scholarly journals Influence of Frequency on the Resolution of Magnetostrictive Bio-Inspired Whisker Sensors

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Ran Zhao ◽  
Bo-wen Wang ◽  
Quan-guo Lu ◽  
Jian-wu Yan ◽  
Xiao-cui Yuan
Keyword(s):  
Vibration Frequency ◽  
Dynamic Testing ◽  
Theoretical Calculations ◽  
Beam Theory ◽  
Experimental System ◽  
Flow Sensors ◽  
Maximum Resolution ◽  
Sensing Model ◽  
Euler Bernoulli Beam ◽  
Good Agreement

Magnetostrictive biomimetic whiskers have been used as tactile and flow sensors. Compared to other types of whiskers, such whiskers have the advantage of being able to perform static and dynamic measurements. For dynamic measurement, the whisker’s resolution changes with varying vibration frequency; however, the mechanism for this influence has not been studied yet. Thus, the aim of this study is to investigate the resolution–frequency correlation. First, the structure and operation principle of the whisker were analyzed. Then, the Euler–Bernoulli beam theory was employed to establish the sensing model of the magnetostrictive whisker. Finally, the mapping relationship between sensor resolution and frequency was obtained. The eigenfrequency analysis was implemented by FEM to obtain the frequency response of the whisker. A vibration experimental system was built for dynamic testing. The experimental results were in good agreement with the theoretical calculations. Furthermore, it was noted that the resolution was positively correlated with frequency, and the maximum resolution was attained at the natural frequency (two peak values appeared at the first-order and second-order eigenfrequencies). Our research reveals the manner in which a whisker sensor’s resolution is affected by the vibration frequency. The theoretical model can be used to predict the resolution of magnetostrictive whisker sensors.

Electrothermally Tunable Bridge Resonator

2016 ◽  
Author(s):  
Amal Z. Hajjaj ◽  
Nouha Alcheikh ◽  
Abdallah Ramini ◽  
Md Abdullah Al Hafiz ◽  
Mohammad I. Younis
Keyword(s):  
Fundamental Frequency ◽  
Beam Theory ◽  
Element Model ◽  
Bernoulli Beam ◽  
Electrothermal Actuation ◽  
Wide Range ◽  
Simulation Results ◽  
Dc Current ◽  
Euler Bernoulli Beam ◽  
Good Agreement

This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of an in-plane clamped-clamped microbeam, bridge, and resonator compressed by a force due to electrothermal actuation. We demonstrate that a single resonator can be operated at a wide range of frequencies. The microbeam is actuated electrothermally, by passing a DC current through it. We show that when increasing the electrothermal voltage, the compressive stress inside the microbeam increases, which leads eventually to its buckling. Before buckling, the fundamental frequency decreases until it drops to very low values, almost to zero. After buckling, the fundamental frequency increases, which is shown to be as high as twice the original resonance frequency. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and to simulation results of a multi-physics finite-element model. A good agreement is found among all the results.

Vibration Analysis of Multi-Cracked Beam Traversed by Moving Masses Using Discrete Element Technique

2013 ◽  
Vol 376 ◽  
pp. 220-223
Author(s):  
Reza Alebrahim ◽  
Nik Abdullah Nik Mohamed ◽  
Sallehuddin Mohamed Haris ◽  
Salvinder Singh Karam Singh
Keyword(s):  
Vibration Analysis ◽  
Beam Theory ◽  
Discrete Element ◽  
Maximum Deflection ◽  
Bernoulli Beam ◽  
Cracked Beam ◽  
Time To Build ◽  
Element Technique ◽  
Euler Bernoulli Beam ◽  
Good Agreement

The vibration analysis of a multi-cracked beam using discrete element technique (DET) was investigated in this study. Undamped simply supported beam was traversed by moving mass with constant speed and Euler Bernoulli beam theory was considered. Cracks are located in different positions and maximum deflection of mid-span was derived and compared. The results showed that increasing numbers of cracks in the beam causes more deflection while maximum deflection of beam takes longer time to build up. The results were validated by solving the equations generated using finite element method (FEM) and their comparison with already established results from previous similar studies (literatures) showed good agreement.

scholarly journals Transverse Vibration of Clamped-Pinned-Free Beam with Mass at Free End

2019 ◽  
Vol 9 (15) ◽  
pp. 2996 ◽  
Author(s):  
Jonathan Hong ◽  
Jacob Dodson ◽  
Simon Laflamme ◽  
Austin Downey
Keyword(s):  
Transverse Vibration ◽  
Theoretical Calculations ◽  
Beam Theory ◽  
High Rate ◽  
Harsh Environments ◽  
Mode Shapes ◽  
Engineering Systems ◽  
Bernoulli Beam ◽  
Euler Bernoulli Beam ◽  
Free Beam

Engineering systems undergoing extreme and harsh environments can often times experience rapid damaging effects. In order to minimize loss of economic investment and human lives, structural health monitoring (SHM) of these high-rate systems is being researched. An experimental testbed has been developed to validate SHM methods in a controllable and repeatable laboratory environment. This study applies the Euler-Bernoulli beam theory to this testbed to develop analytical solutions of the system. The transverse vibration of a clamped-pinned-free beam with a point mass at the free end is discussed in detail. Results are derived for varying pin locations and mass values. Eigenvalue plots of the first five modes are presented along with their respective mode shapes. The theoretical calculations are experimentally validated and discussed.

scholarly journals Highly sensitive low field Lorentz-force MEMS magnetometer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sofiane Ben Mbarek ◽  
Nouha Alcheikh ◽  
Hassen M. Ouakad ◽  
Mohammad I. Younis
Keyword(s):  
Lorentz Force ◽  
Beam Theory ◽  
Sensor Performance ◽  
Low Field ◽  
Highly Sensitive ◽  
Out Of Plane ◽  
Micro Sensor ◽  
Euler Bernoulli Beam ◽  
A Current ◽  
Good Agreement

AbstractWe present a highly sensitive Lorentz-force magnetic micro-sensor capable of measuring low field values. The magnetometer consists of a silicon micro-beam sandwiched between two electrodes to electrostatically induce in-plane vibration and to detect the output current. The method is based on measuring the resonance frequency of the micro-beam around the buckling zone to sense out-of-plane magnetic fields. When biased with a current of 0.91 mA (around buckling), the device has a measured sensitivity of 11.6 T−1, which is five orders of magnitude larger than the state-of-the-art. The measured minimum detectable magnetic field and the estimated resolution of the proposed magnetic sensor are 100 µT and 13.6 µT.Hz−1/2, respectively. An analytical model is developed based on the Euler–Bernoulli beam theory and the Galerkin discretization to understand and verify the micro-sensor performance. Good agreement is shown between analytical results and experimental data. Furthermore, the presented magnetometer is promising for measuring very weak biomagnetic fields.

Free Vibration Analysis of Frames Using the Transfer Dynamic Stiffness Matrix Method

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Tsung-Hsien Tu ◽  
Jen-Fang Yu ◽  
Hsin-Chung Lien ◽  
Go-Long Tsai ◽  
B. P. Wang
Keyword(s):  
Free Vibration ◽  
Stiffness Matrix ◽  
Dynamic Stiffness ◽  
Free Vibration Analysis ◽  
Beam Theory ◽  
System Matrix ◽  
Dynamic Stiffness Matrix ◽  
3D Space ◽  
Euler Bernoulli Beam ◽  
Good Agreement

A method for free vibration of 3D space frame structures employing transfer dynamic stiffness matrix (TDSM) method based on Euler–Bernoulli beam theory is developed in this paper. The exact TDSM of each member is assembled to obtain the system matrix that is frequency dependent. All free vibration eigensolutions including coincident roots for the characteristic equation can be obtained to any desired accuracy using the algorithm developed by Wittrick and Williams (1971, “A General Algorithm for Computing Natural Frequencies of Elastic Structures,” Q. J. Mech. Appl. Math., 24, pp. 263–284). Exact eigenfunction of structures can then be computed using the dynamic shape function and the corresponding eigenvector. The results showed good agreement with those computed by finite element method.

Theoretical and experimental research on slip and uplift of the timber-concrete composite beam

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 7079-7099
Author(s):  
Jianying Chen ◽  
Guojing He ◽  
Xiaodong (Alice) Wang ◽  
Jiejun Wang ◽  
Jin Yi ◽  
...  
Keyword(s):  
Differential Equations ◽  
Deformation Theory ◽  
Concrete Slab ◽  
Theoretical Calculations ◽  
Structural Element ◽  
Structural Efficiency ◽  
Theoretical Investigations ◽  
New Type ◽  
Interlayer Slip ◽  
Good Agreement

Timber-concrete composite beams are a new type of structural element that is environmentally friendly. The structural efficiency of this kind of beam highly depends on the stiffness of the interlayer connection. The structural efficiency of the composite was evaluated by experimental and theoretical investigations performed on the relative horizontal slip and vertical uplift along the interlayer between composite’s timber and concrete slab. Differential equations were established based on a theoretical analysis of combination effects of interlayer slip and vertical uplift, by using deformation theory of elastics. Subsequently, the differential equations were solved and the magnitude of uplift force at the interlayer was obtained. It was concluded that the theoretical calculations were in good agreement with the results of experimentation.

scholarly journals Bi-Dimensional Deflection Estimation by Embedded Fiber Bragg Gratings Sensors

Proceedings ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 3
Author(s):  
Palma ◽  
Palumbo ◽  
Pietra ◽  
Canale ◽  
Alviggi ◽  
...  
Keyword(s):  
Real Time ◽  
Fiber Bragg Gratings ◽  
Beam Theory ◽  
Bragg Gratings ◽  
Strain Sensors ◽  
Structural Monitoring ◽  
Direct Measure ◽  
Large Structure ◽  
Good Agreement ◽  
Classical Beam Theory

In this work, we present and discuss on the deflection estimation of a bi-dimensional panel by using Fiber Bragg Gratings (FBGs) as strain sensors embedded in the structure and a method based on the classical beam theory. The existing difficulties in the direct measure of the deflection are overcome thanks to the proposed technique and a real-time indirect structural monitoring is possible both on small and large structure. In many tests the estimated deflection with the proposed method has been compared with direct deflection measurements obtained with a mechanical comparator showing good agreement. A resolution of few tens of microns over a surface of the order of 1 m2 has been reached.

scholarly journals Etude par résonance magnétique nucléaire de composés organiques contenant des chalcogènes. II. L'éther de diphényle et ses analogues soufré, sélénié et telluré

1979 ◽  
Vol 57 (22) ◽  
pp. 2967-2970 ◽  
Author(s):  
Gabriel Llabrès ◽  
Marcel Baiwir ◽  
Léon Christiaens ◽  
Jean-Louis Piette
Keyword(s):  
Crystal Structure ◽  
Theoretical Calculations ◽  
Heavy Atom ◽  
Mesomeric Effect ◽  
Heavy Atom Effect ◽  
Inductive Effects ◽  
Structure Determinations ◽  
Résonance Magnétique ◽  
Atom Effect ◽  
Good Agreement

The 1Hmr study of the title compounds has revealed a screw conformation, with defined interconversion processes, in good agreement with crystal structure determinations and theoretical calculations. The mesomeric effect of the heteroatom is smaller than in the anisole series, due to steric inhibitions.The 13Cmr enhances, to some extent, these conclusions. In the case of Te compounds, a heavy atom effect adds to the classical mesomeric and inductive effects to account for the experimental observations.

Vibration Analysis of the Flexible Connecting Rod With the Breathing Crack in a Slider-Crank Mechanism

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Yan-Shin Shih ◽  
Chen-Yuan Chung
Keyword(s):  
Governing Equation ◽  
Moving Boundary ◽  
Beam Theory ◽  
Crack Model ◽  
Breathing Crack ◽  
Connecting Rod ◽  
Bernoulli Beam ◽  
The Galerkin Method ◽  
Euler Bernoulli Beam ◽  
Crank Mechanism

This paper investigates the dynamic response of the cracked and flexible connecting rod in a slider-crank mechanism. Using Euler–Bernoulli beam theory to model the connecting rod without a crack, the governing equation and boundary conditions of the rod's transverse vibration are derived through Hamilton's principle. The moving boundary constraint of the joint between the connecting rod and the slider is considered. After transforming variables and applying the Galerkin method, the governing equation without a crack is reduced to a time-dependent differential equation. After this, the stiffness without a crack is replaced by the stiffness with a crack in the equation. Then, the Runge–Kutta numerical method is applied to solve the transient amplitude of the cracked connecting rod. In addition, the breathing crack model is applied to discuss the behavior of vibration. The influence of cracks with different crack depths on natural frequencies and amplitudes is also discussed. The results of the proposed method agree with the experimental and numerical results available in the literature.

Chaotic vibrations of carbon nanotubes subjected to a traversing force considering nonlocal elasticity theory

2021 ◽  
pp. 239779142110633
Author(s):  
Reza Ebrahimi
Keyword(s):  
Nonlocal Parameter ◽  
Power Spectra ◽  
Beam Theory ◽  
Nonlocal Elasticity Theory ◽  
Effective Control ◽  
Maximum Lyapunov Exponent ◽  
Harmonic Force ◽  
Spectra Analysis ◽  
Chaotic Vibrations ◽  
Euler Bernoulli Beam

The existence of chaos in the lateral vibration of the carbon nanotube (CNT) can contribute to source of instability and inaccuracy within the nano mechanical systems. So, chaotic vibrations of a simply supported CNT which is subjected to a traversing harmonic force are studied in this paper. The model of the system is formulated by using nonlocal Euler–Bernoulli beam theory. The equation of motion is solved using the Rung–Kutta method. The effects of the nonlocal parameter, velocity and amplitude of the traversing harmonic force on the nonlinear dynamic response of the system are analyzed by the bifurcation diagrams, phase plane portrait, power spectra analysis, Poincaré map and the maximum Lyapunov exponent. The results indicate that the nonlocal parameter, velocity and amplitude of the traversing harmonic force have considerable effects on the bifurcation behavior and can be used as effective control parameters for avoiding chaos.

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