Continuum Modelling and Analysis of a Class of One and Two Dimensional Elastic Metamaterials with Local Rotation

Continuum Modelling and Analysis of a Class of One and Two Dimensional Elastic Metamaterials with Local Rotation
Author: Antonio J. Schiavone
Publisher:
Total Pages: 0
Release: 2022
Genre: Continuum mechanics
ISBN:

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The group of materials classified as "metamaterials" have accrued great interest in the scientific community as of late for their potential to revolutionize several multidisciplinary applications. Metamaterials are defined as synthetic/man-made materials which have been engineered to possess a number of desired unusual, and often counterintuitive properties which do not occur naturally. The inception of metamaterials into engineering science was in the field of optics when a material exhibiting an apparent negative index of refraction was designed. Following this, so-called "optical metamaterials" were researched and implemented in the field of electromagnetic cloaking, as well as utilized to design superlenses with sub-wavelength resolution. Recently a subclass of metamaterials known as elastic metamaterials has become of great interest to engineering scientists. This is a large class of materials which exhibits one or more unusual elastic properties such as negative Poisson's ratio, negative effective stiffness, negative shear modulus, and many more. Elastic metamaterials have potential for application in the fields of impact mitigation, shock absorption, wave attenuation, energy shielding, and wave guiding, to name a few.\\ In order to facilitate the use of this new class of materials, it is of paramount importance to possess the ability to predict the behaviour of these materials under specific, as well as sufficiently general loading conditions. There are two main ways to do this; the first of which is experimentally, through trial and error, and the second is analytically by creating a mathematical model capable of predicting both material behaviour and effective properties under specific loading conditions. This thesis will focus on the latter method.\\ There exists a myriad of mathematical techniques for material characterization, some of these techniques include homogenization methods, unit cell design, discrete modelling, and continuum modelling. This thesis will focus on the continuum modelling of a class of elastic metamaterials with local rotational effects. Typically, when local effects need to be considered in the framework of a continuum, the micropolar continuum model is the first avenue people explore. In this thesis it will be shown that this model is incapable of capturing all of the salient features present in both one, and two dimensional elastic metamaterials belonging to this class.\\ In this thesis a series of continuum models are developed with increasing generality. First, in the third chapter, a micropolar-type continuum model is derived for a specific one-dimensional double negative metamaterial capable of exhibiting negative mass and/or negative modulus under certain loading frequencies when subject to harmonic loads. This is done by analyzing a discrete structure, obtaining the equations of motion, and then making a continuous approximation to bring the discrete model to the continuum framework. This model is used to evaluate the transient response of a specific one-dimensional semi-infinite elastic metamaterial when subject to an axial impact. In the fourth chapter, a higher order continuum model is developed in a manner very similar to the methodology presented in the third chapter, but with a higher order derivative of the rotational variable $\theta$. This model is then generalized to an entire class of materials, even though it is developed using a representative discrete structure. Harmonic wave propagation is then studied in the same one-dimensional elastic metamaterial that was modelled in the third chapter using this new model, leading to the determination of the stop and passing bands, as well as the determination of the dispersion relation governing the wave propagation. This new model is then compared to both the model in the third chapter, as well as the discrete model to determine the range of suitability. In the fifth chapter a model for a two-dimensional class of elastic metamaterials with local rotation is developed in a slightly different way than in the previous two chapters. In this chapter a set of constitutive laws for the relevant class of materials is proposed, and then a representative discrete metamaterial is modelled, and approximated as a continuum to prove suitability of the model. This model is then used to study harmonic longitudinal (P) and transverse (S) wave propagation in the material, which covers all cases of general two-dimensional wave propagation. The stop and passing bands, as well as the dispersion relations were determined for both wave propagation schemes and the effect of local rotation was analyzed. The sixth chapter uses the model developed in the fifth chapter to study surface wave propagation in a new continuum with local rotation. The dispersion relation of the surface wave is obtained, as well as expressions for the decay parameters, $b1$ and $b2$. The behaviour of the general dispersion relation, as well as some simplified cases are investigated. It is found that surface waves propagating through a continuum with local rotation are dispersive even when the local rotational effects are small compared to the translational ones. Two parameters governing general wave propagation, $f$ and $g$ are identified. The parameter $f$ controls the height of frequency peaks in the dispersion relation, and the parameter $g$ controls the location of the second peak. Furthermore, for values of $f \approx 1$ or greater, surface waves are found to propagate with wavespeeds significantly lower than $c_R$, a phenomenon unique to this continuum. Finally, the motion of the particles residing on the surface of this continuum is determined to be elliptical when subject to surface wave propagation, similar to classical Rayleigh wave propagation.

Structural Modeling of Metamaterials

Structural Modeling of Metamaterials
Author: Vladimir I. Erofeev
Publisher: Springer Nature
Total Pages: 222
Release: 2020-11-13
Genre: Technology & Engineering
ISBN: 303060330X

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This book discusses the theoretical foundations of the structural modeling method applied to metamaterials. This method takes into account the parameters of the crystal lattice, the size of the medium particles, as well as their shape and constants of force interactions between them. It provides mathematical models of metamaterials that offer insights into the qualitative influence of the local structure on the effective elastic moduli of the considered medium and into performing theoretical estimations of these quantities. This book is useful for researchers working in the fields of solid mechanics, physical acoustics, and condensed matter physics, as well as for graduate and postgraduate students studying mathematical modeling methods.

Discrete and Continuum Models for Complex Metamaterials

Discrete and Continuum Models for Complex Metamaterials
Author: Francesco dell'Isola
Publisher: Cambridge University Press
Total Pages: 409
Release: 2020-03-12
Genre: Science
ISBN: 1107087732

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Explores the relationship between discrete and continuum mechanics as a tool to model new and complex metamaterials. Including a comprehensive bibliography and historical review of the field, and a pedagogical mathematical treatment, it is ideal for graduate students and researchers in mechanical and civil engineering, and materials science.

Continuum Methods of Physical Modeling

Continuum Methods of Physical Modeling
Author: Kolumban Hutter
Publisher: Springer Science & Business Media
Total Pages: 645
Release: 2013-11-11
Genre: Science
ISBN: 3662064022

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The book unifies classical continuum mechanics and turbulence modeling, i.e. the same fundamental concepts are used to derive model equations for material behaviour and turbulence closure and complements these with methods of dimensional analysis. The intention is to equip the reader with the ability to understand the complex nonlinear modeling in material behaviour and turbulence closure as well as to derive or invent his own models. Examples are mostly taken from environmental physics and geophysics.

Continuum Mechanics Modeling of Material Behavior

Continuum Mechanics Modeling of Material Behavior
Author: Martin H. Sadd
Publisher: Academic Press
Total Pages: 432
Release: 2018-03-31
Genre: Technology & Engineering
ISBN: 0128116498

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Continuum Mechanics Modeling of Material Behavior offers a uniquely comprehensive introduction to topics like RVE theory, fabric tensor models, micropolar elasticity, elasticity with voids, nonlocal higher gradient elasticity and damage mechanics. Contemporary continuum mechanics research has been moving into areas of complex material microstructural behavior. Graduate students who are expected to do this type of research need a fundamental background beyond classical continuum theories. The book begins with several chapters that carefully and rigorously present mathematical preliminaries: kinematics of motion and deformation; force and stress measures; and general principles of mass, momentum and energy balance. The book then moves beyond other books by dedicating several chapters to constitutive equation development, exploring a wide collection of constitutive relations and developing the corresponding material model formulations. Such material behavior models include classical linear theories of elasticity, fluid mechanics, viscoelasticity and plasticity. Linear multiple field problems of thermoelasticity, poroelasticity and electoelasticity are also presented. Discussion of nonlinear theories of solids and fluids, including finite elasticity, nonlinear/non-Newtonian viscous fluids, and nonlinear viscoelastic materials are also given. Finally, several relatively new continuum theories based on incorporation of material microstructure are presented including: fabric tensor theories, micropolar elasticity, elasticity with voids, nonlocal higher gradient elasticity and damage mechanics. Offers a thorough, concise and organized presentation of continuum mechanics formulation Covers numerous applications in areas of contemporary continuum mechanics modeling, including micromechanical and multi-scale problems Integration and use of MATLAB software gives students more tools to solve, evaluate and plot problems under study Features extensive use of exercises, providing more material for student engagement and instructor presentation

Mathematical Modeling and Numerical Simulation in Continuum Mechanics

Mathematical Modeling and Numerical Simulation in Continuum Mechanics
Author: Ivo Babuska
Publisher: Springer Science & Business Media
Total Pages: 300
Release: 2012-12-06
Genre: Computers
ISBN: 3642562884

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The first international symposium on mathematical foundations of the finite element method was held at the University of Maryland in 1973. During the last three decades there has been great progress in the theory and practice of solving partial differential equations, and research has extended in various directions. Full-scale nonlinear problems have come within the range of nu merical simulation. The importance of mathematical modeling and analysis in science and engineering is steadily increasing. In addition, new possibili ties of analysing the reliability of computations have appeared. Many other developments have occurred: these are only the most noteworthy. This book is the record of the proceedings of the International Sympo sium on Mathematical Modeling and Numerical Simulation in Continuum Mechanics, held in Yamaguchi, Japan from 29 September to 3 October 2000. The topics covered by the symposium ranged from solids to fluids, and in cluded both mathematical and computational analysis of phenomena and algorithms. Twenty-one invited talks were delivered at the symposium. This volume includes almost all of them, and expresses aspects of the progress mentioned above. All the papers were individually refereed. We hope that this volume will be a stepping-stone for further developments in this field.

Continuum Mechanics and Linear Elasticity

Continuum Mechanics and Linear Elasticity
Author: Ciprian D. Coman
Publisher: Springer Nature
Total Pages: 519
Release: 2019-11-02
Genre: Technology & Engineering
ISBN: 9402417710

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This is an intermediate book for beginning postgraduate students and junior researchers, and offers up-to-date content on both continuum mechanics and elasticity. The material is self-contained and should provide readers sufficient working knowledge in both areas. Though the focus is primarily on vector and tensor calculus (the so-called coordinate-free approach), the more traditional index notation is used whenever it is deemed more sensible. With the increasing demand for continuum modeling in such diverse areas as mathematical biology and geology, it is imperative to have various approaches to continuum mechanics and elasticity. This book presents these subjects from an applied mathematics perspective. In particular, it extensively uses linear algebra and vector calculus to develop the fundamentals of both subjects in a way that requires minimal use of coordinates (so that beginning graduate students and junior researchers come to appreciate the power of the tensor notation).

Continuum Modeling in the Physical Sciences

Continuum Modeling in the Physical Sciences
Author: E. van Groesen
Publisher: SIAM
Total Pages: 238
Release: 2007-01-01
Genre: Mathematics
ISBN: 9780898718249

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Mathematical modeling - the ability to apply mathematical concepts and techniques to real-life systems has expanded considerably over the last decades, making it impossible to cover all of its aspects in one course or textbook. Continuum Modeling in the Physical Sciences provides an extensive exposition of the general principles and methods of this growing field with a focus on applications in the natural sciences. The authors present a thorough treatment of mathematical modeling from the elementary level to more advanced concepts. Most of the chapters are devoted to a discussion of central issues such as dimensional analysis, conservation principles, balance laws, constitutive relations, stability, robustness, and variational methods, and are accompanied by numerous real-life examples. Readers will benefit from the exercises placed throughout the text and the challenging problems sections found at the ends of several chapters.

Continuum Modeling

Continuum Modeling
Author: Adrian Muntean
Publisher: Springer
Total Pages: 83
Release: 2015-08-09
Genre: Mathematics
ISBN: 3319221329

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This book develops continuum modeling skills and approaches the topic from three sides: (1) derivation of global integral laws together with the associated local differential equations, (2) design of constitutive laws and (3) modeling boundary processes. The focus of this presentation lies on many practical examples covering aspects such as coupled flow, diffusion and reaction in porous media or microwave heating of a pizza, as well as traffic issues in bacterial colonies and energy harvesting from geothermal wells. The target audience comprises primarily graduate students in pure and applied mathematics as well as working practitioners in engineering who are faced by nonstandard rheological topics like those typically arising in the food industry.

Modeling Materials

Modeling Materials
Author: Ellad B. Tadmor
Publisher: Cambridge University Press
Total Pages: 789
Release: 2011-11-24
Genre: Science
ISBN: 1139500651

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Material properties emerge from phenomena on scales ranging from Angstroms to millimeters, and only a multiscale treatment can provide a complete understanding. Materials researchers must therefore understand fundamental concepts and techniques from different fields, and these are presented in a comprehensive and integrated fashion for the first time in this book. Incorporating continuum mechanics, quantum mechanics, statistical mechanics, atomistic simulations and multiscale techniques, the book explains many of the key theoretical ideas behind multiscale modeling. Classical topics are blended with new techniques to demonstrate the connections between different fields and highlight current research trends. Example applications drawn from modern research on the thermo-mechanical properties of crystalline solids are used as a unifying focus throughout the text. Together with its companion book, Continuum Mechanics and Thermodynamics (Cambridge University Press, 2011), this work presents the complete fundamentals of materials modeling for graduate students and researchers in physics, materials science, chemistry and engineering.