The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform

Sanjeev Kumar Raghuwanshi - One of the best experts on this subject based on the ideXlab platform.

Sumit Kumar Jindal - One of the best experts on this subject based on the ideXlab platform.

Wen Wang - One of the best experts on this subject based on the ideXlab platform.

  • Static and dynamic simulation studies on the AlGaN/GaN pressure sensor
    Semiconductor Science and Technology, 2019
    Co-Authors: Ashu Wang, Lingyan Zeng, Wen Wang
    Abstract:

    In this paper, electro-thermo-mechanical coupled static and dynamic FEM simulations are adopted to study the AlGaN/GaN pressure sensor. The sensor sensitivity is expressed as the drain current change of transistor integrated on the AlGaN/GaN cantilever or Circular Diaphragm with the applied pressure, namely piezoresistive effect, which is caused essentially by the change of piezoelectric polarization charge. In the static simulation study, how the transistor self-heating, gate metal layer, AlGaN donor-like surface states, and bulk acceptor-like traps in GaN influence the sensitivity are separately illustrated. In the dynamic simulation study, transient behavior of the sensor with the bulk acceptor-like traps and dependences of the natural frequency of Circular Diaphragm on the self-heating as well as the position of transistor integrated on the Diaphragm are analyzed. This work would provide useful guidelines for the design and optimization of AlGaN/GaN pressure sensor.

  • non linear deflection of a Circular Diaphragm type piezoactuator under loads of voltage and pressure
    Sensors and Actuators A-physical, 2017
    Co-Authors: Yuanlin Hu, Wen Wang
    Abstract:

    Abstract Analytical non-linear equations are formulated to predict the deflection of a Circular Diaphragm-type piezoactuator, which consists of a passive layer, a bonding layer and a PZT layer. Previous similar analytical solutions presented in the literature are based on thin plates with small deflections (linear problem), however the linear solutions fail to predict the deflection of the piezoactuator when the driven loads, such as voltage and pressure loads, are large. In this research, a non-linear analytical solution for the piezoactuator deflection under loads of voltage and pressure is derived using the principal of minimum energy and the Rayleigh-Ritz method. Each of the three layers in the piezoactuator is considered as an individual layer. The energy associated with the solution includes elastic potential energy of the deformed piezoactuator, electric potential energy in the piezodisc, and the work done by the uniform pressure force. The proposed non-liner solution is validated via static deflection measurements, and it approves that the non-linear analytical results are found to be in a good agreement with the measurements while the linear solution is invalid when the loads are large. Based on the non-linear equations, the effects of the piezoactuator dimensions and the imposed loads on the actuator performance (stroke volume) are also investigated.

  • a theoretical solution of resonant Circular Diaphragm type piezoactuators with added mass loads
    Sensors and Actuators A-physical, 2017
    Co-Authors: Yuanlin Hu, Xin Liang, Wen Wang
    Abstract:

    Abstract A theoretical solution is formulated to analyze the vibration behaviors of Circular Diaphragm-type piezoactuators based on the Hamilton’s principle and Rayleigh-Ritz method, which are particular suitable for modeling the deflection of multilayer structures. Each of the actuator three layers is considered as an individual layer in the modeling. The energy associated with the solution includes the kinetic energy of the actuator, the elastic potential energy of the various layers, the electric potential energy in the piezodisc, and the work done by the force of electric filed. The transverse displacement is separated into a time dependence term and a mode shape term, then the vibrational governing equation is derived using the functional variation, and is approximately solved through the method of multiple scales. Moreover, added mass loads are introduced to the Diaphragm center for the sake of decreasing the resonant frequency, where many MEMS devices, such as gas micropumps and ejectors, have a higher working efficiency. The proposed analytical solution is validated numerically via the finite element method (FEM) and experimentally via measurements; the theoretical results are found to be in good agreement with the FEM results as well as with the experimental results. Furthermore, the effects of mass loads, geometric dimensions and material properties of the piezoactuator on the resonant frequency are discussed.

  • deflection of Circular Diaphragm type piezoactuators coupling with gas compression in micropumps
    Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems, 2017
    Co-Authors: Yuanlin Hu, Xin Liang, Wen Wang
    Abstract:

    An analytical solution is formulated to predict the deflection of Circular piezoactuators for the sake of gas compression in micropumps. The solution is derived from the energy minimization method and Rayleigh–Ritz method based on the Kirchhoff thin plate theory. Energy associated with the micropump includes elastic potential energy of the deflecting actuator, electric potential energy in the piezodiscs and compression work to gas. The proposed analytical solution is validated via the finite element simulations and experimental data. Furthermore, the effects of dimensions and material properties of the piezoactuator on the static pressure rise are discussed; there exist optimal radius ratio of the PZT layer to passive layer, optimal thickness ratio of the PZT layer to passive layer, and optimal ratio of the passive layer thickness to its radius, however, these optimal values are related to pressure load as well. Finally, the static pressure rise and the deflection profile of the piezoactuator have been discussed under the optimal dimensions.

Wen H Ko - One of the best experts on this subject based on the ideXlab platform.

Tongqing Yang - One of the best experts on this subject based on the ideXlab platform.

  • improvement of uneven charge distribution on piezoelectric Circular Diaphragm with notched substrate
    AIP Advances, 2020
    Co-Authors: Yuanbo Li, Yangyiwei Yang, Minghao Li, Tongqing Yang
    Abstract:

    Vibration-based energy harvesting using piezoelectric Circular Diaphragms (PCDs) has drawn much attention in recent decades because of their compatibility with various operation modes. However, it has been revealed that their output distribution over the electrode surface is highly uneven, with less output generated around the edge. In this work, we present a possible structure of a PCD, which consists of a notched substrate (notched PCD), a PZT-5H disk, and an annular mass, in which the charge output around the edge of the PCD can be enhanced. Moreover, the difference in charge production between the outer region (the region with less charge) and the inner region (the region with high charge) is reduced so that the output distribution of the PCD is improved. In the notched-PCD, the perimeter region of the PCD is better utilized, which leads to a higher output power. Finite element analysis is performed in order to provide further information about how the notched substrates affect the output distribution...

  • vibration based energy harvesting with a clamped piezoelectric Circular Diaphragm analysis and identification of optimal structural parameters
    Smart Materials and Structures, 2017
    Co-Authors: Shuai Wang, Yangyiwei Yang, Peter Stein, Baixiang Xu, Tongqing Yang
    Abstract:

    Due to many potential promising applications, vibration-based piezoelectric energy harvesters (VPEH) with a clamped Circular Diaphragm are an intensively studied design in the field of piezoelectric energy harvesters. Nonetheless, their performance still leaves space for improvement, which is the primary target of this article. We define two structural parameters, namely the ratio 1 between the bonding area and the piezoceramic diameter as well as the ratio 2 between the clamping rim and the substrate diameter, to characterize these structures. A vibration model is developed in order to provide an analytical foundation for the identification of optimal parameters 1 and 2. It is verified by finite-element simulations and substantive experiments. The results allow to relate the device performance, including resonance frequency and output power, to 1 and 2. This shows that the output rises with increasing 2, and that the maximum output for a given 2 always lies in the range Based on this observation, an improved harvester structure with a pre-stress of 0.3 N is identified, that exhibits a matched power up to 16.3 mW at 219 Hz. This demonstrates the feasibility to achieve VPEHs with higher outputs and lower eigenfrequency through simultaneous modification of 1 and 2, which is highly beneficial for low-frequency energy harvesting.

  • performance enhancement of pzt material for Circular Diaphragm energy harvester
    Journal of Materials Science: Materials in Electronics, 2015
    Co-Authors: Ying Dong, Tongqing Yang, Zhao Xiao, Xiucai Wang
    Abstract:

    The property of piezoelectric material was one of the keys to optimize energy harvester based on piezoelectric effect. In this paper, the relation between the parameters of piezoelectric material and the performance of Circular Diaphragm energy harvester was studied. Theoretical analysis and idiographic experiment were combined to estimate the dependence of output power on the material parameters: piezoelectric coefficient d33 and dielectric constant e. The results show piezoelectric material with high-d33 and low-e was good for increasing the output power of energy harvester, and the influence of piezoelectric coefficient is more obvious than that of dielectric constant. Among soft PZT, material PZT-51 could best fit energy harvesting. By optimizing PZT material, the energy harvester using single piezoelectric Circular Diaphragm could generate a maximum power of 9.08 mW for a matching load about 45 kΩ and a tip mass of 30 gat its resonant frequency of 178 Hz.

  • energy harvester array using piezoelectric Circular Diaphragm for broadband vibration
    Applied Physics Letters, 2014
    Co-Authors: Zhao Xiao, Ying Dong, Tongqing Yang, Xiucai Wang
    Abstract:

    A piezoelectric generator fabricated by multiple Circular Diaphragm piezoelectric harvesters array is provided to harvest power over a broad range of frequencies. Four harvesters with varies tip masses are incorporated on a board with an area of 98 × 98 mm2. In this case, four strong output power peaks are obtained over frequencies from 120 Hz to 225 Hz. With an optimum load resistance of 15 kΩ, the value of four output power peaks is, respectively, 5.14, 6.65, 9.7, and 10 mW for the generator under an acceleration of 9.8 m/s2. By choosing an appropriate combination of tip masses with piezoelectric elements in array, the frequency range of energy harvesting can be obviously widened to meet the broadband vibration.

  • vibration energy harvesting using a piezoelectric Circular Diaphragm array
    IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2012
    Co-Authors: Wei Wang, Tongqing Yang, Xurui Chen
    Abstract:

    This paper presents a method for harvesting electric energy from mechanical vibration using a mechanically excited piezoelectric Circular membrane array. The piezoelectric Circular Diaphragm array consists of four plates with series and parallel connection, and the electrical characteristics of the array are examined under dynamic conditions. With an optimal load resistor of 160 kω, an output power of 28 mW was generated from the array in series connection at 150 Hz under a prestress of 0.8 N and a vibration acceleration of 9.8 m/s2, whereas a maximal output power of 27 mW can be obtained from the array in parallel connection through a resistive load of 11 kω under the same frequency, prestress, and acceleration conditions. The results show that using a piezoelectric Circular Diaphragm array can significantly increase the output of energy compared with the use of a single plate. By choosing an appropriate connection pattern (series or parallel connections) among the plates, the equivalent impedance of the energy harvesting devices can be tailored to meet the matched load of different applications for maximal power output.