Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: ALE-Lagrangian approach.
Artykuły w czasopismach na temat „ALE-Lagrangian approach”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych artykułów w czasopismach naukowych na temat „ALE-Lagrangian approach”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj artykuły w czasopismach z różnych dziedzin i twórz odpowiednie bibliografie.
1
Zreid, Imadeddin, Ronny Behnke i Michael Kaliske. "ALE formulation for thermomechanical inelastic material models applied to tire forming and curing simulations". Computational Mechanics 67, nr 6 (24.04.2021): 1543–57. http://dx.doi.org/10.1007/s00466-021-02005-5.
Pełny tekst źródłaStreszczenie:
AbstractForming of tires during production is a challenging process for Lagrangian solid mechanics due to large changes in the geometry and material properties of the rubber layers. This paper extends the Arbitrary Lagrangian–Eulerian (ALE) formulation to thermomechanical inelastic material models with special consideration of rubber. The ALE approach based on tracking the material and spatial meshes is used, and an operator-split is employed which splits up the solution within a time step into a mesh smoothing step, a history remapping step and a Lagrangian step. Mesh distortion is reduced in the smoothing step by solving a boundary value problem. History variables are subsequently remapped to the new mesh with a particle tracking scheme. Within the Lagrangian steps, a fully coupled thermomechanical problem is solved. An advanced two-phase rubber model is incorporated into the ALE approach, which can describe green rubber, cured rubber and the transition process. Several numerical examples demonstrate the superior behavior of the developed formulation in comparison to purely Lagrangian finite elements.
2
Minh Thanh, Vu, Sigit P. Santosa, Djarot Widagdo i Ichsan Setya Putra. "Steel Plate Behavior under Blast Loading-Numerical Approach Using LS-DYNA". Applied Mechanics and Materials 842 (czerwiec 2016): 200–207. http://dx.doi.org/10.4028/www.scientific.net/amm.842.200.
Pełny tekst źródłaStreszczenie:
Plate is one of the most common structural elements, which appears in a wide range of applications: steel bridges, blast-resistance door, and armored vehicles. In this paper, the behavior of steel plates under blast loading was studied through numerical approaches using LS DYNA and then the results were compared with the experiment results obtained from existing literatures. The study of a clamped square plate exposed to blast loading in three distinct stand-off distances. Three different methods of modeling blast loading were used, namely: empirical blast method, arbitrary Lagrangian Eulerian (ALE) method, and coupling of Lagrangian and Eulerian method. The empirical blast method was deployed by using key card *LOAD_BLAST in LS-DYNA. In ALE method, Langrangian and Eulerian solution were combined in the same model and the fluid-structure interaction (FSI) handled by coupling algorithm. In coupling method, the engineering load blast in LS-DYNA (*LOAD_BLAST_ENHANCED) was coupled with the ALE solver. In terms of central deflection and computational time, the coupling method appeared to be the best method which is very time-effective and showed a good correlation with the experiment data.
3
ASGARI, ALIASGHAR, i ALI NAYEBI. "IMPLEMENTATION OF THE EULERIAN AND THE ARBITRARY LAGRANGIAN–EULERIAN DESCRIPTIONS IN FINITE ELEMENT SIMULATION OF EXTRUSION PROCESSES". International Journal of Computational Materials Science and Engineering 02, nr 03n04 (grudzień 2013): 1350013. http://dx.doi.org/10.1142/s2047684113500139.
Pełny tekst źródłaStreszczenie:
In this paper, backward and forward–backward-radial extrusion processes of aluminum have been simulated using finite element method. Due to the extreme deformation of the workpiece and the restrictions of the Lagrangian approach to simulate such problems, the arbitrary Lagrangian–Eulerian (ALE) and the Eulerian descriptions have been implemented in backward and forward–backward-radial extrusion processes, respectively. Operator-split method is used to solve the coupled governing equations of the Eulerian and the ALE formulations. To validate the finite element simulations, the results have been compared with experimental data in terms of extrusion load and geometry of final products. A good agreement has been seen between the results demonstrating the capability of the Eulerian and the ALE methods on finite element simulation of extrusion processes.
4
Joyot, P., R. Rakotomalala, O. Pantalé, M. Touratier i N. Hakem. "A numerical simulation of steady state metal cutting". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 212, nr 5 (1.05.1998): 331–41. http://dx.doi.org/10.1243/0954406981521268.
Pełny tekst źródłaStreszczenie:
An arbitrary Lagrangian-Eulerian (ALE) approach is used to model the orthogonal metal cutting in a steady state situation. The thermomechanical model includes the effects of elasticity, plasticity, strain rate, large strains and friction with heat generated between the tool and the chip. The ALE formulation can combine the advantages of both the Eulerian and Lagrangian approaches in a single description. Particularly, problems linked to the free surface in a Eulerian description and those linked to severe mesh distortions in a Lagrangian one can be solved by this formulation. The ALE governing equations are briefly reviewed in this paper; finite element and finite volume methods are used for the discretization of the conservation equations and an explicit time integration is adopted. Only the steady state solution is required; the ALE formulation is exploited to update the free and the contact surfaces. The model predicts the thermomechanical quantities, the chip geometry and the cutting forces from the cutting data and the material and friction parameters. Cutting experiments were performed with 42CD4 steel and comparisons of experimental tool forces and chip geometry with the numerical results are presented.
5
Sridhar, Praveen, Juan Rodríguez Prieto i Kristin de Payrebrune. "Modeling Grinding Processes—Mesh or Mesh-Free Methods, 2D or 3D Approach?" Journal of Manufacturing and Materials Processing 6, nr 5 (13.10.2022): 120. http://dx.doi.org/10.3390/jmmp6050120.
Pełny tekst źródłaStreszczenie:
The objectives of this study are mainly two: (1) to validate whether a single grain scratch process can be modeled in two dimensions under the assumption of plane strain, and (2) to select the best discretization approach to model a single grain scratch process. This paper first focuses on the simulation of the orthogonal cutting process (aluminum alloy A2024 T351) using two mesh-based discretization approaches, the pure Lagrangian method (LAG) and the arbitrary Lagrangian–Eulerian method (ALE), and two particle-based approaches, the particle finite element method (PFEM) and smooth particle hydrodynamics (SPH), for both positive and negative rake angles. Benchmarking of the orthogonal cutting models at a rake angle of γ=20∘ is performed with the results of the process forces (cutting and passive forces) of a turning experiment from the literature. It is shown that all models are able to predict the cutting forces, but not the passive force. The orthogonal cutting model is further extended to simulate the cutting mechanism with negative rake tool geometries typically found in grinding and single grit scratching processes. The effects of the negative rake angles on the discretization approaches are studied. The calculated process forces are also compared to the measurements of the single grit scratch process performed at our laboratory. The 2D orthogonal cutting models significantly overestimate the process forces. One of the reasons why the orthogonal 2D cutting model is inadequate is that it cannot describe the complex mechanisms of material removal such as rubbing, plowing, and cutting. To account for these phenomena in LAG, ALE, and SPH discretization approaches, a 3D scratch model is developed. When comparing the process forces of the 3D model with the experimental measurements, all three discretization approaches show good agreement. However, it can be seen that the ALE model most closely matches the process forces with the experimental results. Finally, the ALE 3D scratch model was subjected to sensitivity analysis by changing the cutting speed, the depth of cut and the tool geometry. The results clearly show that the ALE method not only predicts the process forces and form the trends observed in the scratching experiments, but also predicts the scratch topography satisfactorily. Hence, we conclude that a 3D model is necessary to describe a scratch process and that the ALE method is the best discretization method.
6
WANG, Y. J., N. ZHAO, C. W. WANG i D. H. WANG. "A SECOND-ORDER ADAPTIVE ARBITRARY LAGRANGIAN–EULERIAN METHOD FOR THE COMPRESSIBLE EULER EQUATIONS". Modern Physics Letters B 23, nr 04 (10.02.2009): 583–601. http://dx.doi.org/10.1142/s0217984909017923.
Pełny tekst źródłaStreszczenie:
Most of finite volume schemes in the Arbitrary Lagrangian–Eulerian (ALE) method are constructed on the staggered mesh, where the momentum is defined at the nodes and the other variables (density, pressure and specific internal energy) are cell-centered. However, this kind of schemes must use a cell-centered remapping algorithm twice which is very inefficient. Furthermore, there is inconsistent treatment of the kinetic and internal energies.1 Recently, a new class of cell-centered Lagrangian scheme for two-dimensional compressible flow problems has been proposed in Ref. 2. The main new feature of the algorithm is the introduction of four pressures on each edge, two for each node on each side of the edge. This scheme is only first-order accurate. In this paper, a second-order cell-centered conservative ENO Lagrangian scheme is constructed by using an ENO-type approach to extend the spatial second-order accuracy. Time discretization is based on a second-order Runge–Kutta scheme. Combining a conservative interpolation (remapping) method3,4 with the second-order Lagrangian scheme, a kind of cell-centered second-order ALE methods can be obtained. Some numerical experiments are made with this method. All results show that our method is effective and have second-order accuracy. At last, in order to further increase the resolution of shock regions, we use an adaptive mesh generation based on the variational principle5 as a rezoned strategy for developing a class of adaptive ALE methods. Numerical experiments are also presented to valid the performance of the proposed method.
7
Boman, Romain, i Jean Philippe Ponthot. "Continuous Roll Forming Simulation Using Arbitrary Lagrangian Eulerian Formalism". Key Engineering Materials 473 (marzec 2011): 564–71. http://dx.doi.org/10.4028/www.scientific.net/kem.473.564.
Pełny tekst źródłaStreszczenie:
Due to the length of the mill, accurate modelling of stationary solution of continuous cold roll forming by the finite element method using the classical Lagrangian formulation usually requires a very large mesh leading to huge CPU times. In order to model industrial forming lines including many tools in a reasonable time, the sheet has to be shortened or the element size has to be increased leading to inaccurate results. On top of this, applying loads and boundary conditions on this smaller sheet is usually more difficult than in the continuous case. Moreover, transient dynamic vibrations, which are unnecessarily computed, may appear when the sheet hits each tool, decreasing the convergence rate of the numerical simulation. Beside this classical Lagrangian approach, an alternative method is given by the Arbitrary Lagrangian Eulerian (ALE) formalism which consists in decoupling the motion of the material and the mesh. Starting from an initial guess of the sheet geometry between the rolls, the numerical simulation is performed until the stationary state is reached with a mesh, the nodes of which are fixed in the rolling direction but are free to move on perpendicular plane, following the geometrical boundary of the sheet. The whole forming line can then be modelled using a limited number of brick and contact elements because the mesh is only refined near the tools where bending and contact occur. In this paper, ALE results are compared to previous Lagrangian simulations and experimental measurement on a U-channel, including springback. Advantages of the ALE method are finally demonstrated by the simulation of a tubular rocker panel on a 16-stands forming mill.
8
Ziefle, M., i U. Nackenhorst. "An Internal Variable Update Procedure for the Treatment of Inelastic Material Behavior within an ALE-Description of Rolling Contact". Applied Mechanics and Materials 9 (październik 2007): 157–71. http://dx.doi.org/10.4028/www.scientific.net/amm.9.157.
Pełny tekst źródłaStreszczenie:
Arbitrary Lagrangian Eulerian (ALE) methods provide a well established basis for the numerical analysis of rolling contact problems, the theoretical framework is well developed for elastic constitutive behavior. Special measures are necessary for the treatment of history dependent and explicitly time dependent material behavior within the relative–kinematic ALE– picture. In this presentation a fractional step approach is suggested for the integration of the evolution equation for internal variables. A Time–Discontinuous Galerkin (TDG) method is introduced for the numerical solution of the related advection equations. The advantage of TDG–methods in comparison with more traditional integration schemes is studied in detail. The practicability of the approach is demonstrated by the finite element analysis of rolling tires.
9
Yoo, Yo Han, Young Sik Choi i Joon Won Lee. "Influence of Blast Wave on Behavior of Steel Plate". Applied Mechanics and Materials 619 (sierpień 2014): 28–32. http://dx.doi.org/10.4028/www.scientific.net/amm.619.28.
Pełny tekst źródłaStreszczenie:
The threat of terrorism has led to increased awareness about protecting properties from damage in terrorist attacks. With the rapid growth of the computer industry and progress in the field of finite-element analysis, evaluations of conventional weapons focus more on simulations than on experiments. There are many approaches to simulate blast and impact. These include Eulerian, Lagrangian, multi-material arbitrary Lagrangian-Eulerian (MM-ALE), and the meshless approach of smooth particle hydrodynamics (SPH) methods. Each method has distinct advantages. In this study, finite-element analysis was applied to simulate a 1 kg trinitrotoluene (TNT) blast in front of a 20-mm-thick steel plate. Three different approaches were simulated: Eulerian, MM-ALE, and SPH. Each method gave different results for the von Mises stress distribution, peak pressure, and displacement of the steel plate. A comparison of the three results implies that using one of these three approaches may generate a significant blast simulation.
10
Antona, Rubén, Renato Vacondio, Diego Avesani, Maurizio Righetti i Massimiliano Renzi. "Towards a High Order Convergent ALE-SPH Scheme with Efficient WENO Spatial Reconstruction". Water 13, nr 17 (4.09.2021): 2432. http://dx.doi.org/10.3390/w13172432.
Pełny tekst źródłaStreszczenie:
This paper studies the convergence properties of an arbitrary Lagrangian–Eulerian (ALE) Riemann-based SPH algorithm in conjunction with a Weighted Essentially Non-Oscillatory (WENO) high-order spatial reconstruction, in the framework of the DualSPHysics open-source code. A convergence analysis is carried out for Lagrangian and Eulerian simulations and the numerical results demonstrate that, in absence of particle disorder, the overall convergence of the scheme is close to the one guaranteed by the WENO spatial reconstruction. Moreover, an alternative method for the WENO spatial reconstruction is introduced which guarantees a speed-up of 3.5, in comparison with the classical Moving Least-Squares (MLS) approach.
11
Wang, He Ping, i Xue Ping Zhang. "Thermal-Mechanical Effect on Temperature/Stress Distribution when Orthogonal Cutting Bearing Steel". Key Engineering Materials 407-408 (luty 2009): 420–23. http://dx.doi.org/10.4028/www.scientific.net/kem.407-408.420.
Pełny tekst źródłaStreszczenie:
An explicit dynamic coupled thermal-mechanical Arbitrary Lagrangian Eulerian (ALE) model was established to simulate orthogonal cutting AISI 52100 bearing steel, and its temperature and stress distribution. Based on ABAQUS, The ALE approach effectively simulates plastic flow around round edge of the cutting tool without employing chip separation criteria. The calculation results reveal that cutting speed and cutting depth have great impact on chip morphology, stress and temperature distribution in the finished surface and subsurface, the predicted temperature agrees well with experiment data obtained under the similar cutting conditions as well as the change in chip morphology from continuous to sawtooth as the cutting speed increases.
12
Boman, Romain, i Jean Philippe Ponthot. "Application of the Arbitrary Lagrangian Eulerian Formalism to Stationary Roll Forming Simulations". Advanced Materials Research 189-193 (luty 2011): 1827–33. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.1827.
Pełny tekst źródłaStreszczenie:
Due to the length of the mill, accurate modelling of stationary solution of continuous cold roll forming by the finite element method using the classical Lagrangian formulation usually requires a very large mesh leading to huge CPU times. In order to model industrial forming lines including many tools in a reasonable time, the sheet has to be shortened or the element size has to be increased leading to inaccurate results. On top of this, applying loads and boundary conditions on this smaller sheet is usually more difficult than in the continuous case. Moreover, transient dynamic vibrations, which are unnecessarily computed, may appear when the sheet hits each tool, decreasing the convergence rate of the numerical simulation. Beside this classical Lagrangian approach, an alternative method is given by the Arbitrary Lagrangian Eulerian (ALE) formalism which consists in decoupling the motion of the material and the mesh. Starting from an initial guess of the sheet geometry between the rolls, the numerical simulation is performed until the stationary state is reached with a mesh, the nodes of which are fixed in the rolling direction but are free to move on perpendicular plane, following the geometrical boundary of the sheet. The whole forming line can then be modelled using a limited number of brick and contact elements because the mesh is only refined near the tools where bending and contact occur. In this paper, ALE results are compared to previous Lagrangian simulations and experimental measurement on a U-channel, including springback.
13
Leprevost, Antonin, Vincent Faucher i Maria Adela Puscas. "A Computationally Efficient Dynamic Grid Motion Approach for Arbitrary Lagrange–Euler Simulations". Fluids 8, nr 5 (16.05.2023): 156. http://dx.doi.org/10.3390/fluids8050156.
Pełny tekst źródłaStreszczenie:
The present article addresses the topic of grid motion computation in Arbitrary Lagrange–Euler (ALE) simulations, where a fluid mesh must be updated to follow the displacements of Lagrangian boundaries. A widespread practice is to deduce the motion for the internal mesh nodes from a parabolic equation, such as the harmonic equation, introducing an extra computational cost to the fluid solver. An alternative strategy is proposed to minimize that cost by changing from the parabolic equation to a hyperbolic equation, implementing an additional time derivative term allowing an explicit solution of the grid motion problem. A fictitious dynamic problem is thus obtained for the grid, with dedicated material parameters to be carefully chosen to enhance the computational efficiency and preserve the mesh quality and the accuracy of the physical problem solution. After reminding the basics of the ALE expression of the Navier–Stokes equations and describing the proposed hyperbolic equation for the grid motion problem, the paper provides the necessary characterization of the influence of the fictitious grid parameters and the analysis of the robustness of the new approach compared to the harmonic reference equation on a significant 2D test case. A 3D test case is finally extensively studied in terms of computational performance to highlight and discuss the benefits of the hyperbolic equation for ALE grid motion.
14
Gröger, Benjamin, Jingjing Wang, Tim Bätzel, Andreas Hornig i Maik Gude. "Modelling and Simulation Strategies for Fluid–Structure-Interactions of Highly Viscous Thermoplastic Melt and Single Fibres—A Numerical Study". Materials 15, nr 20 (17.10.2022): 7241. http://dx.doi.org/10.3390/ma15207241.
Pełny tekst źródłaStreszczenie:
A virtual test setup for investigating single fibres in a transverse shear flow based on a parallel-plate rheometer is presented. The investigations are carried out to verify a numerical representation of the fluid–structure interaction (FSI), where Arbitrary Lagrangian–Eulerian (ALE) and computational fluid dynamics (CFD) methods are used and evaluated. Both are suitable to simulate flexible solid structures in a transverse shear flow. Comparative investigations with different model setups and increasing complexity are presented. It is shown, that the CFD method with an interface-based coupling approach is not capable of handling small fibre diameters in comparison to large fluid domains due to mesh dependencies at the interface definitions. The ALE method is more suited for this task since fibres are embedded without any mesh restrictions. Element types beam, solid, and discrete are considered for fibre modelling. It is shown that the beam formulation for ALE and 3D solid elements for the CFD method are the preferred options.
15
Pedro, Josè C., i P. Sibanda. "An Algorithm for the Strong-Coupling of the Fluid-Structure Interaction Using a Staggered Approach". ISRN Applied Mathematics 2012 (20.06.2012): 1–14. http://dx.doi.org/10.5402/2012/391974.
Pełny tekst źródłaStreszczenie:
We present a staggered approach for the solution of the piston fluid-structure problem in a time-dependent domain. The one-dimensional fluid flow is modelled using the nonlinear Euler equations. We investigate the time marching fluid-structure interaction and integrate the fluid and structure equations alternately using separate solvers. The Euler equations are written in moving mesh coordinates using the arbitrary Lagrangian-Eulerian (ALE) approach and discretised in space using the finite element method while the structure is integrated in time using an implicit finite difference Newmark-Wilson scheme. The influence of the time lag is studied by comparing two different structural predictors.
16
Ray, Saurya Ranjan, i Josef Ballmann. "Backward Difference Scheme for Simulating Unsteady Compressible Flow on Deforming Mesh in an Implicit Adaptive Solver". Applied Mechanics and Materials 598 (lipiec 2014): 493–97. http://dx.doi.org/10.4028/www.scientific.net/amm.598.493.
Pełny tekst źródłaStreszczenie:
The paper describes the derivation of the numerical formulation of a second order time accurate and Geometrically Conservative Backward Difference Scheme (BDF) for transient flow simulation of Arbitrary Lagrangian Eulerian (ALE) problems using the control volume approach. The required modification to implement the scheme in an implicit adaptive flow solver is explained. The accuracy and robustness of the current formulation is demonstrated by simulating unsteady flow field over a sinusoidally pitching NACA0012 airfoil with larger allowable timestep in comparison to an existing Mid-point scheme.
17
Jin, Yulan, Ekkehard Holzbecher i Martin Sauter. "A novel modeling approach using arbitrary Lagrangian–Eulerian (ALE) method for the flow simulation in unconfined aquifers". Computers & Geosciences 62 (styczeń 2014): 88–94. http://dx.doi.org/10.1016/j.cageo.2013.10.002.
Pełny tekst źródła
18
Patel, Yogesh Ramesh. "FSI in Wind Turbines: A Review". International Journal of Recent Contributions from Engineering, Science & IT (iJES) 8, nr 3 (30.09.2020): 37. http://dx.doi.org/10.3991/ijes.v8i3.16595.
Pełny tekst źródłaStreszczenie:
This paper provides a brief overview of the research in the field of Fluid-structure interaction in Wind Turbines. Fluid-Structure Interaction (FSI) is the interplay of some movable or deformable structure with an internal or surrounding fluid flow. Flow brought about vibrations of two airfoils used in wind turbine blades are investigated by using a strong coupled fluid shape interplay approach. The approach is based totally on a regularly occurring Computational Fluid Dynamics (CFD) code that solves the Navier-Stokes equations defined in Arbitrary Lagrangian-Eulerian (ALE) coordinates by way of a finite extent method. The need for the FSI in the wind Turbine system is studied and comprehensively presented.
19
Collé, Anthony, Jérôme Limido, Thomas Unfer i Jean-Paul Vila. "Innovative meshless approach for shaped charges applications". Journal of Physics: Conference Series 2154, nr 1 (1.01.2022): 012002. http://dx.doi.org/10.1088/1742-6596/2154/1/012002.
Pełny tekst źródłaStreszczenie:
Abstract We focus here on modelling shaped charges. Combining large deformations, numerous interfaceproductions, and strong damage mechanisms, those events are particularly challenging from a numerical point of view. Eulerian finite element methods are classically used for such modeling.However, they induce very long computation times, accuracy losses (projection algorithms), anddifficulties with opening criteria related to jet fragmentation. Among the Lagrangian approaches, the meshless method called Smoothed Particle Hydrodynamics (SPH) appears as a relevant alternative to prevent such shortcomings. Based on a set of moving interpolation points, it disregards any connectivity between its elements which makes it naturally well suited to handle material failure. Nevertheless, SPH schemes suffer from well-known instabilities questioning their accuracy and activating nonphysical processes,such as numerical fragmentation. Many stabilizing tools are available in the literature however, they either raise conservation and consistency issues or drastically increase the computation times. We propose then to use an alternative scheme called γ-SPH-ALE. Based on the ALE framework, it achieves robust and consistent stabilization through an arbitrary description of motion. Thanks to CFL-like conditions obtained through a nonlinear stability analysis, the scheme stability is ensured. By preventing spurious oscillations in elastic waves and correcting the so-called tensile instability, both stability and accuracy are increased regarding classical approaches. Also, taking advantage of GPU computing, such results are achieved in reduced computation times contrary to classical CPUimplementations. Its implementation on a “Viper” shaped charge shows that the scheme handles the jet generation process as well as its resulting interaction with a target.
20
Bleck, Rainer, Stan Benjamin, Jin Lee i Alexander E. MacDonald. "On the Use of an Adaptive, Hybrid-Isentropic Vertical Coordinate in Global Atmospheric Modeling". Monthly Weather Review 138, nr 6 (1.06.2010): 2188–210. http://dx.doi.org/10.1175/2009mwr3103.1.
Pełny tekst źródłaStreszczenie:
Abstract This article is one in a series describing the functionality of the Flow-Following, Finite-Volume Icosahedral Model (FIM) developed at NOAA’s Earth System Research Laboratory. Emphasis in this article is on the design of the vertical coordinate—the “flow following” aspect of FIM. The coordinate is terrain-following near the ground and isentropic in the free atmosphere. The spatial transition between the two coordinates is adaptive and is based on the arbitrary Lagrangian–Eulerian (ALE) paradigm. The impact of vertical resolution trade-offs between the present hybrid approach and traditional terrain-following coordinates is demonstrated in a three-part case study.
21
Legrand, Pierre, S. Kerampran i M. Arrigoni. "Replacing Detonation by Compressed Balloon Approaches in Finite Element Models". Advances in Civil Engineering 2020 (12.05.2020): 1–16. http://dx.doi.org/10.1155/2020/1497632.
Pełny tekst źródłaStreszczenie:
The evaluation of blast effects from malicious or accidental detonation of an explosive device is really challenging especially on large buildings. Indeed, the time and space scales of the explosion together with the chemical reactions and fluid mechanics make the numerical model really difficult to achieve acceptable structural design. Nevertheless, finite element methods and especially Arbitrary Lagrangian Eulerian (ALE) have been extensively used in the past few decades with some simplifications. Among them, the replacement of the explosive event by a compressed balloon of detonation products has been proven useful in numerous different situations. Unfortunately, the ALE algorithm does not achieve a proper energy balance through the numerical integration of the discrete scheme; this important drawback is not compensated by the use of the classical compressed balloon approach. The paper focuses on increasing the radius of the equivalent ideal gas balloon in order to achieve better energy balance and thus better results at later stages of the blast wave propagation.
22
Cheng, Lei, Guo Jie Huang, Jian Wei Wang, Wei Xiao i Shui Sheng Xie. "Numerical Simulation of Extrusion Process to Produce Complex Aluminum Profiles Using the ALE Approach". Advanced Materials Research 1004-1005 (sierpień 2014): 1260–64. http://dx.doi.org/10.4028/www.scientific.net/amr.1004-1005.1260.
Pełny tekst źródłaStreszczenie:
Although still having certain limitations, the numerical simulation technology has been increasingly applied to aid in optimizing the aluminum extrusion process and die design. In the present research, numerical simulations of the profiles extrusion process were performed, using the Finite Volume Method (FVM) and Finite Element Method (FEM) to make use of the individual merits of the Euler approach and Lagrange approach, respectively. The application of the simulation technology to produce large, complex profiles has, however, been quite limited. In order to solve the limited, numerical simulation of aluminum profiles with large and complicated cross-section in extrusion process was achieved using Arbitrary Lagrangian-Eulerian (ALE) approach, and non-uniform velocities at the die exit, leading to extrudate distortions, were predicted. Extrusion experiments proved that the die with the optimized design could circumvent the distortion problem. The numerical simulation technology can indeed be effectively used to reduce the number of die trials and offer the potential to realize zero die trial.
23
Lei, Peng-Fei, Jia-Zhong Zhang, Wei Kang, Sheng Ren i Le Wang. "Unsteady Flow Separation and High Performance of Airfoil with Local Flexible Structure at Low Reynolds Number". Communications in Computational Physics 16, nr 3 (wrzesień 2014): 699–717. http://dx.doi.org/10.4208/cicp.111013.090514a.
Pełny tekst źródłaStreszczenie:
AbstractThe unsteady flow separation of airfoil with a local flexible structure (LFS) is studied numerically in Lagrangian frames in detail, in order to investigate the nature of its high aerodynamic performance. For such aeroelastic system, the characteristic-based split (CBS) scheme combined with arbitrary Lagrangian-Eulerian (ALE) framework is developed firstly for the numerical analysis of unsteady flow, and Galerkin method is used to approach the flexible structure. The local flexible skin of airfoil, which can lead to self-induced oscillations, is considered as unsteady perturbation to the flow. Then, the ensuing high aerodynamic performances and complex unsteady flow separation at low Reynolds number are studied by Lagrangian coherent structures (LCSs). The results show that the LFS has a significant influence on the unsteady flow separation, which is the key point for the lift enhancement. Specifically, the oscillations of the LFS can induce the generations of moving separation and vortex, which can enhance the kinetic energy transport from main flow to the boundary layer. The results could give a deep understand of the dynamics in unsteady flow separation and flow control for the flow over airfoil.
24
Yoxall, A., J. Luxmoore i E. Rodriguez-Falcon. "Load-path-based modelling strategies for synovial joints". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 223, nr 9 (24.04.2009): 2143–53. http://dx.doi.org/10.1243/09544062jmes1448.
Pełny tekst źródłaStreszczenie:
For designers there is a desire to understand the nature of strength and dexterity with regards to ageing, since by 2020 it is estimated that the majority of the UK population will be over 50 and the ageing processes lead to changes in a person's ability to grasp and manipulate objects. To that end work has been ongoing by the authors to model the human hand using the technique of finite-element (FE) analysis. Initially simple FE models were produced until better knowledge of the necessary issues could be obtained. This incremental approach led to the understanding of the nature of gripping and manipulation of objects before moving on to detailed modelling of skin, joints, and tendons. As part of this work, the authors undertook a detailed study on the most appropriate methods for modelling the synovial joint. The methods chosen were the Lagrangian formulation, arbitrary Lagrangian formulation, smoothed particle hydrodynamics, along with a constrained joint model. Little previous work has been undertaken in this area and is of interest not only for biomechanics modellers, but also for simulation engineers looking to model fluid—structural interaction problems. It was found that the arbitrary Lagrangian Eulerian (ALE) model was probably the most successful when compared against the small amount of data available in the literature.
25
Khalifa, M., i T. Duyun. "CLASSIFICATION AND ZONING OF RIVERINE TERRITORIES OF SMALL TOWNS ON THE EXAMPLE OF THE BELGOROD REGION". Bulletin of Belgorod State Technological University named after. V. G. Shukhov 5, nr 8 (4.08.2020): 101–9. http://dx.doi.org/10.34031/2071-7318-2020-5-8-101-109.
Pełny tekst źródłaStreszczenie:
The paper presents an analytical study for comparing different numerical methods used for the modeling of cutting process using finite element method. The aims of this study is to compare capabilities of FE software package (Deform, AdvantEdge, ANSYS Workbench and ABAQUS). The main stages of modeling are discussed, as well as well-known methods and approaches used for their implementation. Main formulations for description of motion of deformable materials are analyzed to Lagrangian approach, Eulerian approach, Arbitrary Lagrangian Eulerian (ALE) approach. Numerical techniques to model chip separation are grouped as geometrical and physical. In this paper two strategies for time integration, implicit and explicit schemes are reviewed. Various models of friction between the chip and the tool are discussed: Amonton-Coulomb's Law, Prandtl's Law and Zorev. In this work, modeling and simulation of cutting process is carried out by FEM software ABAQUS. As a result of modeling, the stress and strain fields for both the workpiece and the tool are presented, as well as the thermal field of the workpiece and the chip. The numerical results obtained are compared with the results have been carried out previously using software ANSYS Workbench. The numerical values of temperatures, stresses and deformations correspond to traditional concepts of the cutting process, as well as experimental data presented in open sources.
26
Pin, Facundo Del, Sergio Idelsohn, Eugenio Oñate i Romain Aubry. "The ALE/Lagrangian Particle Finite Element Method: A new approach to computation of free-surface flows and fluid–object interactions". Computers & Fluids 36, nr 1 (styczeń 2007): 27–38. http://dx.doi.org/10.1016/j.compfluid.2005.06.008.
Pełny tekst źródła
27
Andreotti, Riccardo, Sergio Abate, Andrea Casaroli, Mauro Quercia, Riccardo Fossati i Marco V. Boniardi. "A Simplified ALE model for finite element simulation of ballistic impacts with bullet splash – development and experimental validation". Frattura ed Integrità Strutturale 15, nr 57 (22.06.2021): 223–45. http://dx.doi.org/10.3221/igf-esis.57.17.
Pełny tekst źródłaStreszczenie:
An original simplified finite element model is proposed to simulate the effects of non-penetrating ballistic impacts causing the so-called bullet splash phenomenon (complete bullet fragmentation), while no fragmentation is caused to the target. The model is based on the Arbitrary Lagrangian Eulerian formulation (ALE) and it simulates the impact as a fluid-structure interaction. The bullet splash phenomenon has been tested by experimental analyses of AISI 304L plates impacted by 9x21 FMJ (full metal jacket) bullets. The model has been developed with the aim of creating a simplified approach to be used in the industry and forensic sciences to simulate the non-penetrating interaction of soft impactors with hard targets. Comparisons between evidence and simulation results lead to the conclusion that the proposed approach can be used in a conservative way to estimate both local and global effects of bullet-splash phenomena.
28
LEVI-HEVRONI, D., A. LEVY, G. BEN-DOR i S. SOREK. "Numerical investigation of the propagation of planar shock waves in saturated flexible porous materials: development of the computer code and comparison with experimental results". Journal of Fluid Mechanics 462 (10.07.2002): 285–306. http://dx.doi.org/10.1017/s0022112002008583.
Pełny tekst źródłaStreszczenie:
The three-dimensional governing equations of the flow field that is developed when an elasto-plastic exible porous medium, capable of undergoing extremely large deformations, is struck head-on by a shock wave, are developed using a multi-phase approach. The one-dimensional version of these equations is solved numerically using an arbitrary Lagrangian–Eulerian (ALE) based numerical code. The numerical predictions are compared qualitatively to experimental results from various sources and good agreement is obtained. This study complements our earlier study in which we developed and solved, using a total variation diminishing (TVD) based numerical code, the governing equations of the flow field that is developed when an elastic rigid porous medium, capable of undergoing only very small deformations, is struck head-on by a shock wave.
29
Suwannachit, Anuwat, i Udo Nackenhorst. "A Novel Approach for Thermomechanical Analysis of Stationary Rolling Tires within an ALE–Kinematic Framework". Tire Science and Technology 41, nr 3 (1.07.2013): 174–95. http://dx.doi.org/10.2346/tire.13.410304.
Pełny tekst źródłaStreszczenie:
ABSTRACT A new computational technique for the thermomechanical analysis of tires in stationary rolling contact is suggested. Different from the existing approaches, the proposed method uses the constitutive description of tire rubber components, such as large deformations, viscous hysteresis, dynamic stiffening, internal heating, and temperature dependency. A thermoviscoelastic constitutive model, which incorporates all the mentioned effects and their numerical aspects, is presented. An isentropic operator-split algorithm, which ensures numerical stability, was chosen for solving the coupled mechanical and energy balance equations. For the stationary rolling-contact analysis, the constitutive model presented and the operator-split algorithm are embedded into the Arbitrary Lagrangian Eulerian (ALE)–relative kinematic framework. The flow of material particles and their inelastic history within the spatially fixed mesh is described by using the recently developed numerical technique based on the Time Discontinuous Galerkin (TDG) method. For the efficient numerical solutions, a three-phase, staggered scheme is introduced. First, the nonlinear, mechanical subproblem is solved using inelastic constitutive equations. Next, deformations are transferred to the subsequent thermal phase for the solution of the heat equations concerning the internal dissipation as a source term. In the third step, the history of each material particle, i.e., each internal variable, is transported through the fixed mesh corresponding to the convective velocities. Finally, some numerical tests with an inelastic rubber wheel and a car tire model are presented.
30
Morvarid, Masoud, Ali Rezghi, Alireza Riasi i Mojtaba Haghighi Yazdi. "3D numerical simulation of laminar water hammer considering pipe wall viscoelasticity and the arbitrary Lagrangian-Eulerian method". World Journal of Engineering 15, nr 2 (9.04.2018): 298–305. http://dx.doi.org/10.1108/wje-08-2017-0236.
Pełny tekst źródłaStreszczenie:
Purpose Analysis of fast transient flow in water pipe systems is an important issue for the prevention of unfavorable pressure oscillations and severe damage to the pipelines. This paper aims to present the performance of three-dimensional (3D) simulation of laminar water hammer caused by fast closure of valve. Design/methodology/approach The viscoelastic behavior of pipe wall is mathematically modeled by using the rheological model of Maxwell. The arbitrary Lagrangian–Eulerian (ALE) method is also used to simulate fluid–structure interaction. In this method, unlike the classical water hammer theory, the acoustic wave velocity is calculated during the numerical simulations and therefore it is not predetermined. Findings Investigating the velocity profiles and the shear stress diagrams for transient flow in elastic pipe showed that the strong effect of viscous forces on the near wall region in conjunction with the influence of inertial forces in the central region of the pipe leads to creation of reverse flow near the pipe wall. Comparing the numerical results obtained for elastic pipe with those of viscoelastic pipe revealed that during transient condition, the viscoelastic wall absorbs the energy of fluid and therefore pressure fluctuations of viscoelastic pipe are damped more quickly. Moreover, the 3D simulation of water hammer confirmed the plane wave hypothesis of water hammer. Originality/value The 3D Navier–Stokes equations are solved considering the viscoelasticity of the pipe and the ALE method using the software package of COMSOL Multiphysics.
31
Kugalur Palanisamy, Nithyaraaj, Edouard Rivière Lorphèvre, Pedro José Arrazola i François Ducobu. "Influence of Coulomb’s Friction Coefficient in Finite Element Modeling of Orthogonal Cutting of Ti6Al4V". Key Engineering Materials 926 (22.07.2022): 1619–28. http://dx.doi.org/10.4028/p-be47dp.
Pełny tekst źródłaStreszczenie:
The reliability of the pertinent parameters set of Johnson-Cook constitutive model is highly linked with the friction condition at the tool-chip-workpiece interface. In the present work, a study on the influence of Coulomb’s friction coefficient on the observables such as forces, chip thickness and chip curvature by FE simulation of orthogonal cutting of Ti6Al4V alloy has been carried out. A FE model with an Arbitrary Lagrangian-Eulerian (ALE) approach is employed to simulate the cutting process for different cutting conditions. The simulated results, for a wide range of friction conditions, are analyzed and compared with experimental results. The analysis show that the Coulomb’s friction coefficient has a direct link with the observables. The paper reveals that for accurate prediction of observables an optimized value of the coefficient of friction in correlation with the parameters values of the constitutive model is imperative.
32
Scholz, Patrick, Dmitry Sidorenko, Ozgur Gurses, Sergey Danilov, Nikolay Koldunov, Qiang Wang, Dmitry Sein, Margarita Smolentseva, Natalja Rakowsky i Thomas Jung. "Assessment of the Finite-volumE Sea ice-Ocean Model (FESOM2.0) – Part 1: Description of selected key model elements and comparison to its predecessor version". Geoscientific Model Development 12, nr 11 (25.11.2019): 4875–99. http://dx.doi.org/10.5194/gmd-12-4875-2019.
Pełny tekst źródłaStreszczenie:
Abstract. The evaluation and model element description of the second version of the unstructured-mesh Finite-volumE Sea ice-Ocean Model (FESOM2.0) are presented. The new version of the model takes advantage of the finite-volume approach, whereas its predecessor version, FESOM1.4 was based on the finite-element approach. The model sensitivity to arbitrary Lagrangian–Eulerian (ALE) linear and nonlinear free-surface formulation, Gent–McWilliams eddy parameterization, isoneutral Redi diffusion and different vertical mixing schemes is documented. The hydrographic biases, large-scale circulation, numerical performance and scalability of FESOM2.0 are compared with its predecessor, FESOM1.4. FESOM2.0 shows biases with a magnitude comparable to FESOM1.4 and simulates a more realistic Atlantic meridional overturning circulation (AMOC). Compared to its predecessor, FESOM2.0 provides clearly defined fluxes and a 3 times higher throughput in terms of simulated years per day (SYPD). It is thus the first mature global unstructured-mesh ocean model with computational efficiency comparable to state-of-the-art structured-mesh ocean models. Other key elements of the model and new development will be described in follow-up papers.
33
Jamai, Hanen, Bernard Pateyron, Habib Sammouda i M. El Ganaoui. "Numerical simulation of vertical Bridgman solidification of CdZnTe". International Journal for Simulation and Multidisciplinary Design Optimization 5 (2014): A23. http://dx.doi.org/10.1051/smdo/2014003.
Pełny tekst źródłaStreszczenie:
The solidification of the singular CdZnTe in axisymetric Vertical Bridgman (VB) cavity is investigated in the current study. The numerical approach is developed by using COMSOL Multiphysics software, which is based on finite elements method (FEM) with Arbitrary Lagrangian-Euleurian (ALE) formulation allowing treating the moving interface. Numerical aspects of different parameters that affect the solidification interface and present an important factor during the crystal growth’s process are presented and analyzed. Especial attention will be paid to investigate the thermophysical properties such as thermal diffusivity, heat capacity. Thermal conductivity and the effect of thermal condition specially the effect of cold temperature Tc which affects significantly the concavity and the convexity of the interface for specific ranges in the solidification of CdZnTe phenomena, but it is of great importance the crystal growth experts are not it given importance. It has been shown that this properties, the effect of Tc, and the variation of interface velocity affect the solid/liquid interface shape and the crystal growth process.
34
Valiorgue, Frédéric, Mathieu Girinon, Eric Feulvarch, Joël Rech i Philippe Gilles. "Local Global Method for the Prediction of Surface Residual Stresses in 3D Turning". Advanced Materials Research 996 (sierpień 2014): 598–602. http://dx.doi.org/10.4028/www.scientific.net/amr.996.598.
Pełny tekst źródłaStreszczenie:
Numerical simulation of turning is still one of the best solutions to understand and improve such a process. Since many years, researchers have tried to use several numerical approaches to go round the difficulties and to set up reliable models (Lagrangian, ALE,…). Currently no perfect complete solution is available and it is time to introduce dedicated models prone to simulate partially the phenomena in order to reach specific conditions linked with real industrial problematics. This paper will present a 3D local global method set up to predict surface residual stresses in finish turning. This approach uses two kinds of simulations. A first one that allows reaching thermo mechanical steady state around the cutting edge and the chip area. A second one which sequences the application of the extracted thermo mechanical fields onto the real workpiece surface. The obtained results concerning the residual stresses fields will then be compared with the ones recorded experimentally.
35
Sheshenin, S. V., i N. B. Artamonova. "The Simulation of the Nonlinear Consolidation of Porous Media". PNRPU Mechanics Bulletin, nr 1 (15.12.2022): 167–76. http://dx.doi.org/10.15593/perm.mech/2022.1.13.
Pełny tekst źródłaStreszczenie:
In this paper, the general formulation of the problem of coupled deformation of a porous deformable medium with a fluid flowing through the pores is formulated, mathematically investigated and numerically implemented within the framework of physical and geometric nonlinearity. We present the formulation of the problem in velocities of solid phase displacements and the rate of pore pressure change in differential and variational forms. A phenomenological approach was used to formulate the mechanical model. The equations of the coupled consolidation model were derived from the general conservation laws of continuum mechanics using spatial averaging over a representative volume element. The consolidation model took into account the change in the porosity and permeability of the medium during deformation. The equations of filtration and porosity change, originally presented in Euler approach, were reformulated in Lagrangian coordinates of the solid phase using the relative fluid velocity according to ALE (Arbitrary Lagrangian - Eulerian) approach. The Gâteaux differentiation technique was used to linearize the variational equilibrium equations. For spatial discretization of the saddle system of equations, the finite element method (FEM) was used: quadratic serendipity elements for approximating the equilibrium equations and Brick type elements for approximating the filtration equation. To solve the system of equilibrium and filtration equations, a generalization of the implicit scheme with internal iterations at each time step by the Uzawa method was used. The results of numerical simulation of elastoplastic deformation of a water-saturated soil under load with fluid outflow are presented. To simulate the constitutive relations of elastoplastic deformation of soil under short-term loads, a generalization of S.S. Grigoryan's model to large deformations is proposed. The calculations were carried out in our own program code. The developed consolidation model can be used to simulate the formation of tracking ruts and unevenness of natural roads, as well as to calculate the uneven settlement of engineering structures.
36
Baranowski, Paweł, Krzysztof Damaziak, Łukasz Mazurkiewicz, Piotr Mertuszka, Witold Pytel, Jerzy Małachowski, Bogumiła Pałac-Walko i Tristan Jones. "Destress Blasting of Rock Mass: Multiscale Modelling and Simulation". Shock and Vibration 2019 (21.07.2019): 1–11. http://dx.doi.org/10.1155/2019/2878969.
Pełny tekst źródłaStreszczenie:
In this paper, a multiscale modelling and simulation of destress blasting of rock mass is presented. The proposed and novel approach combines two separate 3D solutions: the first was obtained for the small-scale problem, face(s) blasting process, and the second for the global scale problem, seismic wave propagation within very large volumes of surrounding rock mass. Both the approaches were based on explicit dynamic modelling methodology using the central difference method. In the local case, the arbitrary Lagrangian–Eulerian (ALE) procedure with the Jones–Wilkins–Lee (JWL) equation defining an explosive material was used. For this purpose, a selected volume of a rock mass comprising a blasted mining face was modelled in detail. From the numerical simulation, pressure distribution over the modelled rock was obtained, which was the basis for an initial condition for the global 3D FE model. The peak particle velocity (ppv) distribution obtained from finite element analysis was compared with experimental outcomes. A reasonable agreement between both results was achieved; therefore, the adopted multiscale modelling approach confirmed its effectiveness and that it can be successfully implemented in further engineering practice.
37
Guo, Zhong-Zhou, Gang Dai, Hua Yang i Wei-Fang Chen. "Unsteady flow simulation of a variable-sweep morphing aircraft coupled with flight control system". International Journal of Modern Physics B 34, nr 14n16 (30.05.2020): 2040073. http://dx.doi.org/10.1142/s0217979220400731.
Pełny tekst źródłaStreszczenie:
Morphing aircraft has adjustable aerodynamic shapes and is suitable for variable flight conditions. And there have been growing interests in recent years. However, the forces and moments are highly nonlinear, bringing challenges in design and modeling of flight control system (FCS). In this paper, unsteady Computational Fluid Dynamics (CFD) simulations are performed by solving the Arbitrary Lagrangian–Eulerian (ALE) governing equations on unstructured dynamic mesh, then unsteady aerodynamic characteristics of a variable-sweep morphing aircraft at hypersonic speed are acquired. The nonlinearity index theory is employed to analyze the nonlinearity of pitching moments. FCS is designed using nonlinear dynamic inversion control, taking attitude angles and sweep angle into consideration. Unsteady flow simulation is performed using unsteady CFD coupled with FCS. Cases of open and close loop morphing flight over the variation of sweep angle corresponding to flight conditions are studied. Results show that the nonlinearity of unsteady forces and moments are significant. The combination of unsteady CFD and FCS provides a powerful approach to the study of morphing aircraft.
38
Tonin, Mateus Guimarães, i Alexandre Luis Braun. "Numerical Model for the Analysis of Fluid-Structure Interaction Problems with Cable Coupling". Defect and Diffusion Forum 427 (14.07.2023): 205–14. http://dx.doi.org/10.4028/p-tquqm7.
Pełny tekst źródłaStreszczenie:
The present work proposes the development of numerical tools for solving fluid-structure interaction (FSI) problems where the structure is coupled with cables. For the numerical treatment of fluids in incompressible flow, the Navier-Stokes and continuity equations are discretized using a semi-implicit version of the characteristic-based split (CBS) method in the context of the finite element method (FEM), where linear tetrahedral elements are used. In the presence of moving structures, the flow equations are described through an arbitrary Lagrangian-Eulerian (ALE) formulation and a numerical scheme of mesh movement is adopted. The structure is treated through a three-dimensional rigid body approach and the cable through an elastic model with geometric nonlinearity and spatial discretization by the nodal position finite element method (NPFEM). The system of equations of motion can be temporally discretized using the implicit Newmark and generalized-α methods and a partitioned coupling scheme is used taking into account fluid-structure and cable-structure couplings. The algorithms proposed here are verified using numerical applications.
39
Pynaert, Niels, Thomas Haas, Jolan Wauters, Guillaume Crevecoeur i Joris Degroote. "Wing Deformation of an Airborne Wind Energy System in Crosswind Flight Using High-Fidelity Fluid–Structure Interaction". Energies 16, nr 2 (4.01.2023): 602. http://dx.doi.org/10.3390/en16020602.
Pełny tekst źródłaStreszczenie:
Airborne wind energy (AWE) is an emerging technology for the conversion of wind energy into electricity. There are many types of AWE systems, and one of them flies crosswind patterns with a tethered aircraft connected to a generator. The objective is to gain a proper understanding of the unsteady interaction of air and this flexible and dynamic system during operation, which is key to developing viable, large AWE systems. In this work, the effect of wing deformation on an AWE system performing a crosswind flight maneuver was assessed using high-fidelity time-varying fluid–structure interaction simulations. This was performed using a partitioned and explicit approach. A computational structural mechanics (CSM) model of the wing structure was coupled with a computational fluid dynamics (CFD) model of the wing aerodynamics. The Chimera/overset technique combined with an arbitrary Lagrangian–Eulerian (ALE) formulation for mesh deformation has been proven to be a robust approach to simulating the motion and deformation of an airborne wind energy system in CFD simulations. The main finding is that wing deformation in crosswind flights increases the symmetry of the spanwise loading. This property could be used in future designs to increase the efficiency of airborne wind energy systems.
40
Sadeh, Sepehr, Glenn H. Gleason, Mohammad I. Hatamleh, Sumair F. Sunny, Haoliang Yu, Arif S. Malik i Dong Qian. "Simulation and Experimental Comparison of Laser Impact Welding with a Plasma Pressure Model". Metals 9, nr 11 (7.11.2019): 1196. http://dx.doi.org/10.3390/met9111196.
Pełny tekst źródłaStreszczenie:
In this study, spatial and temporal profiles of an Nd-YAG laser beam pressure pulse are experimentally characterized and fully captured for use in numerical simulations of laser impact welding (LIW). Both axisymmetric, Arbitrary Lagrangian-Eulerian (ALE) and Eulerian dynamic explicit numerical simulations of the collision and deformation of the flyer and target foils are created. The effect of the standoff distance between the foils on impact angle, velocity distribution, springback, the overall shape of the deformed foils, and the weld strength in lap shear tests are investigated. In addition, the jetting phenomenon (separation and ejection of particles at very high velocities due to high-impact collision) and interlocking of the foils along the weld interface are simulated. Simulation results are compared to experiments, which exhibit very similar deformation and impact behaviors. In contrast to previous numerical studies that assume a pre-defined deformed flyer foil shape with uniform initial velocity, the research in this work shows that incorporation of the actual spatial and temporal profiles of the laser beam and modeling of the corresponding pressure pulse based on a laser shock peening approach provides a more realistic prediction of the LIW process mechanism.
41
Alhashash, Abeer, i Habibis Saleh. "Unsteady free convection in a composite enclosure having flexible wall". Advances in Mechanical Engineering 15, nr 4 (kwiecień 2023): 168781322311679. http://dx.doi.org/10.1177/16878132231167947.
Pełny tekst źródłaStreszczenie:
Transient free convection in a composite enclosure having a cold flexible plate and a hot rigid plate is simulated numerically. It is assumed that the flexible plate is hyper-elastic. A porous layer with various sizes and permeabilities is attached to the rigid plate. The enclosure is filled with water. Fluid flow in the fluid domain was governed by the Navier–Stokes equations, and the flow within a saturated porous layer was governed by the Brinkman-Forchheimer extended Darcy model. The unsteady continuity, momentum, and energy equations are solved using the Arbitrary-Lagrangian-Eulerian (ALE) approach based on the fluid-structure interaction (FSI). It is found that the development of convective flow goes through initial, transitional, and stationary states. Each state interval is shifted by varying the Darcy number and Rayleigh number. In the transitional state, the deformation of the flexible parts reaches its maximum bending. The profile of the flexible plate at steady state is in a sinusoidal shape for the non-Darcy regime, while it is in an asymmetric parabolic shape for the Darcy regime. The steady state is reached for [Formula: see text], [Formula: see text], and [Formula: see text] before [Formula: see text].
42
Grujicic, M., T. He, G. Arakere, H. V. Yalavarthy, C.-F. Yen i B. A. Cheeseman. "Fully coupled thermomechanical finite element analysis of material evolution during friction-stir welding of AA5083". Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 224, nr 4 (15.10.2009): 609–25. http://dx.doi.org/10.1243/09544054jem1750.
Pełny tekst źródłaStreszczenie:
Interactions between the rotating and advancing pin-shaped tool (terminated at one end with a circular—cylindrical shoulder) with the clamped welding plates and the associated material and heat transport during a friction-stir welding (FSW) process are studied computationally using a fully coupled thermomechanical finite element analysis. To surmount potential numerical problems associated with extensive mesh distortions/entanglement, an arbitrary Lagrangian—Eulerian (ALE) formulation was used, which enabled adaptive remeshing (to ensure the continuing presence of a high-quality mesh) while allowing full tracking of the material-free surfaces. To demonstrate the utility of the present computational approach, the analysis is applied to the case of FSW of AA5083 (a solid—solution strengthened and strain-hardened/stabilized Al—Mg wrought alloy). To account for the competition between plastic deformation-controlled strengthening and dynamic recrystallization-induced softening phenomena during the FSW process, the original Johnson—Cook strain and strain-rate hardening and temperature-softening material strength model is modified using the available recrystallization kinetics experimental data. Lastly, the computational results obtained in the present work are compared with their experimental counterparts available in the open literature. This comparison revealed that general trends regarding spatial distribution and temporal evolutions of various material-state quantities and their dependence on the FSW process parameters are reasonably well predicted by the present computational approach.
43
Belver, Ali Vasallo, Álvaro Magdaleno, James Mark William Brownjohn i Antolín Lorenzana. "Performance of a TMD to Mitigate Wind-Induced Interference Effects between Two Industrial Chimneys". Actuators 10, nr 1 (11.01.2021): 12. http://dx.doi.org/10.3390/act10010012.
Pełny tekst źródłaStreszczenie:
The present paper studies the performance of a tuned mass damper (TMD) installed in a 183 m tall chimney located at the edge of the wake shed by another chimney. Numerical and experimental results are available. For the simulations, wind action is considered by solving several 2D flow problems on a selected number of horizontal planes, in the transverse direction to the stacks. On such planes, Navier-Stokes equations are solved to estimate the fluid action at different positions of the chimneys and standard interpolation techniques are applied in the vertical direction. An Arbitrary Lagrangian-Eulerian (ALE) approach is used to consider the moving domain, and a fractional-step scheme is used to solve the fluid field. For the structural modelling, chimneys are meshed using 3D beam finite elements. The time integration procedure used for the structural dynamics is based on the standard second order Bossak method. For each period of time, the fluid problem is solved, the aeroelastic analysis is carried out and the geometry of the fluid mesh of each plane is updated according to the structural movements. With this procedure and model updating techniques, the response of the leeward chimney is evaluated for different scenarios, revealing an interesting dependence of the TMD performance on the wind speed and direction.
44
Labdelli, N., i S. Soulimane. "CONCEPTION OF A NEW GENERATION OF 3D BIOMIMETIC MICROVALVES FOR MEDICAL APPLICATION". Journal of the Serbian Society for Computational Mechanics 14, nr 1 (30.06.2020): 99–112. http://dx.doi.org/10.24874/jsscm.2020.14.01.09.
Pełny tekst źródłaStreszczenie:
This paper reviews the development of a new microvalve with a cone-shaped tube, inspired by venous valves in the human body. Our microvalves allow fluid flow in one direction while restricting the flow in the opposite direction. When a microvalve is used to control the amount of drug delivery, the efficiency between inlet and outlet flow rate is the key control parameter for regulating and controlling the micro channel (opening/closing). This paper is devoted to the numerical study of flow rate changes in different microvalve geometries (3D) using a Fluid Structure Interaction (FSI) method with an Arbitrary Lagrangian Eulerian (ALE) approach. Numerical simulations were carried out in comsol Multiphysics. In addition, the macrovalve performance was analysed for several pressures where the effect of different geometrical parameters such as the length of the anchor, the diameter at the base and the angle of the cone were studied. An efficiency parameter ð¸ð‘“ð‘“ was employed to compare the different structures. For the best design obtained, it was found that the cone angle was the parameter having the most effect on the microvalves’ characteristics, and the forward flow rate was more than doubled compared to the reverse leakage rate.
45
Belver, Ali Vasallo, Álvaro Magdaleno, James Mark William Brownjohn i Antolín Lorenzana. "Performance of a TMD to Mitigate Wind-Induced Interference Effects between Two Industrial Chimneys". Actuators 10, nr 1 (11.01.2021): 12. http://dx.doi.org/10.3390/act10010012.
Pełny tekst źródłaStreszczenie:
The present paper studies the performance of a tuned mass damper (TMD) installed in a 183 m tall chimney located at the edge of the wake shed by another chimney. Numerical and experimental results are available. For the simulations, wind action is considered by solving several 2D flow problems on a selected number of horizontal planes, in the transverse direction to the stacks. On such planes, Navier-Stokes equations are solved to estimate the fluid action at different positions of the chimneys and standard interpolation techniques are applied in the vertical direction. An Arbitrary Lagrangian-Eulerian (ALE) approach is used to consider the moving domain, and a fractional-step scheme is used to solve the fluid field. For the structural modelling, chimneys are meshed using 3D beam finite elements. The time integration procedure used for the structural dynamics is based on the standard second order Bossak method. For each period of time, the fluid problem is solved, the aeroelastic analysis is carried out and the geometry of the fluid mesh of each plane is updated according to the structural movements. With this procedure and model updating techniques, the response of the leeward chimney is evaluated for different scenarios, revealing an interesting dependence of the TMD performance on the wind speed and direction.
46
Priambudi Setyo Pratomo, Hariyo, Fandi Dwiputra Suprianto i Teng Sutrisno. "Preliminary Study on Mesh Stiffness Models for Fluid-structure Interaction Problems". E3S Web of Conferences 130 (2019): 01014. http://dx.doi.org/10.1051/e3sconf/201913001014.
Pełny tekst źródłaStreszczenie:
One of the challenges in modern computational engineering is the simulation of fluid-structure interaction (FSI) phenomena where one of the crucial issues in the multi-physics simulation is the choice of stiffness model for mesh deformation. This paper focuses on the application of iteratively implicit coupling procedure on two transient FSI cases of vortex induced-vibration (VIV) that manifest oscillating flexible structures. The aim is to study various mesh stiffness models in the Laplace equation of diffusion employed within the arbitrary Lagrangian-Eulerian (ALE) methodology to handle the moving mesh. In the first case where a laminar flow interacted with a flexible splitter, it was demonstrated that a near FSI boundaries increased-stiffness model prevails to manage a large deformation of the moving structure as compared to a near volume increased-stiffness model. However, the potential technique could not be exploited to the second FSI configuration, where the effect of the turbulence of flow was included. It was found that the mesh topology near the FSI interface was collapsed. Instead of utilizing the same approach, a mesh stiffness based on a wall distance was found to be auspicious. Thus, the mesh stiffness model in the FSI simulation is case-dependent.
47
Han, Yuzhen, i Huabei Liu. "Finite Element Simulation of Medium-Range Blast Loading Using LS-DYNA". Shock and Vibration 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/631493.
Pełny tekst źródłaStreszczenie:
This study investigated the Finite Element simulation of blast loading using LS-DYNA. The objective is to identify approaches to reduce the requirement of computation effort while maintaining reasonable accuracy, focusing on blast loading scheme, element size, and its relationship with scale of explosion. The study made use of the recently developed blast loading scheme in LS-DYNA, which removes the necessity to model the explosive in the numerical models but still maintains the advantages of nonlinear fluid-structure interaction. It was found that the blast loading technique could significantly reduce the computation effort. It was also found that the initial density of air in the numerical model could be purposely increased to partially compensate the error induced by the use of relatively large air elements. Using the numerical approach, free air blast above a scaled distance of 0.4 m/kg1/3was properly simulated, and the fluid-structure interaction at the same location could be properly duplicated using proper Arbitrary Lagrangian Eulerian (ALE) coupling scheme. The study also showed that centrifuge technique, which has been successfully employed in model tests to investigate the blast effects, may be used when simulating the effect of medium- to large-scale explosion at small scaled distance.
48
Ghiasi, Arya, Seyed Esmaeil Razavi, Abel Rouboa i Omid Mahian. "Numerical study on flow over a confined oscillating cylinder with a splitter plate". International Journal of Numerical Methods for Heat & Fluid Flow 29, nr 5 (7.05.2019): 1629–46. http://dx.doi.org/10.1108/hff-06-2018-0286.
Pełny tekst źródłaStreszczenie:
Purpose This study aims to investigate the effect of the simultaneous usage of active and passive methods (which in this case are rotational oscillation and attached splitter plate, respectively) on the flow and temperature fields to find an optimum situation which this combination results in heat transfer increment and drag reduction. Design/methodology/approach The method of the solution was based on finite volume discretization of Navier–Stokes equations. A dynamic grid is coupled with the solver by the arbitrary Lagrangian–Eulerian (ALE) formulation for modeling cylinder oscillation. Parametric studies were performed by altering oscillation frequency, splitter plate length and Reynolds number. Findings Oscillation in different frequencies was found to be complicated. Higher frequencies provide more heat transfer, but in the lock-on region, they bring remarkable increment to the drag coefficient. It was observed that simultaneous usage of oscillation and splitter plate may have both positive and negative effects on drag reduction and heat transfer increment. Finally F = 2 and L = 0.5 were chosen as an optimum combination. Originality/value In this study, the laminar incompressible flow and heat transfer from a confined rotationally oscillating circular cylinder with an attached splitter plate are investigated. Parametric studies are performed by changing oscillation frequency, splitter plate length and Reynolds number.
49
Liang, Yi, Cheng Wang i Pengtao Sun. "An Interface-Fitted Fictitious Domain Finite Element Method for the Simulation of Neutrally Buoyant Particles in Plane Shear Flow". Fluids 8, nr 8 (12.08.2023): 229. http://dx.doi.org/10.3390/fluids8080229.
Pełny tekst źródłaStreszczenie:
In this paper, an interface-fitted fictitious domain finite element method is developed for the simulation of fluid–rigid particle interaction problems in cases of rotated particles with small displacement, where an interface-fitted mesh is employed for the discrete scheme to capture the fluid–rigid particle interface accurately, thereby improving the solution accuracy near the interface. Moreover, a linearization and decoupling process is presented to release the constraint between velocities of fluid and rigid particles in the finite element space, and to make the developed numerical method easy to be implemented. Our numerical experiments are carried out using two different moving interface-fitted meshes; one is obtained by a rotational arbitrary Lagrangian–Eulerian (ALE) mapping, and the other one through a local smoothing process among interface-cut elements. A unified velocity is defined in the entire domain based on the fictitious domain method, making it easier to develop an interface-fitted mesh generation algorithm in a fixed domain. Both show that the proposed method has a good performance in accuracy for simulating a neutrally buoyant particle in plane shear flow. This approach can be easily extended to fluid–structure interaction problems involving fluids in different states and structures in different shapes with large displacements or deformations.
50
Berger, T., R. Behnke i M. Kaliske. "VISCOELASTIC LINEAR AND NONLINEAR ANALYSIS OF STEADY STATE ROLLING RUBBER WHEELS: A COMPARISON". Rubber Chemistry and Technology 89, nr 3 (1.09.2016): 499–525. http://dx.doi.org/10.5254/rct.16.83804.
Pełny tekst źródłaStreszczenie:
ABSTRACT The influence of a linear viscoelastic model (A) and a nonlinear viscoelastic model (B) for the representation of the temperature-, time- and amplitude-dependent behavior of steady state rolling rubber wheels (e.g., tires) is discussed and highlighted through the example of a so-called Grosch wheel. A viscoelastic benchmark material at large strains is proposed and represented with the help of model A and model B, where equality between the two models is obtained for the small strain regime. The model parameters are given in detail. To represent the steady state motion of axisymmetric rubber wheels, the Arbitrary Lagrangian Eulerian (ALE) framework is used within the finite element method (FEM). First, the simulation approach and the results for steady state rolling viscoelastic axisymmetric rubber wheels are verified by a comparison with the solution results of a commercial simulation approach for linear viscoelasticity at isothermal conditions. Second, the simulation results using model A and model B are compared to highlight the influence of nonlinear relaxation characteristics. Third, temperature effects are assessed based on a thermo-mechanically coupled simulation approach. Finally, the results for models A and B are compared to assess advantages and disadvantages of the model approaches and their significance for the representation of the temperature-, time- and amplitude-dependent material behavior. As global objective quantities, the temperature rise due to rolling and the rolling loss power, as well as the vertical stiffness and the stress state in the rubber component under investigation, are computed and compared.