H. Dumontet

Sorbonne Université | UPMC · Institut Jean Le Rond d'Alembert (IJLRA) - UMR 7190

In this paper, we present an analytical model to analyze reinforced and prestressed concrete beams loaded in combined bending, axial load and shear, in the frame of non linear elasticity. In this model, the equilibrium of the beam is expressed by solving a system of equations, governing beams equilibrium, based on the stiffness matrix of the beam,...

This work aims at providing a multi-scale model to estimate the effective properties of hemp and lime concretes. The microstructures of such materials are characterized by a relatively high filling rate, platy orthotropic particles distributed on a wide range of spatial directions, and a high level of porosity at meso and micro scales. An iterative...

This paper describes research done on a new testing device including its laboratory test procedure; namely, a laboratory punching test for cementitious backfill materials that evaluates their excavatability with a pick. Three-dimensional and two-dimensional numerical studies using a finite element method were carried out according to calibrated par...

Proper design of fibre reinforced polymer (FRP) retrofitted concrete columns requires an appropriate concrete model that describes both confinement sensitivity (i.e increase of the strength and ductility) and dilation characteristic of concrete under the triaxial stress state. In this paper, a confinement-sensitive damage plasticity model for concr...

A new stress resultant nonlinear dissipative constitutive model for reinforced concrete (RC) plates under cyclic solicitations is presented. This constitutive model, named DHRC for Dissipative Homogenised Reinforced Concrete, is expressed within the usual thin plate kinematics framework. It is built by a periodic homogenisation approach using the a...

The present paper is devoted to the proposal of a theoretical formulation for an isotropic damage model with strain gradient. The approach is based on the non-local estimates of Drugan and Willis [1], exposed in terms of energetic methods, for the purpose of damage modelling. We first focus on the derivation of the non-local constitutive equations...

Cette communication synthètise les premières étapes d’un travail de modélisation numérique du comportement des structures en béton armé confiées par des armatures externes en Polymères Rrenforcés de Fibres (PRF). Le comportement du béton y est décrit à l’aide d’un modèle de plasticité couplé à l’endommagement implanté dans le code aux éléments fini...

In this paper, we present an analytical model to analyze reinforced and prestressed concrete beams loaded in combined bending, axial load and shear, in the frame of non linear elasticity. In this model, the equilibrium of the beam is expressed by solving a system of equations, governing beams equilibrium, based on the stiffness matrix of the beam,...

We propose in this work a model for monitoring the behavior of non-linear elasticity of concrete in both compression and tension until the break. This model is determined by applying the principles of damage mechanics and fracture using the actual laws of nonlinear behavior usually admitted in the continuous mechanics of materials (Sargin relations...

This work is based on a dual approach of experiments and micromechanical modeling in order to characterize the failure behaviors of lightweight aggregate concretes (LWAC). Many classes of LWAC were tested, based on five families of lightweight aggregates (LWA) and three types of mortar matrices: normal, high performance (HP) and very high performan...

The flexural behavior of reinforced concrete beams is a well-known problem. In the classical studies about this subject, shear strength is neglected or taken into account by simple formula from the linear theory of elasticity, neglecting flexure and shear interaction. For this reason, these classical methods allow to predict only the flexural fract...

A new stress resultant constitutive model for reinforced concrete plates under cyclic solicitations is presented. This model is built by the periodic homogenisation approach using the averaging method and couples damage of concrete and periodic debonding between concrete and steel rebar. In one-dimensional situations, we derive a closed-form soluti...

Pick excavatability of controlled low-strength materials was experimentally studied to circumvent the fact that current classification systems or empirical excavatability criteria lack relevance (they do not refer to digging facilities and depend on the mix design and the granular skeleton of the material). Manual excavation is separated into two s...

11e Colloque National en Calcul des Structures 13-17 Mai 2013 1 Modèle DHRC de comportement non linéaire de plaques en béton armé sous sollicitations sismiques. Résumé — Un nouveau modèle de comportement, appelé « Dissipative Homogenized Reinforced Concrete (DHRC) model », pour les plaques en béton armé sous sollicitations sismiques est présenté. C...

The aim of this paper is to study the cement paste dehydration effects on the thermo-hydro-mechanical behavior (THM) of concrete at high temperatures. The mathematical formulations of the THM model based on the mechanics of unsaturated porous material are described. The dehydration effects are illustrated by a comparison between experiment and simu...

This paper presents the construction of a global model of reinforced concrete plates dedicated to structures (slabs, walls…) subjected to low and moderate seismic solicitations, formulated according to the Generalized Standard Materials theory [5]. Regarding the context imposed by the applications considered one can identify three main objectives:...

This paper deals with a non-linear micromechanical modeling of hemp and lime concretes based on a iterative multi-scale method derived from the differential scheme and including FEM solving procedures for local problems. The ability of the model to account for the influence of the morphology of shives thanks to FEM simulations is first tested in a...

A damage model for geomaterials and concrete is proposed. This model expresses the anisotropic character induced by the degradation of material. The law of behavior obtained by differentiation of the free energy shows the dissymmetry effect observed in traction–compression loading and the residual strains caused by the damage. The present approach...

A numerical multiscale model is proposed to study the thermo-hydro-mechanical behaviour of cement-based materials. This model is based on a finite element approach coupled to a numerical generation of the material microstructure. A homogenization method is used to calculate the macroscopic thermo-hydro-mechanical properties and the macroscopic hydr...

An approach which combines both experimental techniques and micromechanical modelling is developed in order to characterise the elastic behaviour of lightweight aggregate concretes (LWAC). More than three hundred LWAC specimens with various lightweight aggregate types (5) of several volume ratios and three different mortar matrices (normal, HP, VHP...

In order to determine the role of reinforcement–matrix interfaces in the infiltration of water molecules within a composite material, we introduced a very thin layer that was highly diffusive and trapping between reinforcements and matrix. A finite element discretization of such an extremely thin surface layer poses numerical difficulties. To resol...

The influence of lightweight expanded clay and shale aggregates on the mechanical performances of concrete is studied through their volume fractions and aggregate qualities. A very thorough characterisation of a series of LWAs is completed. The impact of aggregates is not only related to its particle density but also to the shell thickness, the per...

This research is part of a thesis which consists in defining the excavatability of Controlled Low-Strength Materials for trenches (not exceeding 8 MPa). This communication deals with a mortar containing a high volume of air entrained and a cementitious granular material which are both self-compacting. We present their composition and the characteri...

In this paper, an iterative homogenization method is proposed in order to predict the behavior of polydispersed materials. Various families of heterogeneities according to their geometrical or mechanical properties are progressively introduced into a volume of matrix. At each step, the behavior of intermediate medium is obtained by any analytical h...

The aim of this study is to investigate and to simulate damage mechanisms of concrete under fire conditions. A micro-mechanical model has been developed by coupling the effective moduli approach with a finite element model based on the representation of the heterogeneous materials random microstructure. Numerical simulations have been carried out i...

This paper deals with the mechanical behaviour of a sand grouted with a cement-based grout. The injected sand is viewed as a composite material comprising two distinct phases: the initial granular soil and the solidified grout matrix which cements the grains together. As a result, a multiscale modelling approach, the homogenization method of period...

An iterative homogenization approach is proposed in order to predict the nonlinear hydro-mechanical behaviour of porous media. This process is coupled to classical and modified secant extended methods and linear homogenization predictive schemes. At convergence of the iterative process, same equivalent behaviour is obtained for any secant method, a...

The aerated concrete manufacturing process consists in the creation of macro porosity in a micro-mortar matrix with the help of an expansive agent (aluminum powder), which reacts with the water and the lime liberated by the hydration of the binder. Theoretical studies previously conducted on the idealization of aerated concrete have shown that its...

This article presents a numerical method of homogenization in thermo-hydro-mechanic for materials based on the choice of a representative volume in which heterogeneities are generated in random process. The numerical model is used to predict elastic behaviour as well as thermal damage behaviour and the concrete permeability. This numerical model is...

In previous works an homogenization iterative approach has been successfully proposed to predict the linear behavior of reinforced and porous materials. This homogenization process consists to construct the Representative Elementary Volume of the heterogeneous media, by adding gradually to the matrix, low heterogeneity proportions until reaching th...

The modelling of hydromechanical behavior of clayey sediments by homogenization theory is described. The rheological model of clays buried in depth requires a three-dimensional approach and laboratory experiments to quantify the model parameters. An iterative process which can be coupled to any homogenization method is used to model the porous medi...

In this paper the macroscopic elastic properties of injected or cemented sands are derived from the characteristics of the constituents and the analysis of the microstructure using a multi-scale modelling approach. Particular interest is given to the choice of the representative elementary volume, by relying on existing microstructural data. The pe...

This article presents a digital method of homogenization in thermoelasticity based on the choice of a representative volume of the building material. Heterogeneities are generated in a random process. This numerical model developed by Mounajed is implemented in the general finite element code 'SYMPHONIE' of the CSTB. This stochastic method is appli...

: This paper reports the results of a research activity concerning the hygro mechanical behavior and the estimation of the lifetime of syntactic foams used as isolator of immersed oil risers. A multi-scale simplified approach was adopted based on the self-consistent method. An iterative process is also proposed to extend the field of validity of th...

Here, the development of two types of models for describing the transition behaviours of interfacial regions such as interlayers in laminated composites has been presented. The first model is defined based on physical considerations, using a spatial function continuously varying/describing the graded properties of the interlayer, for example, in th...

Two interface models based on physical considerations are proposed to analyze the freeedge effects in unidirectional multilayered composites. The first model is a transition behavior law describing the graded properties of the interlayer between two adjacent layers. It is defined according to the stacking direction and based on a microscopic analys...

This paper presents the results obtained with the simulations of a sandwich rectangular plate made of carbon/epoxy composite when subjected to temperature and humidity cycles. Fickian diffusion process, moisture transport along the interfaces and damage caused by slipping and debonding between the components of the microscopic structure are conside...

Dimensioning of slender structures in reinforced concrete requires study of their global stability. This stability must take into account both types of non linearity: the physical one, which concerns the non linearity of concrete behaviour and the geometric one, which results from the study of the structure on its deformed configuration. The method...

This study deals with the modelling of the mechanical behaviour of an anisotropic porous material made up of ellipsoidal pores uniaxially oriented according to the geometric parameters that characterize porosity. To do so we used a homogenization technique based on the finite element method and the coupling of porosity parameters was taken into acc...

Two interface models are presented using the physical considerations to analyze the free-edge effects in unidirectional multilayered composites. The first model is developed using transition spatial evolution behavior law, defined for an interlayer according to the stacking direction. It is based on a microscopic analysis of the fiber distribution...

The LHC, the next machine to be developed at CERN, will be the first accelerator to collide the quark and gluon constitutents of protons at TeV energies (ten times higher than ever achieved before). The high energy frontier will be explored by two proton-proton detectors, ATLAS and CMS. Their task will be the identification and extremely precise en...

After presenting shortly the main results of the homogenization theory for periodic media, we give two applications related to damage evaluation and simulation for composite materials: (i) simulation of the evolution of damage by fibre rupture in a unidirectional composite, involving parameters defined on the microscale; and (ii) prediction of debo...

We consider an elastic stratified material with a periodic structure and we calculate the local stresses near a free boundary. Assuming that the microscopic displacements and stresses are periodic in the direction of the stratification, an homogenization method gives an approximation of the micro-stresses within the material. Since this approximati...

: The problem of free edge effects is examined with a special emphasis on the interlayer modelling. Currently observed in such materials, the interlayer is constituted by a resin enrichment and a specific fiber distribution which confer to the interlayer a continuous/diffuse behavior. Realistic models have then been developed in order to describe t...

The following extended summary will expose a numerical model using the finite element method to evaluate the concrete homogenized behavior. In this present paper, we describe the model and some results on the damage evolution of a High Strength Concrete subjected to thermal loads.