The Experts below are selected from a list of 12633 Experts worldwide ranked by ideXlab platform
M. Okuyama - One of the best experts on this subject based on the ideXlab platform.
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Buckling control of silicon dioxide diaphragms by lateral stress enhancement for sensitivity improvement of piezoelectric ultrasonic microsensors
Sensors and Actuators A: Physical, 2011Co-Authors: Kaoru Yamashita, T. Watanabe, Tomoya Yoshizaki, Minoru Noda, M. OkuyamaAbstract:Abstract Piezoelectric ultrasonic microsensors have been fabricated using sol–gel derived PZT (Pb(Zr,Ti)O 3 ) thin films on micromachined silicon dioxide diaphragms which are made from a normal silicon wafer instead of the conventional SOI (silicon on insulator) wafer. Layered structure of the PZT capacitor part on the diaphragm has been modified in order to allow the diaphragm to cause a Static Deflection for sensitivity enhancement by controlling the total lateral stress in the diaphragm. Sensors having an island-like structure in the PZT layer have shown an adequate Static Deflection due to a lateral stress caused by silicon dioxide film and revealed over 2 times higher sensitivity than conventional sensors.
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Static Deflection control for sensitivity enhancement of piezoelectric ultrasonic microsensors on silicon dioxide diaphragms
IEEE Sensors, 2009Co-Authors: Kaoru Yamashita, Tomoya Yoshizaki, Minoru Noda, M. OkuyamaAbstract:Sensitivity of piezoelectric ultrasonic microsensors has been enhanced through Static Deflection control on silicon dioxide diaphragm structures. A precise Deflection control process has been developed for fragile SiO 2 diaphragms derived from a both-side oxidized normal silicon wafer. The diaphragms have been re-buckled upward without breaking and the sensitivity has been improved by four times on average on the Deflection-controlled SiO 2 diaphragm sensors.
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diaphragm Deflection control of piezoelectric ultrasonic microsensors for sensitivity improvement
Sensors and Actuators A-physical, 2007Co-Authors: Kaoru Yamashita, Hiroki Nishimoto, M. OkuyamaAbstract:Abstract Arrayed ultrasonic microsensors have been fabricated using piezoelectric PZT (Pb(Zr,Ti)O 3 ) thin film on micromachined silicon diaphragm structures. Static Deflection of the diaphragms strongly affects the sensitivity; upward-deflected diaphragms show much higher sensitivity than downward-deflected diaphragms. Array sensors have been fabricated using modified processes which enable the diaphragms on a chip to deflect upward, and sensitivity has been successfully improved 4–6 times compared to the downward diaphragms.
M Rafiee - One of the best experts on this subject based on the ideXlab platform.
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modeling and mechanical analysis of multiscale fiber reinforced graphene composites nonlinear bending thermal post buckling and large amplitude vibration
International Journal of Non-linear Mechanics, 2018Co-Authors: M Rafiee, Fred Nitzsche, Michel R LabrosseAbstract:Abstract In this paper, a mathematical model was developed to predict the effective material properties of graphene nanoplatelets/fiber/polymer multiscale composites (GFPMC). The large Deflection, post-buckling and free nonlinear vibration of graphene nanoplatelets-reinforced multiscale composite beams were studied through a theoretical study. The governing equations of laminated nanocomposite beams were derived from the Euler–Bernoulli beam theory with von Karman geometric nonlinearity. Halpin–Tsai equations and fiber micromechanics were used in hierarchy to predict the bulk material properties of the multiscale composite. Graphene nanoplatelets (GNPs) were assumed to be uniformly distributed and randomly oriented through the epoxy resin matrix. A semi-analytical approach was used to calculate the large Static Deflection and critical buckling temperature of multiscale multifunctional nanocomposite beams. A perturbation scheme was also employed to determine the nonlinear dynamic response and the nonlinear natural frequencies of the beams with clamped–clamped, and hinged–hinged boundary conditions. The effects of weight percentage of graphene nanoplatelets, volume fraction of fibers, and boundary conditions on the Static Deflection, thermal buckling and post-buckling and linear and nonlinear natural frequencies of the GFPMC beams were investigated in detail. The numerical results showed that the central Deflection and natural frequency were significantly improved by a small percentage of GNPs. However, addition of GNPs led to a lower critical buckling temperature.
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nonlinear free vibration postbuckling and nonlinear Static Deflection of piezoelectric fiber reinforced laminated composite beams
Composites Part B-engineering, 2014Co-Authors: M Rafiee, S Mareishi, K M LiewAbstract:Abstract Large Static Deflection, mechanical and thermal buckling, postbuckling and nonlinear free vibration of laminated composite beams with surface bonded piezoelectric fiber reinforced composite (PFRC) layers under a combined mechanical, thermal and electrical loading are studied in this paper. The temperature rise is considered to be one-dimensional steady state heat conduction in the thickness direction. The governing equations of the piezoelectric fiber reinforced laminated composite beams are derived based on Euler–Bernoulli beam theory and geometric nonlinearity of von Karman. Rectangular representative volume element (RVE) with rectangular fibers has been considered for piezoelectric fiber reinforced composite. Analytical solution of nonlinear bending and postbuckling analyses has been carried out. A perturbation method is then employed to determine the nonlinear vibration behavior and the nonlinear natural frequencies of the beams with simply supported and clamped boundary conditions. Post-buckling load–Deflection and maximum transverse load–Deflection relations have been obtained for the beam under consideration. The effects of the temperature rise, beam geometry parameter, and the volume fraction of the piezoelectric fibers on the linear and nonlinear fundamental natural frequencies of the piezoelectric fiber reinforced composites are investigated through a comprehensive parametric study.
Kaoru Yamashita - One of the best experts on this subject based on the ideXlab platform.
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Buckling control of silicon dioxide diaphragms by lateral stress enhancement for sensitivity improvement of piezoelectric ultrasonic microsensors
Sensors and Actuators A: Physical, 2011Co-Authors: Kaoru Yamashita, T. Watanabe, Tomoya Yoshizaki, Minoru Noda, M. OkuyamaAbstract:Abstract Piezoelectric ultrasonic microsensors have been fabricated using sol–gel derived PZT (Pb(Zr,Ti)O 3 ) thin films on micromachined silicon dioxide diaphragms which are made from a normal silicon wafer instead of the conventional SOI (silicon on insulator) wafer. Layered structure of the PZT capacitor part on the diaphragm has been modified in order to allow the diaphragm to cause a Static Deflection for sensitivity enhancement by controlling the total lateral stress in the diaphragm. Sensors having an island-like structure in the PZT layer have shown an adequate Static Deflection due to a lateral stress caused by silicon dioxide film and revealed over 2 times higher sensitivity than conventional sensors.
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Static Deflection control for sensitivity enhancement of piezoelectric ultrasonic microsensors on silicon dioxide diaphragms
IEEE Sensors, 2009Co-Authors: Kaoru Yamashita, Tomoya Yoshizaki, Minoru Noda, M. OkuyamaAbstract:Sensitivity of piezoelectric ultrasonic microsensors has been enhanced through Static Deflection control on silicon dioxide diaphragm structures. A precise Deflection control process has been developed for fragile SiO 2 diaphragms derived from a both-side oxidized normal silicon wafer. The diaphragms have been re-buckled upward without breaking and the sensitivity has been improved by four times on average on the Deflection-controlled SiO 2 diaphragm sensors.
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diaphragm Deflection control of piezoelectric ultrasonic microsensors for sensitivity improvement
Sensors and Actuators A-physical, 2007Co-Authors: Kaoru Yamashita, Hiroki Nishimoto, M. OkuyamaAbstract:Abstract Arrayed ultrasonic microsensors have been fabricated using piezoelectric PZT (Pb(Zr,Ti)O 3 ) thin film on micromachined silicon diaphragm structures. Static Deflection of the diaphragms strongly affects the sensitivity; upward-deflected diaphragms show much higher sensitivity than downward-deflected diaphragms. Array sensors have been fabricated using modified processes which enable the diaphragms on a chip to deflect upward, and sensitivity has been successfully improved 4–6 times compared to the downward diaphragms.
Lee R White - One of the best experts on this subject based on the ideXlab platform.
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theoretical analysis of the Static Deflection of plates for atomic force microscope applications
Journal of Applied Physics, 1993Co-Authors: John E Sader, Lee R WhiteAbstract:The analysis of the Static Deflection of cantilever plates is of fundamental importance in application to the atomic force microscope (AFM). In this paper we present a detailed theoretical study of the Deflection of such cantilevers. This shall incorporate the presentation of approximate analytical methods applicable in the analysis of arbitrary cantilevers, and a discussion of their limitations and accuracies. Furthermore, we present results of a detailed finite element analysis for a current AFM cantilever, which will be of value to the users of the AFM.
H Nguyenxuan - One of the best experts on this subject based on the ideXlab platform.
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Static and free vibration analyses and dynamic control of composite plates integrated with piezoelectric sensors and actuators by the cell based smoothed discrete shear gap method cs fem dsg3
Smart Materials and Structures, 2013Co-Authors: P Phungvan, T Nguyenthoi, T Ledinh, H NguyenxuanAbstract:The cell-based smoothed discrete shear gap method (CS-FEM-DSG3) using three-node triangular elements was recently proposed to improve the performance of the discrete shear gap method (DSG3) for Static and free vibration analyses of isotropic Mindlin plates. In this paper, the CS-FEM-DSG3 is further extended for Static and free vibration analyses and dynamic control of composite plates integrated with piezoelectric sensors and actuators. In the piezoelectric composite plates, the electric potential is assumed to be a linear function through the thickness of each piezoelectric sublayer. A displacement and velocity feedback control algorithm is used for active control of the Static Deflection and the dynamic response of the plates through closed loop control with bonded or embedded distributed piezoelectric sensors and actuators. The accuracy and reliability of the proposed method is verified by comparing its numerical solutions with those of other available numerical results.
