FEM, which provides a new method for magnetic field measure.","PeriodicalId":208819,"journal":{"name":"2019 14th Symposium on Piezoelectrcity, Acoustic Waves and Device Applications (SPAWDA)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121438893","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}
Pub Date : 2019-11-01DOI: 10.1109/SPAWDA48812.2019.9019240
Jinghui Wu, Longtao Xie, A. Zhang, Jianke Du, K. Hashimoto, Ji Wang
The analysis of surface acoustic waves (SAW) in finite solids with complications such as electrodes is of great importance in resonator design. As a simplification of the analysis of actual SAW resonators, we apply the Rayleigh-Ritz method to an isotropic substrate for the formulation and numerical analysis of effects of electrodes on the wave velocity and frequency spectra.It is shown that accurate results of frequency of Rayleigh waves can be obtained at reasonable costs in the computation of eigenvalues from the dense stiffness and mass matrices. As it is known, the computational time are spread to the numerical integration of elements of matrices and the extraction of eigenvalues of the generalized eigenvalue problem, although the size of matrices is small but the matrices are dense, which is in contrast with the FEM approach.The Rayleigh-Ritz method provides another effective technique in the analysis with possible development of efficient tools for the design of SAW resonators.
{"title":"The Analysis of Surface Acoustic Waves in A Finite Solid with Electrodes by the Rayleigh-Ritz Method","authors":"Jinghui Wu, Longtao Xie, A. Zhang, Jianke Du, K. Hashimoto, Ji Wang","doi":"10.1109/SPAWDA48812.2019.9019240","DOIUrl":"https://doi.org/10.1109/SPAWDA48812.2019.9019240","url":null,"abstract":"The analysis of surface acoustic waves (SAW) in finite solids with complications such as electrodes is of great importance in resonator design. As a simplification of the analysis of actual SAW resonators, we apply the Rayleigh-Ritz method to an isotropic substrate for the formulation and numerical analysis of effects of electrodes on the wave velocity and frequency spectra.It is shown that accurate results of frequency of Rayleigh waves can be obtained at reasonable costs in the computation of eigenvalues from the dense stiffness and mass matrices. As it is known, the computational time are spread to the numerical integration of elements of matrices and the extraction of eigenvalues of the generalized eigenvalue problem, although the size of matrices is small but the matrices are dense, which is in contrast with the FEM approach.The Rayleigh-Ritz method provides another effective technique in the analysis with possible development of efficient tools for the design of SAW resonators.","PeriodicalId":208819,"journal":{"name":"2019 14th Symposium on Piezoelectrcity, Acoustic Waves and Device Applications (SPAWDA)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115125235","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}
Pub Date : 2019-11-01DOI: 10.1109/SPAWDA48812.2019.9019318
Xue-liang Liu, Chao Jiang, Shi-wei Tian, H. Fang, F. Yu, Xian Zhao
Contact stiffness between sensitive elements and electrodes in piezoelectric vibration sensor is one of the basic parameters, which has a direct influence on the characteristic frequency and dynamic performance of the vibration sensors. Since the contact stiffness has been generally neglected, there are few rules in designing and fabricating sensors. In order to solve this problem, a compression-mode piezoelectric vibration sensor using Ba2TiSi2O8 (BTS) single crystals was designed, assembled and tested for high temperature vibration sensing. Stiffness model of the vibration sensor was presented first, followed by BTS single crystal plates preparation, sensor assembly and experimental setup establishment. The fully packaged sensor by laser welding was characterized at temperatures ranged from room temperature to 650 °C under frequency range of 120Hz to 620Hz. Results indicated that the BTS based piezoelectric vibration sensors retained the same sensitivity at 500 °C for a dwell time of 72h, exhibiting a high stability and reliability.
{"title":"Influence of Tighting Torque on the Performance of High Temperature Piezoelectric Vibration Sensor Using BTS Crystal","authors":"Xue-liang Liu, Chao Jiang, Shi-wei Tian, H. Fang, F. Yu, Xian Zhao","doi":"10.1109/SPAWDA48812.2019.9019318","DOIUrl":"https://doi.org/10.1109/SPAWDA48812.2019.9019318","url":null,"abstract":"Contact stiffness between sensitive elements and electrodes in piezoelectric vibration sensor is one of the basic parameters, which has a direct influence on the characteristic frequency and dynamic performance of the vibration sensors. Since the contact stiffness has been generally neglected, there are few rules in designing and fabricating sensors. In order to solve this problem, a compression-mode piezoelectric vibration sensor using Ba2TiSi2O8 (BTS) single crystals was designed, assembled and tested for high temperature vibration sensing. Stiffness model of the vibration sensor was presented first, followed by BTS single crystal plates preparation, sensor assembly and experimental setup establishment. The fully packaged sensor by laser welding was characterized at temperatures ranged from room temperature to 650 °C under frequency range of 120Hz to 620Hz. Results indicated that the BTS based piezoelectric vibration sensors retained the same sensitivity at 500 °C for a dwell time of 72h, exhibiting a high stability and reliability.","PeriodicalId":208819,"journal":{"name":"2019 14th Symposium on Piezoelectrcity, Acoustic Waves and Device Applications (SPAWDA)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124975758","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}
Pub Date : 2019-11-01DOI: 10.1109/SPAWDA48812.2019.9019312
Kai Fang, Bin Wang, Z. Qian, Jia-shi Yang
We propose a specific composition of a beam of a piezoelectric dielectric layer sandwiched between two nonpiezoelectric semiconductor layers. A one-dimensional theoretical model is established for the bending of the beam with shear deformation. A theoretical analysis of a cantilever of such a beam under an end shear force is performed. Results show that an axial electric field develops in the beam because of the shear deformation accompanying bending via the piezoelectric constant e15. The axial electric field drives the charge carriers to the two ends of the beam. Thus the proposed composite beam can be used as a new and basic structure with potential applications in piezotronics when the shear force is present or dominant.
{"title":"Piezopotential in a Composite Piezoelectric Semiconductor Cantilever Produced by Shear Force","authors":"Kai Fang, Bin Wang, Z. Qian, Jia-shi Yang","doi":"10.1109/SPAWDA48812.2019.9019312","DOIUrl":"https://doi.org/10.1109/SPAWDA48812.2019.9019312","url":null,"abstract":"We propose a specific composition of a beam of a piezoelectric dielectric layer sandwiched between two nonpiezoelectric semiconductor layers. A one-dimensional theoretical model is established for the bending of the beam with shear deformation. A theoretical analysis of a cantilever of such a beam under an end shear force is performed. Results show that an axial electric field develops in the beam because of the shear deformation accompanying bending via the piezoelectric constant e15. The axial electric field drives the charge carriers to the two ends of the beam. Thus the proposed composite beam can be used as a new and basic structure with potential applications in piezotronics when the shear force is present or dominant.","PeriodicalId":208819,"journal":{"name":"2019 14th Symposium on Piezoelectrcity, Acoustic Waves and Device Applications (SPAWDA)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125065605","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}
Pub Date : 2019-11-01DOI: 10.1109/SPAWDA48812.2019.9019313
S. Ye, Zhidong Zhou
In this paper, considering the flexoelectric effect, the coupling consequences of local mass density fluctuation and liquid crystal director distribution are analyzed in parallel aligned nematic liquid crystals. Under the applied surface free charge density, the total free energy of liquid crystal system includes the elastic energy, local density energy density, flexoelectric energy and dielectric energy using the director-density coupling theory. Then the Ginzburg-Landau phase field equation of the liquid crystal director evolution and Cahn-Hilliard equation of the local mass density change are established to couple the evolution process and final distribution of the director and local mass density. The distribution curves of liquid crystal director, local mass density are calculated and illustrated. The effects of surface free charge density and material parameters have been discussed in detail. The results show that the Freedericksz transition accompanied by a modulation in the mass density.
{"title":"Consequences of Flexoelectricity on Director Distribution and Local Mass Density Fluctuation in Parallel Aligned Nematic Liquid Crystals","authors":"S. Ye, Zhidong Zhou","doi":"10.1109/SPAWDA48812.2019.9019313","DOIUrl":"https://doi.org/10.1109/SPAWDA48812.2019.9019313","url":null,"abstract":"In this paper, considering the flexoelectric effect, the coupling consequences of local mass density fluctuation and liquid crystal director distribution are analyzed in parallel aligned nematic liquid crystals. Under the applied surface free charge density, the total free energy of liquid crystal system includes the elastic energy, local density energy density, flexoelectric energy and dielectric energy using the director-density coupling theory. Then the Ginzburg-Landau phase field equation of the liquid crystal director evolution and Cahn-Hilliard equation of the local mass density change are established to couple the evolution process and final distribution of the director and local mass density. The distribution curves of liquid crystal director, local mass density are calculated and illustrated. The effects of surface free charge density and material parameters have been discussed in detail. The results show that the Freedericksz transition accompanied by a modulation in the mass density.","PeriodicalId":208819,"journal":{"name":"2019 14th Symposium on Piezoelectrcity, Acoustic Waves and Device Applications (SPAWDA)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129563856","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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