scholarly journals ACCURATE INTERACTIVE ANIMATION OF DEFORMABLE MODELS AT ARBITRARY RESOLUTION

2010 ◽  
Vol 10 (02) ◽  
pp. 175-202 ◽  
Author(s):  
MATTHIEU NESME ◽  
FRANÇOIS FAURE ◽  
YOHAN PAYAN
Keyword(s):  
Patient Specific ◽  
Medical Simulation ◽  
Interactive Simulation ◽  
The Finite Element Method ◽  
Interactive Animation ◽  
Hexahedral Elements ◽  
Complex Shapes ◽  
Volumetric Representation ◽  
Volumetric Rendering ◽  
Theoretical Results

Providing realistic interactive simulation requires a powerful animation method with a highly detailed rendering. Based on continuum mechanics, the finite element method needs a volumetric representation of the object to animate. This paper proposes an automatic method for building meshes that are well adapted to interactive simulation starting from miscellaneous input data. Contrary to commonly used methods based on tetrahedral volume meshing, the object is embedded in a regular grid of deformable hexahedra at an arbitrary resolution. This alleviates the complexities and limitations of tetrahedra and results in regular, well-conditioned meshes. Mass and stiffness are set in order to model the physical properties as accurately as possible at any given resolution, in a manner that takes into account the distribution of material within the hexahedra. This allows us to accurately model the mechanical properties of the partially empty boundary hexahedra, and thus enables us to perform fast simulation at a coarse resolution. The accuracy of this approach is compared to theoretical results. In addition, we extend a fast and robust co-rotational approach to the case of hexahedral elements. This permits simulation of arbitrarily complex shapes at interactive rates. We show how to build the hexahedra directly from surfaces and from segmented scanned data, which is very useful to animate complex artistic models or patient specific models for individual medical simulation. Finally, we show how a fast volumetric rendering can make efficient use of the grid structure.

Experimental Analysis of Velocity Fields in Hot Extrusion of Aluminium Alloy 6351

2011 ◽  
Vol 491 ◽  
pp. 145-150 ◽  
Author(s):  
Marcelo Martins ◽  
Sérgio Tonini Button ◽  
José Divo Bressan
Keyword(s):  
Metal Forming ◽  
Internal Flow ◽  
Hot Extrusion ◽  
Experimental Tests ◽  
Velocity Fields ◽  
The Finite Element Method ◽  
Forming Process ◽  
Complex Shapes ◽  
Metal Forming Process ◽  
Volume Method

Hot extrusion is a metal forming process with a huge importance in the manufacturing of long metallic bars with complex shapes, and because of this, academics and industries are especially interested in better understanding how metal flows during the process. In order to have a reliable computational tool that can help to solve and to obtain material internal flow, experimental tests and numerical simulation with the finite element method were carried out to obtain results of the velocity fields generated in hot direct extrusion of aluminum billets (aluminum alloy 6351). The experimental results of the velocity field will be used to validate a computational code based on the finite volume method.

The Convergence of the H-P Version of the Finite Element Method with Quasi-Uniform Meshes for Three Dimensional Poisson Problems with Edge Singularity

2014 ◽  
Vol 644-650 ◽  
pp. 1551-1555
Author(s):  
Jian Ming Zhang ◽  
Yong He
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Weighted Sobolev Spaces ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Smooth Functions ◽  
Edge Singularity ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Element Method

This paper is concerned with the convergence of the h-p version of the finite element method for three dimensional Poisson problems with edge singularity on quasi-uniform meshes. First, we present the theoretical results for the convergence of the h-p version of the finite element method with quasi-uniform meshes for elliptic problems on polyhedral domains on smooth functions in the framework of Jacobi-weighted Sobolev spaces. Second, we investigate and analyze numerical results for three dimensional Poission problems with edge singularity. Finally, we verified the theoretical predictions by the numerical computation.

scholarly journals Digital printing of shape-morphing natural materials

2021 ◽  
Vol 118 (43) ◽  
pp. e2113715118
Author(s):  
Ze Zhao ◽  
Jatin Kumar ◽  
Youngkyu Hwang ◽  
Jingyu Deng ◽  
Mohammed Shahrudin Bin Ibrahim ◽  
...  
Keyword(s):  
Wide Spectrum ◽  
Substrate Material ◽  
Digital Printing ◽  
Shape Evolution ◽  
The Finite Element Method ◽  
Computational Simulations ◽  
Natural Materials ◽  
Shape Morphing ◽  
Geometrical Features ◽  
Complex Shapes

We demonstrate how programmable shape evolution and deformation can be induced in plant-based natural materials through standard digital printing technologies. With nonallergenic pollen paper as the substrate material, we show how specific geometrical features and architectures can be custom designed through digital printing of patterns to modulate hygrophobicity, geometry, and complex shapes. These autonomously hygromorphing configurations can be “frozen” by postprocessing coatings to meet the needs of a wide spectrum of uses and applications. Through computational simulations involving the finite element method and accompanying experiments, we develop quantitative insights and a general framework for creating complex shapes in eco-friendly natural materials with potential sustainable applications for scalable manufacturing.

An Encounter with Lattice Boltzmann for Biomedical Applications: Interactive Simulation to Support Clinical and Design Decisions

2021 ◽  
Author(s):  
Simone Ferrari ◽  
Simone Ambrogio ◽  
Andrew J Narracott ◽  
Adrian Walker ◽  
Paul D Morris ◽  
...  
Keyword(s):  
Real Time ◽  
Vortex Shedding ◽  
Lattice Boltzmann ◽  
Personalised Medicine ◽  
Free Field ◽  
Sudden Expansion ◽  
Patient Specific ◽  
Interactive Simulation ◽  
Straight Pipe ◽  
Karman Vortex

Abstract Medical device design for personalised medicine requires sophisticated tools for optimisation of biomechanical and biofluidic devices. This paper investigates a new real-time tool for simulating structural and fluid scenarios - ANSYS Discovery Live - and we evaluate its capability in the fluid domain through benchmark flows that all involve steady state flow at the inlet and zero pressure at the outlet. Three scenarios are reported: i. Laminar flow in a straight pipe, ii. vortex shedding from the Karman Vortex, and iii. nozzle flows as characterised by an FDA benchmark geometry. The solver uses a Lattice Boltzmann method requiring a high performance GPU (nVidiaGTX1080, 8GB RAM). Results in each case were compared with the literature and demonstrated credible solutions, all delivered in near real-time: i. The straight pipe delivered parabolic flow after an appropriate entrance length (plug flow inlet conditions), ii. the Karman Vortex demonstrated appropriate vortex shedding as a function of Reynolds number, characterised by Strouhal number in both the free field and within a pipe, and ii the FDA benchmark geometry generated results consistent with the literature in terms of variation of velocity along the centreline and in the radial direction, although deviation from experimental validation was evident in the sudden expansion section of the geometry. This behaviour is similar to previous reported results from Navier-Stokes solvers. A cardiovascular stenosis example is also considered, to provide a more direct biomedical context. The current software framework imposes constraints on inlet/outlet boundary conditions, and only supports limited control of solver discretization without providing full field vector flow data outputs. Nonetheless, numerous benefits result from the interactive interface and almost-real-time solution, providing a tool that may help to accelerate the arrival of improved patient-specific medical devices.

scholarly journals Numerical Investigation of Sloshing in Rectangular Tank with Permeable Baffle

2020 ◽  
Vol 8 (9) ◽  
pp. 671
Author(s):  
Liting Yu ◽  
Mi-An Xue ◽  
Aimeng Zhu
Keyword(s):  
Permeability Coefficient ◽  
Structural Damage ◽  
Maximum Flow ◽  
Arbitrary Lagrangian Eulerian ◽  
The Finite Element Method ◽  
Resonant Frequencies ◽  
Cargo Transport ◽  
Violent Sloshing ◽  
Theoretical Results ◽  
Flow Velocities

Violent sloshing induced by excitation with large amplitudes or resonant frequencies may result in structural damage of the liquid-tank or even the overturning of the liquid cargo transport system. Therefore, impermeable and permeable vertical baffles were investigated numerically to suppress sloshing. The numerical simulations were based on the finite element method and arbitrary Lagrangian–Eulerian (ALE) method. The numerical model was verified by the available experimental data, numerical results and linear theoretical results. Based on the study of the effects of impermeable baffle height, amplitude and frequency of excitation on sloshing, the effects of baffle permeability on sloshing were investigated. Importantly, a critical permeability coefficient that was most effective to suppress sloshing was found. In addition, the maximum flow velocities in the tank with a baffle of small permeability coefficient were smaller than those in the tank with an impermeable baffle. While, the maximum flow velocities under a baffle of large permeability coefficient were larger than those in the tank with an impermeable baffle. Vortices were observed in the whole region of the baffle, tank bottom, tank walls and the free surface in the tank with a permeable baffle.

Dynamic Analysis and Design of Compliant Mechanisms Using the Finite Element Method

2012 ◽  
Vol 163 ◽  
pp. 111-115 ◽  
Author(s):  
Wen Jing Wang ◽  
Li Ge Zhang ◽  
Shu Sheng Bi
Keyword(s):  
Finite Element Method ◽  
Dynamic Model ◽  
Natural Frequency ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
The Finite Element Method ◽  
Dynamic Effects ◽  
Experiment System ◽  
Analysis And Design ◽  
Theoretical Results

Compliant mechanisms gain at least some of their mobility from the deflection of flexible members rather than from movable joints only. Dynamic effects are very important to improving the design of compliant mechanisms. An investigation on the dynamics and synthesis of the compliant mechanisms is presented. The dynamic model of compliant mechanisms is developed at first. The natural frequency and sensitivity are then studied based on the dynamic model. Finally, optimal design of compliant mechanism is investigated. The experimental study of natural frequency is performed. The comparison between the experiment results and the theoretical results verifies the validity of the experiment system and theoretical model.

Structure Analysis with 2D Quadrilateral Meshes Generated by a Label-Driven Subdivision

2016 ◽  
Vol 10 (2) ◽  
pp. 187-194 ◽  
Author(s):  
Bo Liu ◽  
◽  
Kenjiro T. Miura ◽  
Shin Usuki ◽  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Analysis ◽  
Structure Analysis ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Tetrahedral Element ◽  
Hexahedral Elements ◽  
Hexahedral Element ◽  
Preliminary Research

For a structural analysis using the finite element method, a hexahedral element is preferable to a tetrahedral element from the viewpoint of accuracy. However, it is very difficult to subdivide a mesh consisting of hexahedral elements if the shape of the mesh is complicated. Hence, in this paper, as a preliminary research, we use a label-driven subdivision method for a two-dimensional mesh, and show that meshes subdivided nonuniformly can guarantee as much accuracy as meshes with uniform subdivision.

scholarly journals Analysis of Vertical Displacements of the Esperanto Footbridge in Bydgoszcz

2018 ◽  
Vol 28 (2) ◽  
pp. 5-17 ◽  
Author(s):  
Adam Bujarkiewicz ◽  
Jarosław Gajewski ◽  
Tomasz Janiak ◽  
Justyna Sobczak-Piąstka ◽  
Jacek Sztubecki ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Simulations ◽  
The Finite Element Method ◽  
Test Load ◽  
Vertical Displacements ◽  
The Subject ◽  
Theoretical Results ◽  
Element Method

Abstract The subject of the research is a footbridge across the river Brda in Bydgoszcz. The measurements of the footbridge displacements with the test load were undertaken. The paper presents the results of the measurements and compares them with the theoretical results obtained using the finite element method (FEM). On this basis, discrepancy between actual work of the structure and numerical simulations was found. Attempt to explain the reasons for the observed differences and direction of further research were included in the conclusions.

scholarly journals Analysis of the Displacement of Thin-Walled Workpiece Using a High-Speed Camera during Peripheral Milling of Aluminum Alloys

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4771
Author(s):  
Jakub Czyżycki ◽  
Paweł Twardowski ◽  
Natalia Znojkiewicz
Keyword(s):  
Aluminum Alloys ◽  
High Speed ◽  
Cutting Parameters ◽  
Displacement Sensor ◽  
Laser Sensor ◽  
High Speed Camera ◽  
The Finite Element Method ◽  
Peripheral Milling ◽  
Thin Walled ◽  
Theoretical Results

The paper presents the possibilities of a high-speed camera in recording displacements of thin-walled workpiece during milling made of aluminum alloys, which allowed for an analysis in which it was compared to other methods of testing the deflection of such elements. The tests were carried out during peripheral milling with constant cutting parameters. Deflection of thin-walled workpiece due to cutting forces was measured using a high-speed camera and a laser displacement sensor. Additionally, the experimental results were compared with the theoretical results obtained with the use of the finite element method. The research proved the effectiveness of the use of high-speed camera in diagnostics of thin-walled workpieces during milling with an accuracy of up to 11% compared to measurements made with a displacement laser sensor.

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