488 research outputs found
Multiscale mechanical modelling of complex materials and engineering applications 3
No full textP. TROVALUSCI, B. SCHREFLER, Foreword/
DUY KHANH TRINH, RALF JANICKE, NICOLAS AUFFRAY, STEFAN DIEBELS, SAMUEL FOREST, Evaluation of generalized continuum
substitution models for heterogeneous materials/
SWANTJE BARGMANN, BOB SVENDSEN, Rate variational continuum thermodynamic modeling and simulation of GND-based latent hardening in polycrystals/
DAVID GRÉGOIRE, LAURA B. ROJAS-SOLANO, GILLES PIJAUDIER-CABOT, Continuum to discontinuum transition during failure in non-local damage models/
M. BONGUE BOMA, L. SUDAK, S. FEDERICO, Gradient-dependent constitutive laws for a model of micro-cracked bodies/
IOANIS STEFANOU, JEAN SULEM, Micromorphic Continua: application to the homogenization of diatomic masonry columns/
ELISABETH AIGNER, ROMAN LACKNER AND JOSEF EBERHARDSTEINER, Multiscale viscoelastic-viscoplastic model for the prediction of
permanent deformation in
exible pavements/
DANIELA P.BOSO, M. LEFIK, Definition of the stiffness matrix
of a hierachial structure by using virtual testing and artificial neural network
Analisi con modelli tridimensionali del contatto non lineare, fra anelli di supporto dei circuiti poloidali, e volta toroidale della macchina RFX
No full textThermo-hydro-mechanical analysis of partially satured porous materials
No full textPresents a fully coupled numerical model to simulate the slow transient phenomena involving heat and mass transfer in deforming partially saturated porous materials. Makes use of the modified effective stress concept together with the capillary pressure relationship. Examines phase changes (evaporation-condensation(, heat transfer through conduction and convection, as well as latent heat transfer. The governing equations in terms of gas pressure, capillary pressure, temperature and displacements are coupled non-linear differential equations and are discretized by the finite element method in space and by finite differences in the time domain. The model is further validated with respect to a documented experiment on partially saturated soil behaviour, and the effects of two-phase flow, as compared to the one-phase flow solution, are analysed. Two other examples involving drying of a concrete wall and thermoelastic consolidation of partially saturated clay demonstrate the importance of proper physical modelling and of appropriate choice of the boundary conditions
Hygro-thermo-chemo-mechanical modelling of concrete at early ages and beyond. Part II: Shrinkage and creep of concrete
No full textIn Part I of this paper (Int. J. Numer Meth. Eng., in print) a mechanistic model of hygro-thermochemical performance of concrete at early ages has been introduced. Additionally, as compared to the existing models (e.g. J. Eng. Mech. (ASCE) 1995; 121(7):785-794; 1999; 125(9):1018-1027), an effect of relative humidity on cement hydration rate and associated hygro-thermal phenomena have been taken into account. Here we deal with mechanical performance of concrete at early ages and beyond, and in particular, evolution of its strength properties (aging) and deformations (shrinkage and creep strains), described by using the effective stress concept. This allow us for explanation and modelling of phenomena known from experiments, like drying creep (e.g. Mathematical Modeling of Creep and Shrinkage of Concrete. Wiley: Chichester, 1988), or some additional strains, as compared to pure shrinkage, which appear during autogenous deformations of a maturing, sealed concrete sample (e.g. Cement Concrete Res. 2003; 33:223-232). Creep is described by means of the modified microprestress-solidification theory by Bazant et al. (J. Eng. Mech. (ASCE) 1997; 123(11):1188-1194; 1195-1201), with some modifications to take into account the effects of temperature (Comput. Struct. 2002; 80:1511-1521) and relative humidity (Int. J Numer. Meth. Eng., in print; Proceedings of the 5th World Congress for Computational Mechanics (WCCM), Vienna, Austria, 7-12 July 2002), on concrete aging. Shrinkage strains are modelled by using the effective stress principle in the form introduced by Gray and Schrefler (Eur J. Mech. AlSolids 2001; 20:521-538; Appl. Mech. Rev. (ASME) 2002; 55(4):351-388), giving a good agreement with experimental data also for lower values of relative humidity.
Two numerical examples showing comparison of the results obtained by means of our model with some published experimental data are presented. The third one, concerning 2D axial symmetric case, proves numerical robustness of the developed software. All these examples demonstrate the possibilities of the model to analyse both autogenous deformations in maturing concrete and creep phenomena, including drying creep, in concrete elements of different age, sealed or drying, exposed to external load or without any load
Numerical modelling of concrete strains by means of effective stresses, with application to concrete at early ages and at high temperature
No full textEffect of LITS on assessment of the thermal spalling risk for HPC structures at high temperature
No full textNumerical analysis of hygro-thermic behaviour, stresses and damage of concrete at high temperature
No full textA computational analysis of hygro-thermal and mechanical behaviour of concrete structures at high temperature is presented. The evaluation of thermal, hygral and mechanical performance of this material, including damage effects, needs the knowledge of the heat and mass transfer processes. These are simulated within the framework of a coupled model where non-linearities due to high temperatures are accounted for. The constitutive equations are discussed in some detail. The discretization of the governing equations is carried out by Finite Elements in space and Finite Differences in time
A multiphase approach for a unified modelling of fully and partially saturated porous materials by considering air dissolved in water
No full textNumerical model of calcium leaching in cementitious materials, considering the process kinetics and advective calcium transport
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