The Experts below are selected from a list of 777 Experts worldwide ranked by ideXlab platform
L. Eric Cross - One of the best experts on this subject based on the ideXlab platform.
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Nonlinear piezoelectric behavior of ceramic bending mode actuators under strong electric fields
Journal of Applied Physics, 1999Co-Authors: Qing-ming Wang, Ruibin Liu, Qiming Zhang, L. Eric CrossAbstract:The nonlinear electromechanical behavior of cantilevered piezoelectric ceramic bimorph, unimorph, and reduced and internally biased oxide wafer actuators is studied in a wide electric field and frequency range. It is found that under Quasistatic Condition, linear relationships between actuator tip displacement-electric field, and blocking force-electric field are only valid under weak field driving. With increasing the driving field, electromechanical nonlinearity begins to contribute significantly to the actuator performance because of ferroelectric hysteresis behavior associated with piezoelectric lead zirconate titanate (PZT)-type ceramic materials. The bending resonance frequencies of all these actuators vary with the magnitude of the electric field. The decrease of resonance frequency with electric field is explained by the increase of elastic compliance of PZT ceramic due to elastic nonlinearity. Mechanical quality factors of the actuators also depend on the magnitude of electric field strength. No significant temperature increase is observed when actuators are driven near resonance frequency under high electric field.
Qiming Zhang - One of the best experts on this subject based on the ideXlab platform.
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Piezoelectric Bending Actuator, Amplifing factor is proportional to l/t
2017Co-Authors: Ruibin Liu, Qing-ming Wang, Qiming Zhang, V.d. KugelAbstract:device was fabricated which has the following characterizations: 40 layers PSU actuator with a compact dimension: 38 mm xSo mm x 23.6 mm. Two of them arc needed for a device. Diaphragm area is 126mm x 152 mm. At Quasistatic Condition (5Hz) and at the 0.84 kV/cm electric held, 344 ttm displacement could he achieved at the apex of the diaphragm resulted fromthe flextensional amplifying mechanism with an amplification factor more than I I. The sound pressure level in the frequencyrange 100-250 Hz shows better flat behaviour than the acoustic sources studied earlier such as Double Amplifier and PANEL
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Piezoelectric responses in poly(vinylidene fluoride/hexafluoropropylene) copolymers
Applied Physics Letters, 2007Co-Authors: Bret Neese, Qiming Zhang, Yong Wang, Baojin Chu, Kailiang Ren, Sheng Liu, Cheng Huang, James E. WestAbstract:The authors show that a high transverse piezoelectric response with both high piezoelectric d31 (d31=43.1pm∕V) and electromechanical coupling k31 coefficients (k31=0.187), much higher than those in the piezoelectric poly(vinylidene fluoride) and poly(vinylidene fluoride-trifluoroethylene) copolymers, can be obtained in poly(vinylidene fluoride-hexafluoropropylene) [P(VDF-HFP)] 10wt% copolymers under Quasistatic Condition. Furthermore, the copolymers also display a higher d31 coefficient compared to the d33 coefficient, which seems to be unusual compared with most other piezopolymers. The experimental data suggest that the origin of the unusual piezoelectric response in these P(VDF-HFP) copolymers originates from a reversible change between a poled α-like structure and β-like structure. The phase change nature also results in a large frequency dispersion of the piezoelectric response and a smaller d31 (=20.5pm∕V) at 50kHz.
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Nonlinear piezoelectric behavior of ceramic bending mode actuators under strong electric fields
Journal of Applied Physics, 1999Co-Authors: Qing-ming Wang, Ruibin Liu, Qiming Zhang, L. Eric CrossAbstract:The nonlinear electromechanical behavior of cantilevered piezoelectric ceramic bimorph, unimorph, and reduced and internally biased oxide wafer actuators is studied in a wide electric field and frequency range. It is found that under Quasistatic Condition, linear relationships between actuator tip displacement-electric field, and blocking force-electric field are only valid under weak field driving. With increasing the driving field, electromechanical nonlinearity begins to contribute significantly to the actuator performance because of ferroelectric hysteresis behavior associated with piezoelectric lead zirconate titanate (PZT)-type ceramic materials. The bending resonance frequencies of all these actuators vary with the magnitude of the electric field. The decrease of resonance frequency with electric field is explained by the increase of elastic compliance of PZT ceramic due to elastic nonlinearity. Mechanical quality factors of the actuators also depend on the magnitude of electric field strength. No significant temperature increase is observed when actuators are driven near resonance frequency under high electric field.
Qing-ming Wang - One of the best experts on this subject based on the ideXlab platform.
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Piezoelectric Bending Actuator, Amplifing factor is proportional to l/t
2017Co-Authors: Ruibin Liu, Qing-ming Wang, Qiming Zhang, V.d. KugelAbstract:device was fabricated which has the following characterizations: 40 layers PSU actuator with a compact dimension: 38 mm xSo mm x 23.6 mm. Two of them arc needed for a device. Diaphragm area is 126mm x 152 mm. At Quasistatic Condition (5Hz) and at the 0.84 kV/cm electric held, 344 ttm displacement could he achieved at the apex of the diaphragm resulted fromthe flextensional amplifying mechanism with an amplification factor more than I I. The sound pressure level in the frequencyrange 100-250 Hz shows better flat behaviour than the acoustic sources studied earlier such as Double Amplifier and PANEL
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Nonlinear piezoelectric behavior of ceramic bending mode actuators under strong electric fields
Journal of Applied Physics, 1999Co-Authors: Qing-ming Wang, Ruibin Liu, Qiming Zhang, L. Eric CrossAbstract:The nonlinear electromechanical behavior of cantilevered piezoelectric ceramic bimorph, unimorph, and reduced and internally biased oxide wafer actuators is studied in a wide electric field and frequency range. It is found that under Quasistatic Condition, linear relationships between actuator tip displacement-electric field, and blocking force-electric field are only valid under weak field driving. With increasing the driving field, electromechanical nonlinearity begins to contribute significantly to the actuator performance because of ferroelectric hysteresis behavior associated with piezoelectric lead zirconate titanate (PZT)-type ceramic materials. The bending resonance frequencies of all these actuators vary with the magnitude of the electric field. The decrease of resonance frequency with electric field is explained by the increase of elastic compliance of PZT ceramic due to elastic nonlinearity. Mechanical quality factors of the actuators also depend on the magnitude of electric field strength. No significant temperature increase is observed when actuators are driven near resonance frequency under high electric field.
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pseudo shear universal actuator driving flextensional panel diaphragm low frequency acoustic source
Smart Structures and Materials 1998: Smart Structures and Integrated Systems, 1998Co-Authors: Ruibin Liu, Qing-ming Wang, V.d. Kugel, Q M Zhang, L E CrossAbstract:Acoustic source used for Active Noise Control at low frequency (80 - 250 Hz) is designed and developed by using a piezoelectric ceramic actuator and a flextensional panel diaphragm. In order to reach the vibration magnitude and radiation area needed for high and flat sound pressure level in the low frequency range. Pseudo-Shear Universal (PSU) actuator has been used as the driving part which is a new type of multilayer piezoelectric actuator originated from MRL offering the advantages of large displacement and high blocking force; on the other hand, Carbon Fiber Reinforced Composite has been used as the diaphragm material which provides a more rigid structure than conventional loudspeaker paper. A prototype device was fabricated which has the following characterizations: 40 layers PSU actuator with a compact dimension: 38 mm X 50 mm X 23.6 mm. Two of them are needed for a device. Diaphragm area is 126 mm X 152 mm. At Quasistatic Condition (5 Hz) and at the 0.84 kV/cm electric field, 344 micrometers displacement could be achieved at the apex of the diaphragm resulted from the flextensional amplifying mechanism with an amplification factor more than 11. The sound passive level in the frequency range 100 - 250 Hz shows better flat behavior than the acoustic sources studied earlier such as Double Amplifier and PANEL air transducers which exhibit a significant reduction of sound pressure level in the low frequency range. By a slight modification, it is likely to make this device in a total thickness of 10 - 15 mm range. High and stable sound pressure level as well as thin flat structure make it much more competitive in the whole area of applications for low frequency active noise control.
Michael Atzmon - One of the best experts on this subject based on the ideXlab platform.
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Effect of strain rate on the formation of nanocrystallites in an Al-based amorphous alloy during nanoindentation
Journal of Applied Physics, 2003Co-Authors: W. H. Jiang, Frederick E. Pinkerton, Michael AtzmonAbstract:The effect of deformation by nanoindentation on nanocrystallization in amorphous Al90Fe5Gd5 was investigated by transmission electron microscopy. Massive precipitation of nanocrystallites is observed within the indents. Under the Quasistatic Condition used, a temperature rise due to adiabatic heating is likely negligible, confirming that plastic deformation can induce crystallization without a heating effect. The nucleation of nanocrystallites is significantly affected by the strain rate.
Yuanzheng Yang - One of the best experts on this subject based on the ideXlab platform.
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Research on deformation behavior of zirconium-based bulk metallic glasses containing hydrogen with different deformability
International Journal of Hydrogen Energy, 2016Co-Authors: Pingjun Tao, Wenwu Zhang, Li Dongyang, Yuanzheng YangAbstract:Abstract Bulk metallic glasses (BMGs) have absorbed much attention for their potential applications as high-strength materials. However, they are notorious for being extremely brittle, failing in a catastrophic manner. A large number of researches indicated that, BMGs deform through the formation of highly localized shear bands under loading at room temperature, i.e., deformation of the BMGs take places just within very narrow shear bands. However, whether or not all the BMGs, including BMGs with high global deformability and poor plasticity, have the same deformation manner at room temperature is not very clear. In present paper, two Zr-based BMGs, marked by T1 and T2, were prepared via copper-mold vacuum suction casting under the gaseous mixture of hydrogen and argon, of which, T2 presents a large plasticity at room temperature, while T1 is prone to brittleness. The uniaxial compression experiments of T1 and T2 BMGs were carried out under a Quasistatic Condition to investigate the deformation manners of BMGs with different deformability at room temperature. The results showed that the differences of initiation and propagation of shear bands result in the different deformation behavior of T1 and T2 BMGs at room temperature.
