Mass Sensitivity of Nonuniform Microcantilever Beams

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Sajal Sagar Singh ◽  
Prem Pal ◽  
Ashok Kumar Pandey
Keyword(s):  
Nonlinear Response ◽  
Microelectromechanical Systems ◽  
Beam Equation ◽  
Planar Geometry ◽  
Cantilever Beams ◽  
Mass Sensitivity ◽  
Sensing Applications ◽  
Resonance Frequencies ◽  
Tip Mass ◽  
Nonuniform Beam

Microelectromechanical systems (MEMS) based cantilever beams have been widely used in various sensing applications. Previous studies have aimed at increasing the sensitivity of biosensors by reducing the size of cantilever beams to nanoscale. However, the influence of nonuniform cantilever beams on mass sensitivity has rarely been investigated. In this paper, we discuss the mass sensitivity with respect to linear and nonlinear response of nonuniform cantilever beam with linear and quartic variation in width. To do the analysis, we use the nonlinear Euler–Bernoulli beam equation with harmonic forcing. Subsequently, we derive the mode shape corresponding to linear, undamped, free vibration case for different types of beams with a tip mass at the end. After applying the boundary conditions, we obtain the resonance frequencies corresponding to various magnitudes of tip mass for different kinds of beams. To do the nonlinear analysis, we use the Galerkin approximation and the method of multiple scales (MMS). Analysis of linear response indicates that the nondimensional mass sensitivity increases considerably by changing the planar geometry of the beam as compared to uniform beam. At the same time, sensitivity further increases when the nonuniform beam is actuated in higher modes. Similarly, the frequency shift of peak amplitude of nonlinear response for a given nondimensional tip mass increases exponentially and decreases quadratically with tapering parameter, α, for diverging and converging nonuniform beam with quartic variation in width, respectively. For the converging beam, we also found an interesting monotonically decreasing and increasing behavior of mass sensitivity with tapering parameter α giving an extremum point at α=0.5. Overall analysis indicates a potential application of the nonuniform beams with quartic converging width for biomass sensor.

Split beam method for determining mode shapes of cantilever beams under multiple loading conditions

2021 ◽  
pp. 107754632110276
Author(s):  
Jun-Jie Li ◽  
Shuo-Feng Chiu ◽  
Sheng D Chao
Keyword(s):  
Operation Mode ◽  
Point Contact ◽  
Mode Shapes ◽  
Cantilever Beams ◽  
Loading Conditions ◽  
Mechanical Responses ◽  
Relative Contribution ◽  
Resonance Frequencies ◽  
Beam Method ◽  
Multiple Loading

We have developed a general method, dubbed the split beam method, to solve Euler–Bernoulli equations for cantilever beams under multiple loading conditions. This kind of problem is, in general, a difficult inhomogeneous eigenvalue problem. The new idea is to split the original beam into two (or more) effective beams, each of which corresponds to one specific load and bears its own Young’s modulus. The mode shape of the original beam can be obtained by linearly superposing those of the effective beams. We apply the split beam method to simulating mechanical responses of an atomic force microscope probe in the “dynamical” operation mode, under which there are a stabilizing force at the positioner and a point-contact force at the tip. Compared with traditional analytical or numerical methods, the split beam method uses only a few number of basis functions from each effective beam, so a very fast convergence rate is observed in solving both the resonance frequencies and the mode shapes at the same time. Moreover, by examining the superposition coefficients, the split beam method provides a physical insight into the relative contribution of an individual load on the beam.

scholarly journals A Multi-Mode Broadband Vibration Energy Harvester Composed of Symmetrically Distributed U-Shaped Cantilever Beams

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 203
Author(s):  
Xiaohua Huang ◽  
Cheng Zhang ◽  
Keren Dai
Keyword(s):  
Energy Harvester ◽  
Low Frequency ◽  
Experimental Results ◽  
Vibration Energy ◽  
Cantilever Beams ◽  
Resonant Frequencies ◽  
Promising Alternative ◽  
Piezoelectric Energy ◽  
Straight Beam ◽  
Resonance Frequencies

Using the piezoelectric effect to harvest energy from surrounding vibrations is a promising alternative solution for powering small electronic devices such as wireless sensors and portable devices. A conventional piezoelectric energy harvester (PEH) can only efficiently collect energy within a small range around the resonance frequency. To realize broadband vibration energy harvesting, the idea of multiple-degrees-of-freedom (DOF) PEH to realize multiple resonant frequencies within a certain range has been recently proposed and some preliminary research has validated its feasibility. Therefore, this paper proposed a multi-DOF wideband PEH based on the frequency interval shortening mechanism to realize five resonance frequencies close enough to each other. The PEH consists of five tip masses, two U-shaped cantilever beams and a straight beam, and tuning of the resonance frequencies is realized by specific parameter design. The electrical characteristics of the PEH are analyzed by simulation and experiment, validating that the PEH can effectively expand the operating bandwidth and collect vibration energy in the low frequency. Experimental results show that the PEH has five low-frequency resonant frequencies, which are 13, 15, 18, 21 and 24 Hz; under the action of 0.5 g acceleration, the maximum output power is 52.2, 49.4, 61.3, 39.2 and 32.1 μW, respectively. In view of the difference between the simulation and the experimental results, this paper conducted an error analysis and revealed that the material parameters and parasitic capacitance are important factors that affect the simulation results. Based on the analysis, the simulation is improved for better agreement with experiments.

scholarly journals Numerical analysis of an infrared gas sensor utilizing an indium-tin-oxide-based plasmonic slot waveguide

2022 ◽  
Vol 11 (1) ◽  
pp. 15-20
Author(s):  
Parviz Saeidi ◽  
Bernhard Jakoby ◽  
Gerald Pühringer ◽  
Andreas Tortschanoff ◽  
Gerald Stocker ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Noble Metals ◽  
Microelectromechanical Systems ◽  
Propagation Loss ◽  
Slot Waveguide ◽  
Plasmonic Waveguides ◽  
Propagation Length ◽  
Plasmonic Material ◽  
Sensing Applications

Abstract. Plasmonic waveguides have attracted much attention owing to the associated high field intensity at the metal–dielectric interface and their ability to confine the modes at the nanometer scale. At the same time, they suffer from relatively high propagation loss, which is due to the presence of metal. Several alternative materials have been introduced to replace noble metals, such as transparent conductive oxides (TCOs). A particularly popular TCO is indium tin oxide (ITO), which is compatible with standard microelectromechanical systems (MEMS) technology. In this work, the feasibility of ITO as an alternative plasmonic material is investigated for infrared absorption sensing applications: we numerically design and optimize an ITO-based plasmonic slot waveguide for a wavelength of 4.26 µm, which is the absorption line of CO2. Our optimization is based on a figure of merit (FOM), which is defined as the confinement factor divided by the imaginary part of the effective mode index (i.e., the intrinsic damping of the mode). The obtained optimal FOM is 3.2, which corresponds to 9 µm and 49 % for the propagation length (characterizing the intrinsic damping) and the confinement factor, respectively.

Motion of AMB Rotor in Backup Bearings

2002 ◽  
Vol 124 (3) ◽  
pp. 460-464 ◽  
Author(s):  
Sheng Zeng
Keyword(s):  
Chaotic Motion ◽  
Nonlinear Response ◽  
Linear Models ◽  
Rotating Speed ◽  
Harmonic Motion ◽  
Power Failure ◽  
Resonance Frequencies ◽  
Speed Range ◽  
Pass Through ◽  
Bearing System

This paper studies numerically the motion of an AMB rotor when it is supported only by backup bearings. Unlike a linear rotor-bearing system, which always undergoes a harmonic motion, the nonlinear AMB rotor-backup bearing system will undergo irregular or chaotic motion at some rotating speeds. The simulations show that in a wide rotating speed range there are several extra resonance frequencies, which are different from those appearing in well-known linear models. When a power failure occurs to AMB machinery, the AMB rotor should pass through all these resonance frequencies. Under some conditions, the full clearance whirl motion of the rotor in backup bearings will happen, which may lead to damage. In this paper several measures that could reduce the nonlinear response and hence avoid the full clearance motion are discussed.

An Adaptive Self-Sensing Strategy for Piezoelectrically-Actuated Microcantilevers Used in Ultra-Small Mass Sensing Applications

2006 ◽  
Author(s):  
Miheer Gurjar ◽  
Nader Jalili
Keyword(s):  
Adaptive Estimation ◽  
Equations Of Motion ◽  
Optimization Method ◽  
The Self ◽  
Optimization Approach ◽  
Mass Sensing ◽  
Piezoelectric Patch ◽  
Sensing Applications ◽  
Tip Mass ◽  
Microcantilever Beam

This paper presents a mathematical model of a self-sensing microcantilever beam for mass sensing applications. Equations of motion are derived for a microcantilever beam with a tip mass and a piezoelectric patch actuator deposited on the cantilever surface. In the self-sensing mode, the same piezoelectric patch is used for actuation and sensing. Selfinduced voltage signals, which are extracted using a capacitive bridge mechanism, reveal frequency information of the vibrating beam, which in turn, reveals the particle mass. Equations of motion are obtained using the extended Hamilton's principle by considering the microcantilever as a distributed- parameters system. Two methods to estimate the unknown tip mass are presented. The first one is based on an inverse solution to the characteristic equation problem, while the second method uses a constraint-based optimization approach to estimate the tip mass. To improve the self-sensing performance, the need for adaptive estimation of the piezoelectric capacitance is stressed and an online estimation mechanism is presented. Simulations are presented to demonstrate the ability of the model to detect tip mass up to 0.1 femtogram (1 femtogram = 10-15 gm). Further simulation results demonstrate the working of constraint optimization method and adaptive self-sensing mechanism.

MEMS Microresonators for High Temperature Sensor Applications

2009 ◽  
Vol 1222 ◽  
Author(s):  
Dharanipal Doppalapudi ◽  
Richard Mlcak ◽  
Jeremie LeClair ◽  
Patrick Gwynne ◽  
Jeffrey Bridgham ◽  
...  
Keyword(s):  
Microelectromechanical Systems ◽  
Sensor Arrays ◽  
Polycrystalline Materials ◽  
Cantilever Beams ◽  
Sensor Applications ◽  
Single Crystal Sic ◽  
High Temperature Sensor ◽  
Response To Temperature ◽  
Reduced Power Consumption ◽  
Higher Sensitivity

AbstractMicroelectromechanical Systems (MEMS) are being extensively investigated as a means of miniaturizing piezoelectric sensors thereby offering higher sensitivity, reduced power consumption, and ability to form compact multi-sensor arrays. Such devices typically employ one or more silicon micromechanical elements (e.g. membranes, cantilever beams and tethered proof masses) driven electromechanically by a polycrystalline piezoelectric film. The use of polycrystalline materials results in inherently less stable and irreproducible device characteristics. For elevated operating temperatures, more robust and refractory materials are also required. In this paper, we describe a MEMS microresonator array capable of operating to temperatures exceeding 600°C enabled by the integration of epitaxially grown piezoelectric AlN films onto single crystal SiC tethered plates. The operation of the microresonators as sensors is illustrated by examining their response to temperature, pressure and chemical analytes.

Finite element simulation of Love wave sensor for the detection of volatile organic gases

2021 ◽  
Author(s):  
Yan Wang ◽  
Su-Peng Liang ◽  
Shu-Lin Shang ◽  
Yong-Bing Xiao ◽  
Yu-Xin Yuan
Keyword(s):  
Finite Element ◽  
Love Wave ◽  
Gas Sensing ◽  
Resonance Effect ◽  
Acoustic Properties ◽  
Sensitive Material ◽  
Mass Sensitivity ◽  
Sensing Applications ◽  
Wave Sensors ◽  
Organic Gases

Abstract The 3D finite element (3D-FE) simulation and analysis of Love wave sensors based on PIB layers/SiO2/ST-90°X quartz structure, as well as the investigation of coupled resonance effect on the acoustic properties of the devices, are presented in this paper. The mass sensitivity of the basic Love wave device with SiO2 guiding layers solved analytically. And the highest mass sensitivity of 128 m2/kg is obtained as h s/λ =0.175. The sensitivity of the Love wave sensors for sensing VOCs is greatly improved due to the presence of coupled resonance induced by the PIB nanorods on the device surface. The frequency shifts of the sensor corresponding to CH2Cl2, CHCl3, CCl4, C2Cl4, CH3Cl and C2HCl3 with the concentration of 100 ppm are 1.431 kHz, 5.507 kHz, 13.437 kHz, 85.948 kHz, 0.127 kHz and 17.879 kHz, respectively. The viscoelasticity influence of sensitive material on the characteristics of SAW sensors is also studied. Taking account of the viscoelasticity of PIB layers, the sensitivities of SAW sensors with the PIB film and PIB nanorods decay in different degree. The gas sensing property of Love wave sensor with PIB nanorods is superior to that of the PIB films. Meanwhile, the Love wave sensors with PIB sensitive layers show good selectivity to C2Cl4, making it an ideal selection for gas sensing applications.

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