Showing papers on "Micromechanics published in 2010"
TL;DR: In this paper, the effect of fiber, matrix and interface properties on the in-plane shear response of carbon-fiber reinforced epoxy laminates was studied by means of a combination of experiments and numerical simulations.
255 citations
TL;DR: In this paper, a variational principle is formulated for the yield criterion of the effective medium and specialized to a spheroidal representative volume element containing a confocal sgeroidal void and subjected to uniform boundary deformation.
Abstract: Plastic constitutive relations are derived for a class of anisotropic porous materials consisting of coaxial spheroidal voids, arbitrarily oriented relative to the embedding orthotropic matrix. The derivations are based on nonlinear homogenization, limit analysis and micromechanics. A variational principle is formulated for the yield criterion of the effective medium and specialized to a spheroidal representative volume element containing a confocal spheroidal void and subjected to uniform boundary deformation. To obtain closed form equations for the effective yield locus, approximations are introduced in the limit-analysis based on a restricted set of admissible microscopic velocity fields. Evolution laws are also derived for the microstructure, defined in terms of void volume fraction, aspect ratio and orientation, using material incompressibility and Eshelby-like concentration tensors. The new yield criterion is an extension of the well known isotropic Gurson model. It also extends previous analyses of uncoupled effects of void shape and material anisotropy on the effective plastic behavior of solids containing voids. Preliminary comparisons with finite element calculations of voided cells show that the model captures non-trivial effects of anisotropy heretofore not picked up by void growth models.
175 citations
TL;DR: A critical survey on homogenization theory and related techniques applied to micromechanics is presented and the classical as well as the emerging analytical and computational techniques are presented.
Abstract: In this paper, we present a critical survey on homogenization theory and related techniques applied to micromechanics. The validation of homogenization results, the characterization of composite materials and the optimal design of complex structures are issues of great technological importance and are viewed here as a combination of mathematical and mechanical homogenization. The mathematical tools for modeling sequentially layered composites are explained. The influence of initial and boundary conditions on the effective properties in nonlinear problems is clarified and the notion of stability by homogenization is analyzed. Multiscale micromechanics methods are outlined and the classical as well as the emerging analytical and computational techniques are presented. Computation of effective static and dynamical properties of materials with linear or nonlinear constitutive equations is closely related to the development of generalized theories such as the strain-gradient mechanics. Selected applications of these techniques are outlined. Moreover, the extension of kinetic techniques in homogenization and the related inverse imaging problem are presented.
174 citations
TL;DR: In this paper, a critical review of the current work of experiment, theory of micro-nanomechanics, and numerical analysis on characterizing mechanical properties of nanocomposites is presented.
Abstract: This paper presents a critical review of the current work of experiment, theory of micro-nanomechanics, and numerical analysis on characterizing mechanical properties of nanocomposites. First, the classifications of nanomaterials are presented. Then nanoindentation testing and the corresponding finite element modeling are discussed, followed by analytical modeling stiffness of nanocomposites. The analytical models discussed include Voigt and Reuss bounds, Hashin and Shtrikman bounds, Halpin–Tsai model, Cox model, and various Mori and Tanaka models. These micromechanics models predict stiffness of nanocomposites with both aligned and randomly oriented fibers. The emphasis is on numerical modeling includes molecular dynamics modeling and finite element modeling. Three different approaches are discussed in finite element modeling, i.e. multiscale representative volume element (RVE) modeling, unit cell modeling, and object-oriented modeling. Finally, the mechanism of nanocomposite mechanical property enhancement and the ways to improve stiffness and fracture toughness for nanocomposites are discussed.
160 citations
TL;DR: In this paper, the authors investigate the stiffening effect of graphene sheets dispersed in polymer nanocomposites using the Mori-Tanaka micromechanics method and show that a very low content of graphene sheet can considerably enhance the effective stiffness of the composite.
Abstract: We investigate the stiffening effect of graphene sheets dispersed in polymer nanocomposites using the Mori–Tanaka micromechanics method. The effective elastic moduli of graphene sheet-reinforced composites are first predicted by assuming that all the graphene sheets are either aligned or randomly oriented in the polymer matrix while maintaining their platelet-like shape. It is shown that a very low content of graphene sheets can considerably enhance the effective stiffness of the composite. The superiority of graphene sheets as a kind of reinforcement is further verified by a comparison with carbon nanotubes, another promising nanofiller in polymer composites. In addition, we analyze several critical physical mechanisms that may affect the reinforcing effects, including the agglomeration, stacking-up and rolling-up of graphene sheets. The results reveal the extent to which these factors will negatively influence the elastic moduli of graphene sheet-reinforced nanocomposites. This theoretical study may help to understand the relevant experimental results and facilitate the mechanical characterization and optimal synthesis of these kinds of novel and highly promising nanocomposites.
155 citations
TL;DR: In this article, the authors developed a model treating the limestone as a dual porosity medium, with the total porosity partitioned between macroporosity and microporeosity, and they derived an analytic approximation for the unconfined compressive strength associated with failure due to the propagation and coalescence of poreemanated cracks.
Abstract: [1] The analysis of compactant failure in carbonate formations hinges upon a fundamental understanding of the mechanics of inelastic compaction. Microstructural observations indicate that pore collapse in a limestone initiates at the larger pores, and microcracking dominates the deformation in the periphery of a collapsed pore. To capture these micromechanical processes, we developed a model treating the limestone as a dual porosity medium, with the total porosity partitioned between macroporosity and microporosity. The representative volume element is made up of a large pore which is surrounded by an effective medium containing the microporosity. Cataclastic yielding of this effective medium obeys the Mohr-Coulomb or Drucker-Prager criterion, with failure parameters dependent on porosity and pore size. An analytic approximation was derived for the unconfined compressive strength associated with failure due to the propagation and coalescence of pore-emanated cracks. For hydrostatic loading, identical theoretical results for the pore collapse pressure were obtained using the Mohr-Coulomb or Drucker-Prager criterion. For nonhydrostatic loading, the stress state at the onset of shear-enhanced compaction was predicted to fall on a linear cap according to the Mohr-Coulomb criterion. In contrast, nonlinear caps in qualitative agreement with laboratory data were predicted using the Drucker-Prager criterion. Our micromechanical model implies that the effective medium is significantly stronger and relatively pressure-insensitive in comparison to the bulk sample.
152 citations
TL;DR: In this paper, the surface treatment and sizing of reinforcing fibres used for manufacturing composites is discussed. And the role of the interphase in the micromechanics of the failure of fiber composites are also modelled and discussed in an attempt to provide design guidelines for composite manufacture.
Abstract: This paper reviews the surface treatment and sizing of reinforcing fibres used for manufacturing composites. Carbon fibre surface treatment and coating is discussed primarily to identify the mechanism of interphase formation. In this case, adsorption of sizing polymers is shown to be an integral part of the interaction with matrix polymers. ToFSIMS imaging was used to identify the locus of failure and confirm the nature of the interphase. In the case of glass fibres the hydrolysis of the silane coupling agent is shown to be critical. The surface chemistry of the glass controls the degree of polymerisation of the polysiloxane and hence the interaction with the matrix polymer whether it be thermoplastic or thermoset. For completeness a brief review of the surface treatments of advanced polymer fibres is also included. The role of the interphase in the micromechanics of the failure of fibre composites is also modelled and discussed in an attempt to provide design guidelines for composite manufacture.
149 citations
TL;DR: In this paper, the tensile behavior of embedded short carbon nanotubes (CNTs) in a polymer matrix in presence of van der Waals (vdW) interaction as inter-phase region is studied.
135 citations
TL;DR: In this paper, the authors derived a boundary integral expression for calculating Eshelby's tensor field (ETF) in the context of two-dimensional isotropic elasticity and obtained the explicit expressions of ETF and its average for a wide variety of non-elliptical inclusions including arbitrary polygonal ones.
Abstract: The Eshelby problem consists in determining the strain field of an infinite linearly elastic homogeneous medium due to a uniform eigenstrain prescribed over a subdomain, called inclusion, of the medium. The salient feature of Eshelby's solution for an ellipsoidal inclusion is that the strain tensor field inside the latter is uniform. This uniformity has the important consequence that the solution to the fundamental problem of determination of the strain field in an infinite linearly elastic homogeneous medium containing an embedded ellipsoidal inhomogeneity and subjected to remote uniform loading can be readily deduced from Eshelby's solution for an ellipsoidal inclusion upon imposing appropriate uniform eigenstrains. Based on this result, most of the existing micromechanics schemes dedicated to estimating the effective properties of inhomogeneous materials have been nevertheless applied to a number of materials of practical interest where inhomogeneities are in reality non-ellipsoidal. Aiming to examine the validity of the ellipsoidal approximation of inhomogeneities underlying various micromechanics schemes, we first derive a new boundary integral expression for calculating Eshelby's tensor field (ETF) in the context of two-dimensional isotropic elasticity. The simple and compact structure of the new boundary integral expression leads us to obtain the explicit expressions of ETF and its average for a wide variety of non-elliptical inclusions including arbitrary polygonal ones and those characterized by the finite Laurent series. In light of these new analytical results, we show that: (i) the elliptical approximation to the average of ETF is valid for a convex non-elliptical inclusion but becomes inacceptable for a non-convex non-elliptical inclusion; (ii) in general, the Eshelby tensor field inside a non-elliptical inclusion is quite non-uniform and cannot be replaced by its average; (iii) the substitution of the generalized Eshelby tensor involved in various micromechanics schemes by the average Eshelby tensor for non-elliptical inhomogeneities is in general inadmissible.
125 citations
Book•
08 Dec 2010
TL;DR: Computational models for failure in cohesive-frictional materials with stochastically distributed imperfections have been proposed by as mentioned in this paper, where the authors investigate the relationship between grain size distribution and shear banding in sand.
Abstract: Computational models for failure in cohesive-frictional materials with stochastically distributed imperfections.- Modeling of localized damage and fracture in quasibrittle materials.- Microplane modelling and particle modelling of cohesive-frictional materials.- Short-term creep of shotcrete - thermochemoplastic material modelling and nonlinear analysis of a laboratory test and of a NATM excavation by the Finite Element Method.- Thermo-poro-mechanics of rapid fault shearing.- A view on the variational setting of micropolar continua.- Macromodelling of softening in non-cohesive soils.- An experimental investigation of the relationships between grain size distribution and shear banding in sand.- Micromechanics of the elastic behaviour of granular materials.- On sticky-sphere assemblies.- Cohesive granular texture.- Micro-mechanisms of deformation in granular materials: experiments and numerical results.- Scaling properties of granular materials.- Discrete and continuum modelling of granular materials.- Difficulties and limitation of statistical homogenization in granular materials.- From discontinuous models towards a continuum description.- From solids to granulates - Discrete element simulations of fracture and fragmentation processes in geomaterials.- Microscopic modelling of granular materials taking into account particle rotations.- Microstructured materials: local constitutive equation with internal lenght, theoretical and numerical studies.- Damage in a composite material under combined mechanical and hygral load.
120 citations
TL;DR: In this paper, the development of physical and mechanical properties of a thermosetting composite which are relevant to the modelling of residual stresses and process induced deformations are discussed, and the results of previous work on cure kinetics and cure shrinkage of the composite are summarized.
Abstract: In this paper, the development of physical and mechanical properties of a thermosetting composite which are relevant to the modelling of residual stresses and process induced deformations are discussed. Findings of previous work on cure kinetics and cure shrinkage of the composite are summarized. The development of resin modulus throughout the Manufacturer’s Recommended Cure Cycle (MRCC) is modelled by Group Interaction Modelling (GIM). The moduli of AS4/8552 composite are calculated by two micromechanics methods: by an analytical approach based on the Self Consistent Field Micromechanics (SCFM) and by Finite Element Based Micromechanics (FEBM). The predictions show good agreement with the available experimental data and provide a fundamental understanding of how the properties of a thermoset resin and its composite develop through cure.
TL;DR: In this paper, a simple two-step finite element model is developed to predict the spring-in of C-sections parts made of AS4/8552 composite, and the development of resin properties throughout the MRCC were derived using Group Interaction Modelling and the mechanical properties of the composite predicted by using micromechanical models.
Abstract: In this study, a simple two step finite element model is developed to predict the spring-in of C-sections parts made of AS4/8552 composite. The development of resin properties throughout the MRCC were derived using Group Interaction Modelling and the mechanical properties of the composite predicted by using micromechanical models. Important mechanisms during manufacturing that are effective in the formation of residual stresses and shape distortions are defined. The finite element method implemented is composed of two steps before and after the vitrification of the resin. Vitrification is treated as a point at which the material suddenly changes from the rubbery to glassy state with constant properties in each state. The spring-in angles predicted by the finite element analysis are compared to the angles measured on C-section specimens of various lay-ups and thicknesses. The correlation is good showing the validity of the assumptions adopted.
TL;DR: In this article, a study of the micromechanics of granular materials as affected by the direct shear test scale using the discrete element method (DEM) is presented.
Abstract: This paper presents a study of the micromechanics of granular materials as affected by the direct shear test scale using the discrete element method (DEM). Parametric studies were conducted to investigate the effects of specimen length and height scales (in relation to the particle size) on the bulk material shear strength and shear banding behaviour in the direct shear test. A mesh-free strain calculation method previously developed by the authors was used to capture and visualise the evolution of strain localisation inside the direct shear box. Simulation results show that the maximum shear strength measured at the model boundaries increases with decreasing specimen length scale and increasing specimen height scale. Micromechanics-based analysis indicates that the local and global aspects of fabric change and failure are the major mechanisms responsible for the specimen scale effect. Global failure along the primary shear band prevails when the specimen length scale and length to height aspect ratio are...
TL;DR: The use of Raman spectroscopy to investigate micromechanical properties of laminated bacterial cellulose (BC)/poly(l-lactic) acid (PLLA) resin composites is reported for the first time as a means for understanding the fundamental stress-transfer processes in these composites, but also as a tool to select appropriate processing and volume fraction of the reinforcing fibers.
Abstract: Understanding the nature of the interface between nanofibers and polymer resins in composite materials is challenging because of the complexity of interactions that may occur between fibers and between the matrix and the fibers. The ability to select the most efficient amount of reinforcement for stress transfer, making a saving on both cost and weight, is also a key part of composite design. The use of Raman spectroscopy to investigate micromechanical properties of laminated bacterial cellulose (BC)/poly(l-lactic) acid (PLLA) resin composites is reported for the first time as a means for understanding the fundamental stress-transfer processes in these composites, but also as a tool to select appropriate processing and volume fraction of the reinforcing fibers. Two forms of BC networks are investigated, namely, one cultured for 3 days and another for 6 days. The mechanical properties of the latter were found to be higher than the former in terms of Young’s modulus, stress at failure, and work of fracture....
TL;DR: In this paper, a micromechanics-based damage model is proposed for the description of anisotropic damage and the normal opening of microcracks generated by the frictional sliding due to the roughness of crack surface is also considered.
TL;DR: In this paper, a simple procedure to determine the non-linear in-plane lamina shear response of laminated composites is presented, using the ±45° symmetric laminate tensile test results, in conjunction with computational micromechanics.
TL;DR: In this paper, the effect of surface/interface residual stress on the macroscopic plastic behaviors of nanoporous materials and nanocomposites was investigated, where both the surface and interface residual stress and surface-interface elasticity were taken into account.
TL;DR: In this paper, the effect of adhesion is smaller for particles with large aspect ratio compared to those with a small aspect ratio, and several micromechanical deformation processes may occur in PP/wood composites including matrix yielding, debonding, fiber pull-out and fiber fracture.
Abstract: Polypropylene (PP) was reinforced with four natural fillers having different particle characteristics. Interfacial adhesion was changed by the introduction of maleated polypropylene (MAPP). The properties of the studied PP/wood composites depended strongly on interfacial adhesion and on the particle characteristics of the wood. Coupling with functionalized polymer is necessary for the preparation of composites with acceptable properties if the size of the particles is large and their aspect ratio is small. The effect of adhesion is smaller for particles with large aspect ratio. Several micromechanical deformation processes may occur in PP/wood composites including matrix yielding, debonding, fiber pull-out and fiber fracture both parallel and perpendicular to the fiber axis. The processes are competitive and may take place simultaneously and/or consecutively. The inherent properties of the reinforcement may limit the improvement of composite strength. Micromechanical deformation processes determine composite properties irrespectively of their mechanism.
TL;DR: In this article, a new generic approach to achieving large strains in materials with high elastic moduli (5-30 GPa) was proposed, based on creating variable stiffness composite materials which exhibit a controllable change in elastic modulus (bending or axial) and large reversible strain accommodation.
Abstract: Reconfigurable and morphing structures may provide a range of new functionalities such as optimization over broad operational conditions and multi-mission capability. This article introduces a new generic approach to achieving large strains in materials with high elastic moduli (5-30 GPa). The work centers on creating variable stiffness composite materials which exhibit a controllable change in elastic modulus (bending or axial) and large reversible strains (5-15%). We have performed a simulation study to better understand the implication of various geometric design parameters on the elastic and deformation behavior. Using this information, a series of prototype materials were prepared using a commercial shape memory polymer, and measurements on these materials indicate a controllable change in stiffness as a function of temperature with large reversible strain accommodation. We have fabricated and tested several design variations of laminar morphing materials which exhibit structural stiffness values of ...
TL;DR: In this paper, a micromechanics-based constitutive model for granular materials under relatively low confining pressure is proposed, where local plastic sliding at each contact plane is described by a nonassociated plastic flow rule, taking into account pressure sensitivity and normal dilatancy.
TL;DR: The yield prediction capabilities of these models using four different yield criteria are investigated, and the spread in the predicted load between the isotropic and orthotropic material models is investigated.
Abstract: High-order finite-element (FE) analyses with inhomogeneous isotropic material properties have been shown to predict the strains and displacements on the surface of the proximal femur with high accuracy when compared with in vitro experiments. The same FE models with inhomogeneous orthotropic material properties produce results similar to those obtained with isotropic material properties. Herein, we investigate the yield prediction capabilities of these models using four different yield criteria, and the spread in the predicted load between the isotropic and orthotropic material models. Subject-specific high-order FE models of two human femurs were generated from CT scans with inhomogeneous orthotropic or isotropic material properties, and loaded by a simple compression force at the head. Computed strains and stresses by both the orthotropic and isotropic FE models were used to determine the load that predicts 'yielding' by four different 'yield criteria': von Mises, Drucker-Prager, maximum principal stress and maximum principal strain. One of the femurs was loaded by a simple load until fracture, and the force resulting in yielding was compared with the FE predicted force. The surface average of the 'maximum principal strain' criterion in conjunction with the orthotropic FE model best predicts both the yield force and fracture location compared with other criteria. There is a non-negligible influence on the predictions if orthotropic or isotropic material properties are applied to the FE model. All stress-based investigated 'yield criteria' have a small spread in the predicted failure. Because only one experiment was performed with a rather simplified loading configuration, the conclusions of this work cannot be claimed to be either reliable or sufficient, and future experiments should be performed to further substantiate the conclusions.
TL;DR: In this article, a simple method for accessing the elastic properties of microscopic deformable particles is presented, based on measuring the pressure-induced deformation of soft particles as they are forced through a tapered glass microcapillary.
Abstract: We present a simple method for accessing the elastic properties of microscopic deformable particles. This method is based on measuring the pressure-induced deformation of soft particles as they are forced through a tapered glass microcapillary. It allows us to determine both the compressive and the shear modulus of a deformable object in one single experiment. Measurements on a model system of poly-acrylamide microgel particles exhibit good agreement with measurements on bulk gels of identical composition. Our approach is applicable over a wide range of mechanical properties and should thus be a valuable tool for the characterization of a variety of soft and biological materials.
TL;DR: X-ray micro-computed tomography was used to discretize the three-dimensional structure of a commercial titanium foam used in spinal fusion devices to characterize the elasto-plastic deformation behavior.
TL;DR: In this article, a rational homogenization procedure based on transformation field analysis was proposed for determining the in-plane behavior of periodic masonry material. But the results of the proposed procedure were not compared with the results obtained by a nonlinear micromechanical finite element analysis.
Abstract: The paper deals with the problem of the determination of the in-plane behavior of periodic masonry material. The macromechanical equivalent Cosserat medium, which naturally accounts for the absolute size of the constituents, is derived by a rational homogenization procedure based on the Transformation Field Analysis. The micromechanical analysis is developed considering a Cauchy model for masonry components. In particular, a linear elastic constitutive relationship is considered for the blocks, while a nonlinear constitutive law is adopted for the mortar joints, accounting for the damage and friction phenomena occurring during the loading history. Some numerical applications are performed on a Representative Volume Element characterized by a selected commonly used texture, without performing at this stage structural analyses. A comparison between the results obtained adopting the proposed procedure and a nonlinear micromechanical Finite Element Analysis is presented. Moreover, the substantial differences in the nonlinear behavior of the homogenized Cosserat material model with respect to the classical Cauchy one, are illustrated.
TL;DR: In this paper, the deformation of granular materials with different grain shapes was simulated using two-dimensional DEM under different stress-levels and densities, and the evolution rule of stress-induced anisotropy and its limitation as well as the existence of a critical state of fabric were revealed.
Abstract: The mechanical behaviors of granular media are controlled by grain properties and microstructure. The primary property of granular media is denoted by its grain shape, grain size distribution, stiffness, and interparticle friction. The grain shape itself is of particular importance. Microstructures are formed in the connection paths of contact points between grains. In this paper, the deformation of granular materials with different grain shapes was simulated using two-dimensional DEM under different stress-levels and densities. After analyzing the results, the authors investigated fabric changes. The evolution rule of stress-induced anisotropy and its limitation as well as the existence of a critical state of fabric are revealed.
TL;DR: In this paper, a micromechanical finite element approach for the estimation of the effective Young's modulus of single-walled carbon nanotube reinforced composites is described.
Abstract: This paper describes a micromechanical finite element approach for the estimation of the effective Young’s modulus of single-walled carbon nanotube reinforced composites. These composite materials consist of aligned carbon nanotubes that are uniformly distributed within the matrix. Based on micromechanical theory, the Young’s modulus of the nanocomposite is estimated by considering a representative cylindrical volume element. Within the representative volume element, the reinforcement is modeled according to its atomistic microstructure while the matrix is modeled as a continuum medium. Spring-based finite elements are employed to simulate the discrete geometric structure and behavior of each single-walled carbon nanotube. The load transfer conditions between the carbon nanotubes and the matrix are modeled using joint elements of changeable stiffness that connect the two materials, simulating the interfacial region. The proposed model has been tested numerically and yields reasonable results for variable stiffness values of the joint elements. The effect of the interface on the performance of the composite is investigated for various volume fractions. The numerical results are compared with experimental and analytical predictions.
TL;DR: Ghabezloo et al. as mentioned in this paper used a macro-scale experimental study performed on a hardened class G cement paste for evaluation of the complete set of poroelastic parameters of the material.
TL;DR: In this article, a method for quasi-static homogenization of granular microstructures and its embedding into two-scale simulations is presented, where the interparticle contact mechanisms between particles are governed by a Coulomb-type frictional contact.
Abstract: The paper presents a new method for quasi-static homogenization of granular microstructures and its embedding into two-scale simulations. On the coarse scale, a homogenized standard continuum is considered where the granular microstructures are locally attached at each point. These representative volumes are defined by aggregates of discrete solid particles, which may come into contact. On the micromechanical side, the interparticle contact mechanisms between particles is governed by a Coulomb-type frictional contact. In particular, elliptical-shaped plane particles are investigated. A consistent extension of classical stiff, soft and periodic boundary conditions from continuous to granular microstructures induce new classes of micro-to-macro transitions for granular aggregates. These include constraints not only for particle center displacements but also for particle rotations at a driving boundary frame. The stiff and soft constraints at the driving frame of the particle aggregate induce upper and lower bounds of the particle aggregate's stiffness. On the computational side, we outline a unified implementation of the displacement and rotational constraints by penalty methods that proves to be convenient for straightforward integration into discrete element codes. Representative numerical examples with elliptical-shaped particles are investigated, where the macroscopic stress responses for different boundary constraints are comparatively discussed. Finally, we embed the granular microstructures into a coarse graining discrete-to-finite element model, where they govern the micromechanical behavior of a two-scale simulation. Copyright © 2010 John Wiley & Sons, Ltd.
Dissertation•
27 May 2010
TL;DR: In this paper, an experimental, analytical and numerical analysis of steel fiber reinforced self-compacting concrete (SFRSCC) was carried out to obtain a consistent comprehension of the behaviour of this composite material and to collect data for the calibration of the analytical formulations and FEM-based numerical models developed in scope of this research program.
Abstract: The use of steel fibre reinforced self-compacting concrete, SFRSCC, probably, will swiftly increase in the next years, since this composite material introduces several advantages on the concrete technology. In fact, the partial or total replacement of the conventional bar reinforcement by discrete fibres optimizes the construction process. The assembly of the reinforcement bars in the construction of concrete structures has a significant economic impact on the final cost of this type of constructions, due to the man-labour time consuming that it requires. In the modern societies, the cost of the man-labour is significant, so diminishing the man-labour will decrease the overall cost of the construction. In the fresh state, SFRSCC homogeneously spreads due to its own weight, without any additional compaction energy. Driven by its own weight, the concrete has to fill a mould completely without leaving entrapped air, even in the presence of dense steel bar reinforcement. Due to these reasons, SFRSCC is a very promising construction material with a high potential of application, mainly in the cases where fibres can replace the conventional reinforcement. At the present time, however, the SFRSCC technology is not yet fully developed and controlled, and, much less, the mechanical behaviour of the SFRSCC material. The present work aims to increase the knowledge in these areas. Therefore, experimental, analytical and numerical research was carried out. The main purpose was to achieve, as much as possible, a consistent comprehension of the behaviour of this composite material, and to collect data for the calibration of the analytical formulations and FEM-based numerical models developed in scope of this research program. The experimental research covers aspects from distinct scale levels. At a micro-level, the micromechanics aspects of fibre reinforcement are analysed, while at a meso-level, the fibre distribution structure into the hardened concrete is key aspect investigated. The research carried out at a micro/meso level enables to have a deeper understanding of the multiple reinforcement mechanisms and factors that influence the overall composite behaviour at a macro-level. Finally, at a macro-level, the composite mechanical behaviour, namely, the compressive, flexural and uniaxial tensile behaviour is assessed. The gathered experimental information at the distinct studied scale levels enables to acquire a deeper knowledge of the multiple reinforcement mechanisms involved. Finally, an integrated numerical approach was developed, which based on the fibres’ micro-mechanical properties, is able of predicting the mechanical properties of fibre reinforced composites.
TL;DR: In this article, the authors describe an experimental procedure to validate micromechanical models focusing on their global and local thermo-mechanical responses. But the experimental data are used to validate a finite element simulation in which a dislocation-based model of FCC single crystal behavior is implemented.