Compact Model for the Static and Dynamic Behavior of a Piezoelectric Bimorph Actuator for Microfluidic MEMS

2014 ◽  
Author(s):  
Dominik Rumschoettel ◽  
Markus Kagerer ◽  
Franz Irlinger ◽  
Tim C. Lueth
Keyword(s):  
Dynamic Behavior ◽  
Piezoelectric Material ◽  
Dynamic Properties ◽  
Behavioral Model ◽  
Compact Model ◽  
Step Response ◽  
Model Parameters ◽  
Laser Vibrometer ◽  
Static Deflection ◽  
Wide Range

Piezoelectric actuators are commonly used in Micro-Electro-Mechanical Systems (MEMS). They can deliver high forces, large accelerations, and high power densities. However, one of their weaknesses is the comparatively small actuator travel that can be readily achieved. The elongation attainable by a slab of piezoelectric material is only a few tenth of a percent. Therefore, it is often useful to employ mechanical structures which are capable of amplifying those minute deflections. A particularly often used configuration is a sandwich structure consisting of either two differently poled strips of piezoelectric material or a single strip of piezoelectric and a layer of passive material. Such a structure is called a bimorph. If one of the layers is mounted above a cavity, the structure forms a membrane actuator. Because of their capability to displace fluid volume, those actuators are suitable for a wide range of applications in the area of microfluidics, including, but not limited to, micropumps, microvalves, microdroplet generators, and high frequency acoustic transducers. The directed design of those actuators demands the determination of their mechanical and electrical properties in advance. In the present paper a compact model for the characterization of such a bimorphic membrane actuator is presented. The model is based on an analytical description of the bending line of the membrane by means of Euler-Bernoulli-Beam theory. Relationships for the dependency of the actuator deflection and the volume displaced by the membrane on the geometry and the material properties of the actuator are established. Other model parameters like the moving mass and the effective stiffness are also determined. The identified parameters are used to create a behavioral model of the full dynamic characteristics of the actuator. This allows the prediction of the dynamic response to an arbitrary input excitation signal. The model is validated by comparing the predicted static and dynamic behavior of the membrane actuator with empirically derived results. For this purpose a number of test specimen with different actuator geometries are fabricated. The quasi-static deflection of the actuator is monitored with a laser-vibrometer for different drive voltages. Furthermore the dynamic behavior of the actuator is determined by recording its step response function. Overall, a model for the prediction of the static and dynamic behavior of a piezoelectrically driven bimorph membrane actuator is presented. The model validation shows good agreement between the predicted and measured behavior for the quasi-static deflection of the actuator and reasonable agreement for its dynamic properties.

Modeling and Experimental Characterization of Viscoelastic 3D Printed Spring/Damper Systems

2017 ◽  
Author(s):  
Heather L. Lai ◽  
Cuiyu Kuang ◽  
Jared Nelson
Keyword(s):  
Dynamic Behavior ◽  
Material Properties ◽  
Dynamic Properties ◽  
Viscoelastic Materials ◽  
Vibration Isolators ◽  
Damping Behavior ◽  
Wide Range ◽  
3D Printed ◽  
Printed Materials

The development of flexible, viscoelastic materials for consumer 3D printers has provided the opportunity for a wide range of devices with damping behavior such as tuned vibration isolators to be innovatively developed and inexpensively manufactured. However, there is currently little information available about the dynamic behavior of these 3D printed materials necessary for modeling of dynamic behavior prior to print. In order to fully utilize these promising materials, a deeper understanding of the material properties, and the subsequent dynamic behavior is critical. This study evaluates the use of three different types of models: transient response, frequency response and hysteretic response to predict the dynamic behavior of viscoelastic 3D printed materials based on static and dynamic material properties. Models of viscoelastic materials are presented and verified experimentally using two 3D printable materials and two traditional viscoelastic materials. The experimental response of each of the materials shows agreement with the modeled behavior, and underscores the need for improved characterization of the dynamic properties of viscoelastic 3D printable materials.

Dynamic Behavior of Slab Induced by Pedestrian Traffic

2019 ◽  
Vol 19 (12) ◽  
pp. 1950154
Author(s):  
Yan-An Gao ◽  
Qing-Shan Yang ◽  
Yun Dong ◽  
Chao Chen ◽  
Tao-Ping Ye
Keyword(s):  
Dynamic Behavior ◽  
Body Mass ◽  
Dynamic Properties ◽  
Damping Capacity ◽  
Model Parameters ◽  
Leg Stiffness ◽  
Structural Responses ◽  
Pedestrian Traffic ◽  
Mass Spring ◽  
Pseudo Excitation

This study comprehensively explores the dynamic behavior of a slender slab due to the excitation of pedestrian traffic. Three kinds of excitation models are adopted to describe the vibration of the slab induced by pedestrians. A comparison of the structural responses shows that the bipedal model results in larger vibrations than the mass–spring–damper or pseudo-excitation models. Further research indicates that the pedestrians evidently alter the dynamic properties of the slab by affecting its frequency and damping capacity. The slab tends to be more flexible at a lower frequency as the pedestrian walks across its surface while its damping capacity is improved. In contrast, the slab can increase the frequency, while decreasing the damping of the pedestrian model. Thus, the slab also alters the properties of the pedestrians. In addition, an investigation of the bipedal model parameters indicates that the variations of the leg stiffness, damping, and body mass have distinct effects on the slab characteristics and vibrations. In order to assess the response of the slab to a crowd, a new simplified theory is introduced to describe the dynamic properties of the slab under multi-layout excitations, including human influences resulting from different body properties. The results of this study provide potential ways for understanding the vibratory mechanisms of slender structures such as footbridges, grandstands, or stations under crowd excitations.

ТИРИСТОРНЫЙ ЭФФЕКТ В СВЧ ИС, ИЗГОТОВЛЕННЫХ ПО SIGE БИКМОП-ТЕХНОЛОГИЯМ

2020 ◽  
Vol 96 (3s) ◽  
pp. 612-614
Author(s):  
В.В. Елесина ◽  
И.О. Метелкин
Keyword(s):  
Integrated Circuits ◽  
Extraction Procedure ◽  
Compact Model ◽  
Model Parameters ◽  
Cad Systems ◽  
Parameters Extraction ◽  
Sige Bicmos ◽  
Bicmos Integrated Circuits ◽  
Basic Parameters ◽  
Radiation Induced

Проведен анализ случаев возникновения тиристорного эффекта в СВЧ ИС, изготовленных по технологии SiGe БиКМОП, при воздействии ионизирующего излучения. Рассмотрены области СВЧ ИС, чувствительные к возникновению ТЭ, определены основные параметры тиристорных структур. Проведена апробация подхода к восстановлению параметров схемно-топологической радиационно-ориентированной модели тиристорной структуры для САПР. The paper analyzes ionizing radiation induced latchup in microwave SiGe BiCMOS integrated circuits (ICs). Critical parts of ICs sensitive to latchup have been identified and basic parameters of corresponding parasitic thyristor structures have been determined. An approach has been approved to the thyristor structure compact model parameters extraction procedure intended for use in CAD systems.

scholarly journals Inferring Linkage Disequilibrium Between a Polymorphic Marker Locus and a Trait Locus in Natural Populations

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 457-467 ◽  
Author(s):  
Z W Luo ◽  
S H Tao ◽  
Z-B Zeng
Keyword(s):  
Linkage Disequilibrium ◽  
Allele Frequency ◽  
Random Mating ◽  
Natural Populations ◽  
Polymorphic Marker ◽  
Marker Locus ◽  
Model Parameters ◽  
Phenotypic Variance ◽  
Wide Range ◽  
Trait Locus

Abstract Three approaches are proposed in this study for detecting or estimating linkage disequilibrium between a polymorphic marker locus and a locus affecting quantitative genetic variation using the sample from random mating populations. It is shown that the disequilibrium over a wide range of circumstances may be detected with a power of 80% by using phenotypic records and marker genotypes of a few hundred individuals. Comparison of ANOVA and regression methods in this article to the transmission disequilibrium test (TDT) shows that, given the genetic variance explained by the trait locus, the power of TDT depends on the trait allele frequency, whereas the power of ANOVA and regression analyses is relatively independent from the allelic frequency. The TDT method is more powerful when the trait allele frequency is low, but much less powerful when it is high. The likelihood analysis provides reliable estimation of the model parameters when the QTL variance is at least 10% of the phenotypic variance and the sample size of a few hundred is used. Potential use of these estimates in mapping the trait locus is also discussed.

scholarly journals Antifungal Activity of Propyl Disulfide from Neem (Azadirachta indica) in Vapor and Agar Diffusion Assays against Anthracnose Pathogens (Colletotrichum gloeosporioides and Colletotrichum acutatum) in Mango Fruit

2021 ◽  
Vol 9 (4) ◽  
pp. 839
Author(s):  
Muhammad Rafiullah Khan ◽  
Vanee Chonhenchob ◽  
Chongxing Huang ◽  
Panitee Suwanamornlert
Keyword(s):  
Antifungal Activity ◽  
Mycelial Growth ◽  
Colletotrichum Gloeosporioides ◽  
Colletotrichum Acutatum ◽  
Model Parameters ◽  
Pathogenicity Test ◽  
Agar Diffusion ◽  
Wide Range ◽  
Significant Difference ◽  
Diffusion Assay

Microorganisms causing anthracnose diseases have a medium to a high level of resistance to the existing fungicides. This study aimed to investigate neem plant extract (propyl disulfide, PD) as an alternative to the current fungicides against mango’s anthracnose. Microorganisms were isolated from decayed mango and identified as Colletotrichum gloeosporioides and Colletotrichum acutatum. Next, a pathogenicity test was conducted and after fulfilling Koch’s postulates, fungi were reisolated from these symptomatic fruits and we thus obtained pure cultures. Then, different concentrations of PD were used against these fungi in vapor and agar diffusion assays. Ethanol and distilled water were served as control treatments. PD significantly (p ≤ 0.05) inhibited more of the mycelial growth of these fungi than both controls. The antifungal activity of PD increased with increasing concentrations. The vapor diffusion assay was more effective in inhibiting the mycelial growth of these fungi than the agar diffusion assay. A good fit (R2, 0.950) of the experimental data in the Gompertz growth model and a significant difference in the model parameters, i.e., lag phase (λ), stationary phase (A) and mycelial growth rate, further showed the antifungal efficacy of PD. Therefore, PD could be the best antimicrobial compound against a wide range of microorganisms.

scholarly journals Simulation Verification of the Contact Parameter Influence on the Forces’ Course of Cereal Grain Impact against a Stiff Surface

2021 ◽  
Vol 11 (2) ◽  
pp. 466
Author(s):  
Włodzimierz Kęska ◽  
Jacek Marcinkiewicz ◽  
Łukasz Gierz ◽  
Żaneta Staszak ◽  
Jarosław Selech ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Decisive Role ◽  
Force Sensor ◽  
Contact Forces ◽  
Correct Selection ◽  
Contact Parameter ◽  
Cereal Grain ◽  
Wide Range ◽  
The Impact ◽  
Selection Of

The continuous development of computer technology has made it applicable in many scientific fields, including research into a wide range of processes in agricultural machines. It allows the simulation of very complex physical phenomena, including grain motion. A recently discovered discrete element method (DEM) is used for this purpose. It involves direct integration of equations of grain system motion under the action of various forces, the most important of which are contact forces. The method’s accuracy depends mainly on precisely developed mathematical models of contacts. The creation of such models requires empirical validation, an experiment that investigates the course of contact forces at the moment of the impact of the grains. To achieve this, specialised test stations equipped with force and speed sensors were developed. The correct selection of testing equipment and interpretation of results play a decisive role in this type of research. This paper focuses on the evaluation of the force sensor dynamic properties’ influence on the measurement accuracy of the course of the plant grain impact forces against a stiff surface. The issue was examined using the computer simulation method. A proprietary computer software with the main calculation module and data input procedures, which presents results in a graphic form, was used for calculations. From the simulation, graphs of the contact force and force signal from the sensor were obtained. This helped to clearly indicate the essence of the correct selection of parameters used in the tests of sensors, which should be characterised by high resonance frequency.

scholarly journals A Reinforcement Learning Framework for Spiking Networks with Dynamic Synapses

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Karim El-Laithy ◽  
Martin Bogdan
Keyword(s):  
Reinforcement Learning ◽  
Spike Timing ◽  
Neural Representation ◽  
Model Parameters ◽  
Learning Framework ◽  
Reference Target ◽  
Wide Range ◽  
Spiking Network ◽  
Dynamic Synapses ◽  
Exclusive Or

An integration of both the Hebbian-based and reinforcement learning (RL) rules is presented for dynamic synapses. The proposed framework permits the Hebbian rule to update the hidden synaptic model parameters regulating the synaptic response rather than the synaptic weights. This is performed using both the value and the sign of the temporal difference in the reward signal after each trial. Applying this framework, a spiking network with spike-timing-dependent synapses is tested to learn the exclusive-OR computation on a temporally coded basis. Reward values are calculated with the distance between the output spike train of the network and a reference target one. Results show that the network is able to capture the required dynamics and that the proposed framework can reveal indeed an integrated version of Hebbian and RL. The proposed framework is tractable and less computationally expensive. The framework is applicable to a wide class of synaptic models and is not restricted to the used neural representation. This generality, along with the reported results, supports adopting the introduced approach to benefit from the biologically plausible synaptic models in a wide range of intuitive signal processing.

scholarly journals Modelling the Inflation and Elastic Instabilities of Rubber-Like Spherical and Cylindrical Shells Using a New Generalised Neo-Hookean Strain Energy Function

2021 ◽  
Author(s):  
Afshin Anssari-Benam ◽  
Andrea Bucchi ◽  
Giuseppe Saccomandi
Keyword(s):  
Experimental Data ◽  
Energy Function ◽  
Limit Point ◽  
Strain Energy ◽  
Cylindrical Shells ◽  
Strain Energy Function ◽  
Model Parameters ◽  
Wide Range ◽  
Cylindrical Tubes ◽  
Gent Model

AbstractThe application of a newly proposed generalised neo-Hookean strain energy function to the inflation of incompressible rubber-like spherical and cylindrical shells is demonstrated in this paper. The pressure ($P$ P ) – inflation ($\lambda $ λ or $v$ v ) relationships are derived and presented for four shells: thin- and thick-walled spherical balloons, and thin- and thick-walled cylindrical tubes. Characteristics of the inflation curves predicted by the model for the four considered shells are analysed and the critical values of the model parameters for exhibiting the limit-point instability are established. The application of the model to extant experimental datasets procured from studies across 19th to 21st century will be demonstrated, showing favourable agreement between the model and the experimental data. The capability of the model to capture the two characteristic instability phenomena in the inflation of rubber-like materials, namely the limit-point and inflation-jump instabilities, will be made evident from both the theoretical analysis and curve-fitting approaches presented in this study. A comparison with the predictions of the Gent model for the considered data is also demonstrated and is shown that our presented model provides improved fits. Given the simplicity of the model, its ability to fit a wide range of experimental data and capture both limit-point and inflation-jump instabilities, we propose the application of our model to the inflation of rubber-like materials.

scholarly journals Study on Friction in Automotive Shock Absorbers Part 1: Friction Simulation Using a Dynamic Friction Model in the Contact Zone of an FEM Model

Vehicles ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 212-232
Author(s):  
Ludwig Herzog ◽  
Klaus Augsburg
Keyword(s):  
Ride Comfort ◽  
Viscous Friction ◽  
Simulation Method ◽  
Friction Model ◽  
Model Parameters ◽  
Dynamic Friction ◽  
Friction Modeling ◽  
Shock Absorbers ◽  
Operation Conditions ◽  
Wide Range

The important change in the transition from partial to high automation is that a vehicle can drive autonomously, without active human involvement. This fact increases the current requirements regarding ride comfort and dictates new challenges for automotive shock absorbers. There exist two common types of automotive shock absorber with two friction types: The intended viscous friction dissipates the chassis vibrations, while the unwanted solid body friction is generated by the rubbing of the damper’s seals and guides during actuation. The latter so-called static friction impairs ride comfort and demands appropriate friction modeling for the control of adaptive or active suspension systems. In this article, a simulation approach is introduced to model damper friction based on the most friction-relevant parameters. Since damper friction is highly dependent on geometry, which can vary widely, three-dimensional (3D) structural FEM is used to determine the deformations of the damper parts resulting from mounting and varying operation conditions. In the respective contact zones, a dynamic friction model is applied and parameterized based on the single friction point measurements. Subsequent to the parameterization of the overall friction model with geometry data, operation conditions, material properties and friction model parameters, single friction point simulations are performed, analyzed and validated against single friction point measurements. It is shown that this simulation method allows for friction prediction with high accuracy. Consequently, its application enables a wide range of parameters relevant to damper friction to be investigated with significantly increased development efficiency.

Compact Modeling of Forced Flow in Longitudinal Fin Heat Sinks With Tip Bypass

2003 ◽  
Vol 125 (3) ◽  
pp. 319-324 ◽  
Author(s):  
C. B. Coetzer ◽  
J. A. Visser
Keyword(s):  
Pressure Drop ◽  
Heat Sink ◽  
Heat Sinks ◽  
Compact Model ◽  
Forced Flow ◽  
Compact Modeling ◽  
Transfer Coefficients ◽  
Wide Range ◽  
Laminar And Turbulent Flow ◽  
Improved Accuracy

This paper introduces a compact model to predict the interfin velocity and the resulting pressure drop across a longitudinal fin heat sink with tip bypass. The compact model is based on results obtained from a comprehensive study into the behavior of both laminar and turbulent flow in longitudinal fin heat sinks with tip bypass using CFD analysis. The new compact flow prediction model is critically compared to existing compact models as well as to the results obtained from the CFD simulations. The results indicate that the new compact model shows at least a 4.5% improvement in accuracy predicting the pressure drop over a wide range of heat sink geometries and Reynolds numbers simulated. The improved accuracy in velocity distribution between the fins also increases the accuracy of the calculated heat transfer coefficients applied to the heat sinks.

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