The Effects of Geometric Asymmetry on the Dynamic Response of Silicon Nanowires

2011 ◽  
Author(s):  
Molly R. Nelis ◽  
Jeffrey F. Rhoads ◽  
Saeed Mohammadi
Keyword(s):  
Dynamic Response ◽  
Frequency Response ◽  
Silicon Nanowires ◽  
Electrostatic Force ◽  
Resonant Response ◽  
Cross Sectional ◽  
Practical Applications ◽  
Electrostatically Actuated ◽  
Predictive Design ◽  
The Impact

This work investigates the impact of asymmetric cross-sectional geometry on the near-resonant response of electrostatically-actuated silicon nanowires. The work demonstrates that dimensional variances of less than 2% qualitatively alter the near-resonant response of these nanosystems, rendering a non-Lorentzian frequency response structure. Theoretical and experimental results demonstrate that this effect is independent of material properties and device boundary conditions and can be easily modeled using a two-degree-of-freedom system. Proper understanding of this phenomenon is believed to be essential in the characterization of the dynamic response of resonant nanotube and nanowire systems and thus the predictive design and development of such devices. Practical applications of the devices of interest include electrostatic force gradients and mass sensing, both of which can advantageously leverage the unique frequency response structure attendant to these systems.

Casimir and Van Der Waals Effects on Parametric Resonance of Bio-NEMS Circular Plate Resonators

2015 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Reynaldo Oyervides
Keyword(s):  
Frequency Response ◽  
Parametric Resonance ◽  
Elastic Plate ◽  
Electrostatic Force ◽  
Van Der Waals ◽  
Circular Plates ◽  
Electrostatically Actuated ◽  
Sensing Applications ◽  
Fixed Electrode ◽  
Electrode Plate

This paper deals with Casimir and van der Waals effects on the frequency response of parametric resonance of electrostatically actuated NEMS circular plates for bio-sensing applications. The bio-NEMS resonator consists of a clamped circular elastic plate over a fixed electrode plate. A soft AC voltage of frequency near natural frequency between the plates gives an electrostatic force that leads the elastic plate into vibration which leads to parametric resonance that can be used afterwards for biosensing purposes. Frequency response and the effects of Casimir, and van der Waals forces on the response are reported.

Amplitude-Frequency Response for Superharmonic Resonance of Fourth Order of Electrostatically Actuated MEMS Cantilever Resonators

2019 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Christopher Reyes
Keyword(s):  
Frequency Response ◽  
Fourth Order ◽  
Microelectromechanical Systems ◽  
Multiple Scales ◽  
Electrostatic Force ◽  
Damping Force ◽  
Superharmonic Resonance ◽  
Electrostatically Actuated ◽  
Homotopy Analysis ◽  
Ground Plate

Abstract This paper deals with the frequency response of superharmonic resonance of order four of electrostatically actuated MicroElectroMechanical Systems (MEMS) cantilever resonators. The MEMS structure in this work consists of a microcantilever parallel to an electrode ground plate. The MEMS resonator is elelctrostatically actuated through an AC voltage between the cantilever and the ground plate. The voltage is in the category of hard excitation. The AC frequency is near one eight of the natural frequency of the resonator. Since the electrostatic force acting on the resonator is proportional to the square of the voltage, it leads to superharmonic resonance of fourth order. Besides the electrostatic force, the system experiences damping. The damping force in this work is proportional to the velocity of the resonator, i.e. it is linear damping. Three methods are employed in this investigation. First, the Method of Multiple Scales (MMS), a perturbation method, is used predictions of the resonant regions for weak nonlinearities and small to moderate amplitudes. Second, the Homotopy Analysis Method (HAM), and third, the Reduced Order Model (ROM) method using two modes of vibration are also utilized to investigate the resonance. ROM is solved through numerical integration using Matlab in order to simulate time responses of the structure. All methods are in agreement for moderate nonlinearities and small to moderate amplitudes. This work shows that adequate MMS and HAM provide good predictions of the resonance.

Reduced Order Model on DC Bias Effect on the Frequency Response of Electrostatically Actuated Biosensor Microplates

2016 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Christian Reyes
Keyword(s):  
Frequency Response ◽  
Electrostatic Force ◽  
Alternate Current ◽  
Reduced Order Model ◽  
Order Model ◽  
Bias Effect ◽  
Reduced Order ◽  
Electrostatically Actuated ◽  
Ground Plate ◽  
Dc Bias

This paper investigates the frequency response of microplates under electrostatic actuation. The microplate is parallel to a fixed ground plate. The electrostatic force that actuates the system is given by both Alternate Current (AC) and Direct Current (DC) voltages. The AC frequency is set to be near half natural frequency of the structure. Damping influence is also investigated in this paper. The method of investigation is Reduced Order Model. The effects of various parameters on the response of the structure are reported.

Optimum Design of Vibration Absorbers for Structurally Damped Timoshenko Beams

1998 ◽  
Vol 120 (4) ◽  
pp. 833-841 ◽  
Author(s):  
E. Esmailzadeh ◽  
N. Jalili
Keyword(s):  
Dynamic Response ◽  
Shear Deformation ◽  
Beam Theory ◽  
Optimization Procedure ◽  
Vibration Absorbers ◽  
Rotatory Inertia ◽  
Cross Sectional ◽  
Beam Dynamic ◽  
Practical Applications ◽  
Optimal Dynamic

A procedure in designing optimal Dynamic Vibration Absorbers (DVA) for a structurally damped beam system subjected to an arbitrary distributed harmonic force excitation, is presented. The Timoshenko beam theory is used to assess the effects of rotatory inertia and shear deformation. The method provides flexibility of choosing the number of absorbers depending upon the number of significant modes which are to be suppressed. Uniform cross-sectional area is considered for the beam and each absorber is modeled as a spring-mass-damper system. For each absorber with a selected mass, the optimum stiffness and damping coefficients are determined in order to minimize the beam dynamic response at the resonant frequencies for which they are operated. For this purpose, absorbers each tuned to a different resonance, are used to suppress any arbitrarily number of resonances of the beam. The interaction between absorbers is also accounted for in the analysis. The optimum tuning and damping ratios of the absorbers, each tuned to the mode of concern, are determined numerically by sloving a min-max problem. The Direct Updated Method is used in optimization procedure and the results show that the optimum values of the absorber parameters depend upon various factors, namely: the position of the applied force, the location where the absorbers are attached, the position at which the beam response should be minimized, and also the beam characteristics such as boundary conditions, rotatory inertia, shear deformation, structural damping, and cross sectional geometry. Through the given examples, the feasibility of using proposed study is demonstrated to minimize the beam dynamic response over a broad frequency range. The resulting curves giving the non-dimensional absorber parameters can he used for practical applications, and some interesting conclusions can be drown from the study of them.

Hydraulic Modal Analysis in Theory and Practice

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Gudrun Mikota ◽  
Bernhard Manhartsgruber ◽  
Franz Hammerle ◽  
Andreas Brandl
Keyword(s):  
Frequency Response ◽  
Theory And Practice ◽  
Mode Shapes ◽  
Pipeline System ◽  
Response Functions ◽  
Hydraulic Systems ◽  
Modal Assurance Criterion ◽  
Frequency Response Functions ◽  
Practical Applications ◽  
The Impact

Theoretical and experimental modal analyses are treated for hydraulic systems modeled by discrete capacities, inductances, resistances, and fluid lines with dynamic laminar flow. Based on an approximate multi-degrees-of-freedom description, it is shown how hydraulic natural frequencies, damping ratios, and mode shapes can be identified from measured frequency response functions between flow rate excitation and pressure response. Experiments are presented for a pipeline system that includes three side branches and an accumulator. In view of practical applications, two different types of servovalve excitation as well as impact hammer excitation are considered. Pressure is measured by 19 sensors throughout the system. Results are compared in terms of frequency response functions between 50 and 850 Hz, the first five hydraulic modes, and weighted auto modal assurance criteria of experimental mode shapes. Out of the tested excitation devices, the servovalve is clearly preferred; if valves cannot be used, the impact hammer offers a reasonable workaround. For a reduced number of five sensors, different sensor arrangements are assessed by the respective weighted auto modal assurance criteria of experimental mode shapes. A theoretical hydraulic modal model provides a similar assessment. The quality of the theoretical model is confirmed by the weighted modal assurance criterion of theoretical and experimental mode shapes from servovalve excitation.

Analysis of Impact of Bottom Electrode Position on Dynamic Pull-In Parameters of Microcantilevers

2015 ◽  
Vol 645-646 ◽  
pp. 706-718 ◽  
Author(s):  
Shuang Kai Chang ◽  
Gao Fei Zhang ◽  
Zheng You
Keyword(s):  
Present Model ◽  
Bottom Electrode ◽  
Device Performance ◽  
Electrode Position ◽  
Stable Range ◽  
Variable Cross ◽  
Cross Sectional ◽  
Electrostatically Actuated ◽  
Step Voltage ◽  
The Impact

The stable range of MEMS electrostatically actuated beam during the pull-in process is crucial to the device performance. Different devices have specific requirements for stable pull-in region based on their applications. In this paper, Rayleigh-Ritz energy method is used to establish dynamic pull-in model of electrostatic cantilever actuated by a step voltage. Modified trial function is derived according to different position of bottom electrode. The model takes into account the effects of fringe capacitance and variable cross-sectional beam. Published numerical methods and experimental data are used to verify the model . The impact of bottom electrode position on pull-in parameters is analyzed in present model. With fitting empirical equations, pull-in parameters can be easily satisfied through the distribution of bottom electrode, which provide an effective reference for the design of MEMS electrostatically actuated beam under given pull-in parameters .

The Effect of Cross-sectional Geometry on ZT Enhancement in Rough Silicon Nanostructures

2010 ◽  
Vol 1267 ◽  
Author(s):  
Jyothi Swaroop Sadhu ◽  
Marc G Ghossoub ◽  
Sanjiv Sinha
Keyword(s):  
Thermal Conductivity ◽  
Boundary Condition ◽  
Cross Section ◽  
Silicon Nanowires ◽  
Silicon Nanostructures ◽  
Dramatic Reduction ◽  
Cross Sectional ◽  
The Wire ◽  
Phonon Localization ◽  
The Impact

AbstractThe dramatic reduction in the thermal conductivity of rough silicon nanowires is due to phonon localization in the wire resulting from multiple scattering of phonons from the rough walls. We report the dependence of thermal conductivity of the nanowires as a function of the surface roughness and the diameter of the wire by modeling the nanowire as a waveguide. In addition, we estimate the impact of boundary condition, dimensionality and cross section of rough wire on the thermal conductivity. This theoretical model gives insights for tailoring thermal conductivity and enhancing the ZT of silicon to 1 for its use in thermoelectrics

scholarly journals Advanced Integrated Photonic Filters in Silicon Nanowires Designed with Coupled Sagnac Loop Reflectors

2020 ◽  
Author(s):  
David Moss
Keyword(s):  
Silicon Nanowires ◽  
High Performance ◽  
Structural Parameters ◽  
Spectral Slope ◽  
Practical Applications ◽  
Communications Systems ◽  
Switching Functions ◽  
Fabrication Tolerances ◽  
The Impact ◽  
Mode Interference

We theoretically investigate integrated photonic resonators formed by two mutually coupled Sagnac loop reflectors (MC-SLRs). Mode interference in the MC-SLR resonators is tailored to achieve versatile filter shapes with high performance, which enable flexible spectral engineering for diverse applications. By adjusting the reflectivity of the Sagnac loop reflectors (SLRs) as well as the coupling strength between different SLRs, we achieve optical analogues of Fano resonance with ultrahigh spectral slope rates, wavelength interleaving / non-blocking switching functions with significantly enhanced filtering flatness, and compact bandpass filters with improved roll-off. In our designs the requirements for practical applications are considered, together with detailed analyses of the impact of structural parameters and fabrication tolerances. These results highlight the strong potential of MC-SLR resonators as advanced multi-functional integrated photonic filters for flexible spectral engineering in optical communications systems.

Parametric Resonance of MEMS Circular Plate Resonators

2015 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Reynaldo Oyervides
Keyword(s):  
Frequency Response ◽  
Natural Frequency ◽  
Circular Plate ◽  
Parametric Resonance ◽  
Elastic Plate ◽  
Electrostatic Force ◽  
Circular Plates ◽  
Electrostatically Actuated ◽  
Sensing Applications ◽  
Ground Plate

This paper investigates parametric resonance of electrostatically actuated MEMS circular plates for resonator sensing applications. The system consists of a clamped circular elastic plate over a ground plate. Soft AC voltage of frequency near natural frequency of the plate gives the electrostatic force that leads the elastic plate into vibration, more specifically into parametric resonance which can be used afterwards for biosensing purposes. Frequency response and corresponding bifurcations are reported. The effects of damping and voltage are predicted.

Frequency Response of Electrostatically Actuated MEMS Resonators Under Superharmonic Resonance Using MMS

2016 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Christian Reyes
Keyword(s):  
Frequency Response ◽  
Multiple Scales ◽  
Electrostatic Force ◽  
Second Order ◽  
Voltage Response ◽  
Order Problem ◽  
Plate Electrode ◽  
Superharmonic Resonance ◽  
Electrostatically Actuated ◽  
Mems Resonator

This work investigates the voltage response of superharmonic resonance of second order of electrostatically actuated Micro-Electro-Mechanical Systems (MEMS) resonator cantilevers. The results of this work can be used for mass sensors design. The MEMS device consists of MEMS resonator cantilever over a parallel ground plate (electrode) under Alternating Current (AC) voltage. The AC voltage is of frequency near one fourth of the natural frequency of the resonator which leads to the superharmonic resonance of second order. The AC voltage produces an electrostatic force in the category of hard excitations, i.e. for small voltages the resonance is not present while for large voltages resonance occurs and bifurcation points are born. This solution is then used in the first-order problem to find the voltage-amplitude response of the structure. The influences of frequency and damping on the response are investigated. This work opens the door of using smaller AC frequencies for MEMS resonator sensors. The frequency response of the superharmonic resonance of the structure is investigated using the method of multiple scales (MMS).

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