scholarly journals Elastic and viscous bond components in the adhesion of colloidal particles and fibrillated streptococci to QCM-D crystal surfaces with different hydrophobicities using Kelvin–Voigt and Maxwell models

2017 ◽  
Vol 19 (37) ◽  
pp. 25391-25400 ◽  
Author(s):  
Rebecca van der Westen ◽  
Prashant K. Sharma ◽  
Hans De Raedt ◽  
Ijsbrand Vermue ◽  
Henny C. van der Mei ◽  
...  
Keyword(s):  
Phenomenological Models ◽  
Bacterial Adhesion ◽  
Colloidal Particles ◽  
Maxwell Model ◽  
Crystal Surfaces ◽  
Maxwell Models ◽  
Voigt Model

Analysis of initial bacterial adhesion using phenomenological models such as the Kelvin–Voigt model and the Maxwell model.

The Effects of Small Sinusoidal Load Variations in Elastohydrodynamic Line Contacts

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
C. J. Hooke ◽  
G. E. Morales-Espejel
Keyword(s):  
Pressure Distribution ◽  
Maxwell Model ◽  
Total System ◽  
Low Frequencies ◽  
Load Variations ◽  
Entrainment Velocity ◽  
Line Contacts ◽  
Sinusoidal Load ◽  
Voigt Model ◽  
Low Amplitude

A method of determining the response of elastohydrodynamic line contacts to low amplitude, sinusoidal variations in load is presented. It is shown that the load variations alter the Hertz width, cyclically increasing and reducing the effective entrainment velocity. This produces clearance variations in the inlet, which are transported through the conjunction altering the pressure distribution as they pass. The resulting pressure and clearance changes can be many times greater than when the load changes slowly. The results are used to determine the flexibility and damping of the conjunctions. These vary depending on the number of transported waves inside the contact. It is shown that a Maxwell model rather than the usual Voigt model is required to define the contact's behavior. While the Voigt model may be used at low frequencies, it has a damping coefficient that is not unique to the contact but depends on the total system stiffness.

Identification of Viscoelastic Properties of Finite Element Structures With Joints

1997 ◽  
Author(s):  
Torsten Herrmann ◽  
Valdas Chaika
Keyword(s):  
Finite Element ◽  
Viscoelastic Properties ◽  
Sparse Matrix ◽  
Maxwell Model ◽  
Least Square ◽  
Identification Algorithm ◽  
Domain Identification ◽  
Generalized Maxwell Model ◽  
Maxwell Models ◽  
Complex Modal Analysis

Abstract Identification of the damping and stiffness parameters of the composite joints in finite element structures is analyzed. For the modeling of the viscoelastic properties of the joints the classical Voigt-Kelvin and generalized Maxwell model (three parameter solid) are used. A time domain identification algorithm for classically and non-classically damped dynamic systems is developed. It is based on the application of an extended Kalman filter and least square technique. The algorithm uses complex modal analysis and sparse matrix technology. Both force and base excited systems are considered. Experimental verification of the identification results is carried out on a test structure. The accuracy of the modeling of damping in the joint using the Voigt-Kelvin and generalized Maxwell models is investigated.

Robot compliant catching by Maxwell model based Cartesian admittance control

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Le Fu ◽  
Jie Zhao
Keyword(s):  
Control Method ◽  
Maxwell Model ◽  
Admittance Control ◽  
End Effector ◽  
Content Type ◽  
Model Based ◽  
Time Optimal ◽  
Voigt Model ◽  
Optimal Movement ◽  
The Impact

Purpose Admittance control is a typical complaint control methodology. Traditionally, admittance control systems are based on a dynamical relationship described by Voigt model. By contrast, after changing connection of spring and damper, Maxwell model produces different dynamics and has shown better impact absorption performance. This paper aims to design a novel compliant control method based on Maxwell model and implement it in a robot catching scenario. Design/methodology/approach To achieve this goal, this paper proposed a Maxwell model based admittance control scheme. Considering several motion stages involved in one catching attempt, the following approaches are adopted. First, Kalman filter is used to process the position data stream acquired from motion capture system and predict the subsequent object flying trajectory. Then, a linear segments with parabolic blends reaching motion is generated to achieve time-optimal movement under kinematic and joint inherent constraints. After robot reached the desired catching point, the proposed Maxwell model based admittance controller performs such as a cushion to moderate the impact between robot end-effector and flying object. Findings This paper has experimentally demonstrated the feasibility and effectiveness of the proposed method. Compared with typical Voigt model based compliant catching, less object bounding away from end-effector happens and the success rate of catching has been improved. Originality/value The authors proposed a novel Maxwell model based admittance control method and demonstrated its effectiveness in a robot catching scenario. The author’s approach may inspire other related researchers and has great potential of practical usage in a widespread of robot applications.

scholarly journals FE Prediction of Hysteretic Component of Rubber Friction

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
L. Pálfi ◽  
T. Goda ◽  
K. Váradi ◽  
E. Garbayo ◽  
J. M. Bielsa ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Storage Modulus ◽  
Viscoelastic Material ◽  
Loss Factor ◽  
Master Curve ◽  
Reaction Force ◽  
Maxwell Model ◽  
Material Models ◽  
Rubber Friction ◽  
Maxwell Models

The hysteretic part of the friction coefficient for rubber sliding on an ideal rigid, rough surface has been investigated by FE technique. The FE models were created by using two different FE softwares, ABAQUS and MSC.MARC. The surface roughness has been considered by using two different sine waves having a wavelength of 100 μm and 11.11 μm, as well as their superposition. Parameters of the viscoelastic material models of the rubber were gained, firstly from a fit to the measured storage modulus, secondly from a fit to the measured loss factor master curve of the rubber. The effect of viscoelastic material models, comparing 10-term and 40-term generalized Maxwell models was also considered together with the temperature effect between −50 and150°C. According to the results, both postprocessing methods, namely, the reaction force and the energy-based approach, show very similar coefficients of friction. The 40-term Maxwell model fitted to both the storage modulus and loss factor curve provided the most realistic results. The tendency of the FE results has been explained by semianalytical theory.

scholarly journals Identification of the Process of Dynamic Stretching of Threads in Warp-Knitting Technology

2017 ◽  
Vol 17 (4) ◽  
pp. 334-343 ◽  
Author(s):  
Aleksandra Prążyńska ◽  
Zbigniew Mikołajczyk
Keyword(s):  
Standard Model ◽  
Dynamic Stiffness ◽  
Maxwell Model ◽  
Viscosity Coefficient ◽  
Rheological Models ◽  
Zener Model ◽  
Dynamic Stretching ◽  
Input Parameters ◽  
Voigt Model ◽  
Stretching Process

Abstract The publication presents a theoretical study of the susceptibility of rheological models of threads to dynamic stretching in the context of modern, highly efficient textile technologies. Input parameters of the four analyzed models, the Kelvin-Voigt model, the Maxwell model, Standard model 2, and the Zener model, corresponded to the actual values of the coefficients of viscosity, elasticity, kinematic and dynamic loading, and stretching speed for the analyzed polyester silk threads produced in a knitting process, with knitting speeds from 700 to 1,600 courses/min. The research proves that the tested thread models behave differently in the stretching process-the Kelvin-Voigt model is sensitive to both the increases in kinematic loading and viscosity coefficient, Standard model 2 is only susceptible to dynamic stiffness, and the Zener model is significantly sensitive to kinematic loading. All responses of the models increase with the increase in stretching speeds. The obtained results indicate substantial “accuracy tolerance” in setting input parameters while identifying dynamics of the knitting process on warp-knitting machines.

NUMERICAL AND ULTRASONIC EXPERIMENTAL SIMULATIONS OF ELASTIC WAVE PROPAGATION AROUND HOLLOW CYLINDER

2012 ◽  
Vol 20 (02) ◽  
pp. 1240008 ◽  
Author(s):  
M. PERTON ◽  
F. J. SÁNCHEZ-SESMA ◽  
J. H. SPURLIN ◽  
E. FLORES ◽  
M. NAVARRETE ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Analytical Approach ◽  
Maxwell Model ◽  
Wave Number ◽  
Experimental Setup ◽  
Arrival Times ◽  
Voigt Model ◽  
Sonic Logging ◽  
Reduced Scale ◽  
Good Agreement

A laser-ultrasonic experimental setup was used to study, at a reduced scale, the wave propagation inside and around fluid-filled wells. Simulations tools were also developed and calibrated from comparisons with experimental signals. These tools serve as a connection to realistic scale. A semi-analytical approach, the discrete wave number method was first used to compute signals in a simplified geometrical configuration. This method is fast enough to be used in the identification of the main parameters that describe at best the experimental signals. Then a finite difference scheme was implemented in order to describe accurately the actual well. The two methods describe the attenuation mechanisms by using the Kelvin–Voigt model for the solid and the Maxwell model for the fluid. Comparisons between numerical and experimental waveforms, obtained in the two fundamental elastic configurations: the fast and the slow formations, show very good agreement in arrival times, waveforms and relative amplitudes. This satisfactory result provides insights useful for the recognition and interpretation of wave propagation in complex media. Such is the case of modern sonic-logging technology.

Modelling One-Dimensional Fractional Impact Using Basic Fractional Viscoelastic Models

2016 ◽  
Author(s):  
Arman Dabiri ◽  
Eric A. Butcher ◽  
Morad Nazari
Keyword(s):  
Maxwell Model ◽  
Viscoelastic Materials ◽  
One Dimensional ◽  
Viscoelastic Models ◽  
Depth Separation ◽  
Voigt Model ◽  
Impact Problems ◽  
Force Displacement ◽  
Enormous Number ◽  
Impact Models

Viscoelastic materials can be mathematically represented using integer- or order models. It has been shown in different studies that modeling a viscoelastic material usually requires an enormous number of parameters. Fractional viscoelastic models have been shown to be advantageous over integer viscoelastic models in the representation of viscoelastic materials, specifically when the system has memory or hereditary property. However, to the authors’ knowledge, no study has yet been done about fractional impact models. Thus, in this paper, fractional modified Kelvin-Voigt model and fractional Maxwell model are introduced as one-dimensional fractional impact models for basic fractional viscoelastic materials. The force-displacement hysteresis curves are obtained by using the fractional Chebyshev collocation method and the gradient of impact force, penetration depth, separation depth, and the coefficient of restitution are studies. It is shown numerically that fractional viscoelastic models behave more realistic than their integer counterparts in one-dimensional impact problems.

scholarly journals Mechanical Models of Pattern and Form in Biological Tissues: The Role of Stress–Strain Constitutive Equations

2021 ◽  
Vol 83 (7) ◽  
Author(s):  
Chiara Villa ◽  
Mark A. J. Chaplain ◽  
Alf Gerisch ◽  
Tommaso Lorenzi
Keyword(s):  
Pattern Formation ◽  
Balance Equation ◽  
Constitutive Equations ◽  
Constitutive Models ◽  
Maxwell Model ◽  
Biological Tissues ◽  
Force Balance ◽  
Stress Strain ◽  
Stress Strain Relation ◽  
Voigt Model

AbstractMechanical and mechanochemical models of pattern formation in biological tissues have been used to study a variety of biomedical systems, particularly in developmental biology, and describe the physical interactions between cells and their local surroundings. These models in their original form consist of a balance equation for the cell density, a balance equation for the density of the extracellular matrix (ECM), and a force-balance equation describing the mechanical equilibrium of the cell-ECM system. Under the assumption that the cell-ECM system can be regarded as an isotropic linear viscoelastic material, the force-balance equation is often defined using the Kelvin–Voigt model of linear viscoelasticity to represent the stress–strain relation of the ECM. However, due to the multifaceted bio-physical nature of the ECM constituents, there are rheological aspects that cannot be effectively captured by this model and, therefore, depending on the pattern formation process and the type of biological tissue considered, other constitutive models of linear viscoelasticity may be better suited. In this paper, we systematically assess the pattern formation potential of different stress–strain constitutive equations for the ECM within a mechanical model of pattern formation in biological tissues. The results obtained through linear stability analysis and the dispersion relations derived therefrom support the idea that fluid-like constitutive models, such as the Maxwell model and the Jeffrey model, have a pattern formation potential much higher than solid-like models, such as the Kelvin–Voigt model and the standard linear solid model. This is confirmed by the results of numerical simulations, which demonstrate that, all else being equal, spatial patterns emerge in the case where the Maxwell model is used to represent the stress–strain relation of the ECM, while no patterns are observed when the Kelvin–Voigt model is employed. Our findings suggest that further empirical work is required to acquire detailed quantitative information on the mechanical properties of components of the ECM in different biological tissues in order to furnish mechanical and mechanochemical models of pattern formation with stress–strain constitutive equations for the ECM that provide a more faithful representation of the underlying tissue rheology.

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