VI ECCOMAS Young Investigators Conference

The 6th ECCOMAS Young Investigators Conference YIC2021 will take place from July 7th through 9th, 2021 at Universitat Politècnica de València, Spain. The main objective is to bring together in a relaxed environment young students, researchers and professors from all areas related with computational science and engineering, as in the previous YIC conferences series organized under the auspices of the European Community on Computational Methods in Applied Sciences (ECCOMAS). Participation of senior scientists sharing their knowledge and experience is thus critical for this event.

YIC 2021 is organized at Universitat Politécnica de València by the Sociedad Española de Métodos Numéricos en Ingeniería (SEMNI) and the Sociedad Española de Matemática Aplicada (SEMA). It is promoted by the ECCOMAS.

The main goal of the YIC 2021 conference is to provide a forum for presenting and discussing the current state-of-the-art achievements on Computational Methods and Applied Sciences, including theoretical models, numerical methods, algorithmic strategies and challenging engineering applications.

YIC is the conference that launched the ECCOMAS foccused in Young researchers of thematic conferfences. It is a medium-size conference (an average of 130-170 delegates) which allows for dynamic and fruitful exchanges between the participants.

URI permanente para esta colecciónhttps://riunet.upv.es/handle/10251/186460

Examinar

Mostrando 1 - 20 de 46

Access status: Abierto ,
Sea ice strength development from freezing to melting in the Antarctic marginal ice zone
(Editorial Universitat Politècnica de València, 2022-05-11) Paul, Felix; Mielke, T.; Audh, R.; Lupascu, D.C.; National Research Foundation, South Africa
[EN] Sea ice growth in the Marginal Ice Zone of the Antarctic is one of the largest annual changes on earth with a huge impact on the global climate and ecology system. The principles of sea ice growth and melting in the MIZ of the Antarctic is yet not as well researched as its polar counterpart in the north.For this study, pancake ice, consolidated ice and floe ice were analyzed with a compression test in July, October and November 2019 in the marginal ice zone of the Antarctic. Newly formed pancake ice in July showed the highest compressive strength in the bottom layer (3 MPa), whereas consolidated ice was strongest at the top (5 MPa). Consolidated ice in October and November had the highest compressive strength in a middle layer with up to 13.5 MPa, the maximum strength at the top was 3 MPa. Floe ice, consisting of destroyed pack ice, did not show a clear strength development over sea ice depth.
Access status: Abierto ,
An adaptive discrete Newton method for regularization-free Bingham model
(Editorial Universitat Politècnica de València, 2022-05-11) Fatima, Arooj; Turek, Stefan; Ouazzi, Abderrahim; Afaq, Muhammad Aaqib; Deutsche Forschungsgemeinschaft; TU Dortmund University
[EN] Developing a numerical and algorithmic tool which correctly identifies unyielded regions in yield stress fluid flow is a challenging task. Two approaches are commonly used to handle the singular behaviour at the yield surface, i.e. the Augmented Lagrangian approach and the regularization approach, respectively. Generally in the regularization approach, solvers do not perform efficiently when the regularization parameter gets very small. In this work, we use a formulation introducing a new auxiliary stress. The three field formulation of the yield stress fluid corresponds to a regularization-free Bingham formulation. The resulting set of equations arising from the three field formulation is solved efficiently and accurately by a monolithic finite element method. The velocity and pressure are discretized by the higher order stable FEM pair Q2/Pdisc 1 and the auxiliary stress is discretized by the Q2 element. Furthermore, this problem is highly nonlinear and presents a big challenge to any nonlinear solver. Therefore, we developed a new adaptive discrete Newton method, which evaluates the Jacobian with the divided difference approach. We relate the step length to the rate of the actual nonlinear reduction for achieving a robust adaptive Newton method. We analyse the solvability of the problem along with the adaptive Newton method for Bingham fluids by doing numerical studies for a prototypical configuration ”viscoplastic fluid flow in a channel”.
Access status: Abierto ,
Efficient and Higher-Order Accurate Split-Step Methods for Generalised Newtonian Fluid Flow
(Editorial Universitat Politècnica de València, 2022-05-11) Schussnig, Richard; Pacheco, Douglas; Kaltenbacher, Manfred; Fries, Thomas-Peter; TU Graz, Internationale Beziehungen und Mobilitätsprogramme
[EN] In numerous engineering applications, such as polymer or blood flow, the dependence of fluid viscosity on the local shear rate plays an important role. Standard techniques using inf-sup stable finite elements lead to saddle-point systems posing a challenge even for state-ofthe-art solvers and preconditioners. Alternatively, projection schemes or time-splitting methods decouple equations for velocity and pressure, resulting in easier to solve linear systems. Although pressure and velocity correction schemes of high-order accuracy are available for Newtonian fluids, the extension to generalised Newtonian fluids is not a trivial task. Herein, we present a split-step scheme based on an explicit-implicit treatment of pressure, viscosity and convection terms, combined with a pressure Poisson equation with fully consistent boundary conditions. Then, using standard equal-order finite elements becomes possible. Stability, flexibility and efficiency of the splitting scheme is showcased in two challenging applications involving aortic aneurysm flow and human phonation.
Access status: Abierto ,
Shape Optimization for Thermal Insulation Problems
(Editorial Universitat Politècnica de València, 2022-05-11) Tozza, Silvia; Toraldo, Gerardo; Ministero dell'università e della ricerca, Italia
[EN] In this work we consider two domains: an external domain whose geometry varies, and an internal fixed one. From the thermal insulation viewpoint, we are considering a body to be insulated, enveloped in a layer of insulator, and we want to find the best shape for the thermal insulator, in terms of heat dispersion. Mathematically, our problem is described by an elliptic partial differential equation with Dirichlet-Robin boundary conditions.
Access status: Abierto ,
A Space-Time FE Level-set method for convection coupled phase-change processes
(Editorial Universitat Politècnica de València, 2022-05-11) Boledi, Leonardo; Terschanski, Benjamin; Elgeti, Stefanie; Kowalski, Julia; Bundesministerium für Wirtschaft und Energie, Alemania; Helmholtz School for Data Science in Life, Earth and Energy
[EN] Phase transition processes have great relevance for both engineering and scientific applications. In production engineering, for instance, metal welding and alloy solidification are topics of ongoing research.In this contribution we focus on the convection coupled solid-liquid phase change of a single species, e.g. water. The material is assumed to be incompressible within the two phases, but we account for density changes across the phase interface. To describe the process, we need to solve the incompressible Navier-Stokes equations and the heat equation for both phases over time. The position of the phase interface is tracked with a Level-set method. The Level-set function is advected according to the propagation speed of the phase interface. Such velocity field depends on local energy conservation across the interface and is modelled as the Stefan condition. This formulation requires us to approximate the heat flux discontinuity across the interface based on the evolving temperature and velocity fields.To model the temperature and velocity fields within each phase, we employ the Space-Time Finite Element method. However, commonly used interpolation functions, such as piecewise linear functions, fail to capture discontinuous derivatives over one element that are needed to assess the Level-set's transport term. Available solutions to this matter, such as local enrichment with Extended Finite Elements, are often not compatible with existing Space-Time Finite Element codes and require extensive implementation work. Instead, we consider a conceptually simpler method and we decide to extend the Ghost Cell technique to Finite Element meshes. The idea is that we can separate the two subdomains associated with each phase and solve two independent temperature problems. We prescribe the melting temperature at an additional node close to the interface and we retrieve the required heat flux.In this work we describe the Ghost Cell method applied to our Space-Time Finite Element solver. First, we verify numerical results against analytical solutions, then we demonstrate more complex test cases in 2D and 3D.
Access status: Abierto ,
Energy-momentum time integration of gradient-based models for fiber-bending stiffness in anisotropic thermo-viscoelastic continua
(Editorial Universitat Politècnica de València, 2022-05-11) Dietzsch, Julian; Groß, Michael; Kalaimani, Iniyan; Deutsche Forschungsgemeinschaft
[EN] For our research, we are motivated by dynamic simulations of 3D fiber-reinforced materials in lightweight structures. In such materials, the material reinforcement is performed by fiber rovings with a separate bending stiffness, which can be modelled by a second order gradient of the deformation mapping. Therefore, we extend a thermo-viscoelastic Cauchy continuum for fiber-matrix composites with single fibers by an independent field for the gradient of the right Cauchy-Green tensor. On the other hand, we focus on numerically stable dynamic long-time simulations with locking free meshes, and thus use higher-order accurate energy-momentum schemes emanating from mixed finite element methods. Hence, we adapt the variational-based space-time finite element method to the new material formulation, and additionally include independent fields to obtain well-known mixed finite elements. As representative numerical example, Cook’s cantilever beam is considered. We primarily analyze the influence of the fiber bending stiffness, as well as the spatial and time convergence up to cubic order. Furthermore, we look at the influence of the physical dissipation in the material.
Access status: Abierto ,
Computing the jump-term in space-time FEM for arbitrary temporal interpolation
(Editorial Universitat Politècnica de València, 2022-05-11) Salzmann, Eugen; Zwickey, Florian; Elgeti, Stefanie; Deutsche Forschungsgemeinschaft
[EN] One approach with rising popularity in analyzing time-dependent problems in scienceand engineering is the so-called space-time finite-element method that utilized finiteelementsin both space and time. A common ansatz in this context is to divide the meshin temporal direction into so-called space-time slabs, which are subsequently weaklyconnected in time with a Discontinuous Galerkin approach. The corresponding jumpterm,which is responsible for imposing the weak continuity across space-time slabs canbe challenging to compute, in particular in the context of deforming domains. Ensuringa conforming discretization of the space-time slab at the top and bottom in timedirection simplifies the handling of this term immensely. Otherwise, a computationallyexpensive and error prone projection of the solution from one time-level to another isnecessary. However, when it comes to simulations with deformable domains, e.g. forfree-surface flows, ensuring conforming meshes is quite laborious. A possible solutionto this challenge is to extrude a spatial mesh in time at each time-step resulting in theso-called time-discontinuous prismatic space-time (D-PST) method[1]. However, thisprocedure is restricted to finite-elements of 1st order in time.We present a novel algorithmic approach for arbitrarily discretized meshes by flippingthe mesh in time-direction for each time-step. This ansatz allows for a simple evaluationof the jump-term as the mesh is always conforming. The cost of flipping the mesharound its symmetry plane in time scales with the number of nodes, which makes itcomputationally cheaper than an additional update of the mesh to enforce conformity orthe evaluation of a projection. We validate the approach on various physical problemswith and without deforming domains.
Access status: Abierto ,
Railway rolling noise mitigation through optimal track design
(Editorial Universitat Politècnica de València, 2022-05-11) Andrés Ruiz, Víctor; Martínez Casas, José; Carballeira, Javier; Denia Guzmán, Francisco; Thompson, D. J.; Escuela Técnica Superior de Ingeniería Aeroespacial y Diseño Industrial; Departamento de Ingeniería Mecánica y de Materiales; Centro de Investigación en Ingeniería Mecánica; Instituto Universitario de Investigación Concertado de Ingeniería Mecánica y Biomecánica; Agencia Estatal de Investigación; European Regional Development Fund; Ministerio de Educación y Ciencia
[EN] The main goal of the present work lies in the identification of the railway track properties that influence acoustic radiation, as well as in the analysis of these properties for the reduction of sound levels. This is achieved through a dynamic model of the railway wheel and track that allows the study of rolling noise, produced as a result of the wheel/rail interaction. Once the vibrational response of the railway components is determined, the sound power radiated by them is evaluated. The influence of the track properties on the sound radiation is determined by analysing the acoustic power results of different track configurations. From the results obtained, a number of guidelines are presented for noise mitigation of the involved railway elements. Between the worst and the best track design, there are differences of approximately 7.4 dB(A) in the radiation considering the wheel, rail and sleeper noise.
Access status: Abierto ,
Model-order reduction for nonlinear dynamics including nonlinearities induced by damage
(Editorial Universitat Politècnica de València, 2022-05-11) Daby-Seesaram, Alexandre; Fau, Amélie; Charbonnel, Pierre Étienne; Néron, David
[EN] Assessing the probability of failure of a structure under seismic loading requires the simulation of a great number of similar nonlinear computations. A model-order reduction strategy is proposed for decreasing the computational cost associated to each nonlinear simulation. In this contribution, the method is illustrated to evaluate the damage evolution in a primary circuit piping component of a pressurized water reactor, subjected to accidental seismic input. Piping components are described with a damageable elasto-plastic material exhibiting a preliminary damage pattern.
Access status: Abierto ,
Solution of heat transfer inverse problem in thin film irradiated by laser
(Editorial Universitat Politècnica de València, 2022-05-11) Korczak, Anna; Mucha, Waldemar; Silesian University of Technology
[EN] The presented article deals with inverse problems in nanoscale heat transfer identification problems [1]. Heat flow in solids can be modelled using various models. When dealing with objects of small dimensions, of the order of nanometres, and with fast heating processes, comparable to relaxation times, then it is reasonable to use molecular dynamics or the Boltzmann transport equation (BTE) [2]. The presented coupled system of Boltzmann transport equations has the advantage over molecular dynamics that it has a less complicated mathematical apparatus and calculations proceed faster. A thin film irradiated by ultrashort laser pulse is modeled using BTE. Heat transfer parameters of the model are identified using evolutionary algorithm – an optimization algorithm inspired on biological evolution of species. Multicriterial identification is characterized as an optimization problem where the difference between obtained and expected results is minimized.
Access status: Abierto ,
Reducing computational time for FEM postprocessing through the use of feedforward neural networks
(Editorial Universitat Politècnica de València, 2022-05-11) Zlatić, Martin; Čanađija, Marko; Croatian Science Foundation
[EN] With the recent surge in neural network usage, machine learning libraries have become more convenient to use and implement. In this paper we investigate the possibility of using neural networks in order to faster process displacements obtained from finite element calculation and replace existing post-processing procedures. The method is implemented on 2D finite elements for their relative ease of usage and manipulation. A speed up is observed in comparison to traditional methods of post-processing. Possible further applications of this method are also presented in this paper.
Access status: Abierto ,
A vibroacoustic model of the stationary railway wheel for sound radiation prediction through an axisymmetric approach
(Editorial Universitat Politècnica de València, 2022-05-11) Andrés Ruiz, Víctor; Martínez Casas, José; Carballeira, Javier; Denia Guzmán, Francisco; Escuela Técnica Superior de Ingeniería Aeroespacial y Diseño Industrial; Departamento de Ingeniería Mecánica y de Materiales; Instituto Universitario de Investigación Concertado de Ingeniería Mecánica y Biomecánica; Centro de Investigación en Ingeniería Mecánica; Agencia Estatal de Investigación; European Regional Development Fund; Ministerio de Educación y Ciencia
[EN] In the literature, different dynamic models of the railway wheel have been developed to predict its sound radiation; however, there are still certain aspects that can be improved. Specifically, the high computational cost of these models, either because they solve the fluidstructure interaction or because they solve the dynamics and acoustics of the three-dimensional wheel, makes it difficult to carry out numerous simulations with the aim of achieving quieter designs. In the present work, a vibroacoustic model of the stationary wheel is developed through an axisymmetric approach, yielding an efficient and comprehensive acoustic prediction tool. The calculation methodology consists of, firstly, adopting an axisymmetric approach to solve the vibratory dynamics of the wheel from its cross-section, using finite element techniques; subsequently, the acoustic radiation of the three-dimensional wheel is calculated from the dynamics of the aforementioned section through an analytical formulation. Finally, the vibroacoustic model developed is validated via comparison with commercial software that solves the fluid-structure interaction, showing the aforementioned computational advantages that the former has over the latter.
Access status: Abierto ,
An Isogeometric Element Formulation for Linear Two-Dimensional Elasticity Based on the Airy Equation
(Editorial Universitat Politècnica de València, 2022-05-11) Held, Susanne; Dornisch, Wolfgang; Azizi, Nima
[EN] The aim of this work is to derive a formulation for linear two-dimensional elasticity using just one degree of freedom. This degree of freedom is used to directly discretize the Airy bipotential equation, which requires higher order basis functions. Isogeometric structural analysis is based on shape functions of the geometry description in Computer-Aided design software. These shape functions can easily fulfill the continuity requirement of the bipotential equation. Thus, an Airy element formulation can be obtained through isogeometric methods. In this contribution Non-Uniform Rational B-splines are used to discretize the domain and to solve the occurring differential equations. Numerical examples demonstrate the accuracy of the evolved formulation for a quadratic plate under different load situations.
Access status: Abierto ,
Dynamic response of periodic infinite structure to arbitrary moving load based on the Finite Element Method
(Editorial Universitat Politècnica de València, 2022-05-11) Gil-Romero, Jaime; Gregori Verdú, Santiago; Tur, M.; Fuenmayor Fernández, Francisco-Javier; Escuela Técnica Superior de Ingeniería Aeroespacial y Diseño Industrial; Departamento de Ingeniería Mecánica y de Materiales; Instituto Universitario de Investigación Concertado de Ingeniería Mecánica y Biomecánica; Escuela Técnica Superior de Ingeniería Industrial; Agencia Estatal de Investigación
[EN] A common problem in railway engineering is the dynamic of repetitive structures subject to moving loads. Bridges, rails or catenaries are the most representative periodic structures, over which the train acts as a moving exciter. Usually, these structures are long enough to consider that their dynamic response is in permanent regime. To assume the steady-state regime some features have to be considered: infinite length structure, perfect periodicity and constant velocity of the moving load. This paper adopts these assumptions and provides the steady-state solution of a generic periodic structure subject to an arbitrary and also periodic moving load. The structure is divided into repetitive blocks modelled by the Finite Element Method. By applying the periodicity condition it is possible to consider the entire structure dynamics with only one block. The problem is stated in the frequency domain and moved back to time domain by means of Discrete Fourier Transform.
Access status: Abierto ,
Comparison of numerical and experimental strain distributions in composite panel for aerospace applications
(Editorial Universitat Politècnica de València, 2022-05-11) Mucha, Waldemar; Kuś, Wacław; Viana, Júlio; Nunes, João; Silesian University of Technology
[EN] In structural applications of aerospace industry, weight efficiency, understood as minimal weight and maximal stiffness, is of great importance. This criterion can be achieved by composite lightweight structures. Typical structures for aforementioned applications are sandwich panels (e.g., with honeycomb core) and stiffened panels (e.g., with blade ribs, T-bar ribs, or hat ribs). In this paper, a hat-stiffened panel, made of carbon/epoxy woven composite, is considered. Results of experiments, consisting of loading the panel and measuring exciting forces and strains (using strain gages), are presented. The results are compared to strains distribution obtained from finite element model of the panel.
Access status: Abierto ,
Influence of track modelling in modal parameters of railway bridges composed by single-track adjacent decks
(Editorial Universitat Politècnica de València, 2022-05-11) Sánchez Quesada, Juan; Moliner, E.; Romero, A.; Galvín, P.; Martínez-Rodrigo, M.D.; Agencia Estatal de Investigación; European Regional Development Fund; Junta de Andalucía; Generalitat Valenciana; Universitat Jaume I
[EN] A significant number of railway bridges composed by simply-supported (SS) spans are present in existing railway lines. Special attention must be paid to short to medium span length structures, as they are prone to experience high vertical acceleration levels at the deck, due to their low weight and damping, compromising the travelling comfort and the structural integrity. The accurate prediction of the dynamic response of these bridges is a complex issue since it is affected by uncertain factors such as structural damping and complex interaction mechanisms such as vehicle-bridge, soil-structure or track-bridge interaction. Concerning track-bridge interaction, experimental evidences of a dynamic coupling exerted by the ballasted track between subsequent SS spans and also between structurally independent single-track twin adjacent decks have been reported in the literature [1, 2]. Nevertheless, this phenomenon is frequently disregarded due to the computational cost of models including the track and due to the uncertainties in the mechanical parameters that define the track system. The present work contributes to the study of the coupling effect exerted by the ballasted track between independent structures in railway bridges. With this purpose two 3D finite element (FE) track-bridge interaction models are implemented. The former includes a continuous representation of the track components meshing the sleepers, ballast and sub-ballast with solid FE. In the latter, the track is represented as a 2D discrete three-layer model where the mass, stiffness and damping of the components are concentrated at the sleepers locations. The numerical models are updated with experimental measurements performed on an existing railway bridge in a view to evaluate (i) the influence of the track continuity on the bridge modal parameters and on the train-induced vibrations; (ii) the adequacy of the implemented numerical models and (iii) the importance of the track-bridge interaction for an accurate prediction of the vertical acceleration levels under operating conditions.
Access status: Abierto ,
Adjoint-based methods for optimization and goal-oriented error control applied to fluid-structure interaction: implementation of a partition-of-unity dual-weighted residual estimator for stationary forward FSI problems in deal.II
(Editorial Universitat Politècnica de València, 2022-05-11) Wick, Thomas; Deutsche Forschungsgemeinschaft
[EN] In this work, we implement goal-oriented error control and spatial mesh adaptivity for stationary fluid-structure interaction (FSI). The a posteriori error estimator is accomplished using the dual-weighted residual method in which the adjoint equation arises. The fluid-structure interaction problem is formulated within a variational-monolithic framework using arbitrary Lagrangian-Eulerian coordinates. The overall problem is nonlinear and solved with Newton’s method. We specifically consider the FSI-1 benchmark problem in which quantities of interest include the elastic beam displacements, drag, and lift. The implementation is based on the deal.II finite element library and provided open-source published on github https://github.com/tommeswick/goal-oriented-fsi. Possible extensions are discussed in the source code and in the conclusions of this paper.
Access status: Abierto ,
Multigrid Reduced in Time for Isogeometric Analysis
(Editorial Universitat Politècnica de València, 2022-05-11) Tielen, Roel; Möller, Matthias; Vuik, Kees
[EN] Isogeometric analysis (IGA) extends the finite element method (FEM) by employing high-order B-spline basis functions. Combined with method-of-lines time integration, IGA has become a competitive alternative to FEM for time-dependent problems. As processor clock frequencies plateau while core counts increase, however, classical sequential time integrators are increasingly the bottleneck in large-scale simulations. Multigrid Reduction in Time (MGRIT) is a parallel-in-time algorithm that exposes concurrency not only in space but also along the temporal dimension. This paper presents, to the best of our knowledge, the first application of MGRIT to discretizations arising from IGA. We evaluate its (parallel) performance across a variety of geometries, MGRIT hierarchies, and time-integration schemes. Numerical experiments show that MGRIT converges independently of mesh width, B-spline degree, and time-step size (Δt), and achieves high parallel efficiency within the IGA framework.
Access status: Abierto ,
Design and modelling of bioinspired 3D printed structures
(Editorial Universitat Politècnica de València, 2022-05-11) Garrido, Conrado; Alabort, Enrique; Barba, Daniel
[EN] Metamaterials are those that, through human engineering, have unusual properties that cannot be commonly found in nature. Recently, these metamaterials have been gaining importance due to the introduction of additive manufacturing technologies. Specifically, metamaterials known as lattice structures have advantages over bulk solid materials, such as increased strength and specific stiffness. However, in order to exploit these advantages of these exotic materials, we need robust and accurate tools to tailor and design their properties. The objective of this work is to present a complete systematic study of the different approaches for metamaterial computational design evaluating their advantages and drawbacks in terms of computational efficiency and accuracy in predicting the metamaterial mechanical properties.
Access status: Abierto ,
Simulation of the contact wire wear evolution in high speed overhead contact lines
(Editorial Universitat Politècnica de València, 2022-05-11) Gregori Verdú, Santiago; Gil-Romero, Jaime; Tur, Manuel; Pedrosa, Ana M.; Fuenmayor Fernández, Francisco-Javier; Escuela Técnica Superior de Ingeniería Aeroespacial y Diseño Industrial; Departamento de Ingeniería Mecánica y de Materiales; Instituto Universitario de Investigación Concertado de Ingeniería Mecánica y Biomecánica; Escuela Técnica Superior de Ingeniería Industrial; Agencia Estatal de Investigación
[EN] The overhead contact line or catenary is the structure composed of support elements and wires responsible for the power supply of the locomotive through sliding contact with the pantograph. This contact causes wear not only on the pantograph contact strips but also in the contact wire, which produces a reduction on its effective section and eventually its replacement, resulting in the stoppage of the rolling stock with its associate economical and operational drawbacks. For this reason, it is important for catenary designers to count with appropriate tools able to predict the contact wire wear behaviour for extending the service life of the system. This work proposes a strategy to simulate the long-term contact wire wear evolution considering the mutual influence between the dynamic behaviour and wear of the system. The method is based on two pillars: the efficient simulation of the catenary-pantograph dynamic interaction and a heuristic wear model which considers mechanical wear due to friction and electrical wear produced by Joule effect and electric arcs. With the proposed simulation tool, we analyse the effect on the long-term contact wire worn height of the train speed.

Examinar

Envíos recientes