Quality factor, static and dynamic responses of miniature galfenol actuator at wide range of temperature

2011 ◽  
Vol 6 (36) ◽  
Author(s):  
Mojtaba Ghodsi
Keyword(s):  
Quality Factor ◽  
Dynamic Responses ◽  
Wide Range

scholarly journals Dynamic Responses of Electrically Driven Quartz Tuning Fork and qPlus Sensor: A Comprehensive Electromechanical Model for Quartz Tuning Fork

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2686
Author(s):  
Manhee Lee ◽  
Bongsu Kim ◽  
Sangmin An ◽  
Wonho Jhe
Keyword(s):  
Resonance Frequency ◽  
Quality Factor ◽  
Tuning Fork ◽  
Quartz Tuning Fork ◽  
Dynamic Responses ◽  
Peak Amplitude ◽  
Quantitative Prediction ◽  
Dynamic Features ◽  
Electromechanical Model ◽  
Different Characteristics

A quartz tuning fork and its qPlus configuration show different characteristics in their dynamic features, including peak amplitude, resonance frequency, and quality factor. Here, we present an electromechanical model that comprehensively describes the dynamic responses of an electrically driven tuning fork and its qPlus configuration. Based on the model, we theoretically derive and experimentally validate how the peak amplitude, resonance frequency, quality factor, and normalized capacitance are changed when transforming a tuning fork to its qPlus configuration. Furthermore, we introduce two experimentally measurable parameters that are intrinsic for a given tuning fork and not changed by the qPlus configuration. The present model and analysis allow quantitative prediction of the dynamic characteristics in tuning fork and qPlus, and thus could be useful to optimize the sensors’ performance.

scholarly journals A Curve-Shaped Beam Bistable Piezoelectric Energy Harvester with Variable Potential Well: Modeling and Numerical Simulation

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 995
Author(s):  
Xiaoyu Chen ◽  
Xuhui Zhang ◽  
Luyang Chen ◽  
Yan Guo ◽  
Fulin Zhu
Keyword(s):  
Energy Harvesting ◽  
Energy Harvester ◽  
Dynamic Responses ◽  
Force Model ◽  
Potential Well ◽  
Shaped Beam ◽  
Piezoelectric Energy ◽  
Straight Beam ◽  
Wide Range ◽  
Variable Potential

To improve the energy harvesting performance of an energy harvester, a novel bistable piezoelectric energy harvester with variable potential well (BPEH-V) is proposed by introducing a spring to the external magnet from a curve-shaped beam bistable harvester (CBH-C). First, finite element simulation was performed in COMSOL software to validate that the curved beam configuration was superior to the straight beam in power generation performance, which benefits energy harvesting. Moreover, the nonlinear magnetic model was obtained by using the magnetic dipoles method, and the nonlinear restoring force model of the curve-shaped beam was acquired based on fitting the experimental data. The corresponding coupled governing equations were derived by using generalized Hamilton’s principle, the dynamic responses were obtained by solving the coupling equations with the ode45 method. Finally, the numerical simulations showed that the proposed harvester can make interwell oscillations easier due to the spring being efficiently introduced to pull down the potential barrier compared with the conventional bistable harvester. Spring stiffness has a great impact on characteristics of the system, and a suitable stiffness contributes to realize large-amplitude interwell oscillations over a wide range of excitation, especially in the low excitation condition.

scholarly journals Research on Dynamic Response of Slopes With Weak Interlayers Under Mining Blasting Vibration

2022 ◽  
Vol 9 ◽  
Author(s):  
Xiaochao Zhang ◽  
Qingwen Yang ◽  
Xiangjun Pei ◽  
Ruifeng Du
Keyword(s):  
Dynamic Response ◽  
Internal Structure ◽  
Explosive Charge ◽  
Blast Loading ◽  
Dynamic Responses ◽  
Internal Dynamic ◽  
Explosive Energy ◽  
Wide Range ◽  
Blasting Excavation ◽  
Weak Interlayer

As blasting technology starts to be used in a wide range of areas, blast loading has led to an increasing number of geological disasters such as slope deformation, collapses, and soil slippage. Slopes with weak interlayers are more likely to be deformed and damaged under the influence of blast loading. It is of great importance to study the evolution for the deformation of slopes with weak interlayers during blasting excavation. This study constructed a slope model with a weak interlayer to investigate the influence of different factors of blasting, including explosive charge, blast radius, blast origin, and multi-hole blasting, on the internal dynamic response. The deformation mechanism of slopes with weak interlayers under the influence of blast loading was analyzed. Test results show that each layer of the model had a different displacement response (uncoordinated dynamic response) to blasting with various factors. Explosive energy and the pattern of dynamic response of each layer varied depending on different settings of blasting factors such as explosive charge, blast radius, blast origin, and detonation initiation method. When the explosive energy produced under the influence of various factors was small, the change in the uncoordinated dynamic response between layers was significant, and the change gradually became less significant as the explosive energy increased. Therefore, this study has proposed the concept of critical explosive energy, and it is speculated that when the explosive energy produced with various factors is less than critical explosive energy, the dynamic response is mainly affected by the internal structure of the slope (property difference induced geologic layers). In other words, the uncoordinated motion of material’s particles in each layer is caused by different limitations and the degree of movement of the particles, which leads to the uncoordinated dynamic response and uncoordinated deformation of each layer. If the explosive energy is greater than the critical value, the dynamic response of each layer is mainly affected by the explosive energy. The differences in the internal structure of the slope are negligible, and the incoordination of dynamic responses between layers gradually weakens and tends to synchronize.

Hydrodynamic Analysis of Multi-Body Floating Piers

2008 ◽  
Author(s):  
Zahra Tajali ◽  
Mehdi Shafieefar ◽  
Mahmood Akhyani
Keyword(s):  
Transfer Functions ◽  
Three Dimensional ◽  
Diffraction Method ◽  
Dynamic Responses ◽  
Floating Structure ◽  
Hydrodynamic Analysis ◽  
Wide Range ◽  
The Individual ◽  
Multi Body ◽  
Wave Induced

Hydrodynamic analysis of a floating multi-body pier interacting with incident waves is carried out in the present research and results of wave-induced motions and structural responses are described. The objective is to develop a procedure which can be used to analyze the motions of such a floating structure consisting of a number of rigid pontoons linked together. Also, optimization of pontoons geometry for a desired length of the pier is examined. In this regard, different alternative arrangements of pontoons with different numbers and dimensions are studied and dynamic responses of these alternatives are investigated. Analysis of the multi-body floating structure is carried out in the frequency domain. The wave-induced forces and the responses are computed by three-dimensional diffraction method. To examine the effect of using different pontoons on pier hydrodynamic response, motion-amplitude transfer functions (RAO) and connector forces for a wide range of wave frequency and heading angle are computed. Results include the absolute and relative responses of the individual pontoons and prediction of pier motions for a wide variety of pontoon geometries in different wave frequencies and heading angles. Also results include effects of pontoons dimension on the response of structure and present heave, roll and pitch motions for floating pier structural system.

Field Test and Analysis on Impact Factor Spectrum for a Continuous Bridge under Random Traffic Flow

2011 ◽  
Vol 250-253 ◽  
pp. 1226-1231
Author(s):  
Wan Shui Han ◽  
Tao Wang ◽  
Su Jing Yuan
Keyword(s):  
Impact Factor ◽  
Field Test ◽  
Extreme Values ◽  
Dynamic Responses ◽  
Impact Factors ◽  
Vehicle Speed ◽  
Dynamic Displacement ◽  
Vehicle Weight ◽  
Wide Range ◽  
The Impact

Field test and analysis were carried out for dynamic responses on a continuous bridge under open traffic. The inspection, testing and analysis for the tested bridge mainly consist of the measurement of pavement roughness and analysis on power spectral density, the testing and analysis on natural vibration characteristics, the observation of traffic loads under open traffic and the corresponding measurements of dynamic displacement and acceleration on bridge. To determine impact factors in terms of measured dynamic displacement responses, low pass Butterworth filter is used for filtering the dynamic part of measured dynamic displacement and the static extreme values are reserved. Finally, the relationship between impact factors and vehicle weight, vehicle speed is studied. It was found that impact factor tends to decrease with increasing vehicle weight, and integrally speaking, the impact factor increases gradually as the vehicle speed is increased within a wide range.

scholarly journals Tunable structure and dynamics of active liquid crystals

2018 ◽  
Vol 4 (10) ◽  
pp. eaat7779 ◽  
Author(s):  
Nitin Kumar ◽  
Rui Zhang ◽  
Juan J. de Pablo ◽  
Margaret L. Gardel
Keyword(s):  
Topological Defects ◽  
Dynamic Responses ◽  
Internal Stresses ◽  
Activity Levels ◽  
Active System ◽  
Wide Range ◽  
Active Liquid ◽  
Directional Motion ◽  
Potential Applications ◽  
Defect Interactions

Active materials are capable of converting free energy into directional motion, giving rise to notable dynamical phenomena. Developing a general understanding of their structure in relation to the underlying nonequilibrium physics would provide a route toward control of their dynamic behavior and pave the way for potential applications. The active system considered here consists of a quasi–two-dimensional sheet of short (≈1 μm) actin filaments driven by myosin II motors. By adopting a concerted theoretical and experimental strategy, new insights are gained into the nonequilibrium properties of active nematics over a wide range of internal activity levels. In particular, it is shown that topological defect interactions can be led to transition from attractive to repulsive as a function of initial defect separation and relative orientation. Furthermore, by examining the +1/2 defect morphology as a function of activity, we found that the apparent elastic properties of the system (the ratio of bend-to-splay elastic moduli) are altered considerably by increased activity, leading to an effectively lower bend elasticity. At high levels of activity, the topological defects that decorate the material exhibit a liquid-like structure and adopt preferred orientations depending on their topological charge. Together, these results suggest that it should be possible to tune internal stresses in active nematic systems with the goal of designing out-of-equilibrium structures with engineered dynamic responses.

Mechanical Quality Factor of Lead Zirconate Titanate/Epoxy Composites

2000 ◽  
Vol 628 ◽  
Author(s):  
K.C. Cheng ◽  
H.L.W. Chan ◽  
S.W. Or ◽  
C.L. Choy
Keyword(s):  
Quality Factor ◽  
Lead Zirconate Titanate ◽  
Lead Zirconate ◽  
Mechanical Quality Factor ◽  
Epoxy Composites ◽  
Ceramic Phase ◽  
Zirconate Titanate ◽  
Wide Range ◽  
Mechanical Quality ◽  
Piezoelectric Lead Zirconate Titanate

ABSTRACTThe mechanical quality factor Qm of 1–3 piezoelectric lead zirconate titanate/epoxy composites with ceramic volume fractions φ ranging from 0.18 to 0.82 has been measured. This range of φ is wider than those previously investigated by other workers. The width-to-thickness ratio of the ceramic phase is sufficiently small that there are no significant mode couplings. The observed Qm agrees well with the prediction of the parallel model. It is found that Qm increases from 34 to 100 as φ changes from 0 to 0.82 and then increases sharply to reach a high value of 600 at φ = 1. Therefore Qm can be tailored to give a wide range of values by varying φ.

scholarly journals A System Dynamics Model of Fire-Tube Shell Boiler

1994 ◽  
Vol 116 (4) ◽  
pp. 745-754 ◽  
Author(s):  
B. J. Huang ◽  
P. Y. Ko
Keyword(s):  
System Dynamics ◽  
Linear Time ◽  
Estimation Method ◽  
Operating Conditions ◽  
Dynamic Responses ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
Wide Range ◽  
Perturbed Model ◽  
Tube Shell

A system dynamics model of fire-tube shell boiler was developed. The derivation of the dynamics model started with a nonlinear time-variant dynamic modeling based on the transport phenomena in the fire-tube boiler. A linear time-invariant perturbed model around steady-state operating points was then derived. The identifiable parameters τmw, τwa, K, β, and τd were identified by using field test data and least-squares estimation method; the coefficients C’s were, meanwhile, directly predicted by using the small-perturbation relations. Empirical correlations of the identifiable parameters were further derived to account for the variation of parameters with operating conditions. The present perturbed model is thus semi-empirical and can describe the dynamic behaviour of fire-tube boilers over a wide range of operating conditions. The predictions of dynamic responses using the present model were shown to agree very well with the test results.

Effects of ZnO Addition and Sintering Temperature on Dielectric Properties of MgTiO3 Ceramic

2014 ◽  
Vol 616 ◽  
pp. 145-152 ◽  
Author(s):  
Xiao Li Ji ◽  
Fang Yi ◽  
Song Zhang ◽  
Cheng C. Zhai ◽  
Peng Fei Hu
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Quality Factor ◽  
Glass Phase ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric ◽  
Wide Range ◽  
Porosity Defects

The effects of ZnO addition and sintering temperature on dielectric properties of MgTiO3 ceramics were investigated. The results showed that addition ZnO not only reduce the sintering temperature but also improve the density and dielectric properties of MgTiO3 ceramics. (Mg1-xZnx)TiO3 (MZT) ceramics shows microwave dielectric properties in a wide range of sintering temperature when x = 0.1, 0.2, 0.3. At x ≥ 0.4, the density of ceramics decreased and porosity, defects and glass phase increased with increased doping of ZnO, resulting in the increase of dielectric loss of MZT and reduce of quality factor.

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