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Characterization of the Mechanical Behavior of Hemp-Clay Composites

Haboubi Chaimae, Barhdadi El Hassane, Haboubi Khadija, Hammoudani Yahya El, Sadoune Zouhair, El Abdouni Aouatif, Dimane Fouad

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 2

71--77

EN

In the present study, micromechanical modeling techniques were employed to examine the mechanical properties of a hemp/clay composite material. This composite consists of hemp fibers incorporated into a clay matrix, a configuration chosen in response to environmental considerations and the natural advantages of hemp fibers, which include their lightweight nature and their considerable strength and stiffness relative to their weight. The approach adopted incorporates both localization and homogenization methodologies along with the three-phase model to provide an in-depth analysis of the composite's behavior. The findings from this theoretical model show a promising correlation with empirical data, demonstrating the model's efficacy in capturing the composite's mechanical response.

2

Modeling of polymer/clay nanocomposites by an iterative micromechanical approach

Mohyeddin A., Fereidoon A.

Archives of Mechanics

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2012

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Vol. 64, nr 6

541-554

EN

An iterative micromechanical method is presented in order to predict the elastic constants of composites and nanocomposites including arbitrarily oriented reinforcement particles. The proposed method is capable of introducing into the matrix any kind of heterogeneity based on its dimension, orientation, mechanical properties and volume fraction. The efficiency and convergence of solution method is studied by computing the elasticity tensor of a unidirectional particulate composite. It is then applied to model the elastic behavior of nylon-6/clay nanocomposite with taking into consideration the probability distribution of aspect ratio and orientation of effective particles. The results are validated by comparison with available experimental data.

3

Hyperelastic behavior of cellular structures based on micromechanical modeling at small strain

Janus-Michalska M.

Archives of Mechanics

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2011

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Vol. 63, nr 1

3-3

EN

The present paper extends recent effective, linear anisotropic elasticity model [6, 7] for cellular materials by implying geometric nonlinearity, which is built as the constitutive relation between Green’s Lagrangean strain in the tensor and the second Piola–Kirchhoff stress tensor and strain potential formulation. Cellular materials may easily experience large deformations due to large pores-to-volume ratio, since such a deformation on the macroscopic level usually requires smaller deformations of the individual struts constituting the skeleton. The formulation based on micromechanical modeling assumes that essential macroscopic features of mechanical behavior on a macro scale, can be inferred from the deformation response of a representative volume element. Open-cell materials with diverse regular skeleton structures are considered. The initial stiffness tensor components for anisotropic continuum are expressed as fuctions of microstructural parameters, such as skeleton geometric data of representative volume element and skeleton material properties. Since large strains in skeleton structure are characteristic for elasto-plastic behavior, interest is focused on the large displacement and small strain cases. Examples involving numerical tests on cellular materials under homogenoeous strain, relevant to simple shearing and to uniaxial or biaxial loading in the tensile and compressive range, are considered.

4

Effective models describing elastic behaviour of cellular materials

Janus-Michalska M.

Archives of Metallurgy and Materials

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2005

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Vol. 50, iss. 3

595-608

EN

The aim of this paper is to formulate an effective anisotropic continuum for cellular materials based on micromechanical modeling. It corresponds to recent trend, of searching for advanced materials tailored to special requirements, which is based on intrinsic relation between structure and macroscopic properties. Open-cell materials with diverse structures representing different types of symmetries are considered. It is assumed that essential macroscopic features of mechanical behaviour can be inferred from the deformation response of a representative volume element. The structural mechanics methods are applied for a beam model of skeleton. An analytical formulation of force-displacement relations for the skeleton struts is found by considering the affinity of nodal displacement in tensile, bending and shear deformations. The concept of multiscale modeling leads to formulation of equivalent continuum as an effective model. Such an approach is typical for micromechanics. The stiffness tensor may be produced for anisotropic solid depending on material properties of the solid phase and topological arrangement of a cellular structure using the micro-macro transition. The analysis based on the assumption of linear elasticity leads to the analytical solution. Graphical representation of choosen material constants is performed. The possibility to model the influence of morphology and topology parameters is studied. The proposed theoretical framework of micromechanical modeling can be extended to nonlinear behaviour, plasticity and failure analysis. For such problems numerical approach is required.

PL

Poszukiwanie nowych wielofunkcyjnych materiałów odpowiada najnowszym tendencjom tworzenia materiałów o założonych z góry własnościach w tym również własnościach mechanicznych. Takie modelowanie oparte jest na znajomości relacji pomiędzy strukturą wewnętrzną a własnościami materiału w skali makro. Ustalenie tych relacji jest podstawowym zadaniem, którego rozwiązanie prowadzi do skonstruowania modelu efektywnego. Obiektem rozważań są materiały komórkowe o komórkach otwartych, które tworzą szkielet mikrostruktury o regularnym przestrzennym układzie oraz pianki charakteryzujące się układem nieregularnym. Własności mechaniczne takich struktur można wyznaczyć w oparciu o szczegółową analizę komórki reprezentatywnej, z postaci której można wnioskować o symetrii materiału. W pracy zastosowano typową dla mikromechaniki koncepcję modelowania dwuskalowego, która prowadzi do sformułowania continuum zastepczego jako modelu efektywnego. Analizę kinematyczną w strukturze przeprowadzono przy spostrzeżeniu podobieństwa przemieszczeń względnych komórek dla jednorodnych stanów odkształceń materiału w skali makro. Szkielet struktury modelowano jako belkę Timoshenki wyprowadzając relacje siła-przemieszczenie w szkielecie poprzez sztywnosci osiowe i giętne belek. Dla określenia naprężenia efektywnego continuum zastosowano definicje uśrednionych naprężeń rzeczywistych w szkielecie. Powyższy algorytm pozwala wyznaczyć składowe tensora sztywności dla materiału anizotropowego jako funkcje sztywności elementów składowych i parametrów opisujących geometrię komórki reprezentatywnej. Praca zawiera prezentację graficzną wybranych stałych materiałowych dla poszczególnych struktur ze wskazaniem na możliwość modelowania wskazanych własności sprężystych materiału.