Improved Modeling of a Dynamic Mirror With Antagonistic Piezoelectric Stack Actuation

2011 ◽  
Author(s):  
James A. Mynderse ◽  
Ann M. Whitney ◽  
George T. C. Chiu
Keyword(s):  
Experimental Data ◽  
Laser Beam ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Beam Steering ◽  
Proposed Model ◽  
Mechanical Compliance ◽  
Charging Dynamics ◽  
Good Agreement ◽  
Shunt Circuit

An enhanced model of a dynamic mirror actuator (DMA) for laser beam steering is presented. The DMA is driven by an antagonistic pair of piezoelectric stack actuators (PESA). The proposed model of the DMA employs explicit PESA charging dynamics and an adjustable PESA shunt circuit to address the frequency-dependent effective mechanical compliance term in several previous models from literature. The proposed DMA model with shunt circuit accurately predicts the first damped natural frequency of the DMA with a shunt circuit across each PESA. Simulation and experimental data are presented. Good agreement is shown between the predicted and measured damped first natural frequencies.

Modeling of a Dynamic Mirror Actuator

2010 ◽  
Author(s):  
James A. Mynderse ◽  
George T. C. Chiu
Keyword(s):  
Experimental Data ◽  
Laser Beam ◽  
Linear Model ◽  
Natural Frequency ◽  
Beam Steering ◽  
Constitutive Models ◽  
Higher Order ◽  
Piezoelectric Stacks

A novel dual-actuated dynamic mirror actuator (DMA) is presented for laser beam steering. The DMA is driven by a pair of piezoelectric stack actuaors (PESAs). The piezoelectric stacks are modeled using a linear model and five variations of constitutive models from literature. The resulting DMA models are simulated. While the constitutive models capture some higher order dynamics, the linear model provides the best combination of accuracy to experimental data and simplicty of model between DC and the first natural frequency of the DMA. For control of the DMA up to the first natural frequency of the DMA, a linear model should be adequate.

Vibrations of an Intermediately Supported U-Bend Tube

1975 ◽  
Vol 97 (1) ◽  
pp. 23-32 ◽  
Author(s):  
L. S. S. Lee
Keyword(s):  
Natural Frequency ◽  
Natural Frequencies ◽  
Experimental Tests ◽  
Bending Stiffness ◽  
Stiffness Ratio ◽  
Plane Vibration ◽  
Straight Beam ◽  
Out Of Plane ◽  
Straight Segments ◽  
Good Agreement

Vibrations of an intermediately supported U-bend tube fall into two independent classes as an incomplete ring of single span does, namely, the in-plane vibration and the coupled twist-bending out-of-plane vibration. Natural frequencies may be expressed in terms of a coefficient p which depends on the stiffness ratio k, the ratio of lengths of spans, and the supporting conditions. The effect of the torsional flexibility of a curved bar acts to release the bending stiffness of a straight beam and hence decrease the natural frequency. Some conclusions for an incomplete ring of single span may not be equally well applicable to the U-tube case due to the effects of intermediate supports and the presence of the supporting straight segments. Results of the analytical predictions and the experimental tests of an intermediately supported U-tube are in good agreement.

scholarly journals Modelling the Characteristics of Ring-Shaped Magnetoelastic Force Sensor in Mohri’s Configuration

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 266 ◽  
Author(s):  
Anna Ostaszewska-Liżewska ◽  
Roman Szewczyk ◽  
Peter Raback ◽  
Mika Malinen
Keyword(s):  
Experimental Data ◽  
High Sensitivity ◽  
Force Sensor ◽  
Inhomogeneous Distribution ◽  
The Finite Element Method ◽  
The Core ◽  
Magnetoelastic Effect ◽  
Proposed Model ◽  
Distribution Of Stresses ◽  
Good Agreement

Magnetoelastic force sensors exhibit high sensitivity and robustness. One commonly used configuration of force sensor with a ring-shaped core was presented by Mohri at al. In this configuration force is applied in the direction of a diameter of the core. However, due to inhomogeneous distribution of stresses, model of such sensor has not been presented yet. This paper is filling the gap presenting a new method of modelling the magnetoelastic effect, which is especially suitable for the finite element method. The presented implementation of proposed model is in good agreement with experimental data and creates new possibilities of modelling other devices utilizing magnetoelastic effect.

Analysis and Validation of Cutting Forces Prediction Models in Micromachining

2006 ◽  
Vol 526 ◽  
pp. 13-18 ◽  
Author(s):  
H. Perez ◽  
Antonio Vizan Idoipe ◽  
J. Perez ◽  
J. Labarga
Keyword(s):  
Experimental Data ◽  
Cutting Force ◽  
Cutting Forces ◽  
Prediction Models ◽  
Precision Machining ◽  
New Model ◽  
Proposed Model ◽  
On Line ◽  
Machine Control ◽  
Good Agreement

Many investigations have been developed related to precision machining with features in the millimetre scale. In this paper different cutting force models for micromilling are analyzed and compared. A new model based on specific cutting force that also considers run-out errors has been developed. The estimated cutting forces obtained with this model had good agreement with the experimental data. Also, the proposed model allows to be implemented within the machine control for the on-line optimization of the micromilling process.

Identification of Natural Frequency of Bearing Rotor Based on GA-SVM

2012 ◽  
Vol 443-444 ◽  
pp. 27-33
Author(s):  
Tian Ran Ma ◽  
Fei Hu Qin ◽  
Rui Xue Liu ◽  
Feng Jie Zhang
Keyword(s):  
Experimental Data ◽  
Support Vector Machine ◽  
Natural Frequency ◽  
Rolling Bearing ◽  
Linear Mapping ◽  
Support Vector ◽  
Non Linear ◽  
Experimental Values ◽  
Rotor Structure ◽  
Good Agreement

During identify natural frequency of bearing rotor, due to the complex non-linear relationship among the factors which influence natural frequency, so it is hard to establish a complete and accurate theoretical model. Based on the generalization and approximation of non-linear mapping capability of support vector machine (SVM) and the powerful ability of global optimization of the genetic algorithm (GA), the paper through optimizing the SVM by GA, establishes combined Genetic Support Vector Machine (GA-SVM). The method establishes the mapping between the natural frequency of a rolling bearing rotor and the various parameters, which reduces the rotor structure for the study similar to the natural frequency of the calculation of the workload greatly. Using the model to indentify the natural frequency of bearing rotor under different parameters, then compare identification value with experimental values shows that projections in good agreement with the experimental data.

Novel Model for the Optical Function: Application to Hexagonal Gan

2001 ◽  
Vol 677 ◽  
Author(s):  
Y. Chan ◽  
Aleksandra B. Djurišić ◽  
E. Herbert Li
Keyword(s):  
Experimental Data ◽  
Closed Form ◽  
Dielectric Function ◽  
Absorption Edge ◽  
Low Energy ◽  
Optical Function ◽  
Complex Dielectric Function ◽  
Proposed Model ◽  
Novel Model ◽  
Good Agreement

ABSTRACTIn this work we propose an analytical expression for the complex dielectric function that includes both discrete and continuum exciton effects. The model is based on the work of Elliott and the proposed model has been applied to modeling the experimental data for the hexagonal GaN. We have obtained good agreement with the experimental data. The model assumes Lorentzian broadening in order to obtain dielectric function equations in analytically closed form. We show that Lorentzian broadened dielectric function decays more slowly than the experimental data for hexagonal GaN at the low energy side. This indicates that the broadening of the absorption edge in GaN is not purely Lorentzian. The agreement with the experimental data can be improved using adjustable broadening modification.

scholarly journals Thermodynamic modelling of the binary indium-lithium system, a promising li-ion battery material

2021 ◽  
pp. 41-41
Author(s):  
Wojciech Gierlotka ◽  
Władysław Gąsior ◽  
Adam Dębski ◽  
Miłosz Zabrocki
Keyword(s):  
Experimental Data ◽  
Ternary Systems ◽  
Calphad Approach ◽  
Li Ion Battery ◽  
System A ◽  
Proposed Model ◽  
Component Systems ◽  
Li Ion ◽  
Battery Material ◽  
Good Agreement

The binary In - Li system is a promising Li-ion battery anode material as well as a part of the important ternary Ge - In - Li system. The thermodynamic descriptions of metallic systems are widely used to retrieve information necessary for alloy applications. In this work, a thermodynamic model of a binary indium - lithium system prepared by the Calphad approach is proposed. The liquid phase was described by an associate model, and the solid phases determined by the ab-initio calculation were included in thermodynamic modeling. The obtained set of self-consistent thermodynamic parameters well reproduces the available experimental data and enables further calculations of multi-component systems. A good agreement between the calculations and the available experimental data was found. The proposed model can be used for further descriptions of ternary systems.

Empirical estimation of engine-integration noise for high bypass ra-tio turbofan engines

2021 ◽  
Vol 263 (2) ◽  
pp. 4511-4519
Author(s):  
Incheol Lee ◽  
Yingzhe Zhang ◽  
Dakai Lin
Keyword(s):  
Experimental Data ◽  
Pressure Side ◽  
Empirical Estimation ◽  
Low Frequencies ◽  
High Frequencies ◽  
Turbofan Engines ◽  
Proposed Model ◽  
The Impact ◽  
Bypass Ratio ◽  
Good Agreement

To investigate the impact of installation on jet noise from modern high-bypass-ratio turbofan engines, a model-scale noise experiment with a jet propulsion system and a fuselage model in scale was conducted in the anechoic wind tunnel of ONERA, CEPRA 19. Two area ratios (an area of the secondary nozzle over an area of the primary nozzle), 5 and 7, and various airframe configurations such as wing positions relative to the tip of the engine nacelle and flap angles, were considered. Based on the analysis of experimental data, an empirical model for the prediction of engine installation noise was proposed. The model comprises two components: one is the interaction be-tween the jet and the pressure side of the wing, and the other is the interaction between the jet and the flap tip. The interaction between the jet and the pressure side of the wing contributes to the noise at the low frequencies (≤ 1.5 kHz), and the interaction between the jet and the flap tip con-tributes to the noise at the high frequencies. The proposed model showed a good agreement with the experimental data.

VLE Determination of Carbon Dioxide Loaded Aqueous Alkanolamine Mixtures Using Modified Kent Eisenberg Model

2017 ◽  
Vol 231 (11-12) ◽  
Author(s):  
Humbul Suleman ◽  
Abdulhalim Shah Maulud ◽  
Zakaria Man
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Model Parameters ◽  
Thermodynamic Models ◽  
Carbon Dioxide Absorption ◽  
Proposed Model ◽  
Wide Range ◽  
Experimental Values ◽  
Good Agreement

AbstractA computationally simple thermodynamic framework has been presented to correlate the vapour-liquid equilibria of carbon dioxide absorption in five representative types of alkanolamine mixtures. The proposed model is an extension of modified Kent Eisenberg model for the carbon dioxide loaded aqueous alkanolamine mixtures. The model parameters are regressed on a large experimental data pool of carbon dioxide solubility in aqueous alkanolamine mixtures. The model is applicable to a wide range of temperature (298–393 K), pressure (0.1–6000 kPa) and alkanolamine concentration (0.3–5 M). The correlated results are compared to the experimental values and found to be in good agreement with the average deviations ranging between 6% and 20%. The model results are comparable to other thermodynamic models.

Kinetic Model of Thermoelastic Martensite Transformation in Niti and NiMn Based Shape Memory Alloys

1995 ◽  
Vol 398 ◽  
Author(s):  
K. H. Wu ◽  
J.D. Shi ◽  
F. Yang ◽  
Z. J. Pu
Keyword(s):  
Experimental Data ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensite Transformation ◽  
Quantitative Model ◽  
Proposed Model ◽  
Series Of Experiments ◽  
The Relationship ◽  
Kinetics Of ◽  
Good Agreement

ABSTRACTA new, quantitative model was developed to describe the martensite transformation kinetics of thermoelastic shape memory alloys (SMAs). In addition, a series of experiments were conducted to study the Kinetics of thermoelastic martensite transformation in four SMA systems: NiTi, NiTi-15at%Hf, NiTi-20at%Zr and NiMn-7.5at%Ti alloys. Comparisons between data of the kinetic of martensite transformation with the present theoretic models show that the proposed model is in good agreement and concurs with the experimental data. Also, a comparison of data from the proposed model with data from existing kinetic models, such as Liang's and Magee's [1,7], indicates that the proposed model can better describe the experimental data, including the relationship between dξ(T)/dT and ξ, and dξ(T)/dT and T.

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