Mass and Position Determination in MEMS Resonant Mass Sensors: Theoretical and Experimental Investigation

2016 ◽  
Author(s):  
Adam Bouchaala ◽  
Ali H. Nayfeh ◽  
Nizar Jaber ◽  
Mohammad I. Younis
Keyword(s):  
Experimental Investigation ◽  
Perturbation Technique ◽  
Closed Form Expression ◽  
Lower Electrode ◽  
Electrostatically Actuated ◽  
Mass Sensors ◽  
Resonance Frequencies ◽  
Theoretical Predictions ◽  
Modes Of Vibration ◽  
Resonant Mass Sensors

We present a method to determine accurately the position and mass of an entity attached to the surface of an electrostatically actuated clamped-clamped microbeam implemented as a mass sensor. In the theoretical investigation, the microbeam is modeled as a nonlinear Euler-Bernoulli beam and a perturbation technique is used to develop a closed-form expression for the frequency shift due to an added mass at a specific location on the microbeam surface. The experimental investigation was conducted on a microbeam made of Polyimide with a special lower electrode to excite both of the first and second modes of vibration. Using an ink-jet printer, we deposited droplets of polymers with a defined mass and position on the surface of the microbeam and we measured the shifts in its resonance frequencies. The theoretical predictions of the mass and position of the deposited droplets match well with the experimental measurements.

An Experimental Investigation of Auditors' Liability: Implications for Social Welfare and Exploration of Deviations from Theoretical Predictions

2000 ◽  
Vol 75 (4) ◽  
pp. 429-451 ◽  
Author(s):  
Ronald R. King ◽  
Rachel Schwartz
Keyword(s):  
Experimental Investigation ◽  
Social Welfare ◽  
Strict Liability ◽  
Liability Rule ◽  
Optimal Response ◽  
Legal Regimes ◽  
Theoretical Predictions ◽  
Best Responses

This paper reports the results of an experiment designed to investigate how legal regimes affect social welfare. We investigate four legal regimes, each consisting of a liability rule (strict or negligence) and a damage measure (out-of-pocket or independent-of-investment). The results of the experiment are for the most part consistent with the qualitative predictions of Schwartz's (1997) model; however, subjects' actual choices deviate from the point predictions of the model. We explore whether these deviations arise because: (1) subjects form faulty anticipations of their counterparts' actions and/or (2) subjects do not choose the optimal responses given their anticipations. We find that subjects behave differently under the four regimes in terms of anticipation errors and departures from best responses. For example, subjects playing the role of auditors anticipate investments most accurately under the regime with strict liability combined with out-of-pocket damages, but are least likely to choose the optimal response given their anticipations. This finding implies that noneconomic factors likely play a role in determining subjects' choices.

The Static and Dynamic Behavior of MEMS Arches Under Electrostatic Actuation

2009 ◽  
Author(s):  
Hassen M. Ouakad ◽  
Mohammad I. Younis ◽  
Fadi M. Alsaleem ◽  
Ronald Miles ◽  
Weili Cui
Keyword(s):  
Multiple Scales ◽  
Perturbation Technique ◽  
Dynamical Behavior ◽  
Primary Resonance ◽  
Reduced Order Model ◽  
Harmonic Load ◽  
Order Model ◽  
Reduced Order ◽  
Electrostatically Actuated ◽  
Model Equations

In this paper, we investigate theoretically and experimentally the static and dynamic behaviors of electrostatically actuated clamped-clamped micromachined arches when excited by a DC load superimposed to an AC harmonic load. A Galerkin based reduced-order model is used to discretize the distributed-parameter model of the considered shallow arch. The natural frequencies of the arch are calculated for various values of DC voltages and initial rises of the arch. The forced vibration response of the arch to a combined DC and AC harmonic load is determined when excited near its fundamental natural frequency. For small DC and AC loads, a perturbation technique (the method of multiple scales) is also used. For large DC and AC, the reduced-order model equations are integrated numerically with time to get the arch dynamic response. The results show various nonlinear scenarios of transitions to snap-through and dynamic pull-in. The effect of rise is shown to have significant effect on the dynamical behavior of the MEMS arch. Experimental work is conducted to test polysilicon curved microbeam when excited by DC and AC loads. Experimental results on primary resonance and dynamic pull-in are shown and compared with the theoretical results.

MEMS Microresonators Based on Nanocrystalline Silicon

2004 ◽  
Vol 808 ◽  
Author(s):  
J. Gaspar ◽  
T. Adrega ◽  
V. Chu ◽  
J. P. Conde
Keyword(s):  
Energy Dissipation ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Quality Factors ◽  
Electrostatically Actuated ◽  
Glass Substrates ◽  
Boron Doped ◽  
Resonance Frequencies ◽  
Geometrical Dimensions

ABSTRACTThis paper describes the fabrication and characterization of thin-film nanocrystalline silicon microresonators processed at temperatures below 110°C on glass substrates. The microelectromechanical structures consist of surface micromachined bridges of boron-doped hydrogenated nanocrystalline silicon (p+-nc-Si:H) deposited at 100°C by hot-wire chemical vapor deposition (HWCVD). The microbridges, which are suspended over an Al gate electrode, are electrostatically actuated and the mechanical resonance is detected in vacuum using an optical setup. The resonance frequency and energy dissipation in p+-nc-Si:H based resonators are studied as a function of the geometrical dimensions of the microstructures. Resonance frequencies between 700 kHz and 36 MHz and quality factors as high as 2000 are observed. A Young's modulus of 160 GPa for the structural bridge film is extracted from the experimental data using an electromechanical model and the main intrinsic energy dissipation mechanisms in nc-Si:H microresonators are discussed.

scholarly journals Voltage–Amplitude Response of Superharmonic Resonance of Second Order of Electrostatically Actuated MEMS Cantilever Resonators

2019 ◽  
Vol 14 (3) ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Martin A. Botello ◽  
Christian A. Reyes ◽  
Julio S. Beatriz
Keyword(s):  
Numerical Integration ◽  
Multiple Scales ◽  
Low Voltage ◽  
Second Order ◽  
Voltage Amplitude ◽  
Amplitude Response ◽  
Superharmonic Resonance ◽  
Bifurcation Points ◽  
Electrostatically Actuated ◽  
Modes Of Vibration

This paper investigates the voltage–amplitude response of superharmonic resonance of second order (order two) of alternating current (AC) electrostatically actuated microelectromechanical system (MEMS) cantilever resonators. The resonators consist of a cantilever parallel to a ground plate and under voltage that produces hard excitations. AC frequency is near one-fourth of the natural frequency of the cantilever. The electrostatic force includes fringe effect. Two kinds of models, namely reduced-order models (ROMs), and boundary value problem (BVP) model, are developed. Methods used to solve these models are (1) method of multiple scales (MMS) for ROM using one mode of vibration, (2) continuation and bifurcation analysis for ROMs with several modes of vibration, (3) numerical integration for ROM with several modes of vibration, and (4) numerical integration for BVP model. The voltage–amplitude response shows a softening effect and three saddle-node bifurcation points. The first two bifurcation points occur at low voltage and amplitudes of 0.2 and 0.56 of the gap. The third bifurcation point occurs at higher voltage, called pull-in voltage, and amplitude of 0.44 of the gap. Pull-in occurs, (1) for voltage larger than the pull-in voltage regardless of the initial amplitude and (2) for voltage values lower than the pull-in voltage and large initial amplitudes. Pull-in does not occur at relatively small voltages and small initial amplitudes. First two bifurcation points vanish as damping increases. All bifurcation points are shifted to lower voltages as fringe increases. Pull-in voltage is not affected by the damping or detuning frequency.

Voltage Response of Superharmonic Resonance of Electrostatically Actuated MEMS Resonators: Comparison Between Boundary Value Problem Model and Reduced Order Model

2018 ◽  
Author(s):  
Julio Beatriz ◽  
Martin Botello ◽  
Dumitru I. Caruntu
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Boundary Value ◽  
Mode Shapes ◽  
Voltage Response ◽  
Order Model ◽  
Partial Differential ◽  
Reduced Order ◽  
Electrostatically Actuated ◽  
Modes Of Vibration

This paper deals with the voltage response of electrostatically actuated NEMS resonators at superharmonic resonance. In this work a comparison between Boundary Value Problem (BVP) model, and Reduced Order Model (ROM) is conducted for this type of resonance. BVP model is developed from the partial differential equation by replacing the time derivatives with finite differences. So, the partial differential equation is replaced by a sequence of boundary value problems, one for each step in time. Matlab’s function bvp4c is used to numerically integrate the BVPs. ROMs are based on Galerkin procedure and use the mode shapes of the resonator as a basis of functions. Therefore, the partial differential equation is replaced by a system of differential equations in time. The number of the equations in the system is equal to the number of mode shapes (or modes of vibration) used in the ROM. One mode of vibration ROM is solved using the method of multiple scales. Two modes of vibration ROM is numerically integrated using Matlab’s function ode15s in order to obtain time responses, and a continuation and bifurcation analysis is conducted using AUTO 07P. The effects of different nonlinearities in the system on the voltage response are reported. This work shows that BVP model is a valid method to predict the voltage response of a micro/nano cantilevers.

Quad Band Planar Inverted F Antenna for Smart Phone

2014 ◽  
Vol 573 ◽  
pp. 394-399
Author(s):  
R. Manikandan ◽  
P.K. Jawahar
Keyword(s):  
High Frequency ◽  
Smart Phone ◽  
Analysis And Design ◽  
High Frequency Structure Simulator ◽  
Low Profile ◽  
Resonance Frequencies ◽  
Theoretical Predictions ◽  
Communication Devices ◽  
Device Miniaturization ◽  
Good Agreement

In recent years, the demand for compact handheld communication devices has grown significantly. For device miniaturization antenna size is to be reduced. Micro strip and PIFA have been used for past few years. Since it has low profile geometry it can be embedded into devices. This project is to develop a Quad band small size Planar Inverted F Antenna (PIFA) for the operation in modern multi-band mobile transceiver system. Various techniques for analysis and design of such antenna investigated in this project. The design curve is used to design Quad band Planar inverted F Antenna to operate at the 900, 1800, 2100 and 3500 MHz bands. Since High Frequency Structure Simulator (HFSS) simulation result agrees well with the theoretical predictions, this project also designed through HFSS. An antenna designed at the four desired band and optimized to adjust the four resonance frequencies using HFSS simulation. The substrate FR4 (εr=4.4 & tanδ = 0.02) are in good agreement with the simulation result. Further bandwidth enhancements by making defects in the substrate at particular area were need of much reflection.

Experimental Investigation of Isolated and Simultaneous Internal Resonances in Suspended Cables

1995 ◽  
Vol 117 (4) ◽  
pp. 385-391 ◽  
Author(s):  
C. L. Lee ◽  
N. C. Perkins
Keyword(s):  
Experimental Investigation ◽  
Large Amplitude ◽  
Resonant Response ◽  
Modal Interactions ◽  
Internal Resonances ◽  
Theoretical Predictions ◽  
Suspended Cables ◽  
Elastic Cables

The near resonant response of suspended elastic cables driven by harmonic, planar excitation is investigated experimentally. Measurements of large amplitude cable motions confirm previous theoretical predictions of fundamental classes of internally-resonant responses. For particular magnitudes of equilibrium curvature, strong modal interactions arise through isolated (two-mode) or simultaneous (three-mode) internal resonances. Four qualitatively different periodic responses are observed: (1) pure planar response, (2) 2:1 internally resonant nonplanar response, (3) 1:1 internally resonant nonplanar response, and (4) simultaneous, 2:2:1 internally resonant nonplanar response. Quasiperiodic responses are also observed.

Frequency Response of Parametric Resonance of Electrostatically Actuated Circular Plates Under Hard Excitations

2019 ◽  
Author(s):  
Julio Beatriz ◽  
Dumitru I. Caruntu
Keyword(s):  
Frequency Response ◽  
Parametric Resonance ◽  
Multiple Scales ◽  
Method Of Multiple Scales ◽  
Reduced Order Model ◽  
Circular Plates ◽  
Order Model ◽  
Reduced Order ◽  
Electrostatically Actuated ◽  
Modes Of Vibration

Abstract In this paper, the Method of Multiple Scales, and the Reduced Order Model method of two modes of vibration are used to investigate the amplitude-frequency response of parametric resonance of electrostatically actuated circular plates under hard excitations. Results show that the Method of Multiple Scales is accurate for low voltages. However, it starts to separate from the Reduced Order Model results as the voltage values are larger. The Method of Multiple Scales is good for low amplitudes and weak non-linearities. Furthermore the Reduced Order Model running with AUTO 07p is validated and calibrated using the 2 Term ROM time responses.

Sign in / Sign up

Export Citation Format

Share Document