G. Yang

Nova Scotia Museum, Halifax, Nova Scotia, Canada

Are you G. Yang?

Claim your profile

Publications (18)10.26 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Resonance characterisation has been used to determine the variation of the independent piezoelectric, elastic, and dielectric material coefficients, as well as the electromechanical coupling factors, of typical soft and hard lead zirconate titanate (PZT) ceramics as a function of temperature ranging from -165degC to 195degC. The piezoelectric coefficients and the dielectric permittivities generally increased with temperature for both types of PZT whereas the elastic compliance coefficients exhibited broad peaks over parts of the temperature range. Thermal hysteresis was also observed over the temperature cycle.
    Applications of Ferroelectrics, 2007. ISAF 2007. Sixteenth IEEE International Symposium on; 07/2007
  • [Show abstract] [Hide abstract]
    ABSTRACT: Electric-field-induced phase transitions and piezoelectric properties of <001>-oriented Pb(Mg1/3Nb2/3)O3-32%PbTiO3 (PMN-PT) single crystals have been investigated as a function of temperature. It was found that the phase transitions and piezoelectric properties for PMN-PT crystals are strongly dependent on temperature. The measurements of polarization and longitudinal strain as a function of a unipolar electric field show that the field for the induced monoclinic-tetragonal phase transition decreases linearly with temperature in the range between 23 °C and 75 °C. Raising the temperature can stabilize the tetragonal phase in <001>-oriented PMN-PT crystals. The effective longitudinal piezoelectric constant, d33, in the monoclinic phase increases with temperature. Meanwhile in the field-induced tetragonal phase, d33 is much smaller and has little change with temperature. The electric-field-induced phase transition from a cubic phase to a tetragonal phase was observed at 125 °C.
    Proceedings of SPIE - The International Society for Optical Engineering 05/2005; DOI:10.1117/12.598152 · 0.20 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Dielectric elastomers are known to produce large transverse strains in response to electrically induced Maxwell stresses and thus provide a useful form of electromechanical actuation. The transverse strain response of silicone (Dow Corning HS III RTV) based Maxwell stress actuators have been measured earlier as a function of driving electric field, frequency and pre-load. Experimental results show that a pre-load initially causes an increase in the strain. However, this increase appears to be a function of the relative geometries of the electroded area and of the specimen itself. The transverse strains in these materials decrease when larger values of pre-load are applied. Models of hyperelasticity that are capable of describing the large deformation of polymer materials have been used to interpret our results. Numerical finite element simulations of the material's behavior using a hyperelastic model provides good agreement with most of our observations on the electric field and pre-strain dependencies of the transverse strain.
    Smart Materials and Structures 01/2005; 5759:134-143. DOI:10.1117/12.598160 · 2.45 Impact Factor
  • 11th CF/DRDC International Meeting on Naval Applications of Materials Technology, Halifax, Nova Scotia; 01/2005
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Some electroactive polymers show large electric-field-induced strain. However, it is difficult to characterize the transverse strain response, especially the dynamic response, under high driving electric fields. In this work, a transverse strain measurement system based on a ZYGO laser Doppler interferometer has been developed. This system can measure transverse strain responses of polymer actuators of different sizes over a wide displacement and frequency range. By using this system, we have investigated the electric-field-induced strains of electroactive polymer actuators fabricated from silicone (Dow Corning HSIII RTV) films. The static and dynamic strains of the actuators have been measured under various driving electric fields and mechanical loads. Our results show that the polymers exhibit a non-linear relationship between strain and driving field. Mechanical loads have a significant effect on transverse strain responses. Transverse strains of 3.25% (static) and 2.08% (dynamic at 1 Hz) have been obtained under a load-free condition. Our experimental results can be understood on the basis of hyperelastic theory. The actuation of an electroactive polymer actuator is not only determined by its material properties, but also by the actuator structure.
    Applications of Ferroelectrics, 2004. ISAF-04. 2004 14th IEEE International Symposium on; 09/2004
  • G. Yang, W. Ren, J. P. Szabo
    The Eleventh International Congress on Sound and Vibration, St. Petersburg, Russia; 01/2004
  • 7th Cansmart Meeting, International Workshop on Smart Materials and Structures, Montreal, Quebec; 01/2004
  • [Show abstract] [Hide abstract]
    ABSTRACT: We have investigated the electromechanical response of piezoelectric ceramics as a function of the amplitude and frequency of large electric fields and studied the effects of dc bias fields. In order to characterize the materials under these conditions, a ZMI 2000 laser interferometer system from Zygo Corp. has been installed and modified to directly measure the strains of ferroelectric ceramics. This system uses a heterodyne detection technique and has the advantages of phase detection, wide bandwidth, high stability, and easy optical alignment. Our experiment has been used to determine the strain of lead zirconate titanate (PZT) ceramics as a function of electric fields and as a function of frequency in the low frequency range. From these measurements the piezoelectric coefficients d33, d31, and d15 have been determined as a function of applied field and frequency. In addition the dependence of the piezoelectric coefficients under an applied dc bias field has been studied under quasistatic and under resonance conditions. Some of our measurements have provided evidence of the time dependence of the piezoelectric response. Results on a range of soft and hard PZT ceramics manufactured by EDO Corp. are presented. These results are discussed within the context of extrinsic contributions to the piezoelectric response. © 2003 American Institute of Physics.
    Journal of Applied Physics 07/2003; 94(2):1155-1162. DOI:10.1063/1.1587008 · 2.19 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Laser Doppler interferometry has been used to determine the strain and piezoelectric response of Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) electrostrictive ceramics as a function of electric fields up to 4 MV m-1, frequencies between 0.1 Hz and 2.5 kHz and DC bias fields up to 3 MV m-1. The strain and polarization of PMN-15 with a composition of 0.9PMN-0.1PT and PMN-38 with a composition of 0.85PMN-0.15PT both produced by TRS ceramics, have been measured at room temperature. The strain and polarization responses of PMN-15 ceramics under an electric field up to 4 MV m-1 have been fitted to a polynomial model. The results suggest that a quadratic dependence of strain on polarization is not valid for large electric fields and that higher-order terms must be included. Our measurements showed that the effective piezoelectric coefficient, d33, of PMN-15 ceramics had a maximum value of 800 pm V-1 at a bias field of 0.67 MV m-1 and had little frequency dependence in the frequency range from 1 Hz up to 2.5 kHz. PMN-38 ceramic showed a maximum d33 of 1200 pm V-1 at a bias field of 0.43 MV m-1 and the d33 of this material showed a clear frequency dependence from 1 Hz up to 2.5 kHz.
    Journal of Physics D Applied Physics 06/2002; 35(13):1550. DOI:10.1088/0022-3727/35/13/316 · 2.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The problem of determining the drive waveform that produces a desired output from a hysteretic, saturating material is considered both theoretically and experimentally. The specific problem of interest is the production of a high-amplitude, but monofrequency, sinusoidal polarization response. (The techniques presented could also be used to control other physical variables, such as the strain, if desired.) Two sample materials were considered, one of which is characterized by relatively low hysteresis tan delta approximate to0.03) and tested using mechanical prestresses of 20.7 MPa (3 kpsi) and 41.4 MPa (6 kpsi), and the other of which is characterized by relatively high hysteresis (tan (delta approximate to0.11), and tested without a prestress. Both samples were fabricated from the electrostrictive material lead magnesium niobate (PMN), although a magnetostrictive material (such as Terfenol-D) could have been tested instead. The samples were subjected to a bias voltage and prestress in order to simulate conditions that might arise in a full transducer. By analytically inverting a theory of hysteresis [J. C. Piquette and S. E. Forsythe, J. Acoust. Soc. Am. 106, 3317-3327 (1999) and J. Acoust Soc. Am. 106, 3328-3334 (1999)], the required (predistorted) drive waveform was determined. Both semi-major and minor hysteresis loops, in both polarization and strain, were measured and the parameters of the theory determined by least-squares fitting. The measurements were obtained under quasi-static conditions, with drive frequencies at or below 10 Hz. The observed fits of theory to data are of high quality. The theory was then inverted analytically to determine the drive required to produce the desired monofrequency polarization response, having a peak polarization value approximately equal to that achieved using a biased sinusoid of AC amplitude equal to the bias. The total harmonic distortion (THD) in the output polarization resulting from the inverting drive, computed using 10 harmonics, was experimentally observed to be about an order of magnitude less than that resulting from a biased sinusoid in all cases. It is shown that the hysteresis loop arising when using the distortion-reducing drive is of smaller area than that obtained when driving with a sinusoid to achieve the same polarization amplitude. Thus, the distortion-reducing drive results in a smaller loss per cycle than is obtained with a sinusoidal drive. (C) 2001 Acoustical Society of America.
    The Journal of the Acoustical Society of America 08/2001; 110(2). DOI:10.1121/1.1381537 · 1.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Sensors and actuators based on piezoelectric ceramics are finding an increasingly large variety of applications under a very wide range of environmental conditions and applied signals. Some actuator applications require the piezoelectric materials to support large mechanical loads and produce high strain output. In order to accomplish this requirement of higher strains, large electric fields must be applied. This results in a significant non-linear behavior and hence affects the performance of the material. It is therefore important to understand the behavior and properties of these materials over a large range of temperature, frequency and applied electric fields and mechanical stresses. We have measured some of the dielectric, elastic and piezoelectric constants of soft (EC-65, EC-76) and hard (EC-64, EC-69) lead zirconate titanate (PZT) piezoelectric ceramics, manufactured by EDO Ceramics, as a function of temperature, frequency, applied field and applied stress. We have also determined the dependence of the piezoelectric constants on an applied DC bias voltage or stress. The time dependence of the piezoelectric response in the piezoelectric ceramics has also been studied. A summary of the results will be presented. Most of these results can be understood on the basis of the extrinsic contributions to the piezoelectric response that arises from the existence of domains in the material.
    Proceedings of SPIE - The International Society for Optical Engineering 07/2001; DOI:10.1117/12.432738 · 0.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A laser Doppler interferometer system has been used to measure the strains of ferroelectric ceramics. The strains and polarisation of piezoelectric and electrostrictive ceramics have been investigated as a function of electric fields up to 4 MV/m in the frequency range from 0.01 Hz up to 1 kHz. The field and frequency dependence of the appropriate material constants have been calculated. Results on a range of piezoelectric PZT and electrostrictive PMN-PT ceramic materials are presented.
    Ferroelectrics 01/2001; 261(1):27-32. DOI:10.1080/00150190108216260 · 0.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Piezoelectric ceramics are often used under compressive stress. It is therefore important to know the properties of these materials as a function of applied stress. We have developed an experiment that allows us to find the piezoelectric charge coefficient d33, elastic compliance S 33, and dielectric constant ϵ 33 as a function of uniaxial stress in the poled direction. Both dynamic and static measurements can be carried out. The dynamic and static coefficients differ from each other because of the different proportions of reversible and irreversible domain changes that contribute to them and each coefficient can be important in specific applications. Dynamic results for stresses up to 160 MPa on a soft and a hard piezoelectric Lead Zirconate Titanate (PZT) ceramics are presented. The time dependence of the measurement has also been investigated. It was found that the experimental results were strongly dependent on the material type, history of the specimen, stress level, and the time scale of the measurement.
    Ferroelectrics 01/2001; 262(1-4):207-212. DOI:10.1080/00150190108225151 · 0.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The temperature dependence of the material properties of PMN-PT-La (0.85/0.15/1%) electrostrictive ceramics manufactured by TRS Ceramics Inc. have been investigated. The measurements reported here include: the temperature and frequency dependence of dielectric permittivity and dissipation, the quasi-static strain as a function of applied electric field, and the DC biased resonance characterisation of the dielectric, elastic and electromechanical coefficients at temperatures below, near, and above Tmax.
    Ferroelectrics 01/2001; 262(1-4):201-206. DOI:10.1080/00150190108225150 · 0.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We have measured some of the dielectric, elastic, and piezoelectric constants of several types of PZT piezoelectric ceramics, manufactured by EDO Corporation, as a function of applied electric field and mechanical stress. Both the high frequency impedance resonance method and the low frequency response of the material under electrical and mechanical excitations were employed to determine these constants. We present the dependence of these material constants on an applied DC bias voltage and on an applied mechanical stress. Most of the results can be understood on the basis of the extrinsic contributions to the piezoelectric response that arises from the existence of domains in the materials
    Ultrasonics Symposium, 2000 IEEE; 11/2000
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A Zygo laser interferometer system has been used to measure the strain induced in piezoelectric lead zirconate titanate (PZT) and electrostrictive lead magnesium niobate (PMN) based ceramics. The piezoelectric coefficients d<sub>33</sub>, d<sub>31</sub> and d<sub>15 </sub> of PZT ceramics have been determined as a function of electric field and frequency. The strain and polarization of PMN-PT ceramics have been measured at AC fields of up to 4 MV/m. For PMN-based ceramics, the results suggest that a quadratic relation of strain with polarization (S=Q·P<sup>2</sup>) is not valid at high electric fields and higher order terms must be considered. DC bias measurements at room temperature showed that the maximum d<sub>33</sub> of PMN-15 ceramics was 800 pm/V at the bias field of 0.67 MV/m and had little frequency dependence in the frequency range from 1 Hz up to 2.5 kHz. However, PMN-38 ceramic, with a maximum d<sub>33</sub> of 1200 pm/V at the bias field of 0.43 MV/m, showed frequency dependence from 1 Hz up to 2.5 kHz
    Applications of Ferroelectrics, 2000. ISAF 2000. Proceedings of the 2000 12th IEEE International Symposium on; 02/2000
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Piezoelectric ceramics are often used under compressive stress. We have measured the dynamic value of the piezoelectric charge coefficient, d<sub>33</sub>, as a function of uniaxial stress in the poled direction. Results on two types of PZT ceramics manufactured by EDO Corporation are presented; in general, they show a nonlinear behaviour with an initial increase in d<sub>33</sub> as the stress increases followed by a significant decrease. The time dependence of the measurement has also been investigated and these studies indicate that the stress induced extrinsic contributions take a finite time to appear and that, over longer time periods, the stress causes ageing
    Applications of Ferroelectrics, 2000. ISAF 2000. Proceedings of the 2000 12th IEEE International Symposium on; 02/2000
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Smart structures based on piezoelectric materials are now finding applications in a wide variety of environmental conditions. We have used the impedance resonance technique to measure the impedance spectra of lead zirconate titanate ceramic specimens over temperatures ranging between 0ºC and 100ºC. The analysis of the radial, thickness, thickness shear and length extensional modes of resonance have allowed us to determine the temperature dependence of the complete reduced matrix of material constants, [s E , ε T , d], and our results are presented. We have also studied the effect of multiple heating cycles on the material and have observed the occurrence of thermal hysteresis. The causes and the significance of this hysteresis are analysed.