38 research outputs found
Finite element modelling of thermo-elasto-plastic multiphase porous materials
No full textThe numerical model is based on a fully coupled heat and multiphase flow model in deforming porous media. The porous medium is assumed to be a multiphase system where interstitial connected voids of the solid matrix may be filled with liquid water, water vapour and dry air. To handle this multiphase system, the general frame of averaging theories is used in deriving the governing equations. Phase changes of water (evaporation-condensation, adsorption-desorption) and heat transfer through conduction and convection, as well as latent heat transfer are considered.
The elasto-plastic behaviour of the solid skeleton is assumed homogeneous and isotropic; the effective stress state is limited by the temperature and capillary pressure dependent ACMEG-TS yield surface. The governing equations are discretized in space and time by means of the finite element method.
The numerical examples will show applications of the full set of equations. Validation of the implementation of the constitutive model is made by selected comparison between model simulation and experimental results for different combinations of thermo-hydro-mechanical loading paths. Coupled heat, water and gas flow in deforming porous media are validated against existing numerical solutions. Some cases of non-isothermal elasto-plastic consolidation of a soil column of Boom clay loaded by thermal, mechanical or environmental conditions are also studied. The coupled thermo-hydro-mechanical behaviour of the material caused by thermal and mechanical loads is analysed
Multi-physics modelling of thermo-elasto-plastic saturated/unsaturated porous materials
No full textThis paper presents a formulation for the computational analysis of thermo-elasto-plastic multiphase porous materials based on Porous Media Mechanics, with the aim to simulate geo-environmental engineering problems analysed as multi-physics coupled problems.
The numerical model is based on a fully coupled heat and multiphase flow model in deforming porous media. The porous medium is assumed to be a multiphase system where interstitial connected voids of the solid matrix may be filled with liquid water, water vapour and dry air. To handle this multiphase system, the general frame of averaging theories is used in deriving the governing equations. Phase changes of water (evaporation-condensation, adsorption-desorption) and heat transfer through conduction and convection, as well as latent heat transfer are considered.
The elasto-plastic behaviour of the solid skeleton is assumed homogeneous and isotropic; the effective stress state is limited by the temperature and capillary pressure dependent ACMEG-Ts yield surface. The governing equations are discretized in space and time by means of the finite element method.
The numerical examples will show applications of the full set of equations. In choosing the examples, validation of the model will be kept in mind. Validation of the implementation of the constitutive model is made by selected comparison between model simulation and experimental results for different combinations of thermo-hydro-mechanical loading paths. Coupled heat, water and gas flow in deforming porous media are validated against existing numerical solutions, e.g. [1]. The constitutive laws are validated against physical experiments in saturated and unsaturated conditions. Applications to the modelling of non-isothermal elasto-plastic consolidation at different partially saturated initial conditions or due to heating or desiccation are described
Multi-physics modelling of thermo-elasto-plastic multi-phase porous materials
No full textIn this work, the general ACMEG-TS thermo-elasto-plastic constitutive model for saturat-ed/unsaturated clayey soils has been implemented in the finite element code COMES-GEO for the analysis of non-isothermal saturated/partially saturated deformable porous materials.
The numerical model is based on a fully coupled heat and multiphase flow model in de-forming porous media. The porous medium is assumed to be a multiphase system where in-terstitial connected voids of the solid matrix may be filled with liquid water, water vapor and dry air. The general frame of averaging theories has been used in deriving the governing equations. Phase changes of water (evaporation-condensation, adsorption-desorption) and heat transfer through conduction and convection, as well as latent heat transfer are considered.
The elasto-plastic behavior of the solid skeleton is assumed homogeneous and isotropic; the effective stress state is limited by the temperature and capillary pressure dependent ACMEG-TS yield surface. The governing equations are discretized in space and time by means of the finite element method.
The numerical examples will show applications of the full set of equations. Validation of the implementation of the constitutive model is made by selected comparison between model simulation and experimental results for different combinations of thermo-hydro-mechanical loading paths. The non-isothermal elasto-plastic consolidation of a soil column of Boom clay loaded by thermal, mechanical or environmental conditions is studied, aiming to analyze the effects of the environmental loads on this material candidate for an underground nuclear waste storage facility
The Influence Of The Specimen Set-Up In The Measurement Of Sound Absorption In A Reverberant Room
No full textThermo-Elasto-Plastic Consolidation Analysis with Water Phase Change
No full textThe aim of this work is the numerical study of the thermal consolidation process in the framework of coupled thermo-hydro-mechanical (THM) behavior of soils including water phase change.
In recent years, increasing interest in thermo-hydro-mechanical analysis of saturated and partially saturated porous materials is observed, because of a wide spectrum of their engineering applications. An area of particular interest is Environmental Geomechanics, where some challenging problems are of interest. Examples are subsidence above gas reservoirs, injection of other fluids into deep or superficial aquifers, long-term storage of carbon dioxide, problems linked with soil failure such as the onset of flowslides and catastrophic landslides, problems connected with nuclear and other hazardous waste disposal and geothermal structures or groundwater.
In all the aforementioned situations, the soil or rock need to be considered as multiphase porous medium in isothermal or non-isothermal conditions, made of a solid phase and voids containing one or more fluids, in which the interaction between all the components of the material cannot be neglected. In case of liquid and gaseous fluids, capillary effects cannot be a priori neglected, and also phase change for liquid water and its vapor can play a role.
For enabling significant predictive simulations to be carried out, suitable physical and mathematical models have to be developed. Then, coupled Thermo-Hydro-Mechanical (THM) finite element codes are of paramount importance for simulation and analysis of geo-environmental engineering problems.
A step in the development of a suitable physical, mathematical and numerical model for the simulation of geo-environmental engineering problems is presented here. To this end, the general ACMEG-TS thermo-elasto-plastic constitutive model for saturated/unsaturated clayley soils, has been implemented in the finite element code COMES-GEO for the analysis of non-isothermal saturated/partially saturated deformable porous materials.
The numerical model is based on a fully coupled heat and multiphase flow model in deforming porous media. The porous medium is assumed to be a multiphase system where interstitial connected voids of the solid matrix may be filled with liquid water, water vapor and dry air. The general frame of averaging theories has been used in deriving the governing equations. Phase changes of water (evaporation-condensation, adsorption-desorption) and heat transfer through conduction and convection, as well as latent heat transfer are considered.
The elasto-plastic behavior of the solid skeleton is assumed homogeneous and isotropic; the effective stress state is limited by the temperature and capillary pressure dependent ACMEG-TS yield surface. The governing equations are discretized in space and time by means of the finite element method.
The numerical examples will show applications of the full set of equations. Coupled heat, water and gas flow in deforming porous media are validated against existing numerical solutions. The non-isothermal elasto-plastic consolidation of a soil column of Boom clay loaded by thermal, mechanical or environmental conditions is studied in detail, aiming to analyze the effects of the environmental loads on this material candidate for an underground nuclear waste storage facility. A case where the temperature is above the bowling value and water phase change develops is also studied
Finite element modelling of thermo-elasto-plastic multiphase porous materials
No full textThe aim of this paper is numerical analysis of the coupled hydro-thermo-mechanical (HTM) behavior of soils, considered as deformable multiphase porous materials. A fully coupled finite element model for non-isothermal elasto-plastic multiphase materials based on Porous Media Mechanics was therefore developed. In particular, the ACMEG-TS thermo-elastoplastic constitutive model for variably saturated clayey soils was implemented in the finite element COMES-GEO code for analysis of non-isothermal deformable multiphase porous materials. Numerical validation of the implemented model was carried out with selected simulations of various HTM loading paths. A case of non-isothermal consolidation of a soil column and the first results of the HTM behavior of a deep nuclear waste disposal site in case of failure of canisters are also shown
Finite element modelling of thermo-elasto-plastic unsaturated porous materials with application to nuclear waste disposal
No full textinfo:eu-repo/semantics/nonPublishe
Proposal for a reference floor for hollow brick and concrete slab based on Italian experiences
No full textThe estimation of acoustical performance of horizontal partitions, from the performance of elements and components using EN 12354 Standard do not actually provides satisfactory results when applied to the floors made by hollow brick and concrete beams, typical of Italian and Mediterranean area building technology. In this paper is reported an overview of measurements performed in situ, independently by different researchers, on various typology of hollow brick and concrete bare floors in several construction sites in different Italian regions. The purpose of this study is to identify an empirical spectrum of normalized sound pressure level of a reference floor realized in hollow brick and concrete in order to provide a useful and simple tool for estimating the noise performance of the most popular building technology of floor in Italy
Acoustical behaviour of bare floor in hollow brick and concrete (Italian building technology)
No full textThe estimation of impact sound insulation of horizontal partitions, evaluated from the performance of elements using EN 12354 Standard, do not actually provides satisfactory results when applied to the floors realized in hollow brick and concrete, typical of Italian building technology. Over the last years many comparisons between in situ measurements and empirical estimations have been made, both by Italian Universities and Research Institutes and by professionals and consultants, who have shown indisputably great differences between the results obtained through estimation models and the measured data. In this paper is reported an overview of measurements performed in situ, independently by different researchers, on various typology of hollow brick and concrete bare floors in several construction sites in different Italian regions. The purpose of this study is to identify an empirical spectrum of the normalized impact sound pressure level of a floor reference realized hollow brick and concrete in order to provide a useful and simple tool for estimate the noise performance of the most popular building technology of floor in Italy
Proposal for a reference floor for hollow brick and concrete slabs based on Italian experiences
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