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The study of free motion of the rotor-type micromechanical gyro sensing element as a round orthotropic plate clamped at its center was based on the Timoshenko-Mindlin plate theory. Fixation of the rotor at its center was modeled as the clamped edge of a small-radius inner hole of the plate. The mathematical model of the sensing element motion was designed in accordance with the assumptions made in...
Deformation and vibration of thin-wall workpieces during machining could induce residual stresses in the final products, which makes real-time monitoring of the strain field critical to optimizing machining process and minimizing workpiece stresses. However, traditional methods based on strain-gauge measurements are inapplicable because materials are removed during machining. Illustrated in the context...
An improvement in the resonant microcantilever-based sensor's sensitivity is proposed by varying the microcantilever weight distribution. The relationship between the resonant frequency of different microcantilevers and their dimensions is investigated using the analytical method and finite element method. The principle to increase the resonant frequency drift when the target gas is absorbed by the...
For shape reconstruction of the flexible plate structure with perceptive distributed orthogonal curvature information, a new online curvature calibration method for flexible structure is researched. Virtual standard circle-arcs of the measured flexible structure are obtained by finite element method to substitute real standard circle-arcs in traditional curvature calibration methods. The curvature...
We report the theory, design methodology and experiment of an electrostatically actuated silicon-plate Phononic Bandgap (PnBG) crystal architecture. This architecture is a high-order distributed mechanical system comprised of a two-dimensional PnBG crystal which is truncated to finite periodicity and suspended from the substrate utilizing tethers. Electrostatic actuation mitigates the use of piezoelectric...
A new deflection shape function that can predict the deflection profile of a uniformly loaded microfabricated clamped square membrane with a much higher accuracy compared to existing models has been presented. The model has been developed by using an empirical data fit technique to identify new terms and new parameter values that compensate for the deviation of the existing deflection shape functions...
As a fundamental system identification experiment, modal test with an accurate result has great effects on the subsequent work, which is often restricted by many unavoidable factors. This paper discussed the method of properly selecting response and exciting points with the modal pre-test analysis based on an existing FEA modal to guide and improve the execution of modal test. A modal test was performed...
This paper deals with the problem of vibration based health monitoring (VHM) in multi-stable asymmetrical laminated composite structures. Multi-stable asymmetrical laminates can be snapped between two or more geometries. The ability of snapping between two or more geometries in multi-stable composite structures makes them vulnerable to delaminate. Because of these reason early detection of damage...
A highly accurate analytical method to calculate capacitance of MEMS capacitive type sensors with circular membranes has been presented. The method determines the center deflection of the membrane by taking account of the electrostatic pressure due to the bias voltage, external pressure, residual stress, and nonlinear spring hardening effect during large deflection. A new deflection shape function...
In this work, a three dimensional finite element model for solidly mounted film bulk acoustic resonator (SMFBAR) devices is developed and simulated. The simulation is performed using the CoventorWareTM platform to analyze the performance of the device. The influence of the shape of the top electrode and its thickness on the sensitivity SMFBAR based sensors was investigated. Two different electrode...
The paper is focused on the influence of packaging technologies on the performance of inertial MEMS sensors. System simulations of MEMS are vital to evaluate and optimize the interplay of transducer cells with the sensor electronics. Special emphasis must be put on packaging aspects in order to assess the impact of environmental and operating conditions on functional parameters as capacitance offset...
We demonstrate an advanced design procedure to fabricate resonators based on flexible plates with piezoelectric films. Two design strategies are considered: i) optimized response (actuation or sensing) in a given mode; ii) implementation of a modal transducer by filtering specific modes. Sensors/actuators were designed by optimizing the surface electrode shape in both dimensions. A numerical finite...
Lateral Field Electroded (LFE) sensors may be used to measure the permittivity and conductivity (electrical properties) of liquids in contact with the surface opposite the electroded side. Our previous Finite Element Analysis (FEA) calculations studied these devices for the two quartz boundary conditions of surface-charge-free and grounded. Those results helped sort out which thickness-shear modes...
We present a theoretical calculation and experimental results for an isolated acoustic wave. The experimental device is modeled by finite element method (FEM) for the structure AlN/ZnO/diamond. The phase velocity in the AlN/ZnO/diamond structure was investigated by theoretical calculations. It was found that the AlN thickness must be at least more than 3lambda/2 to obtain a negligible surface displacement...
The dynamic characteristics of an accelerometerpsilas shell is analyzed. To avoid resonance and subsequent failure, the shellpsilas natural frequencies and harmonic response are important considerations in structure optimization, for they significantly influence the performance of the sensors. The finite element analysis software ANSYS was applied to get the vibration characteristics of the shell...
In this paper the issue of modeling for control design with application to fusion devices is discussed. Given the difficulty to provide analytical solutions to the equations describing the system dynamics, the use of numerical tools for evaluating different control architectures is required. Although standard tools for computer aided control system design (CACSD) can be usefully employed for both...
This study provides an efficient and feasible solution to enhance the sensitivity of traditional piezoelectric tactile sensor based on introducing structural electrode upon the sensing material. A sandwich structure for flexible tactile sensor consists of top and bottom soft substrates made of Polystyrene, and in between of two soft substrates a piezoelectric thin film, PVDF, and a PDMS microstructures...
This paper introduces a new generation of magnetic field sensors, based on the spherical harmonics decomposition concept. The measurement principle is similar to a spatial filtering: according to the coil shape, the sensors are just sensitive to a specific component of the multipolar expansion. Five coil shapes are determined, in order to account for the first two orders of the harmonic decomposition...
Lateral field electroded (LFE) sensors have been recently introduced that can study the permittivity and conductivity (electrical properties) of liquids in contact with the surface opposite the electroded side. The unique feature of these sensors is that the response depends in part on changes in the electrical field distribution in the quartz blank due to the electrical properties in the liquid....
This paper considers mechanical stress and strain in a piezoresistive cantilever sensor under surface stress loading, which is the loading condition that occurs in biochemical sensing applications. Finite element simulations examine the piezoresistor sensitivity due to changes in cantilever length, width, and thickness, and piezoresistor size, location, and depth. A few unexpected results are found...
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