Articles de revistahttp://hdl.handle.net/2117/4282019-07-18T07:33:35Z2019-07-18T07:33:35ZLagrangian analysis of multiscale particulate flows with the particle finite element methodOñate Ibáñez de Navarra, EugenioCeligueta Jordana, Miguel ÁngelLatorre Sánchez, Juan SalvadorCasas González, GuillermoRossi, RiccardoRojek, Jerzyhttp://hdl.handle.net/2117/1348112019-06-26T03:24:52Z2019-06-19T19:00:49ZLagrangian analysis of multiscale particulate flows with the particle finite element method
Oñate Ibáñez de Navarra, Eugenio; Celigueta Jordana, Miguel Ángel; Latorre Sánchez, Juan Salvador; Casas González, Guillermo; Rossi, Riccardo; Rojek, Jerzy
We present a Lagrangian numerical technique for the analysis of flows incorporating physical particles of different sizes. The numerical approach is based on the particle finite element method (PFEM) which blends concepts from particle-based techniques and the FEM. The basis of the Lagrangian formulation for particulate flows and the procedure for modelling the motion of small and large particles that are submerged in the fluid are described in detail. The numerical technique for analysis of this type of multiscale particulate flows using a stabilized mixed velocity-pressure formulation and the PFEM is also presented. Examples of application of the PFEM to several particulate flows problems are given.
The final publication is available at Springer via http://dx.doi.org/10.1007/s40571-014-0012-9
2019-06-19T19:00:49ZOñate Ibáñez de Navarra, EugenioCeligueta Jordana, Miguel ÁngelLatorre Sánchez, Juan SalvadorCasas González, GuillermoRossi, RiccardoRojek, JerzyWe present a Lagrangian numerical technique for the analysis of flows incorporating physical particles of different sizes. The numerical approach is based on the particle finite element method (PFEM) which blends concepts from particle-based techniques and the FEM. The basis of the Lagrangian formulation for particulate flows and the procedure for modelling the motion of small and large particles that are submerged in the fluid are described in detail. The numerical technique for analysis of this type of multiscale particulate flows using a stabilized mixed velocity-pressure formulation and the PFEM is also presented. Examples of application of the PFEM to several particulate flows problems are given.Comparative study on sheet metal forming processes by numerical modelling and experimentSosnowski, WlodzimierzOñate Ibáñez de Navarra, EugenioAgelet de Saracibar Bosch, Carloshttp://hdl.handle.net/2117/1311382019-04-03T03:08:03Z2019-04-02T15:23:42ZComparative study on sheet metal forming processes by numerical modelling and experiment
Sosnowski, Wlodzimierz; Oñate Ibáñez de Navarra, Eugenio; Agelet de Saracibar Bosch, Carlos
In this paper some results of a wide experimental program are presented and compared with some finite element solution of sheet metal forming problems using a viscous shell formulation.
2019-04-02T15:23:42ZSosnowski, WlodzimierzOñate Ibáñez de Navarra, EugenioAgelet de Saracibar Bosch, CarlosIn this paper some results of a wide experimental program are presented and compared with some finite element solution of sheet metal forming problems using a viscous shell formulation.The intrinsic time for the streamline upwind/Petrov-Galerkin formulation using quadratic elementsCodina, RamonOñate Ibáñez de Navarra, EugenioCervera Ruiz, Miguelhttp://hdl.handle.net/2117/1311332019-04-03T03:09:06Z2019-04-02T15:02:36ZThe intrinsic time for the streamline upwind/Petrov-Galerkin formulation using quadratic elements
Codina, Ramon; Oñate Ibáñez de Navarra, Eugenio; Cervera Ruiz, Miguel
In this paper the functions of the Péclet number that appear in the intrinsic time of the streamline upwind/Petrov-Galerkin (SUPG) formulation are analyzed for quadratic elements. Some related issues such as the computation of the characteristic element length and the introduction of source terms in the one-dimensional model problem are also addressed.
2019-04-02T15:02:36ZCodina, RamonOñate Ibáñez de Navarra, EugenioCervera Ruiz, MiguelIn this paper the functions of the Péclet number that appear in the intrinsic time of the streamline upwind/Petrov-Galerkin (SUPG) formulation are analyzed for quadratic elements. Some related issues such as the computation of the characteristic element length and the introduction of source terms in the one-dimensional model problem are also addressed.Análisis no lineal de tanques criogénicos bajo cargas térmicasOliver Olivella, XavierOñate Ibáñez de Navarra, EugenioPeraire Guitart, JaumeChueca Castedo, Rosa Marianahttp://hdl.handle.net/2117/1264532019-01-24T10:54:35Z2019-01-09T20:08:58ZAnálisis no lineal de tanques criogénicos bajo cargas térmicas
Oliver Olivella, Xavier; Oñate Ibáñez de Navarra, Eugenio; Peraire Guitart, Jaume; Chueca Castedo, Rosa Mariana
2019-01-09T20:08:58ZOliver Olivella, XavierOñate Ibáñez de Navarra, EugenioPeraire Guitart, JaumeChueca Castedo, Rosa MarianaAnalysis of the discharge capacity of radial gated-spillways using CFD and ANN: Oliana Dam case studySalazar González, FernandoMorán Moya, RafaelRossi, RiccardoOñate Ibáñez de Navarra, Eugeniohttp://hdl.handle.net/2117/1136692019-01-24T10:52:12Z2018-02-02T20:05:25ZAnalysis of the discharge capacity of radial gated-spillways using CFD and ANN: Oliana Dam case study
Salazar González, Fernando; Morán Moya, Rafael; Rossi, Riccardo; Oñate Ibáñez de Navarra, Eugenio
The paper focuses on the analysis of radial-gated spillways, which is carried out by the solution of a numerical model based on the finite element method (FEM). The Oliana Dam is considered as a case study and the discharge capacity is predicted both by the application of a level-set-based free-surface solver and by the use of traditional empirical formulations. The results of the analysis are then used for training an artificial neural network to allow real-time predictions of the discharge in any situation of energy head and gate opening within the operation range of the reservoir. The comparison of the results obtained with the different methods shows that numerical models such as the FEM can be useful as a predictive tool for the analysis of the hydraulic performance of radial-gated spillways.
2018-02-02T20:05:25ZSalazar González, FernandoMorán Moya, RafaelRossi, RiccardoOñate Ibáñez de Navarra, EugenioThe paper focuses on the analysis of radial-gated spillways, which is carried out by the solution of a numerical model based on the finite element method (FEM). The Oliana Dam is considered as a case study and the discharge capacity is predicted both by the application of a level-set-based free-surface solver and by the use of traditional empirical formulations. The results of the analysis are then used for training an artificial neural network to allow real-time predictions of the discharge in any situation of energy head and gate opening within the operation range of the reservoir. The comparison of the results obtained with the different methods shows that numerical models such as the FEM can be useful as a predictive tool for the analysis of the hydraulic performance of radial-gated spillways.A compressible Lagrangian framework for the simulation of the underwater implosion of large air bubblesKamran, KamranRossi, RiccardoOñate Ibáñez de Navarra, EugenioIdelsohn Barg, Sergio Rodolfohttp://hdl.handle.net/2117/1136682019-01-24T11:46:10Z2018-02-02T20:02:18ZA compressible Lagrangian framework for the simulation of the underwater implosion of large air bubbles
Kamran, Kamran; Rossi, Riccardo; Oñate Ibáñez de Navarra, Eugenio; Idelsohn Barg, Sergio Rodolfo
A fully Lagrangian compressible numerical framework for the simulation of underwater implosion of a large air bubble is presented. Both air and water are considered compressible and the equations for the Lagrangian shock hydrodynamics are stabilized via a variationally consistent multiscale method. A nodally perfect matched definition of the interface is used and then the kinetic variables, pressure and density, are duplicated at the interface level. An adaptive mesh generation procedure, which respects the interface connectivities, is applied to provide enough refinement at the interface level. This framework is verified by several benchmarks which evaluate the behavior of the numerical scheme for severe compression and expansion cases. This model is then used to simulate the underwater implosion of a large cylindrical bubble, with a size in the order of cm. We observe that the conditions within the bubble are nearly uniform until the converging pressure wave is strong enough to create very large pressures near the center of the bubble. These bubble dynamics occur on very small spatial (0.3 mm), and time (0.1 ms) scales. During the final stage of the collapse Rayleigh–Taylor instabilities appear at the interface and then disappear when the rebounce starts. At the end of the rebounce phase the bubble radius reaches 50% of its initial value and the bubble recover its circular shape. It is when the second collapse starts, with higher mode shape instabilities excited at the bubble interface, that leads to the rupture of the bubble. Several graphs are presented and the pressure pulse detected in the water is compared by experiment.
2018-02-02T20:02:18ZKamran, KamranRossi, RiccardoOñate Ibáñez de Navarra, EugenioIdelsohn Barg, Sergio RodolfoA fully Lagrangian compressible numerical framework for the simulation of underwater implosion of a large air bubble is presented. Both air and water are considered compressible and the equations for the Lagrangian shock hydrodynamics are stabilized via a variationally consistent multiscale method. A nodally perfect matched definition of the interface is used and then the kinetic variables, pressure and density, are duplicated at the interface level. An adaptive mesh generation procedure, which respects the interface connectivities, is applied to provide enough refinement at the interface level. This framework is verified by several benchmarks which evaluate the behavior of the numerical scheme for severe compression and expansion cases. This model is then used to simulate the underwater implosion of a large cylindrical bubble, with a size in the order of cm. We observe that the conditions within the bubble are nearly uniform until the converging pressure wave is strong enough to create very large pressures near the center of the bubble. These bubble dynamics occur on very small spatial (0.3 mm), and time (0.1 ms) scales. During the final stage of the collapse Rayleigh–Taylor instabilities appear at the interface and then disappear when the rebounce starts. At the end of the rebounce phase the bubble radius reaches 50% of its initial value and the bubble recover its circular shape. It is when the second collapse starts, with higher mode shape instabilities excited at the bubble interface, that leads to the rupture of the bubble. Several graphs are presented and the pressure pulse detected in the water is compared by experiment.A fast and accurate method to solve the incompressible Navier-Stokes equationsIdelsohn Barg, Sergio RodolfoNigro, NorbertoGimenez, JuanRossi, RiccardoMartí, Julio Marcelohttp://hdl.handle.net/2117/1136672019-01-24T16:13:59Z2018-02-02T19:57:55ZA fast and accurate method to solve the incompressible Navier-Stokes equations
Idelsohn Barg, Sergio Rodolfo; Nigro, Norberto; Gimenez, Juan; Rossi, Riccardo; Martí, Julio Marcelo
Purpose: The purpose of this paper is to highlight the possibilities of a novel Lagrangian formulation in dealing with the solution of the incompressible Navier-Stokes equations with very large time steps.
Design/methodology/approach: The design of the paper is based on introducing the origin of this novel numerical method, originally inspired on the Particle Finite Element Method (PFEM), summarizing the previously published theory in its moving mesh version. Afterwards its extension to fixed mesh version is introduced, showing some details about the implementation.
Findings: The authors have found that even though this method was originally designed to deal with heterogeneous or free-surface flows, it can be competitive with Eulerian alternatives, even in their range of optimal application in terms of accuracy, with an interesting robustness allowing to use large time steps in a stable way.
Originality/value: With this objective in mind, the authors have chosen a number of benchmark examples and have proved that the proposed algorithm provides results which compare favourably, both in terms of solution time and accuracy achieved, with alternative approaches, implemented in in-house and commercial codes.
2018-02-02T19:57:55ZIdelsohn Barg, Sergio RodolfoNigro, NorbertoGimenez, JuanRossi, RiccardoMartí, Julio MarceloPurpose: The purpose of this paper is to highlight the possibilities of a novel Lagrangian formulation in dealing with the solution of the incompressible Navier-Stokes equations with very large time steps.
Design/methodology/approach: The design of the paper is based on introducing the origin of this novel numerical method, originally inspired on the Particle Finite Element Method (PFEM), summarizing the previously published theory in its moving mesh version. Afterwards its extension to fixed mesh version is introduced, showing some details about the implementation.
Findings: The authors have found that even though this method was originally designed to deal with heterogeneous or free-surface flows, it can be competitive with Eulerian alternatives, even in their range of optimal application in terms of accuracy, with an interesting robustness allowing to use large time steps in a stable way.
Originality/value: With this objective in mind, the authors have chosen a number of benchmark examples and have proved that the proposed algorithm provides results which compare favourably, both in terms of solution time and accuracy achieved, with alternative approaches, implemented in in-house and commercial codes.A contact algorithm for shell problems via Delaunay-based meshing of the contact domainKamran, KamranRossi, RiccardoOñate Ibáñez de Navarra, Eugeniohttp://hdl.handle.net/2117/1136662019-01-24T11:46:10Z2018-02-02T19:52:52ZA contact algorithm for shell problems via Delaunay-based meshing of the contact domain
Kamran, Kamran; Rossi, Riccardo; Oñate Ibáñez de Navarra, Eugenio
The simulation of the contact within shells, with all of its different facets, represents still an open challenge in Computational Mechanics. Despite the effort spent in the development of techniques for the simulation of general contact problems, an all-seasons algorithm applicable to complex shell contact problems is yet to be developed. This work focuses on the solution of the contact between thin shells by using a technique derived from the particle finite element method together with a rotation-free shell triangle. The key concept is to define a discretization of the contact domain (CD) by constructing a finite element mesh of four-noded tetrahedra that describes the potential contact volume. The problem is completed by using an assumed-strain approach to define an elastic contact strain over the CD.
2018-02-02T19:52:52ZKamran, KamranRossi, RiccardoOñate Ibáñez de Navarra, EugenioThe simulation of the contact within shells, with all of its different facets, represents still an open challenge in Computational Mechanics. Despite the effort spent in the development of techniques for the simulation of general contact problems, an all-seasons algorithm applicable to complex shell contact problems is yet to be developed. This work focuses on the solution of the contact between thin shells by using a technique derived from the particle finite element method together with a rotation-free shell triangle. The key concept is to define a discretization of the contact domain (CD) by constructing a finite element mesh of four-noded tetrahedra that describes the potential contact volume. The problem is completed by using an assumed-strain approach to define an elastic contact strain over the CD.Multi-scale analysis of the early damage mechanics of ferritized ductile ironFernandino, D.O.Cisilino, A. P.Toro, S.P.J., Sánchezhttp://hdl.handle.net/2117/1067652019-01-24T10:24:52Z2017-07-24T14:44:08ZMulti-scale analysis of the early damage mechanics of ferritized ductile iron
Fernandino, D.O.; Cisilino, A. P.; Toro, S.; P.J., Sánchez
A multi-scale analysis of the linear elastic and the early damage stages of ferritic ductile iron is introduced in this work. The methodology combines numerical and experimental analyses in the macro and micro scales. Experiments in the micro-scale are used for the characterization of the material micro constituents and the assessment of the micro-scale damage mechanisms; experiments in the macro-scale provide the data to calibrate and validate the models. The 2D multi-scale problem is modeled using the pre-critical regime of the Failure-Oriented Multi-Scale Variational Formulation, which is implemented via a FE2 approach. Finite element analysis in the micro-scale is customized to account for plastic deformation and matrix-nodule debonding. The multi-scale model is found effective for capturing the sequence and extent of the damage mechanisms in the micro-scale and to estimate, via inverse analyses, parameters of the matrix-nodule debonding law. Results allow to develop new insights for the better understanding of the ductile iron damage mechanics and to draw conclusions related to the modeling aspects of the multi-scale simulation.
2017-07-24T14:44:08ZFernandino, D.O.Cisilino, A. P.Toro, S.P.J., SánchezA multi-scale analysis of the linear elastic and the early damage stages of ferritic ductile iron is introduced in this work. The methodology combines numerical and experimental analyses in the macro and micro scales. Experiments in the micro-scale are used for the characterization of the material micro constituents and the assessment of the micro-scale damage mechanisms; experiments in the macro-scale provide the data to calibrate and validate the models. The 2D multi-scale problem is modeled using the pre-critical regime of the Failure-Oriented Multi-Scale Variational Formulation, which is implemented via a FE2 approach. Finite element analysis in the micro-scale is customized to account for plastic deformation and matrix-nodule debonding. The multi-scale model is found effective for capturing the sequence and extent of the damage mechanisms in the micro-scale and to estimate, via inverse analyses, parameters of the matrix-nodule debonding law. Results allow to develop new insights for the better understanding of the ductile iron damage mechanics and to draw conclusions related to the modeling aspects of the multi-scale simulation.Optimization-based design of a heat flux concentratorPeralta, IgnacioFachinotti, Víctor D.Ciarbonetti, Ángel A.http://hdl.handle.net/2117/1005242019-04-30T15:08:37Z2017-02-02T18:52:05ZOptimization-based design of a heat flux concentrator
Peralta, Ignacio; Fachinotti, Víctor D.; Ciarbonetti, Ángel A.
To gain control over the diffusive heat flux in a given domain, one needs to engineer a thermal metamaterial with a specific distribution of the generally anisotropic thermal conductivity throughout the domain. Until now, the appropriate conductivity distribution was usually determined using transformation thermodynamics. By this way, only a few particular cases of heat flux control in simple domains having simple boundary conditions were studied. Thermal metamaterials based on optimization algorithm provides superior properties compared to those using the previous methods. As a more general approach, we propose to define the heat control problem as an optimization problem where we minimize the error in guiding the heat flux in a given way, taking as design variables the parameters that define the variable microstructure of the metamaterial. In the present study we numerically demonstrate the ability to manipulate heat flux by designing a device to concentrate the thermal energy to its center without disturbing the temperature profile outside it.
2017-02-02T18:52:05ZPeralta, IgnacioFachinotti, Víctor D.Ciarbonetti, Ángel A.To gain control over the diffusive heat flux in a given domain, one needs to engineer a thermal metamaterial with a specific distribution of the generally anisotropic thermal conductivity throughout the domain. Until now, the appropriate conductivity distribution was usually determined using transformation thermodynamics. By this way, only a few particular cases of heat flux control in simple domains having simple boundary conditions were studied. Thermal metamaterials based on optimization algorithm provides superior properties compared to those using the previous methods. As a more general approach, we propose to define the heat control problem as an optimization problem where we minimize the error in guiding the heat flux in a given way, taking as design variables the parameters that define the variable microstructure of the metamaterial. In the present study we numerically demonstrate the ability to manipulate heat flux by designing a device to concentrate the thermal energy to its center without disturbing the temperature profile outside it.