Differential quasivariational inequalities in contact mechanics

2018 ◽  
Vol 24 (3) ◽  
pp. 845-861 ◽  
Author(s):  
Zhenhai Liu ◽  
Mircea Sofonea
Keyword(s):  
Contact Mechanics ◽  
Contact Problems ◽  
Quasivariational Inequality ◽  
Quasivariational Inequalities ◽  
Abstract Result ◽  
New Class ◽  
Physical Setting ◽  
Uniqueness Of The Solution ◽  
The Mathematical Model ◽  
Weak Solvability

We consider a new class of differential quasivariational inequalities, i.e. a nonlinear system that couples a differential equation with a time-dependent quasivariational inequality, both defined on abstract Banach spaces. We state and prove a general fixed principle that provides the existence and the uniqueness of the solution of the system. Then we consider a relevant particular setting for which our abstract result holds. We proceed with two examples that arise in Contact Mechanics. For each example, we describe the physical setting, the mathematical model and the assumption on the data. Then we state the variational formulation of each model, which is in the form of a differential quasivariational inequality. Finally, we apply our abstract results to provide the unique weak solvability of the corresponding contact problems.

scholarly journals A class of parabolic evolutionary quasivariational inequalities in contact mechanics

2020 ◽  
Vol 36 (1) ◽  
pp. 45-47
Author(s):  
CHEN TAO ◽  
HUANG NAN-JING ◽  
XIAO YI-BIN
Keyword(s):  
Contact Mechanics ◽  
Existence And Uniqueness ◽  
Quasivariational Inequality ◽  
Quasivariational Inequalities ◽  
Mild Conditions ◽  
Element Free Galerkin ◽  
Uniqueness Of The Solution ◽  
Spatial Approximation ◽  
Element Free ◽  
Forward Euler

In this paper, we obtain an existence and uniqueness of the solution for a class of parabolic evolutionary quasivariational inequalities in contact mechanics under some mild conditions. We also study an error estimate for the parabolic evolutionary quasivariational inequality by employing the forward Euler difference scheme and the element-free Galerkin spatial approximation.

scholarly journals Existence Results for General Mixed Quasivariational Inequalities

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Muhammad Aslam Noor ◽  
Khalida Inayat Noor
Keyword(s):  
Variational Inequality ◽  
Existence Results ◽  
Quasivariational Inequality ◽  
Quasivariational Inequalities ◽  
Auxiliary Principle ◽  
Existence Of A Solution ◽  
Auxiliary Principle Technique ◽  
New Class ◽  
Special Cases

We consider and study a new class of variational inequality, which is called the general mixed quasivariational inequality. We use the auxiliary principle technique to study the existence of a solution of the general mixed quasivariational inequality. Several special cases are also discussed. Results proved in this paper may stimulate further research in this area.

scholarly journals CONTACT PROBLEMS FOR NONLINEARLY ELASTIC MATERIALS: WEAK SOLVABILITY INVOLVING DUAL LAGRANGE MULTIPLIERS

2010 ◽  
Vol 52 (2) ◽  
pp. 160-178 ◽  
Author(s):  
A. MATEI ◽  
R. CIURCEA
Keyword(s):  
Lagrange Multipliers ◽  
Variational Equation ◽  
Small Deformation ◽  
Contact Problems ◽  
Point Theory ◽  
The Body ◽  
Elastic Materials ◽  
Weak Formulation ◽  
Nonlinearly Elastic ◽  
Weak Solvability

AbstractA class of problems modelling the contact between nonlinearly elastic materials and rigid foundations is analysed for static processes under the small deformation hypothesis. In the present paper, the contact between the body and the foundation can be frictional bilateral or frictionless unilateral. For every mechanical problem in the class considered, we derive a weak formulation consisting of a nonlinear variational equation and a variational inequality involving dual Lagrange multipliers. The weak solvability of the models is established by using saddle-point theory and a fixed-point technique. This approach is useful for the development of efficient algorithms for approximating weak solutions.

SENSITIVITY ANALYSIS AND IDENTIFIABILITY OF A MATHEMATICAL MODEL OF A CHEMICAL REACTION

2021 ◽  
pp. 14-18
Author(s):  
Л.Ф. Сафиуллина
Keyword(s):  
Mathematical Model ◽  
Inverse Problem ◽  
Sensitivity Analysis ◽  
Chemical Reaction ◽  
Reaction Model ◽  
Numerical Calculations ◽  
Specific Reaction ◽  
Uniqueness Of The Solution ◽  
The Mathematical Model ◽  
Kinetics Of

В статье рассмотрен вопрос идентифицируемости математической модели кинетики химической реакции. В процессе решения обратной задачи по оценке параметров модели, характеризующих процесс, нередко возникает вопрос неединственности решения. На примере конкретной реакции продемонстрирована необходимость проводить анализ идентифицируемости модели перед проведением численных расчетов по определению параметров модели химической реакции. The identifiability of the mathematical model of the kinetics of a chemical reaction is investigated in the article. In the process of solving the inverse problem of estimating the parameters of the model, the question arises of the non-uniqueness of the solution. On the example of a specific reaction, the need to analyze the identifiability of the model before carrying out numerical calculations to determine the parameters of the reaction model was demonstrated.

Damping and Bandgap Characteristics of a Viscoelastic Tensegrity Damper

2021 ◽  
pp. 1-47
Author(s):  
Mohamed Raafat ◽  
Amr Baz
Keyword(s):  
Mathematical Model ◽  
Material Characterization ◽  
Structural Vibrations ◽  
New Class ◽  
Structural Applications ◽  
Theoretical Predictions ◽  
Specific Frequency ◽  
The Mathematical Model ◽  
Theory And Experiments

Abstract A theoretical and experimental investigation of a new class of a tensegrity-based structural damper is presented. The damper is not only capable of attenuating undesirable structural vibrations, as all conventional dampers, but also capable of completely blocking the transmission of vibration over specific frequency bands by virtue of its periodicity. Such dual functionality distinguishes the tensegrity damper over its counterparts of existing structural dampers. Particular emphasis is placed here in presenting the concept and developing the mathematical model of the dynamics of a unit cell the damper. The model is then coupled with a Floquet-Bloch analysis in order to identify the bandgap characteristics of the damper. The predictions of the mathematical model are validated experimentally using a prototype of the damper which is built using 3D printing. A comprehensive material characterization of the damper is performed followed by a detailed extraction of the static and dynamic behavior of the damper in order to validate the theoretical predictions. Close agreement is observed between theory and experiments. The developed theoretical and experimental techniques provide invaluable means for the design of this new class of dampers particularly for critical structural applications.

On the Singularities in Fracture and Contact Mechanics

2008 ◽  
Vol 75 (5) ◽  
Author(s):  
Fazil Erdogan ◽  
Murat Ozturk
Keyword(s):  
Contact Mechanics ◽  
Integral Equations ◽  
Mixed Boundary ◽  
Complex Function ◽  
Three Dimensional ◽  
Contact Problems ◽  
Cauchy Kernel ◽  
Square Root ◽  
Complex Function Theory ◽  
Graded Materials

Generally, the mixed boundary value problems in fracture and contact mechanics may be formulated in terms of integral equations. Through a careful asymptotic analysis of the kernels and by separating nonintegrable singular parts, the unique features of the unknown functions can then be recovered. In mechanics and potential theory, a characteristic feature of these singular kernels is the Cauchy singularity. In the absence of other nonintegrable kernels, Cauchy kernel would give a square-root or conventional singularity. On the other hand, if the kernels contain, in addition to a Cauchy singularity, other nonintegrable singular terms, the application of the complex function theory would show that the solution has a non-square-root or unconventional singularity. In this article, some typical examples from crack and contact mechanics demonstrating unique applications of such integral equations will be described. After some remarks on three-dimensional singularities, the key examples considered will include the generalized Cauchy kernels, membrane and sliding contact mechanics, coupled crack-contact problems, and crack and contact problems in graded materials.

Numerical analysis of history-dependent variational–hemivariational inequalities with applications to contact problems

2015 ◽  
Vol 26 (4) ◽  
pp. 427-452 ◽  
Author(s):  
MIRCEA SOFONEA ◽  
WEIMIN HAN ◽  
STANISŁAW MIGÓRSKI
Keyword(s):  
Numerical Analysis ◽  
Real World ◽  
Viscoelastic Body ◽  
Contact Problems ◽  
Uniqueness Result ◽  
Constitutive Law ◽  
Hemivariational Inequalities ◽  
New Class ◽  
Nonlinear Anal ◽  
Dependence Result

A new class of history-dependent variational–hemivariational inequalities was recently studied in Migórski et al. (2015Nonlinear Anal. Ser. B: Real World Appl.22, 604–618). There, an existence and uniqueness result was proved and used in the study of a mathematical model which describes the contact between a viscoelastic body and an obstacle. The aim of this paper is to continue the analysis of the inequalities introduced in Migórski et al. (2015Nonlinear Anal. Ser. B: Real World Appl.22, 604–618) and to provide their numerical analysis. We start with a continuous dependence result. Then we introduce numerical schemes to solve the inequalities and derive error estimates. We apply the results to a quasistatic frictional contact problem in which the material is modelled with a viscoelastic constitutive law, the contact is given in the form of normal compliance, and friction is described with a total slip-dependent version of Coulomb's law.

Direct Current/Alternating Current Magnetohydrodynamic Micropump of a Hybrid Nanofluid Through a Vertical Annulus With Heat Transfer

2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Y. A. S. El-Masry ◽  
Y. Abd Elmaboud ◽  
M. A. Abdel-Sattar
Keyword(s):  
Heat Transfer ◽  
Direct Current ◽  
Biomedical Applications ◽  
Alternating Current ◽  
Hybrid Nanofluid ◽  
Titanium Oxide Nanoparticles ◽  
New Class ◽  
The Laplace Transform ◽  
Vertical Annulus ◽  
The Mathematical Model

Abstract Gold nanoparticles (AuNPs) are increasingly being widely used in several biomedical applications for their compatibility of synthesis and less toxicity. The mixture of gold and titanium oxide nanoparticles is suspended in water to make a new class of nanofluid, which is called a hybrid nanofluid. The problem of direct current (DC)/alternating current (AC) magnetohydrodynamic (MHD) micropump of the hybrid nanofluid through a porous medium in the gap between vertical coaxial microtubes with heat transfer has been discussed. The mathematical model is established and then solved with the help of the Laplace transform. The inversion of the transformed functions is calculated numerically. The velocity, the flowrate, the pressure, and the heat transfer are discussed graphically. The higher concentration of the mixture of particles enhances the stream so that the required pressure is small. Moreover, it is found that the variation of the Nusselt number is noticeable by increasing the concentrations of nanoparticles, but this variation vanishes near the outer tube.

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