Sonia Vrech - Academia.edu (original) (raw)
Papers by Sonia Vrech
Mecánica Computacional, 2016
In this work, the discontinuous bifurcation condition is evaluated for Recycled Aggregate Concret... more In this work, the discontinuous bifurcation condition is evaluated for Recycled Aggregate Concretes (RAC) in limit states by means of the description of the localization indicator, based on the acoustic or localization tensor. This is performed in the framework of a thermodynamically consistent non-local plasticity for quasi-brittle materials like concrete, based on gradient plasticity and fracture energy homogenization. Explicit solutions for brittle failure conditions are proposed in the form of discontinuous bifurcation and they provide relevant information regarding the variation of the transition point of brittle-ductile failure modes with the recycled aggregate content and confining pressure. Finally, numerical results demonstrate the performance of the localization indicator for different confinement pressures and recycled aggregate contents.
Mecánica Computacional, 2008
Resumen. El comportamiento de falla de materiales cuasi-frágiles como hormigones varía fuertemente
Mecánica Computacional, Nov 19, 2019
Journal of Applied Mechanics, 2006
In this work the geometrical method for the assessment of discontinuous bifurcation conditions is... more In this work the geometrical method for the assessment of discontinuous bifurcation conditions is extended to encompass gradient-dependent plasticity. To this end, the gradient-dependent localization condition is cast in the form of an elliptical envelope condition in the coordinates of Mohr. The results in this work demonstrate the capability of thermodynamically consistent gradient-dependent elastoplastic model formulations to suppress the localized failure modes of the classical plasticity that take place when the hardening/softening modulus H¯ equals the critical value for localization H¯c, provided the characteristic length l remains positive.
Mechanics Research Communications
En este trabajo se desarrolla el analisis analitico y geometrico de las propiedades de localizaci... more En este trabajo se desarrolla el analisis analitico y geometrico de las propiedades de localizacion del modelo constitutivo elastoplastico de Leon - Drucker-Prager (LDP) termodinamicamente consistente, para materiales cuasi-fragiles como el hormigon. Esta formulacion constitutiva basada en la teoria de gradientes y en conceptos de energia de fractura, incluye una longitud interna de gradientes que depende fuertemente del estado de presion hidrostatica y representa una medida del volumen del solido que participa en el proceso de degradacion. Esta propiedad permite predecir apropiada y precisamente la transicion del modo de falla fragil a ductil que caracteriza al comportamiento de los materiales cuasi-fragiles sometidos a niveles de confinamiento crecientes. Los resultados del analisis analitico y geometrico de los indicadores de localizacion de deformaciones ilustran la capacidad del modelo constitutivo elastoplastico LDP de reproducir modos de falla difusa para estados de compresion...
En este trabajo se presenta el proyecto de fabricacion de un dispositivo que integra un equipo de... more En este trabajo se presenta el proyecto de fabricacion de un dispositivo que integra un equipo de medicion de pulsos ultrasonicos y elementos electronicos para el calculo indirecto de los parametros elasticos: modulo de Young y coeficiente de Poisson, y de las propiedades mecanicas: resistencia a compresion y a traccion uniaxiales, mediante el analisis numerico de mediciones de la velocidad de una onda de 50 Khz a traves de los elementos del hormigon endurecido (probetas, vigas, columnas, etc). Mediante la programacion en C++ del microcontrolador se realizaran los calculos de los parametros elasticos y propiedades mecanicas con funciones de aproximacion propuestas para tal fin. La calibracion del equipamiento se realizara a partir de una serie de ensayos de laboratorio desarrollados en el marco de esta investigacion.
En los ultimos anos se han desarrollado numerosos modelos numericos para analizar elementos estru... more En los ultimos anos se han desarrollado numerosos modelos numericos para analizar elementos estructurales de hormigon, sin embargo es necesario profundizar el estudio del comportamiento del hormigon cuando este se fisura. El objetivo de este trabajo es reproducir numericamente la respuesta de elementos de hormigon simple, mediante tecnicas de Elementos Finitos Enriquecidos EFEM, con la adopcion de leyes cohesivas adecuadas para analizar la fisura. El presente modelo constitutivo se calibra a partir de los resultados de ensayos experimentales de probetas sometidas a traccion y flexion. La comparacion de los resultados numericos con los experimentales prueba la validez del modelo utilizado.
In this work, conditions for discontinuous bifurcation in limit states are derived and evaluated ... more In this work, conditions for discontinuous bifurcation in limit states are derived and evaluated in quasi - brittle materials like concrete, for variable stress states, loading conditions and high temperature scenarios . This is performed in the framework of a thermodynamically consistent non - local poroplastic constitutive theory for quasi - brittle materials subjected to high temperature [1]. Thereby, gradient poroplasticity and fracture energy - based homogenization are combined to describe the post peak behavior of porous media when subjected to long term exposure of temperature. For the numerical implementation of the model, the consistent tangent operator is developed and the dual mixed FE formulation for thermodynamically consistent gradient plasticity by Vrech and Etse [2] is considered, which was extended to porous media by Mroginski and Etse [3]. The explicit solutions for brittle failure conditions in the form of disco ntinuous bifurcation as well as the formulation for ...
El avance y desarrollo de la tecnologia de materiales cuasi-fragiles como hormigones con propieda... more El avance y desarrollo de la tecnologia de materiales cuasi-fragiles como hormigones con propiedades fisicas y quimicas mejoradas ha alcanzado en el presente niveles superlativos. Muchos de estos logros se deben en parte al estudio del comportamiento mecanico de los materiales. En el presente articulo se desarrollan aspectos teoricos de la simulacion computacional del comportamiento de falla de materiales cuasi-fragiles basada en la combinacion de metodos de elementos finitos y discretos, para ser aplicados en el modelado numerico de hormigones y morteros. En este sentido, se plantea el analisis de los aspectos teoricos mas relevantes con el objetivo de simular el comportamiento mecanico multiescala de materiales cuasifragiles a partir de la combinacion de dos metodos numerico-computacionales de probada eficiencia: el Metodo de los Elementos Finitos (MEF) a nivel macroscopico y el Metodo de los Elementos Discretos (MED) a nivel mesoscospico, logrando asi una herramienta numerica sup...
La rodilla es la articulacion mas grande en el cuerpo formada por estructuras oseas y cartilagino... more La rodilla es la articulacion mas grande en el cuerpo formada por estructuras oseas y cartilaginosas y soporta altos valores de cargas, de hasta varias veces el peso corporal. Es vulnerable a lesiones durante actividades deportivas y a condiciones degenerativas como la artrosis. Los medicos prescriben comunmente las rodilleras u ortesis para las patologias que involucran dolor y laxitud. En un trabajo anterior, Garcia Cabello (2017) propuso una ortesis de aluminio y acrilonitrilo butadieno estireno (ABS) para abaratar los costos de la misma al personalizarla mediante fabricacion con una impresora 3D. El presente trabajo representa una primera etapa en la evaluacion del comportamiento mecanico del prototipo de ortesis mencionado, realizada mediante simulaciones computacionales utilizando el Metodo Elementos Finitos (MEF). Se analizan los esfuerzos que soporta en el caso de lesiones de ligamentos laterales de rodilla con cargas verticales, laterales y combinadas. Como resultado, se ve...
En el presente trabajo se presenta el analisis analitico y geometrico de localizacion de deformac... more En el presente trabajo se presenta el analisis analitico y geometrico de localizacion de deformaciones plasticas en modelos de plasticidad regularizada mediante teoria de gradientes. A partir del metodo geometrico de localizacion, basado en la solucion analitica de la singularidad del tensor de localizacion, se determinan los parametros criticos de falla discontinua para diferentes estados tensionales. Se aplica al modelo material de von Mises. La representacion geometrica de la condicion de localizacion en las coordenadas de tensiones de Mohr, demuestra claramente las ventajas de la formulacion de gradientes en lo que respecta a su capacidad regularizante.
Conditions for discontinuous bifurcation in limit states of thermodynamically consistent micropla... more Conditions for discontinuous bifurcation in limit states of thermodynamically consistent microplane theory for cohesive-frictional materials like concrete are evaluated by means of analytical methods. Explicit solutions for brittle failure conditions in the form of discontinuous bifurcation are proposed. Numerical analysis are comparatively assessed for different limit stress states regarding both microplane and macroscopic response. Macroscopic critical values are computed by analytical and geometrical methods. The results in this work illustrate the capabilities of the thermodynamically consistent microplane theory to reproduce localized failure modes in uniaxial tension, uniaxial compression and simple shear regimes of cohesive-frictional materials like concrete.
International Journal of Fracture, 2018
This work focuses on the evaluation of temperature effects on concrete failure behavior and modes... more This work focuses on the evaluation of temperature effects on concrete failure behavior and modes by means of a realistic thermodynamically consistent non-local poroplastic constitutive model, previously developed by the authors, which is modified in this work. In this regard, two original contributions are presented and discussed. Firstly, and based on significant published experimental results related to this very complex aspect such as the effects of temperature in concrete failure, a temperature dependent non-associated flow rule is introduced to the poroplastic constitutive model to more accurately account for the temperature dependent inelastic volumetric behavior of concrete in post-peak regime. This is crucial for improving overall model accuracy, particularly regarding the temperature effects on concrete released energy during degradation processes. Secondly, and more importantly, the explicit solution of the localization condition in terms of the
Materials Science and Engineering: C, 2019
This article reviews the current state of the art of additive manufacturing techniques for the pr... more This article reviews the current state of the art of additive manufacturing techniques for the production of bone tissue engineering (BTE) scaffolds. The most well-known of these techniques include: stereolithography, selective laser sintering, fused deposition modelling and three-dimensional printing. This review analyses in detail the basic physical principles and main applications of these techniques and presents a list of biomaterials for BTE applications, including commercial trademarks. It also describes and compares the main advantages and disadvantages and explains the highlights of each additive manufacturing technique and their evolution. Finally, is discusses both their capabilities and limitations and proposes potential strategies to improve this field. Scaffold, Bone, Tissue Engineering, Additive Manufacturing
Computers & Structures, 2017
A gradient plasticity theory is extended to predict the mechanical failure behavior of concrete w... more A gradient plasticity theory is extended to predict the mechanical failure behavior of concrete with recycled aggregates. A relevant feature of the novel constitutive formulation is its full consistency with the thermodynamic laws regarding hardening and softening response behaviors. The proposed model includes a formulation of a maximum strength surface which is dependent on the recycled aggregate content. While the hardening law is formulated in the framework of classical-local elastoplasticity, the postpeak behavior is described by means of a non-local gradient and fracture-energy-based law. Thereby, the gradient and fracture-energy characteristic lengths are described in terms of the acting confining pressure and the recycled aggregate content. The formulation of the proposed constitutive theory is complemented by the description of the associated localization indicator, based on the acoustic or localization tensor. Finally, numerical results are presented to demonstrate the predictive capabilities of the proposed model and the performance of the localization indicator for different critical stresses and recycled aggregate contents.
Journal of Biomechanics, 2016
The vibrissal system of the rat refers to specialized hairs the animal uses for tactile sensory p... more The vibrissal system of the rat refers to specialized hairs the animal uses for tactile sensory perception. Rats actively move their whiskers in a characteristic way called "whisking". Interaction with the environment produces elastic deformation of the whiskers, generating mechanical signals in the whiskerfollicle complex. Advances in our understanding of the vibrissal complex biomechanics is of interest not only for the biological research field, but also for biomimetic approaches. The recent development of whisker numerical models has contributed to comprehending its sophisticated movements and its interactions with the follicle. The great diversity of behavioral patterns and complexities of the whiskerfollicle ensemble encouraged the creation of many different biomechanical models. This review analyzes most of the whisker biomechanical models that have been developed so far. This review was written so as to render it accessible to readers coming from different research areas.
Construction and Building Materials, 2016
h i g h l i g h t s A thermodynamically consistent gradient poroplastic model is proposed. The RA... more h i g h l i g h t s A thermodynamically consistent gradient poroplastic model is proposed. The RAC effect is considered by a concrete mixture recycling factor. Numerical results demonstrate good accuracy to predict failure behavior.
Mecánica Computacional, 2016
In this work, the discontinuous bifurcation condition is evaluated for Recycled Aggregate Concret... more In this work, the discontinuous bifurcation condition is evaluated for Recycled Aggregate Concretes (RAC) in limit states by means of the description of the localization indicator, based on the acoustic or localization tensor. This is performed in the framework of a thermodynamically consistent non-local plasticity for quasi-brittle materials like concrete, based on gradient plasticity and fracture energy homogenization. Explicit solutions for brittle failure conditions are proposed in the form of discontinuous bifurcation and they provide relevant information regarding the variation of the transition point of brittle-ductile failure modes with the recycled aggregate content and confining pressure. Finally, numerical results demonstrate the performance of the localization indicator for different confinement pressures and recycled aggregate contents.
Mecánica Computacional, 2008
Resumen. El comportamiento de falla de materiales cuasi-frágiles como hormigones varía fuertemente
Mecánica Computacional, Nov 19, 2019
Journal of Applied Mechanics, 2006
In this work the geometrical method for the assessment of discontinuous bifurcation conditions is... more In this work the geometrical method for the assessment of discontinuous bifurcation conditions is extended to encompass gradient-dependent plasticity. To this end, the gradient-dependent localization condition is cast in the form of an elliptical envelope condition in the coordinates of Mohr. The results in this work demonstrate the capability of thermodynamically consistent gradient-dependent elastoplastic model formulations to suppress the localized failure modes of the classical plasticity that take place when the hardening/softening modulus H¯ equals the critical value for localization H¯c, provided the characteristic length l remains positive.
Mechanics Research Communications
En este trabajo se desarrolla el analisis analitico y geometrico de las propiedades de localizaci... more En este trabajo se desarrolla el analisis analitico y geometrico de las propiedades de localizacion del modelo constitutivo elastoplastico de Leon - Drucker-Prager (LDP) termodinamicamente consistente, para materiales cuasi-fragiles como el hormigon. Esta formulacion constitutiva basada en la teoria de gradientes y en conceptos de energia de fractura, incluye una longitud interna de gradientes que depende fuertemente del estado de presion hidrostatica y representa una medida del volumen del solido que participa en el proceso de degradacion. Esta propiedad permite predecir apropiada y precisamente la transicion del modo de falla fragil a ductil que caracteriza al comportamiento de los materiales cuasi-fragiles sometidos a niveles de confinamiento crecientes. Los resultados del analisis analitico y geometrico de los indicadores de localizacion de deformaciones ilustran la capacidad del modelo constitutivo elastoplastico LDP de reproducir modos de falla difusa para estados de compresion...
En este trabajo se presenta el proyecto de fabricacion de un dispositivo que integra un equipo de... more En este trabajo se presenta el proyecto de fabricacion de un dispositivo que integra un equipo de medicion de pulsos ultrasonicos y elementos electronicos para el calculo indirecto de los parametros elasticos: modulo de Young y coeficiente de Poisson, y de las propiedades mecanicas: resistencia a compresion y a traccion uniaxiales, mediante el analisis numerico de mediciones de la velocidad de una onda de 50 Khz a traves de los elementos del hormigon endurecido (probetas, vigas, columnas, etc). Mediante la programacion en C++ del microcontrolador se realizaran los calculos de los parametros elasticos y propiedades mecanicas con funciones de aproximacion propuestas para tal fin. La calibracion del equipamiento se realizara a partir de una serie de ensayos de laboratorio desarrollados en el marco de esta investigacion.
En los ultimos anos se han desarrollado numerosos modelos numericos para analizar elementos estru... more En los ultimos anos se han desarrollado numerosos modelos numericos para analizar elementos estructurales de hormigon, sin embargo es necesario profundizar el estudio del comportamiento del hormigon cuando este se fisura. El objetivo de este trabajo es reproducir numericamente la respuesta de elementos de hormigon simple, mediante tecnicas de Elementos Finitos Enriquecidos EFEM, con la adopcion de leyes cohesivas adecuadas para analizar la fisura. El presente modelo constitutivo se calibra a partir de los resultados de ensayos experimentales de probetas sometidas a traccion y flexion. La comparacion de los resultados numericos con los experimentales prueba la validez del modelo utilizado.
In this work, conditions for discontinuous bifurcation in limit states are derived and evaluated ... more In this work, conditions for discontinuous bifurcation in limit states are derived and evaluated in quasi - brittle materials like concrete, for variable stress states, loading conditions and high temperature scenarios . This is performed in the framework of a thermodynamically consistent non - local poroplastic constitutive theory for quasi - brittle materials subjected to high temperature [1]. Thereby, gradient poroplasticity and fracture energy - based homogenization are combined to describe the post peak behavior of porous media when subjected to long term exposure of temperature. For the numerical implementation of the model, the consistent tangent operator is developed and the dual mixed FE formulation for thermodynamically consistent gradient plasticity by Vrech and Etse [2] is considered, which was extended to porous media by Mroginski and Etse [3]. The explicit solutions for brittle failure conditions in the form of disco ntinuous bifurcation as well as the formulation for ...
El avance y desarrollo de la tecnologia de materiales cuasi-fragiles como hormigones con propieda... more El avance y desarrollo de la tecnologia de materiales cuasi-fragiles como hormigones con propiedades fisicas y quimicas mejoradas ha alcanzado en el presente niveles superlativos. Muchos de estos logros se deben en parte al estudio del comportamiento mecanico de los materiales. En el presente articulo se desarrollan aspectos teoricos de la simulacion computacional del comportamiento de falla de materiales cuasi-fragiles basada en la combinacion de metodos de elementos finitos y discretos, para ser aplicados en el modelado numerico de hormigones y morteros. En este sentido, se plantea el analisis de los aspectos teoricos mas relevantes con el objetivo de simular el comportamiento mecanico multiescala de materiales cuasifragiles a partir de la combinacion de dos metodos numerico-computacionales de probada eficiencia: el Metodo de los Elementos Finitos (MEF) a nivel macroscopico y el Metodo de los Elementos Discretos (MED) a nivel mesoscospico, logrando asi una herramienta numerica sup...
La rodilla es la articulacion mas grande en el cuerpo formada por estructuras oseas y cartilagino... more La rodilla es la articulacion mas grande en el cuerpo formada por estructuras oseas y cartilaginosas y soporta altos valores de cargas, de hasta varias veces el peso corporal. Es vulnerable a lesiones durante actividades deportivas y a condiciones degenerativas como la artrosis. Los medicos prescriben comunmente las rodilleras u ortesis para las patologias que involucran dolor y laxitud. En un trabajo anterior, Garcia Cabello (2017) propuso una ortesis de aluminio y acrilonitrilo butadieno estireno (ABS) para abaratar los costos de la misma al personalizarla mediante fabricacion con una impresora 3D. El presente trabajo representa una primera etapa en la evaluacion del comportamiento mecanico del prototipo de ortesis mencionado, realizada mediante simulaciones computacionales utilizando el Metodo Elementos Finitos (MEF). Se analizan los esfuerzos que soporta en el caso de lesiones de ligamentos laterales de rodilla con cargas verticales, laterales y combinadas. Como resultado, se ve...
En el presente trabajo se presenta el analisis analitico y geometrico de localizacion de deformac... more En el presente trabajo se presenta el analisis analitico y geometrico de localizacion de deformaciones plasticas en modelos de plasticidad regularizada mediante teoria de gradientes. A partir del metodo geometrico de localizacion, basado en la solucion analitica de la singularidad del tensor de localizacion, se determinan los parametros criticos de falla discontinua para diferentes estados tensionales. Se aplica al modelo material de von Mises. La representacion geometrica de la condicion de localizacion en las coordenadas de tensiones de Mohr, demuestra claramente las ventajas de la formulacion de gradientes en lo que respecta a su capacidad regularizante.
Conditions for discontinuous bifurcation in limit states of thermodynamically consistent micropla... more Conditions for discontinuous bifurcation in limit states of thermodynamically consistent microplane theory for cohesive-frictional materials like concrete are evaluated by means of analytical methods. Explicit solutions for brittle failure conditions in the form of discontinuous bifurcation are proposed. Numerical analysis are comparatively assessed for different limit stress states regarding both microplane and macroscopic response. Macroscopic critical values are computed by analytical and geometrical methods. The results in this work illustrate the capabilities of the thermodynamically consistent microplane theory to reproduce localized failure modes in uniaxial tension, uniaxial compression and simple shear regimes of cohesive-frictional materials like concrete.
International Journal of Fracture, 2018
This work focuses on the evaluation of temperature effects on concrete failure behavior and modes... more This work focuses on the evaluation of temperature effects on concrete failure behavior and modes by means of a realistic thermodynamically consistent non-local poroplastic constitutive model, previously developed by the authors, which is modified in this work. In this regard, two original contributions are presented and discussed. Firstly, and based on significant published experimental results related to this very complex aspect such as the effects of temperature in concrete failure, a temperature dependent non-associated flow rule is introduced to the poroplastic constitutive model to more accurately account for the temperature dependent inelastic volumetric behavior of concrete in post-peak regime. This is crucial for improving overall model accuracy, particularly regarding the temperature effects on concrete released energy during degradation processes. Secondly, and more importantly, the explicit solution of the localization condition in terms of the
Materials Science and Engineering: C, 2019
This article reviews the current state of the art of additive manufacturing techniques for the pr... more This article reviews the current state of the art of additive manufacturing techniques for the production of bone tissue engineering (BTE) scaffolds. The most well-known of these techniques include: stereolithography, selective laser sintering, fused deposition modelling and three-dimensional printing. This review analyses in detail the basic physical principles and main applications of these techniques and presents a list of biomaterials for BTE applications, including commercial trademarks. It also describes and compares the main advantages and disadvantages and explains the highlights of each additive manufacturing technique and their evolution. Finally, is discusses both their capabilities and limitations and proposes potential strategies to improve this field. Scaffold, Bone, Tissue Engineering, Additive Manufacturing
Computers & Structures, 2017
A gradient plasticity theory is extended to predict the mechanical failure behavior of concrete w... more A gradient plasticity theory is extended to predict the mechanical failure behavior of concrete with recycled aggregates. A relevant feature of the novel constitutive formulation is its full consistency with the thermodynamic laws regarding hardening and softening response behaviors. The proposed model includes a formulation of a maximum strength surface which is dependent on the recycled aggregate content. While the hardening law is formulated in the framework of classical-local elastoplasticity, the postpeak behavior is described by means of a non-local gradient and fracture-energy-based law. Thereby, the gradient and fracture-energy characteristic lengths are described in terms of the acting confining pressure and the recycled aggregate content. The formulation of the proposed constitutive theory is complemented by the description of the associated localization indicator, based on the acoustic or localization tensor. Finally, numerical results are presented to demonstrate the predictive capabilities of the proposed model and the performance of the localization indicator for different critical stresses and recycled aggregate contents.
Journal of Biomechanics, 2016
The vibrissal system of the rat refers to specialized hairs the animal uses for tactile sensory p... more The vibrissal system of the rat refers to specialized hairs the animal uses for tactile sensory perception. Rats actively move their whiskers in a characteristic way called "whisking". Interaction with the environment produces elastic deformation of the whiskers, generating mechanical signals in the whiskerfollicle complex. Advances in our understanding of the vibrissal complex biomechanics is of interest not only for the biological research field, but also for biomimetic approaches. The recent development of whisker numerical models has contributed to comprehending its sophisticated movements and its interactions with the follicle. The great diversity of behavioral patterns and complexities of the whiskerfollicle ensemble encouraged the creation of many different biomechanical models. This review analyzes most of the whisker biomechanical models that have been developed so far. This review was written so as to render it accessible to readers coming from different research areas.
Construction and Building Materials, 2016
h i g h l i g h t s A thermodynamically consistent gradient poroplastic model is proposed. The RA... more h i g h l i g h t s A thermodynamically consistent gradient poroplastic model is proposed. The RAC effect is considered by a concrete mixture recycling factor. Numerical results demonstrate good accuracy to predict failure behavior.