WorldWideScience

Sample records for pretest 3d finite

  1. Stabilized Finite Elements in FUN3D

    Science.gov (United States)

    Anderson, W. Kyle; Newman, James C.; Karman, Steve L.

    2017-01-01

    A Streamlined Upwind Petrov-Galerkin (SUPG) stabilized finite-element discretization has been implemented as a library into the FUN3D unstructured-grid flow solver. Motivation for the selection of this methodology is given, details of the implementation are provided, and the discretization for the interior scheme is verified for linear and quadratic elements by using the method of manufactured solutions. A methodology is also described for capturing shocks, and simulation results are compared to the finite-volume formulation that is currently the primary method employed for routine engineering applications. The finite-element methodology is demonstrated to be more accurate than the finite-volume technology, particularly on tetrahedral meshes where the solutions obtained using the finite-volume scheme can suffer from adverse effects caused by bias in the grid. Although no effort has been made to date to optimize computational efficiency, the finite-element scheme is competitive with the finite-volume scheme in terms of computer time to reach convergence.

  2. Pre-test analysis for identification of natural circulation instabilities in TALL-3D facility

    International Nuclear Information System (INIS)

    Kööp, Kaspar; Jeltsov, Marti; Grishchenko, Dmitry; Kudinov, Pavel

    2017-01-01

    Highlights: • Global optimum search method was used to identify a region of instability. • Parametric study was used for detailed investigation of system behavior modes. • The results include identification of sustained mass flow rate oscillations. • Recommendations are made for selection of optimal experimental conditions. - Abstract: TALL-3D facility is a lead-bismuth eutectic (LBE) thermal-hydraulic loop designed to provide experimental data on thermal-hydraulics phenomena for validation of stand-alone and coupled System Thermal Hydraulics (STH) and Computational Fluid Dynamics (CFD) codes. Pre-test analysis is crucial for proper choice of experimental conditions at which the experimental data would be most useful for code validation and benchmarking. The goal of this work is to identify these conditions at which the experiment is challenging for the STH codes yet minimizes the 3D-effects from the test section on the loop dynamics. The analysis is focused on the identification of limit cycle flow oscillations in the TALL-3D facility main heater leg using a global optimum search tool GA-NPO to find a general region in the parameter space where oscillatory behavior is expected. As a second step a grid study is conducted outlining the boundaries between different stability modes. Phenomena, simulation results and methodology for selection of the test parameters are discussed in detail and recommendations for experiments are provided.

  3. Pre-test analysis for identification of natural circulation instabilities in TALL-3D facility

    Energy Technology Data Exchange (ETDEWEB)

    Kööp, Kaspar, E-mail: kaspar@safety.sci.kth.se; Jeltsov, Marti, E-mail: marti@safety.sci.kth.se; Grishchenko, Dmitry, E-mail: dmitry@safety.sci.kth.se; Kudinov, Pavel, E-mail: pavel@safety.sci.kth.se

    2017-04-01

    Highlights: • Global optimum search method was used to identify a region of instability. • Parametric study was used for detailed investigation of system behavior modes. • The results include identification of sustained mass flow rate oscillations. • Recommendations are made for selection of optimal experimental conditions. - Abstract: TALL-3D facility is a lead-bismuth eutectic (LBE) thermal-hydraulic loop designed to provide experimental data on thermal-hydraulics phenomena for validation of stand-alone and coupled System Thermal Hydraulics (STH) and Computational Fluid Dynamics (CFD) codes. Pre-test analysis is crucial for proper choice of experimental conditions at which the experimental data would be most useful for code validation and benchmarking. The goal of this work is to identify these conditions at which the experiment is challenging for the STH codes yet minimizes the 3D-effects from the test section on the loop dynamics. The analysis is focused on the identification of limit cycle flow oscillations in the TALL-3D facility main heater leg using a global optimum search tool GA-NPO to find a general region in the parameter space where oscillatory behavior is expected. As a second step a grid study is conducted outlining the boundaries between different stability modes. Phenomena, simulation results and methodology for selection of the test parameters are discussed in detail and recommendations for experiments are provided.

  4. Comparison of different coupling CFD–STH approaches for pre-test analysis of a TALL-3D experiment

    Energy Technology Data Exchange (ETDEWEB)

    Papukchiev, Angel, E-mail: angel.papukchiev@grs.de [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Garching n. Munich (Germany); Jeltsov, Marti; Kööp, Kaspar; Kudinov, Pavel [KTH Royal Institute of Technology, Stockholm (Sweden); Lerchl, Georg [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Garching n. Munich (Germany)

    2015-08-15

    Highlights: • Thermal-hydraulic system codes and CFD tools are coupled. • Pre-test calculations for the TALL-3D facility are performed. • Complex flow and heat transfer phenomena are modeled. • Comparative analyses have been performed. - Abstract: The system thermal-hydraulic (STH) code ATHLET was coupled with the commercial 3D computational fluid dynamics (CFD) software package ANSYS CFX to improve ATHLET simulation capabilities for flows with pronounced 3D phenomena such as flow mixing and thermal stratification. Within the FP7 European project THINS (Thermal Hydraulics of Innovative Nuclear Systems), validation activities for coupled thermal-hydraulic codes are being carried out. The TALL-3D experimental facility, operated by KTH Royal Institute of Technology in Stockholm, is designed for thermal-hydraulic experiments with lead-bismuth eutectic (LBE) coolant at natural and forced circulation conditions. GRS carried out pre-test simulations with ATHLET–ANSYS CFX for the TALL-3D experiment T01, while KTH scientists perform these analyses with the coupled code RELAP5/STAR CCM+. In the experiment T01 the main circulation pump is stopped, which leads to interesting thermal-hydraulic transient with local 3D phenomena. In this paper, the TALL-3D behavior during T01 is analyzed and the results of the coupled pre-test calculations, performed by GRS (ATHLET–ANSYS CFX) and KTH (RELAP5/STAR CCM+) are directly compared.

  5. TAURUS, Post-processor of 3-D Finite Elements Plots

    International Nuclear Information System (INIS)

    Brown, B.E.; Hallquist, J.O.; Kennedy, T.

    2002-01-01

    Description of program or function: TAURUS reads the binary plot files generated by the LLNL three-dimensional finite element analysis codes, NIKE3D (NESC 9725), DYNA3D (NESC 9909), TACO3D (NESC 9838), TOPAZ3D (NESC9599) and GEMINI and plots contours, time histories, and deformed shapes. Contours of a large number of quantities may be plotted on meshes consisting of plate, shell, and solid type elements. TAURUS can compute a variety of strain measures, reaction forces along constrained boundaries, and momentum. TAURUS has three phases: initialization, geometry display with contouring, and time history processing

  6. Comparison of 3-D finite elements for incompressible fluid flow

    International Nuclear Information System (INIS)

    Robichaud, M.; Tanguy, P.A.

    1985-01-01

    In recent years, the finite element method applied to the solution of incompressible fluid flow has been in constant evolution. In the present state-of-the-art, 2-D problems are solved routinely and reliable results are obtained at a reasonable cost. In 3-D the finite element method is still undergoing active research and many methods have been proposed to solve the Navier-Stokes equations at 'low cost'. These methods have in common the choice of the element which has a trilinear velocity and a discontinuous constant pressure (Q1-PO). The prohibitive cost of 3-D finite element method in fluid flow is the reason for this choice: the Q1-PO is the simplest and the cheapest 3-D element. However, as mentioned in (5) and (6), it generates 'spurious' pressure modes phenomenon called checkerboarding. On regular mesh these spurious modes can be filtered but on distorted mesh the pressure solution is meaningless. (author)

  7. The Finite Element Numerical Modelling of 3D Magnetotelluric

    Directory of Open Access Journals (Sweden)

    Ligang Cao

    2014-01-01

    Full Text Available The ideal numerical simulation of 3D magnetotelluric was restricted by the methodology complexity and the time-consuming calculation. Boundary values, the variation of weighted residual equation, and the hexahedral mesh generation method of finite element are three major causes. A finite element method for 3D magnetotelluric numerical modeling is presented in this paper as a solution for the problem mentioned above. In this algorithm, a hexahedral element coefficient matrix for magnetoelluric finite method is developed, which solves large-scale equations using preconditioned conjugate gradient of the first-type boundary conditions. This algorithm is verified using the homogeneous model, and the positive landform model, as well as the low resistance anomaly model.

  8. 3D finite element simulations of high velocity projectile impact

    Directory of Open Access Journals (Sweden)

    Ožbolt Joško

    2015-01-01

    Full Text Available An explicit three-dimensional (3D finite element (FE code is developed for the simulation of high velocity impact and fragmentation events. The rate sensitive microplane material model, which accounts for large deformations and rate effects, is used as a constitutive law. In the code large deformation frictional contact is treated by forward incremental Lagrange multiplier method. To handle highly distorted and damaged elements the approach based on the element deletion is employed. The code is then used in 3D FE simulations of high velocity projectile impact. The results of the numerical simulations are evaluated and compared with experimental results. It is shown that it realistically predicts failure mode and exit velocities for different geometries of plain concrete slab. Moreover, the importance of some relevant parameters, such as contact friction, rate sensitivity, bulk viscosity and deletion criteria are addressed.

  9. 3-D finite element simulation for ultrasonic propagation in tooth.

    Science.gov (United States)

    Sun, Xiaoqing; Witzel, Erich A; Bian, Hongxin; Kang, Shaoying

    2008-07-01

    Ultrasonic testing of the tooth has been suggested as an alternative method of identifying dental pathology. Due to the complex geometry and low transmission efficiency of ultrasonic signals in tooth structures, it is difficult to establish one-to-one correspondence between ultrasonic behaviour and specific tooth pathologies both in vitro and in vivo. In order to facilitate ultrasonic diagnosis in dental applications, finite element modeling (FEM) was used to simulate ultrasonic wave propagation in teeth with several dental conditions. 3-D finite element tooth models were developed. The geometry of the tooth models was defined by 3-D images generated by scanning real tooth samples using an X-ray computerized tomography machine. Poro-elastic material was used to simulate the mechanical behaviour of the dentine. Numerical simulations of ultrasonic wave propagation were performed on the 3-D FEM models altered to mimic various dental conditions. The software ABAQUS was used as the calculator in the simulation. Excellent replication of ultrasonic behaviours by the FEM simulation was demonstrated through comparison of the simulation results with those of the actual ultrasonic testing on tooth specimens. Pathologies, such as caries, were also simulated on the finite element models. The unique influence of each dental condition on the patterns of ultrasonic waves propagating through the tooth (A-scan) was observed. Through FEM simulation, the influence of a particular dental pathology on ultrasonic wave pattern can be studied without the impact of other parameters. This will lead to a better understanding of how ultrasound could be applied to the diagnosis of pathology within teeth.

  10. Modelling of Shaft Orbiting with 3-D Solid Finite Elements

    Directory of Open Access Journals (Sweden)

    J. Yu

    1999-01-01

    Full Text Available A 3-D solid finite element model which can include bending, torsional, axial and other motions is proposed to analyse dynamic responses of shafts. For uniform shafts, this model shows consistency with beam theories when bending vibration is examined. For non-uniform shafts such as tapered ones, however, this model gives much more reliable and accurate results than beam theories which use an assumption that plane sections remain plane. Reduction procedures can be applied which involve only small matrix operations for such a system with a large number of degrees of freedom. The equations of motion have been consistently derived in a rotating frame. Shaft orbiting motion is then defined in this frame, giving a clear view of its trajectories. Forced responses due to excitation in the rotating frame have been examined to find some characteristics of the orbiting shaft. Resonant orbiting frequencies, i.e., natural frequencies of rotating shafts, can be determined in terms of the rotating or fixed frame. Trajectories of transverse displacements have been found to be varying with the forcing frequencies. At resonance, a uniform shaft will only have forward or backward orbiting motion with circular orbits. For other forcing frequencies, however, even a uniform shaft could present both forward and backward orbiting motions with non-circular orbits at different locations along its length. It is anticipated that modelling of shaft orbiting in the rotating frame with the proposed 3-D solid finite elements will lead to accurate dynamic stress evaluation.

  11. Finite volume and finite element methods applied to 3D laminar and turbulent channel flows

    Science.gov (United States)

    Louda, Petr; Sváček, Petr; Kozel, Karel; Příhoda, Jaromír

    2014-12-01

    The work deals with numerical simulations of incompressible flow in channels with rectangular cross section. The rectangular cross section itself leads to development of various secondary flow patterns, where accuracy of simulation is influenced by numerical viscosity of the scheme and by turbulence modeling. In this work some developments of stabilized finite element method are presented. Its results are compared with those of an implicit finite volume method also described, in laminar and turbulent flows. It is shown that numerical viscosity can cause errors of same magnitude as different turbulence models. The finite volume method is also applied to 3D turbulent flow around backward facing step and good agreement with 3D experimental results is obtained.

  12. Finite volume and finite element methods applied to 3D laminar and turbulent channel flows

    Energy Technology Data Exchange (ETDEWEB)

    Louda, Petr; Příhoda, Jaromír [Institute of Thermomechanics, Czech Academy of Sciences, Prague (Czech Republic); Sváček, Petr; Kozel, Karel [Czech Technical University in Prague, Fac. of Mechanical Engineering (Czech Republic)

    2014-12-10

    The work deals with numerical simulations of incompressible flow in channels with rectangular cross section. The rectangular cross section itself leads to development of various secondary flow patterns, where accuracy of simulation is influenced by numerical viscosity of the scheme and by turbulence modeling. In this work some developments of stabilized finite element method are presented. Its results are compared with those of an implicit finite volume method also described, in laminar and turbulent flows. It is shown that numerical viscosity can cause errors of same magnitude as different turbulence models. The finite volume method is also applied to 3D turbulent flow around backward facing step and good agreement with 3D experimental results is obtained.

  13. Automated finite element modelling of 3D woven textiles

    OpenAIRE

    Zeng, Xuesen; Long, A.C.; Clifford, M.J.; Probst-Schendzielorz, S.; Schmitt, M.W.

    2011-01-01

    The advance of 3D fabric technology allows tailored material structure in different directions for optimised performance. 3D fabrics open up increasing applications in automotive, medical, energy and many other areas. This paper explores highly automated techniques to simulate 3D fabric geometry and mechanical behaviour. The basis of the work starts from TexGen,an open source software package developed at the University of Nottingham. A complex variety of 3D fabrics can be defined as subclass...

  14. Beam section stiffness properties usig 3D finite elements

    DEFF Research Database (Denmark)

    Couturier, Philippe; Krenk, Steen; Høgsberg, Jan Becker

    2013-01-01

    The cross-section properties of a beam is characterized by a six by six stiffness matrix, relating the six generalized strains to the conjugate section forces. The problem is formulated as a single-layer finite element model of a slice of the beam, on which the six deformation modes are imposed v...... Lagrange multipliers. The Lagrange multipliers represent the constraining forces, and thus combine to form the cross-section stiffness matrix. The theory is illustrated by a simple isotropic cross-section....

  15. 3D Finite Element Modeling of Sliding Wear

    Science.gov (United States)

    2013-12-01

    formulation. The spin tensor is responsible for pure rotation. Mathematically their relations can be expressed as [31]: L = D +W (C-21) 1 2 TD L+ L (C-22...3.87 AISI-1080 Steel AISI Steel 1045[31]. 0.7 3.6 0.17 0.25 0.6 Table D-9 JC Dynamic Failure Parameters 1d 2d 3d 4d 5d 0 5 0 [1 ( )]f r m T Td T T 225...Contact and Rubbing of Flat Surfaces,” Journal of Applied Physics, 24(8): 981–988, August 1953. 3. Archard, J. F. “The Temperature of Rubbing

  16. Generalized mixed finite element method for 3D elasticity problems

    Science.gov (United States)

    Qing, Guanghui; Mao, Junhui; Liu, Yanhong

    2017-06-01

    Without applying any stable element techniques in the mixed methods, two simple generalized mixed element (GME) formulations were derived by combining the minimum potential energy principle and Hellinger-Reissner (H-R) variational principle. The main features of the GME formulations are that the common C0 -continuous polynomial shape functions for displacement methods are used to express both displacement and stress variables, and the coefficient matrix of these formulations is not only automatically symmetric but also invertible. Hence, the numerical results of the generalized mixed methods based on the GME formulations are stable. Displacement as well as stress results can be obtained directly from the algebraic system for finite element analysis after introducing stress and displacement boundary conditions simultaneously. Numerical examples show that displacement and stress results retain the same accuracy. The results of the noncompatible generalized mixed method proposed herein are more accurate than those of the standard noncompatible displacement method. The noncompatible generalized mixed element is less sensitive to element geometric distortions.

  17. Structural and Economic Viability of 2D/3D Finite Element Analysis ...

    African Journals Online (AJOL)

    Consequently, this paper examines the structural and economic viability of arched conical roof truss system based on 2D/3D finite element method analysis. Analysis of the results showed that truss members were subjected to higher axial forces in 2D analysis than 3D analysis, which will result to overdesign of the structural ...

  18. Modifications of the PRONTO 3D finite element program tailored to fast burst nuclear reactor design

    International Nuclear Information System (INIS)

    Oscar, D.S.; Attaway, S.W.; Miller, J.D.

    1991-08-01

    This update discusses modifications of PRONTO 3D tailored to the design of fast burst nuclear reactors. A thermoelastic constitutive model and spatially variant thermal history load were added for this special application. Included are descriptions of the thermoelastic constitutive model and the thermal loading algorithm, two example problems used to benchmark the new capability, a user's guide, and PRONTO 3D input files for the example problems. The results from PRONTO 3D thermoelastic finite element analysis are benchmarked against measured data and finite difference calculations. PRONTO 3D is a three-dimensional transient solid dynamics code for analyzing large deformations of highly non-linear materials subjected to high strain rates. The code modifications are implemented in PRONTO 3D Version 5.3.3. 12 refs., 30 figs., 9 tabs

  19. Sampling of finite elements for sparse recovery in large scale 3D electrical impedance tomography

    International Nuclear Information System (INIS)

    Javaherian, Ashkan; Moeller, Knut; Soleimani, Manuchehr

    2015-01-01

    This study proposes a method to improve performance of sparse recovery inverse solvers in 3D electrical impedance tomography (3D EIT), especially when the volume under study contains small-sized inclusions, e.g. 3D imaging of breast tumours. Initially, a quadratic regularized inverse solver is applied in a fast manner with a stopping threshold much greater than the optimum. Based on assuming a fixed level of sparsity for the conductivity field, finite elements are then sampled via applying a compressive sensing (CS) algorithm to the rough blurred estimation previously made by the quadratic solver. Finally, a sparse inverse solver is applied solely to the sampled finite elements, with the solution to the CS as its initial guess. The results show the great potential of the proposed CS-based sparse recovery in improving accuracy of sparse solution to the large-size 3D EIT. (paper)

  20. Sampling of finite elements for sparse recovery in large scale 3D electrical impedance tomography.

    Science.gov (United States)

    Javaherian, Ashkan; Soleimani, Manuchehr; Moeller, Knut

    2015-01-01

    This study proposes a method to improve performance of sparse recovery inverse solvers in 3D electrical impedance tomography (3D EIT), especially when the volume under study contains small-sized inclusions, e.g. 3D imaging of breast tumours. Initially, a quadratic regularized inverse solver is applied in a fast manner with a stopping threshold much greater than the optimum. Based on assuming a fixed level of sparsity for the conductivity field, finite elements are then sampled via applying a compressive sensing (CS) algorithm to the rough blurred estimation previously made by the quadratic solver. Finally, a sparse inverse solver is applied solely to the sampled finite elements, with the solution to the CS as its initial guess. The results show the great potential of the proposed CS-based sparse recovery in improving accuracy of sparse solution to the large-size 3D EIT.

  1. 3-D finite element analysis of claw-poled stepping motor

    International Nuclear Information System (INIS)

    Kawase, Yoshihiro; Yamaguchi, Tadashi; Mizuno; Koike, Yoshikazu

    2002-01-01

    Stepping motors are widely used for various electric instruments. It is necessary for the optimum design to analyze the magnetic field accurately. The 3-D finite element method with edge elements taking into account the rotation of the rotor has been applied to analyze the magnetic field of a claw-poled stepping motor. (Author)

  2. Residual fatigue life evaluation of rail at squats seeds using 3D explicit finite element analysis

    NARCIS (Netherlands)

    Deng, X.; Naeimi, M.; Li, Z.; Qian, Z.

    2014-01-01

    A modeling procedure to predict the residual fatigue life of rail at squats seeds is developed in this article. Two models are involved: a 3D explicit Finite Element (FE) model to compute the stress and strain at squats in rail, and the J-S fatigue damage model to determine the residual fatigue life

  3. Investigation of a Hybrid Winding Concept for Toroidal Inductors using 3D Finite Element Modeling

    DEFF Research Database (Denmark)

    Schneider, Henrik; Andersen, Thomas; Mønster, Jakob Døllner

    2013-01-01

    This paper investigates a hybrid winding concept for a toroidal inductor by simulating the winding resistance as a function of frequency. The problem of predicting the resistance of a non-uniform and complex winding shape is solved using 3D Finite Element Modeling. A prototype is built and tested...

  4. A Comparison of Continuous Mass-lumped Finite Elements and Finite Differences for 3D

    NARCIS (Netherlands)

    Zhebel, E.; Minisini, S.; Kononov, A.; Mulder, W.A.

    2012-01-01

    The finite-difference method is widely used for time-domain modelling of the wave equation because of its ease of implementation of high-order spatial discretization schemes, parallelization and computational efficiency. However, finite elements on tetrahedral meshes are more accurate in complex

  5. The Use of Direct Solver in Vector Finite Element Modeling for Calculating 3-D Magnetotelluric Responses

    International Nuclear Information System (INIS)

    Prihantoro, Rudy; Sutarno, Doddy; Nurhasan

    2016-01-01

    In this work, we seek numerical solution of 3-D Magnetotelluric (MT) using edge- based finite element method. This approach is a variant of standard finite element method and commonly referred as vector finite-element (VFE) method. Nonphysical solutions usually occurred when the solution is sought using standard finite element which is a node based element. Vector finite element attempt to overcome those nonphysical solutions by using the edges of the element as vector basis. The proposed approach on solving second order Maxwell differential equation of 3-D MT is using direct solver rather than iterative method. Therefore, divergence correction to accelerate the rate of convergence for its iterative solution is no longer needed. The utilization of direct solver has been verified previously for correctness by comparing the resulting solution to those given by analytical solution, as well as the solution come from the other numerical methods, for earth layered model, 2-D models and COMMEMI 3D-2 model. In this work, further verification resulted from recent comparison model of Dublin Test Model 1 (DTM1) is presented. (paper)

  6. Divergence correction schemes in finite difference method for 3D tensor CSAMT in axial anisotropic media

    Science.gov (United States)

    Wang, Kunpeng; Tan, Handong; Zhang, Zhiyong; Li, Zhiqiang; Cao, Meng

    2017-05-01

    Resistivity anisotropy and full-tensor controlled-source audio-frequency magnetotellurics (CSAMT) have gradually become hot research topics. However, much of the current anisotropy research for tensor CSAMT only focuses on the one-dimensional (1D) solution. As the subsurface is rarely 1D, it is necessary to study three-dimensional (3D) model response. The staggered-grid finite difference method is an effective simulation method for 3D electromagnetic forward modelling. Previous studies have suggested using the divergence correction to constrain the iterative process when using a staggered-grid finite difference model so as to accelerate the 3D forward speed and enhance the computational accuracy. However, the traditional divergence correction method was developed assuming an isotropic medium. This paper improves the traditional isotropic divergence correction method and derivation process to meet the tensor CSAMT requirements for anisotropy using the volume integral of the divergence equation. This method is more intuitive, enabling a simple derivation of a discrete equation and then calculation of coefficients related to the anisotropic divergence correction equation. We validate the result of our 3D computational results by comparing them to the results computed using an anisotropic, controlled-source 2.5D program. The 3D resistivity anisotropy model allows us to evaluate the consequences of using the divergence correction at different frequencies and for two orthogonal finite length sources. Our results show that the divergence correction plays an important role in 3D tensor CSAMT resistivity anisotropy research and offers a solid foundation for inversion of CSAMT data collected over an anisotropic body.

  7. High-order finite difference solution for 3D nonlinear wave-structure interaction

    DEFF Research Database (Denmark)

    Ducrozet, Guillaume; Bingham, Harry B.; Engsig-Karup, Allan Peter

    2010-01-01

    This contribution presents our recent progress on developing an efficient fully-nonlinear potential flow model for simulating 3D wave-wave and wave-structure interaction over arbitrary depths (i.e. in coastal and offshore environment). The model is based on a high-order finite difference scheme...... OceanWave3D presented in [1, 2]. A nonlinear decomposition of the solution into incident and scattered fields is used to increase the efficiency of the wave-structure interaction problem resolution. Application of the method to the diffraction of nonlinear waves around a fixed, bottom mounted circular...

  8. Implementation of Generalized Modes in a 3D Finite Difference Based Seakeeping Model

    DEFF Research Database (Denmark)

    Andersen, Matilde H.; Amini Afshar, Mostafa; Bingham, Harry B.

    This work is an extension of the finite difference potential flow solver OceanWave3D-Seakeepingdeveloped by Afshar (2014) to include generalized modes. The continuity equation is solvedusing a fourth-order centered finite difference scheme which requires that the entire fluid domainis discretized...... to the sparse nature of the coefficient matrix. Thesolver is built using the open source framework Overture which consists of C++ libraries forsolving partial differential equations on overlapping grids and has a built-in overlapping gridgenerator Ogen....

  9. Confining pressure effects on stress intensity factors: A 3D finite ...

    African Journals Online (AJOL)

    Revue Synthèse N° 19, Décembre 2008. M.R.M. Aliha et al. 33. Confining pressure effects on stress intensity factors: A 3D finite element analysis. M.R.M. Aliha, M.R. Ayatollahi et M.M.S. Mousavi. Fatigue and Fracture Lab., Department of Mechanical Engineering,. Iran University of Science and Technology, Narmak, Tehran, ...

  10. Application of 3D X-ray CT data sets to finite element analysis

    International Nuclear Information System (INIS)

    Bossart, P.L.; Martz, H.E.; Brand, H.R.; Hollerbach, K.

    1995-01-01

    Finite Element Modeling (FEM) is becoming more important as industry drives toward concurrent engineering. A fundamental hindrance to fully exploiting the power of FEM is the human effort required to acquire complex part geometry, particularly as-built geometry, as a FEM mesh. Many Quantitative Non Destructive Evaluation (QNDE) techniques that produce three-dimensional (3D) data sets provide a substantial reduction in the effort required to apply FEM to as-built parts. This paper describes progress at LLNL on the application of 3D X-ray computed tomography (CT) data sets to more rapidly produce high-quality FEM meshes of complex, as-built geometries. Issues related to the volume segmentation of the 3D CT data as well as the use of this segmented data to tailor generic hexahedral FEM meshes to part specific geometries are discussed. The application of these techniques to FEM analysis in the medical field is reported here

  11. 3D Finite Element Modelling of Drilling Process of Al2024-T3 Alloy with solid tooling and Experimental Validation

    DEFF Research Database (Denmark)

    Davoudinejad, Ali; Tosello, Guido

    2017-01-01

    Drilling is an indispensable process for many manufacturing industries due to its importance for assembling components. This study presents a 3D finite element modelling (3D FEM) approach for drilling process of aluminium 2024-T3. The 3D model of drilling tools for two facet HSSCo and four facet...... area were determined numerically. The results confirm the ability and advantage of 3D FE modelling of the drilling process....

  12. An unsteady finite-difference scheme for 3-D incompressible Navier-Stokes equations

    Science.gov (United States)

    Shin, Byeong R.; Ikohagi, Toshiaki; Daiguji, Hisaaki

    An implicit finite-difference SMAC scheme is developed for solving unsteady 3D incompressible Navier-Stokes equations in general curvilinear coordinates. The time-dependent momentum equations of contravariant velocity components are solved by the approximate-factorization method and the Newton iterative method. Alternatively, an elliptic equation in pressure derived by decoupling the continuity equation from the momentum equations is solved by the Chebyshev SLOR method using a staggered mesh system. An unsteady 3D duct flow over a backward-facing step is computed and presented at a high Reynolds number. The present scheme is found to be robust on supercomputing for the unsteady flow simulation of long time runs.

  13. A 3D finite volume scheme for the simulation of edge plasma in Tokamaks*

    Directory of Open Access Journals (Sweden)

    Bilanceri M.

    2013-12-01

    Full Text Available A finite volume method in cylindrical coordinates for the simulation of the edge region in tokamaks is proposed. In contrast to standard methods, which require the projected form of the equations in curvilinear coordinates, a new method is proposed. This technique is based on the discretization on the vector form of the equations and then on the projection on the basis of the curvilinear system associated to each control volume. The proposed methodology has been validated on several simple test cases and applied on a 3D simulation of a reduced MHD model.

  14. Parallel goal-oriented adaptive finite element modeling for 3D electromagnetic exploration

    Science.gov (United States)

    Zhang, Y.; Key, K.; Ovall, J.; Holst, M.

    2014-12-01

    We present a parallel goal-oriented adaptive finite element method for accurate and efficient electromagnetic (EM) modeling of complex 3D structures. An unstructured tetrahedral mesh allows this approach to accommodate arbitrarily complex 3D conductivity variations and a priori known boundaries. The total electric field is approximated by the lowest order linear curl-conforming shape functions and the discretized finite element equations are solved by a sparse LU factorization. Accuracy of the finite element solution is achieved through adaptive mesh refinement that is performed iteratively until the solution converges to the desired accuracy tolerance. Refinement is guided by a goal-oriented error estimator that uses a dual-weighted residual method to optimize the mesh for accurate EM responses at the locations of the EM receivers. As a result, the mesh refinement is highly efficient since it only targets the elements where the inaccuracy of the solution corrupts the response at the possibly distant locations of the EM receivers. We compare the accuracy and efficiency of two approaches for estimating the primary residual error required at the core of this method: one uses local element and inter-element residuals and the other relies on solving a global residual system using a hierarchical basis. For computational efficiency our method follows the Bank-Holst algorithm for parallelization, where solutions are computed in subdomains of the original model. To resolve the load-balancing problem, this approach applies a spectral bisection method to divide the entire model into subdomains that have approximately equal error and the same number of receivers. The finite element solutions are then computed in parallel with each subdomain carrying out goal-oriented adaptive mesh refinement independently. We validate the newly developed algorithm by comparison with controlled-source EM solutions for 1D layered models and with 2D results from our earlier 2D goal oriented

  15. Co-simulation coupling spectral/finite elements for 3D soil/structure interaction problems

    Science.gov (United States)

    Zuchowski, Loïc; Brun, Michael; De Martin, Florent

    2018-05-01

    The coupling between an implicit finite elements (FE) code and an explicit spectral elements (SE) code has been explored for solving the elastic wave propagation in the case of soil/structure interaction problem. The coupling approach is based on domain decomposition methods in transient dynamics. The spatial coupling at the interface is managed by a standard coupling mortar approach, whereas the time integration is dealt with an hybrid asynchronous time integrator. An external coupling software, handling the interface problem, has been set up in order to couple the FE software Code_Aster with the SE software EFISPEC3D.

  16. 3D Finite Volume Modeling of ENDE Using Electromagnetic T-Formulation

    Directory of Open Access Journals (Sweden)

    Yue Li

    2012-01-01

    Full Text Available An improved method which can analyze the eddy current density in conductor materials using finite volume method is proposed on the basis of Maxwell equations and T-formulation. The algorithm is applied to solve 3D electromagnetic nondestructive evaluation (E’NDE benchmark problems. The computing code is applied to study an Inconel 600 work piece with holes or cracks. The impedance change due to the presence of the crack is evaluated and compared with the experimental data of benchmark problems No. 1 and No. 2. The results show a good agreement between both calculated and measured data.

  17. Parallel 3D Finite Element Particle-in-Cell Simulations with Pic3P

    Energy Technology Data Exchange (ETDEWEB)

    Candel, A.; Kabel, A.; Lee, L.; Li, Z.; Ng, C.; Schussman, G.; Ko, K.; /SLAC; Ben-Zvi, I.; Kewisch, J.; /Brookhaven

    2009-06-19

    SLAC's Advanced Computations Department (ACD) has developed the parallel 3D Finite Element electromagnetic Particle-In-Cell code Pic3P. Designed for simulations of beam-cavity interactions dominated by space charge effects, Pic3P solves the complete set of Maxwell-Lorentz equations self-consistently and includes space-charge, retardation and boundary effects from first principles. Higher-order Finite Element methods with adaptive refinement on conformal unstructured meshes lead to highly efficient use of computational resources. Massively parallel processing with dynamic load balancing enables large-scale modeling of photoinjectors with unprecedented accuracy, aiding the design and operation of next-generation accelerator facilities. Applications include the LCLS RF gun and the BNL polarized SRF gun.

  18. Pathophysiological aspects of cystocele with a 3D finite elements model.

    Science.gov (United States)

    Lamblin, Géry; Mayeur, Olivier; Giraudet, Géraldine; Jean Dit Gautier, Estelle; Chene, Gautier; Brieu, Mathias; Rubod, Chrystèle; Cosson, Michel

    2016-11-01

    The objective of this study is to design a 3D biomechanical model of the female pelvic system to assess pelvic organ suspension theories and understand cystocele mechanisms. A finite elements (FE) model was constructed to calculate the impact of suspension structure geometry on cystocele. The sample was a geometric model of a control patient's pelvic organs. The method used geometric reconstruction, implemented by the biomechanical properties of each anatomic structure. Various geometric configurations were simulated on the FE method to analyse the role of each structure and compare the two main anatomic theories. The main outcome measure was a 3D biomechanical model of the female pelvic system. The various configurations of bladder displacement simulated mechanisms underlying medial, lateral and apical cystocele. FE simulation revealed that pubocervical fascia is the most influential structure in the onset of median cystocele (essentially after 40 % impairment). Lateral cystocele showed a stronger influence of arcus tendineus fasciae pelvis (ATFP) on vaginal wall displacement under short ATFP lengthening. In apical cystocele, the uterosacral ligament showed greater influence than the cardinal ligament. Suspension system elongation increased displacement by 25 % in each type of cystocele. A 3D digital model enabled simulations of anatomic structures underlying cystocele to better understand cystocele pathophysiology. The model could be used to predict cystocele surgery results and personalising technique by preoperative simulation.

  19. 3D finite element modelling of force transmission and particle fracture of sand

    Energy Technology Data Exchange (ETDEWEB)

    Imseeh, Wadi H.; Alshibli, Khalid A. (Tennessee-K)

    2018-02-01

    Global compressive loading of granular media causes rearrangements of particles into a denser configuration. Under 1D compression, researchers observed that particles initially translate and rotate which lead to more contacts between particles and the development of force chains to resist applied loads. Particles within force chains resist most of the applied loads while neighbor particles provide lateral support to prevent particles within force chains from buckling. Several experimental and numerical models have been proposed in the literature to characterize force chains within granular materials. This paper presents a 3D finite element (FE) model that simulates 1D compression experiment on F-75 Ottawa sand. The FE mesh of particles closely matched 3D physical shape of sand particles that were acquired using 3D synchrotron micro-computed tomography (SMT) technique. The paper presents a quantitative assessment of the model, in which evolution of force chains, fracture modes, and stress-strain relationships showed an excellent agreement with experimental measurements reported by Cil et al. Alshibli (2017).

  20. 3D CSEM inversion based on goal-oriented adaptive finite element method

    Science.gov (United States)

    Zhang, Y.; Key, K.

    2016-12-01

    We present a parallel 3D frequency domain controlled-source electromagnetic inversion code name MARE3DEM. Non-linear inversion of observed data is performed with the Occam variant of regularized Gauss-Newton optimization. The forward operator is based on the goal-oriented finite element method that efficiently calculates the responses and sensitivity kernels in parallel using a data decomposition scheme where independent modeling tasks contain different frequencies and subsets of the transmitters and receivers. To accommodate complex 3D conductivity variation with high flexibility and precision, we adopt the dual-grid approach where the forward mesh conforms to the inversion parameter grid and is adaptively refined until the forward solution converges to the desired accuracy. This dual-grid approach is memory efficient, since the inverse parameter grid remains independent from fine meshing generated around the transmitter and receivers by the adaptive finite element method. Besides, the unstructured inverse mesh efficiently handles multiple scale structures and allows for fine-scale model parameters within the region of interest. Our mesh generation engine keeps track of the refinement hierarchy so that the map of conductivity and sensitivity kernel between the forward and inverse mesh is retained. We employ the adjoint-reciprocity method to calculate the sensitivity kernels which establish a linear relationship between changes in the conductivity model and changes in the modeled responses. Our code uses a direcy solver for the linear systems, so the adjoint problem is efficiently computed by re-using the factorization from the primary problem. Further computational efficiency and scalability is obtained in the regularized Gauss-Newton portion of the inversion using parallel dense matrix-matrix multiplication and matrix factorization routines implemented with the ScaLAPACK library. We show the scalability, reliability and the potential of the algorithm to deal with

  1. Finite-Element-Based Discretization and Regularization Strategies for 3D Inverse Electrocardiography

    Science.gov (United States)

    Wang, Dafang; Kirby, Robert M.; Johnson, Chris R.

    2011-01-01

    We consider the inverse electrocardiographic problem of computing epicardial potentials from a body-surface potential map. We study how to improve numerical approximation of the inverse problem when the finite element method is used. Being ill-posed, the inverse problem requires different discretization strategies from its corresponding forward problem. We propose refinement guidelines that specifically address the ill-posedness of the problem. The resulting guidelines necessitate the use of hybrid finite elements composed of tetrahedra and prism elements. Also in order to maintain consistent numerical quality when the inverse problem is discretized into different scales, we propose a new family of regularizers using the variational principle underlying finite element methods. These variational-formed regularizers serve as an alternative to the traditional Tikhonov regularizers, but preserves the L2 norm and thereby achieves consistent regularization in multi-scale simulations. The variational formulation also enables a simple construction of the discrete gradient operator over irregular meshes, which is difficult to define in traditional discretization schemes. We validated our hybrid element technique and the variational regularizers by simulations on a realistic 3D torso/heart model with empirical heart data. Results show that discretization based on our proposed strategies mitigates the ill-conditioning and improves the inverse solution, and that the variational formulation may benefit a broader range of potential-based bioelectric problems. PMID:21382763

  2. CONSTOR registered V/TC drop tests. Pre-test analysis by finite element method

    International Nuclear Information System (INIS)

    Voelzer, W.; Koenig, S.; Klein, K.; Tso, C.F.; Owen, S.; Monk, C.

    2004-01-01

    The CONSTOR registered family of steel-concrete-steel sandwich cask designs have been developed to fulfil both the internationally valid IAEA criteria for transportation and the requirements for long-term intermediate storage in the US and various European countries. A comprehensive drop testing programme using a full-scale prototype test cask (CONSTOR registered V/TC) has been developed as part of the application for a transport license in both Germany and the US. The drop tests using the full-scale cask will be performed by BAM at test facilities in Horstwalde. The tests will include five different 9m drops onto flat unyielding targets and seven different 1m drops onto a punch. The first drop test, a 9m side drop, will be performed during PATRAM 2004. The other drop tests will take place during the following year. The development of the cask design and the formulation of the drop test programme has been supported by an extensive series of finite element analyses. The objectives of the finite element analyses were; to provide an intermediate step in demonstrating the performance of the CONSTOR registered in fulfilling the requirements of 10 CFR 71 and the IAEA transport regulations. To justify the selection of drop tests. To predict the performance of V/TC during the drop tests. To estimate the strain and acceleration time histories at measuring points on the test cask and to aid in the setting up of the test instrumentation. To develop an analysis model that can be used in future safety analyses for transport and storage license applications and which can confidently be used to demonstrate the performance of the package. This paper presents an overview of the analyses performed, including a summary of all the different drop orientations that were considered. The major assumptions employed during the analyses are also discussed, as are the specifics of the modelling techniques that were employed. At the end of the paper, the key results obtained from the analyses

  3. Computational Finite Element Software Assisted Development of a 3D Inductively Coupled Power Transfer System

    Directory of Open Access Journals (Sweden)

    P. Raval

    2014-02-01

    Full Text Available To date inductively coupled power transfer (ICPT systems have already found many practical applications including battery charging pads. In fact, current charging platforms tend to largely support only one- or two-dimensional planar movement in load. This paper proposes a new concept of extending the aspect ratios of the operating power transfer volume of ICPT systems to support arbitrary three dimensional load movements with respect to the primary coils. This is done by use of modern finite element method analysis software to propose the primary and secondary magnetic structures of such an ICPT system. Firstly, two primary magnetic structures are proposed based on contrasting modes of operation and different field directions. This includes a single-phase and multi-phase current model. Next, a secondary magnetic structure is customized to be compatible with both primary structures. The resulting system is shown to produce a 3D power transfer volume for battery cell charging applications.

  4. A least-squares finite element method for 3D incompressible Navier-Stokes equations

    Science.gov (United States)

    Jiang, Bo-Nan; Lin, T. L.; Hou, Lin-Jun; Povinelli, Louis A.

    1993-01-01

    The least-squares finite element method (LSFEM) based on the velocity-pressure-vorticity formulation is applied to three-dimensional steady incompressible Navier-Stokes problems. This method can accommodate equal-order interpolations, and results in symmetric, positive definite algebraic system. An additional compatibility equation, i.e., the divergence of vorticity vector should be zero, is included to make the first-order system elliptic. The Newton's method is employed to linearize the partial differential equations, the LSFEM is used to obtain discretized equations, and the system of algebraic equations is solved using the Jacobi preconditioned conjugate gradient method which avoids formation of either element or global matrices (matrix-free) to achieve high efficiency. The flow in a half of 3D cubic cavity is calculated at Re = 100, 400, and 1,000 with 50 x 52 x 25 trilinear elements. The Taylor-Gortler-like vortices are observed at Re = 1,000.

  5. Solving Elliptical Equations in 3D by Means of an Adaptive Refinement in Generalized Finite Differences

    Directory of Open Access Journals (Sweden)

    Luis Gavete

    2018-01-01

    Full Text Available We apply a 3D adaptive refinement procedure using meshless generalized finite difference method for solving elliptic partial differential equations. This adaptive refinement, based on an octree structure, allows adding nodes in a regular way in order to obtain smooth transitions with different nodal densities in the model. For this purpose, we define an error indicator as stop condition of the refinement, a criterion for choosing nodes with the highest errors, and a limit for the number of nodes to be added in each adaptive stage. This kind of equations often appears in engineering problems such as simulation of heat conduction, electrical potential, seepage through porous media, or irrotational flow of fluids. The numerical results show the high accuracy obtained.

  6. Finite volume method in 3-D curvilinear coordinates with multiblocking procedure for radiative transport problems

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, P.; Steven, M.; Issendorff, F.V.; Trimis, D. [Institute of Fluid Mechanics (LSTM), University of Erlangen-Nuremberg, Cauerstrasse 4, D 91058 Erlangen (Germany)

    2005-10-01

    The finite volume method of radiation is implemented for complex 3-D problems in order to use it for combined heat transfer problems in connection with CFD codes. The method is applied for a 3-D block structured grid in a radiatively participating medium. The method is implemented in non-orthogonal curvilinear coordinates so that it can handle irregular structure with a body-fitted structured grid. The multiblocking is performed with overlapping blocks to exchange the information between the blocks. Five test problems are considered in this work. In the first problem, present work is validated with the results of the literature. To check the accuracy of multiblocking, a single block is divided into four blocks and results are validated against the results of the single block simulated alone in the second problem. Complicated geometries are considered to show the applicability of the present procedure in the last three problems. Both radiative and non-radiative equilibrium situations are considered along with an absorbing, emitting and scattering medium. (author)

  7. 3D finite element model of the chinchilla ear for characterizing middle ear functions.

    Science.gov (United States)

    Wang, Xuelin; Gan, Rong Z

    2016-10-01

    Chinchilla is a commonly used animal model for research of sound transmission through the ear. Experimental measurements of the middle ear transfer function in chinchillas have shown that the middle ear cavity greatly affects the tympanic membrane (TM) and stapes footplate (FP) displacements. However, there is no finite element (FE) model of the chinchilla ear available in the literature to characterize the middle ear functions with the anatomical features of the chinchilla ear. This paper reports a recently completed 3D FE model of the chinchilla ear based on X-ray micro-computed tomography images of a chinchilla bulla. The model consisted of the ear canal, TM, middle ear ossicles and suspensory ligaments, and the middle ear cavity. Two boundary conditions of the middle ear cavity wall were simulated in the model as the rigid structure and the partially flexible surface, and the acoustic-mechanical coupled analysis was conducted with these two conditions to characterize the middle ear function. The model results were compared with experimental measurements reported in the literature including the TM and FP displacements and the middle ear input admittance in chinchilla ear. An application of this model was presented to identify the acoustic role of the middle ear septa-a unique feature of chinchilla middle ear cavity. This study provides the first 3D FE model of the chinchilla ear for characterizing the middle ear functions through the acoustic-mechanical coupled FE analysis.

  8. 3D viscous time dependent analysis of a slow moving landslide by finite elements

    Science.gov (United States)

    Bru, Guadalupe; Fernández-Merodo, Josè Antonio; García-Davalillo, Juan Carlos; Herrera, Gerardo

    2017-04-01

    A methodology to study the cinematic behavior in time and 3D effects of slow moving landslides is presented by its application to the Portalet landslide, located in the Spanish Central Pyrenees. The area is characterize by the presence of several complex landslides triggered by glacial retreat and developed in weathered Devonian and Carboniferous slate materials. In summer 2004, the toe of two paleolanslides was excavated in order to construct a parking area, which reactivated the preexistent rupture surfaces and generated a new and smaller roto-translational landslide of about 5·105m3. Works were paralyzed and the road A-136 connecting Spain and France was temporary closed. In 2006 stabilizing solutions were performed, although surface and deep monitoring data reveal that the landslide is currently active. In this work the cinematic behavior of the Portalet parking landslide has been reproduced since the excavation in 2004 until 2016 by an advanced 3D finite element model (FEM) analysis. A detailed 3D litho-stratigraphic geometry has been defined using the information available from previous works(1-3): real topography, geological profiles, ground water level and material properties. The first step has been a stability analysis using the shear stress reduction (SSR) technique to calibrate the value of the friction angle of the soil layer where the rupture surface develops. In this step the sensibility of the mesh size has been studied, as is a critical parameter. Secondly, stability analysis results have been verified by simulating the parking excavation with a static analysis using Mohr-Coulomb elastoplastic failure criteria. In the last step the behavior of the landslide has been recreated using a hydromechanic coupled formulation for displacements and interstitial water pressure (u-pw), a simple elevation ground water model calculated from daily rainfall and a Perzyna viscous constitutive model of the solid skeleton which represent the creep detected by

  9. Development of a 3D finite element model of lens microcirculation

    Directory of Open Access Journals (Sweden)

    Vaghefi Ehsan

    2012-09-01

    Full Text Available Abstract Background It has been proposed that in the absence of a blood supply, the ocular lens operates an internal microcirculation system. This system delivers nutrients, removes waste products and maintains ionic homeostasis in the lens. The microcirculation is generated by spatial differences in membrane transport properties; and previously has been modelled by an equivalent electrical circuit and solved analytically. While effective, this approach did not fully account for all the anatomical and functional complexities of the lens. To encapsulate these complexities we have created a 3D finite element computer model of the lens. Methods Initially, we created an anatomically-correct representative mesh of the lens. We then implemented the Stokes and advective Nernst-Plank equations, in order to model the water and ion fluxes respectively. Next we complemented the model with experimentally-measured surface ionic concentrations as boundary conditions and solved it. Results Our model calculated the standing ionic concentrations and electrical potential gradients in the lens. Furthermore, it generated vector maps of intra- and extracellular space ion and water fluxes that are proposed to circulate throughout the lens. These fields have only been measured on the surface of the lens and our calculations are the first 3D representation of their direction and magnitude in the lens. Conclusion Values for steady state standing fields for concentration and electrical potential plus ionic and fluid fluxes calculated by our model exhibited broad agreement with observed experimental values. Our model of lens function represents a platform to integrate new experimental data as they emerge and assist us to understand how the integrated structure and function of the lens contributes to the maintenance of its transparency.

  10. Feeding biomechanics of Late Triassic metoposaurids (Amphibia: Temnospondyli): a 3D finite element analysis approach.

    Science.gov (United States)

    Fortuny, Josep; Marcé-Nogué, Jordi; Konietzko-Meier, Dorota

    2017-06-01

    The Late Triassic freshwater ecosystems were occupied by different tetrapod groups including large-sized anamniotes, such as metoposaurids. Most members of this group of temnospondyls acquired gigantic sizes (up to 5 m long) with a nearly worldwide distribution. The paleoecology of metoposaurids is controversial; they have been historically considered passive, bottom-dwelling animals, waiting for prey on the bottom of rivers and lakes, or they have been suggested to be active mid-water feeders. The present study aims to expand upon the paleoecological interpretations of these animals using 3D finite element analyses (FEA). Skulls from two taxa, Metoposaurus krasiejowensis, a gigantic taxon from Europe, and Apachesaurus gregorii, a non-gigantic taxon from North America, were analyzed under different biomechanical scenarios. Both 3D models of the skulls were scaled to allow comparisons between them and reveal that the general stress distribution pattern found in both taxa is clearly similar in all scenarios. In light of our results, both previous hypotheses about the paleoecology of these animals can be partly merged: metoposaurids probably were ambush and active predators, but not the top predators of these aquatic environments. The FEA results demonstrate that they were particularly efficient at bilateral biting, and together with their characteristically anteropositioned orbits, optimal for an ambush strategy. Nonetheless, the results also show that these animals were capable of lateral strikes of the head, suggesting active hunting of prey. Regarding the important skull size differences between the taxa analyzed, our results suggest that the size reduction in the North American taxon could be related to drastic environmental changes or the increase of competitors. The size reduction might have helped them expand into new ecological niches, but they likely remained fully aquatic, as are all other metoposaurids. © 2017 Anatomical Society.

  11. Accurate, finite-volume methods for 3D MHD on unstructured Lagrangian meshes

    International Nuclear Information System (INIS)

    Barnes, D.C.; Rousculp, C.L.

    1998-10-01

    Previous 2D methods for magnetohydrodynamics (MHD) have contributed both to development of core code capability and to physics applications relevant to AGEX pulsed-power experiments. This strategy is being extended to 3D by development of a modular extension of an ASCI code. Extension to 3D not only increases complexity by problem size, but also introduces new physics, such as magnetic helicity transport. The authors have developed a method which incorporates all known conservation properties into the difference scheme on a Lagrangian unstructured mesh. Because the method does not depend on the mesh structure, mesh refinement is possible during a calculation to prevent the well known problem of mesh tangling. Arbitrary polyhedral cells are decomposed into tetrahedrons. The action of the magnetic vector potential, A · δl, is centered on the edges of this extended mesh. For ideal flow, this maintains ∇ · B = 0 to round-off error. Vertex forces are derived by the variation of magnetic energy with respect to vertex positions, F = -∂W B /∂r. This assures symmetry as well as magnetic flux, momentum, and energy conservation. The method is local so that parallelization by domain decomposition is natural for large meshes. In addition, a simple, ideal-gas, finite pressure term has been included. The resistive diffusion part is calculated using the support operator method, to obtain an energy conservative, symmetric method on an arbitrary mesh. Implicit time difference equations are solved by preconditioned, conjugate gradient methods. Results of convergence tests are presented. Initial results of an annular Z-pinch implosion problem illustrate the application of these methods to multi-material problems

  12. High‐order rotated staggered finite difference modeling of 3D elastic wave propagation in general anisotropic media

    KAUST Repository

    Chu, Chunlei

    2009-01-01

    We analyze the dispersion properties and stability conditions of the high‐order convolutional finite difference operators and compare them with the conventional finite difference schemes. We observe that the convolutional finite difference method has better dispersion properties and becomes more efficient than the conventional finite difference method with the increasing order of accuracy. This makes the high‐order convolutional operator a good choice for anisotropic elastic wave simulations on rotated staggered grids since its enhanced dispersion properties can help to suppress the numerical dispersion error that is inherent in the rotated staggered grid structure and its efficiency can help us tackle 3D problems cost‐effectively.

  13. Plasmonic Resonances for Spectroscopy Applications using 3D Finite-Difference Time-Domain Models

    Science.gov (United States)

    Ravi, Aruna

    Tuning plasmonic extinction resonances of sub-wavelength scale structures is essential to achieve maximum sensitivity and accuracy. These resonances can be controlled with careful design of nanoparticle geometries and incident wave attributes. In the first part of this dissertation, plasmonically enhanced effects on hexagonal-arrays of metal nanoparticles, metal-hole arrays (micro-mesh), and linear-arrays of metal nanorings are analyzed using three-dimensional Finite-Difference Time-Domain (3D-FDTD) simulations. The effect of particle size, lattice spacing, and lack of monodispersity of a self-assembled, hexagonal array layer of silver (Ag) nanoparticles on the extinction resonance is investigated to help determine optimal design specifications for efficient organic solar power harvesting. The enhancement of transmission resonances using plasmonic thin metal films with arrays of holes which enable recording of scatter-free infrared (IR) transmission spectra of individual particles is also explored. This method is quantitative, non-destructive and helps in better understanding the interaction of light with sub-wavelength particles. Next, plasmonically enhanced effects on linear arrays of gold (Au) rings are studied. Simulations employing 3D-FDTD can be used to determine the set of geometrical parameters to attain localized surface plasmon resonance (LSPR). The shifts in resonances due to changes in the effective dielectric of the structure are investigated, which is useful in sensing applications. Computational models enrich experimental studies. In the second part of this dissertation, the effect of particle size, shape and orientation on the IR spectra is investigated using 3D-FDTD and Mie-Bruggeman models. This computational analysis is extended to include clusters of particles of mixed composition. The prediction of extinction and absorption spectra of single particles of mixed composition helps in interpreting their physical properties and predict chemical

  14. Three-dimensional quantification of vorticity and helicity from 3D cine PC-MRI using finite-element interpolations.

    Science.gov (United States)

    Sotelo, Julio; Urbina, Jesús; Valverde, Israel; Mura, Joaquín; Tejos, Cristián; Irarrazaval, Pablo; Andia, Marcelo E; Hurtado, Daniel E; Uribe, Sergio

    2018-01-01

    We propose a 3D finite-element method for the quantification of vorticity and helicity density from 3D cine phase-contrast (PC) MRI. By using a 3D finite-element method, we seamlessly estimate velocity gradients in 3D. The robustness and convergence were analyzed using a combined Poiseuille and Lamb-Ossen equation. A computational fluid dynamics simulation was used to compared our method with others available in the literature. Additionally, we computed 3D maps for different 3D cine PC-MRI data sets: phantom without and with coarctation (18 healthy volunteers and 3 patients). We found a good agreement between our method and both the analytical solution of the combined Poiseuille and Lamb-Ossen. The computational fluid dynamics results showed that our method outperforms current approaches to estimate vorticity and helicity values. In the in silico model, we observed that for a tetrahedral element of 2 mm of characteristic length, we underestimated the vorticity in less than 5% with respect to the analytical solution. In patients, we found higher values of helicity density in comparison to healthy volunteers, associated with vortices in the lumen of the vessels. We proposed a novel method that provides entire 3D vorticity and helicity density maps, avoiding the used of reformatted 2D planes from 3D cine PC-MRI. Magn Reson Med 79:541-553, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  15. A New Energy-Based Method for 3-D Finite-Element Nonlinear Flux Linkage computation of Electrical Machines

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Rasmussen, Peter Omand; Ritchie, Ewen

    2011-01-01

    This paper presents a new method for computation of the nonlinear flux linkage in 3-D finite-element models (FEMs) of electrical machines. Accurate computation of the nonlinear flux linkage in 3-D FEM is not an easy task. Compared to the existing energy-perturbation method, the new technique......-perturbation method. The new method proposed is validated using experimental results on two different permanent magnet machines....

  16. Fluido-Dynamic and Electromagnetic Characterization of 3D Carbon Dielectrophoresis with Finite Element Analysis

    Directory of Open Access Journals (Sweden)

    Rodrigo Martinez-Duarte

    2008-12-01

    Full Text Available The following work presents the fluido-dynamic and electromagnetic characterization of an array of 3D electrodes to be used in high throughput and high efficiency Carbon Dielectrophoresis (CarbonDEP applications such as filters, continuous particle enrichment and positioning of particle populations for analysis. CarbonDEP refers to the induction of Dielectrophoresis (DEP by carbon surfaces. The final goal is, through an initial stage of modeling and analysis, to reduce idea-to-prototype time and cost of CarbonDEP devices to be applied in the health care field. Finite Element Analysis (FEA is successfully conducted to model flow velocity and electric fields established by polarized high aspect ratio carbon cylinders, and its planar carbon connecting leads, immersed in a water-based medium. Results demonstrate correlation between a decreasing flow velocity gradient and an increasing electric field gradient toward electrodes’ surfaces which is optimal for selected CarbonDEP applications. Simulation results are experimentally validated in the proposed applications.

  17. A new 3D finite element model of the IEC 60318-1 artificial ear

    Science.gov (United States)

    Bravo, Agustín; Barham, Richard; Ruiz, Mariano; López, Juan Manuel; DeArcas, Guillermo; Recuero, Manuel

    2008-08-01

    The artificial ear specified in IEC 60318-1 is used for the measurement of headphones and has been designed to present an acoustic load equivalent to that of normal human ears. In this respect it is specified in terms of an acoustical impedance, and modelled by a lumped parameter approach. However, this has some inherent frequency limitations and becomes less valid as the acoustic wavelength approaches the characteristic dimensions within the device. In addition, when sound propagates through structures such as narrow tubes, annular slits or over sharp corners, noticeable thermal and viscous effects take place causing further departure from the lumped parameter model. A new numerical model has therefore been developed, which gives proper consideration to the aforementioned effects. Both kinds of losses can be simulated by means of the LMS Virtual Lab acoustic software which facilitates finite and boundary element modelling of the whole artificial ear. A full 3D model of the artificial ear has therefore been developed based on key dimensional data found in IEC 60318-1. The model has been used to calculate the acoustical impedance, and the results compared with the corresponding data determined from the lumped parameter model. The numerical simulation of the artificial ear has been shown to provide realistic results, and is a powerful tool for developing a detailed understanding of the device. It is also proving valuable in the revision of IEC 60318-1 that is currently in progress.

  18. A Lower Limb-Pelvis Finite Element Model with 3D Active Muscles.

    Science.gov (United States)

    Mo, Fuhao; Li, Fan; Behr, Michel; Xiao, Zhi; Zhang, Guanjun; Du, Xianping

    2018-01-01

    A lower limb-pelvis finite element (FE) model with active three-dimensional (3D) muscles was developed in this study for biomechanical analysis of human body. The model geometry was mainly reconstructed from a male volunteer close to the anthropometry of a 50th percentile Chinese male. Tissue materials and structural features were established based on the literature and new implemented experimental tests. In particular, the muscle was modeled with a combination of truss and hexahedral elements to define its passive and active properties as well as to follow the detailed anatomy structure. Both passive and active properties of the model were validated against the experiments of Post-Mortem Human Surrogate (PMHS) and volunteers, respectively. The model was then used to simulate driver's emergency braking during frontal crashes and investigate Knee-Thigh-Hip (KTH) injury mechanisms and tolerances of the human body. A significant force and bending moment variance was noted for the driver's femur due to the effects of active muscle forces during emergency braking. In summary, the present lower limb-pelvis model can be applied in various research fields to support expensive and complex physical tests or corresponding device design.

  19. Finite-Difference Algorithm for Simulating 3D Electromagnetic Wavefields in Conductive Media

    Science.gov (United States)

    Aldridge, D. F.; Bartel, L. C.; Knox, H. A.

    2013-12-01

    Electromagnetic (EM) wavefields are routinely used in geophysical exploration for detection and characterization of subsurface geological formations of economic interest. Recorded EM signals depend strongly on the current conductivity of geologic media. Hence, they are particularly useful for inferring fluid content of saturated porous bodies. In order to enhance understanding of field-recorded data, we are developing a numerical algorithm for simulating three-dimensional (3D) EM wave propagation and diffusion in heterogeneous conductive materials. Maxwell's equations are combined with isotropic constitutive relations to obtain a set of six, coupled, first-order partial differential equations governing the electric and magnetic vectors. An advantage of this system is that it does not contain spatial derivatives of the three medium parameters electric permittivity, magnetic permeability, and current conductivity. Numerical solution methodology consists of explicit, time-domain finite-differencing on a 3D staggered rectangular grid. Temporal and spatial FD operators have order 2 and N, where N is user-selectable. We use an artificially-large electric permittivity to maximize the FD timestep, and thus reduce execution time. For the low frequencies typically used in geophysical exploration, accuracy is not unduly compromised. Grid boundary reflections are mitigated via convolutional perfectly matched layers (C-PMLs) imposed at the six grid flanks. A shared-memory-parallel code implementation via OpenMP directives enables rapid algorithm execution on a multi-thread computational platform. Good agreement is obtained in comparisons of numerically-generated data with reference solutions. EM wavefields are sourced via point current density and magnetic dipole vectors. Spatially-extended inductive sources (current carrying wire loops) are under development. We are particularly interested in accurate representation of high-conductivity sub-grid-scale features that are common

  20. Robust and scalable 3-D geo-electromagnetic modelling approach using the finite element method

    Science.gov (United States)

    Grayver, Alexander V.; Bürg, Markus

    2014-07-01

    We present a robust and scalable solver for time-harmonic Maxwell's equations for problems with large conductivity contrasts, wide range of frequencies, stretched grids and locally refined meshes. The solver is part of the fully distributed adaptive 3-D electromagnetic modelling scheme which employs the finite element method and unstructured non-conforming hexahedral meshes for spatial discretization using the open-source software deal.II. We use the complex-valued electric field formulation and split it into two real-valued equations for which we utilize an optimal block-diagonal pre-conditioner. Application of this pre-conditioner requires the solution of two smaller real-valued symmetric problems. We solve them by using either a direct solver or the conjugate gradient method pre-conditioned with the recently introduced auxiliary space technique. The auxiliary space pre-conditioner reformulates the original problem in form of several simpler ones, which are then solved using highly efficient algebraic multigrid methods. In this paper, we consider the magnetotelluric case and verify our numerical scheme by using COMMEMI 3-D models. Afterwards, we run a series of numerical experiments and demonstrate that the solver converges in a small number of iterations for a wide frequency range and variable problem sizes. The number of iterations is independent of the problem size, but exhibits a mild dependency on frequency. To test the stability of the method on locally refined meshes, we have implemented a residual-based a posteriori error estimator and compared it with uniform mesh refinement for problems up to 200 million unknowns. We test the scalability of the most time consuming parts of our code and show that they fulfill the strong scaling assumption as long as each MPI process possesses enough degrees of freedom to alleviate communication overburden. Finally, we refer back to a direct solver-based pre-conditioner and analyse its complexity in time. The results show

  1. 3D Staggered-Grid Finite-Difference Simulation of Acoustic Waves in Turbulent Moving Media

    Science.gov (United States)

    Symons, N. P.; Aldridge, D. F.; Marlin, D.; Wilson, D. K.; Sullivan, P.; Ostashev, V.

    2003-12-01

    Acoustic wave propagation in a three-dimensional heterogeneous moving atmosphere is accurately simulated with a numerical algorithm recently developed under the DOD Common High Performance Computing Software Support Initiative (CHSSI). Sound waves within such a dynamic environment are mathematically described by a set of four, coupled, first-order partial differential equations governing small-amplitude fluctuations in pressure and particle velocity. The system is rigorously derived from fundamental principles of continuum mechanics, ideal-fluid constitutive relations, and reasonable assumptions that the ambient atmospheric motion is adiabatic and divergence-free. An explicit, time-domain, finite-difference (FD) numerical scheme is used to solve the system for both pressure and particle velocity wavefields. The atmosphere is characterized by 3D gridded models of sound speed, mass density, and the three components of the wind velocity vector. Dependent variables are stored on staggered spatial and temporal grids, and centered FD operators possess 2nd-order and 4th-order space/time accuracy. Accurate sound wave simulation is achieved provided grid intervals are chosen appropriately. The gridding must be fine enough to reduce numerical dispersion artifacts to an acceptable level and maintain stability. The algorithm is designed to execute on parallel computational platforms by utilizing a spatial domain-decomposition strategy. Currently, the algorithm has been validated on four different computational platforms, and parallel scalability of approximately 85% has been demonstrated. Comparisons with analytic solutions for uniform and vertically stratified wind models indicate that the FD algorithm generates accurate results with either a vanishing pressure or vanishing vertical-particle velocity boundary condition. Simulations are performed using a kinematic turbulence wind profile developed with the quasi-wavelet method. In addition, preliminary results are presented

  2. Electro-thermal equivalent 3D Finite Element Model of a Single Neuron.

    Science.gov (United States)

    Cinelli, I; Destrade, M; Duffy, M; McHugh, P

    2017-09-14

    We propose a novel approach for modelling the inter-dependence of electrical and mechanical phenomena in nervous cells, by using electro-thermal equivalences in finite element (FE) analysis so that existing thermo-mechanical tools can be applied. First, the equivalence between electrical and thermal properties of the nerve materials is established, and results of a pure heat conduction analysis performed in Abaqus CAE Software 6.13-3 are validated with analytical solutions for a range of steady and transient conditions. This validation includes the definition of equivalent active membrane properties that enable prediction of the action potential. Then, as a step towards fully coupled models, electro-mechanical coupling is implemented through the definition of equivalent piezoelectric properties of the nerve membrane using the thermal expansion coefficient, enabling prediction of the mechanical response of the nerve to the action potential. Results of the coupled electro-mechanical model are validated with previously published experimental results of deformation for the squid giant axon, crab nerve fibre and garfish olfactory nerve fibre. A simplified coupled electro-mechanical modelling approach is established through an electro-thermal equivalent FE model of a nervous cell for biomedical applications. One of the key findings is the mechanical characterization of the neural activity in a coupled electro-mechanical domain, which provides insights into the electro-mechanical behaviour of nervous cells, such as thinning of the membrane. This is a first step towards modelling 3D electro-mechanical alteration induced by trauma at nerve bundle, tissue and organ levels.

  3. Time-stepping stability of continuous and discontinuous finite-element methods for 3-D wave propagation

    NARCIS (Netherlands)

    Mulder, W.A.; Zhebel, E.; Minisini, S.

    2013-01-01

    We analyse the time-stepping stability for the 3-D acoustic wave equation, discretized on tetrahedral meshes. Two types of methods are considered: mass-lumped continuous finite elements and the symmetric interior-penalty discontinuous Galerkin method. Combining the spatial discretization with the

  4. Evaluation of the 3D finite element method using a tantalum rod for osteonecrosis of the femoral head.

    Science.gov (United States)

    Shi, Jingsheng; Chen, Jie; Wu, Jianguo; Chen, Feiyan; Huang, Guangyong; Wang, Zhan; Zhao, Guanglei; Wei, Yibing; Wang, Siqun

    2014-12-06

    The aim of this study was to contrast the collapse values of the postoperative weight-bearing areas of different tantalum rod implant positions, fibula implantation, and core decompression model and to investigate the advantages and disadvantages of tantalum rod implantation in different ranges of osteonecrosis in comparison with other methods. The 3D finite element method was used to establish the 3D finite element model of normal upper femur, 3D finite element model after tantalum rod implantation into different positions of the upper femur in different osteonecrosis ranges, and other 3D finite element models for simulating fibula implant and core decompression. The collapse values in the weight-bearing area of the femoral head of the tantalum rod implant model inside the osteonecrosis area, implant model in the middle of the osteonecrosis area, fibula implant model, and shortening implant model exhibited no statistically significant differences (p>0.05) when the osteonecrosis range was small (60°). The stress values on the artificial bone surface for the tantalum rod implant model inside the osteonecrosis area and the shortening implant model exhibited statistical significance (posteonecrosis area can reduce the collapse values in the weight-bearing area when osteonecrosis of the femoral head (ONFH) was in a certain range, thereby obtaining better clinical effects. When ONFH was in a large range (120°), the tantalum rod implantation inside the osteonecrosis area, shortening implant or fibula implant can reduce the collapse values of the femoral head, as assessed by other methods.

  5. DIF3D: a code to solve one-, two-, and three-dimensional finite-difference diffusion theory problems

    International Nuclear Information System (INIS)

    Derstine, K.L.

    1984-04-01

    The mathematical development and numerical solution of the finite-difference equations are summarized. The report provides a guide for user application and details the programming structure of DIF3D. Guidelines are included for implementing the DIF3D export package on several large scale computers. Optimized iteration methods for the solution of large-scale fast-reactor finite-difference diffusion theory calculations are presented, along with their theoretical basis. The computational and data management considerations that went into their formulation are discussed. The methods utilized include a variant of the Chebyshev acceleration technique applied to the outer fission source iterations and an optimized block successive overrelaxation method for the within-group iterations. A nodal solution option intended for analysis of LMFBR designs in two- and three-dimensional hexagonal geometries is incorporated in the DIF3D package and is documented in a companion report, ANL-83-1

  6. Rn3D: A finite element code for simulating gas flow and radon transport in variably saturated, nonisothermal porous media

    International Nuclear Information System (INIS)

    Holford, D.J.

    1994-01-01

    This document is a user's manual for the Rn3D finite element code. Rn3D was developed to simulate gas flow and radon transport in variably saturated, nonisothermal porous media. The Rn3D model is applicable to a wide range of problems involving radon transport in soil because it can simulate either steady-state or transient flow and transport in one-, two- or three-dimensions (including radially symmetric two-dimensional problems). The porous materials may be heterogeneous and anisotropic. This manual describes all pertinent mathematics related to the governing, boundary, and constitutive equations of the model, as well as the development of the finite element equations used in the code. Instructions are given for constructing Rn3D input files and executing the code, as well as a description of all output files generated by the code. Five verification problems are given that test various aspects of code operation, complete with example input files, FORTRAN programs for the respective analytical solutions, and plots of model results. An example simulation is presented to illustrate the type of problem Rn3D is designed to solve. Finally, instructions are given on how to convert Rn3D to simulate systems other than radon, air, and water

  7. Lagrangian Finite Element Method for 3D time-dependent viscoelastic flow computation using integral constitutive models

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz

    2000-01-01

    A new technique for the numerical 3D simulation of time dependent flow of viscoelastic fluid is presented. The technique is based on a Lagrangian kinematics description of the fluid flow. The fluid is described by the Rivlin Sawyer integral constitutive equation. The method (referred to as the 3D...... Lagrangian Integral Method) is a finite element method where Galerkons method is used for solving the governing equation in rectangular coordinates numerically. In the present implementation the velocity and pressure fields are approximated with tri-linear and constant shape functions, respectivly.The 3D LIM......) and polymeric solutions. Secondly, the 3D-LIM has also been applied to calculate the inflation of a thick sheet of a polymeric melt into a elliptic cylinder. These problems all include free surfaces. As the governing equations are solved for the particle positions, the motion of surfaces can be followed easily...

  8. Finite-element discretization of 3D energy-transport equations for semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Gadau, Stephan

    2007-07-01

    demonstrated in detail. We compare these new iterations with a standard method that is complemented by a feature to fit in the current context. A further innovation is the computation of solutions in three-dimensional domains, which are still rare. Special attention is paid to applicability of the 3D simulation tools. The programs are designed to have justifiable working complexity. The simulation results of some models of contemporary semiconductor devices are shown and detailed comments on the results are given. Eventually, we make a prospect on future development and enhancements of the models and of the algorithms that we used. (orig.)

  9. Lagrangian Finite Element Method for 3D Time-Dependent Viscoelastic Flow Computations using Integral Models

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz

    2000-01-01

    The 3D-LIM has as yet been used to simulate the following two three-dimensional problems. First, the method has been used to simulete for viscoelastic end-plate instability that occurs under certain conditions in the transient filament stretching apparatus for pressure sensitive adhesives...... (polymeric melts) and polymeric solutions. Secondly, the 3D-LIM has also been applied to calculate the inflation of a thick sheet of a polymer melt into an elliptic cylinder. These problems all include free surfaces. As the governing equations are solved for the particle positions, the motion of surfaces can...... be followed easily even in 3D viscoelastic flow....

  10. 3D Finite Element Simulation of Micro End-Milling by Considering the Effect of Tool Run-Out

    DEFF Research Database (Denmark)

    Davoudinejad, Ali; Tosello, Guido; Parenti, Paolo

    2017-01-01

    Understanding the micro milling phenomena involved in the process is critical and difficult through physical experiments. This study presents a 3D finite element modeling (3D FEM) approach for the micro end-milling process on Al6082-T6. The proposed model employs a Lagrangian explicit finite...... element formulation to perform coupled thermo-mechanical transient analyses. FE simulations were performed at different cutting conditions to obtain realistic numerical predictions of chip formation, temperature distribution, and cutting forces by considering the effect of tool run-out in the model....... The radial run-out is a significant issue in micro milling processes and influences the cutting Stability due to chip load and force variations. The Johnson–Cook (JC) material constitutive model was applied and its constants were determined by an inverse method based on the experimental cutting forces...

  11. Stress-strain distribution at bone-implant interface of two splinted overdenture systems using 3D finite element analysis

    OpenAIRE

    Hussein, Mostafa Omran

    2013-01-01

    PURPOSE This study was accomplished to assess the biomechanical state of different retaining methods of bar implant-overdenture. MATERIALS AND METHODS Two 3D finite element models were designed. The first model included implant overdenture retained by Hader-clip attachment, while the second model included two extracoronal resilient attachment (ERA) studs added distally to Hader splint bar. A non-linear frictional contact type was assumed between overdentures and mucosa to represent sliding an...

  12. Proposal for element size and time increment selection guideline by 3-D finite element method for elastic waves propagation analysis

    International Nuclear Information System (INIS)

    Ishida, Hitoshi; Meshii, Toshiyuki

    2008-01-01

    This paper proposes a guideline for selection of element size and time increment by 3-D finite element method, which is applied to elastic wave propagation analysis for a long distance of a large structure. An element size and a time increment are determined by quantitative evaluation of strain, which must be 0 on the analysis model with a uniform motion, caused by spatial and time discretization. (author)

  13. Evaluation of the 3D Finite Element Method Using a Tantalum Rod for Osteonecrosis of the Femoral Head

    Science.gov (United States)

    Shi, Jingsheng; Chen, Jie; Wu, Jianguo; Chen, Feiyan; Huang, Gangyong; Wang, Zhan; Zhao, Guanglei; Wei, Yibing; Wang, Siqun

    2014-01-01

    Background The aim of this study was to contrast the collapse values of the postoperative weight-bearing areas of different tantalum rod implant positions, fibula implantation, and core decompression model and to investigate the advantages and disadvantages of tantalum rod implantation in different ranges of osteonecrosis in comparison with other methods. Material/Methods The 3D finite element method was used to establish the 3D finite element model of normal upper femur, 3D finite element model after tantalum rod implantation into different positions of the upper femur in different osteonecrosis ranges, and other 3D finite element models for simulating fibula implant and core decompression. Results The collapse values in the weight-bearing area of the femoral head of the tantalum rod implant model inside the osteonecrosis area, implant model in the middle of the osteonecrosis area, fibula implant model, and shortening implant model exhibited no statistically significant differences (p>0.05) when the osteonecrosis range was small (60°). The stress values on the artificial bone surface for the tantalum rod implant model inside the osteonecrosis area and the shortening implant model exhibited statistical significance (p<0.01). Conclusions Tantalum rod implantation into the osteonecrosis area can reduce the collapse values in the weight-bearing area when osteonecrosis of the femoral head (ONFH) was in a certain range, thereby obtaining better clinical effects. When ONFH was in a large range (120°), the tantalum rod implantation inside the osteonecrosis area, shortening implant or fibula implant can reduce the collapse values of the femoral head, as assessed by other methods. PMID:25479830

  14. Microseismic Monitoring and 3D Finite Element Analysis of the Right Bank Slope, Dagangshan Hydropower Station, during Reservoir Impounding

    Science.gov (United States)

    Liu, Xingzong; Tang, Chun'an; Li, Lianchong; Lv, Pengfei; Liu, Hongyuan

    2017-07-01

    The right bank slope of Dagangshan hydropower station in China has complex geological conditions and is subjected to high in situ stress. Notably, microseismic activities in the right bank slope occurred during reservoir impounding. This paper describes the microseismic monitoring technology, and three-dimensional (3D) finite element analysis is used to explore the microseismic activities and damage mechanisms in the right bank slope during reservoir impounding. Based on data obtained from microseismic monitoring, a progressive microseismic damage model is proposed and implemented for 3D finite element analysis. The safety factor for the right bank slope after reservoir impoundment obtained from the 3D finite element analysis, which included the effects of progressive microseismic damage, was 1.10, indicating that the slope is stable. The microseismic monitoring system is able to capture the slope disturbance during reservoir impounding in real time and is a powerful tool for qualitatively assessing changes in slope stability over time. The proposed progressive microseismic damage model adequately simulates the changes in the slope during the impoundment process and provides a valuable tool for evaluating slope stability.

  15. Meshing Preprocessor for the Mesoscopic 3D Finite Element Simulation of 2D and Interlock Fabric Deformation

    Science.gov (United States)

    Wendling, A.; Daniel, J. L.; Hivet, G.; Vidal-Sallé, E.; Boisse, P.

    2015-12-01

    Numerical simulation is a powerful tool to predict the mechanical behavior and the feasibility of composite parts. Among the available numerical approaches, as far as woven reinforced composites are concerned, 3D finite element simulation at the mesoscopic scale leads to a good compromise between realism and complexity. At this scale, the fibrous reinforcement is modeled by an interlacement of yarns assumed to be homogeneous that have to be accurately represented. Among the numerous issues induced by these simulations, the first one consists in providing a representative meshed geometrical model of the unit cell at the mesoscopic scale. The second one consists in enabling a fast data input in the finite element software (contacts definition, boundary conditions, elements reorientation, etc.) so as to obtain results within reasonable time. Based on parameterized 3D CAD modeling tool of unit-cells of dry fabrics already developed, this paper presents an efficient strategy which permits an automated meshing of the models with 3D hexahedral elements and to accelerate of several orders of magnitude the simulation data input. Finally, the overall modeling strategy is illustrated by examples of finite element simulation of the mechanical behavior of fabrics.

  16. A 3D finite strain phenomenological constitutive model for shape memory alloys considering martensite reorientation

    Science.gov (United States)

    Arghavani, J.; Auricchio, F.; Naghdabadi, R.; Reali, A.; Sohrabpour, S.

    2010-06-01

    Most devices based on shape memory alloys experience both finite deformations and non-proportional loading conditions in engineering applications. This motivates the development of constitutive models considering finite strain as well as martensite variant reorientation. To this end, in the present article, based on the principles of continuum thermodynamics with internal variables, a three-dimensional finite strain phenomenological constitutive model is proposed taking its basis from the recent model in the small strain regime proposed by Panico and Brinson (J Mech Phys Solids 55:2491-2511, 2007). In the finite strain constitutive model derivation, a multiplicative decomposition of the deformation gradient into elastic and inelastic parts, together with an additive decomposition of the inelastic strain rate tensor into transformation and reorientation parts is adopted. Moreover, it is shown that, when linearized, the proposed model reduces exactly to the original small strain model.

  17. 3-d finite element model development for biomechanics: a software demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Hollerbach, K.; Hollister, A.M.; Ashby, E.

    1997-03-01

    Finite element analysis is becoming an increasingly important part of biomechanics and orthopedic research, as computational resources become more powerful, and data handling algorithms become more sophisticated. Until recently, tools with sufficient power did not exist or were not accessible to adequately model complicated, three-dimensional, nonlinear biomechanical systems. In the past, finite element analyses in biomechanics have often been limited to two-dimensional approaches, linear analyses, or simulations of single tissue types. Today, we have the resources to model fully three-dimensional, nonlinear, multi-tissue, and even multi-joint systems. The authors will present the process of developing these kinds of finite element models, using human hand and knee examples, and will demonstrate their software tools.

  18. Multigrid Finite Element Method in Calculation of 3D Homogeneous and Composite Solids

    Directory of Open Access Journals (Sweden)

    A.D. Matveev

    2016-12-01

    Full Text Available In the present paper, a method of multigrid finite elements to calculate elastic three-dimensional homogeneous and composite solids under static loading has been suggested. The method has been developed based on the finite element method algorithms using homogeneous and composite three-dimensional multigrid finite elements (MFE. The procedures for construction of MFE of both rectangular parallelepiped and complex shapes have been shown. The advantages of MFE are that they take into account, following the rules of the microapproach, heterogeneous and microhomogeneous structures of the bodies, describe the three-dimensional stress-strain state (without any simplifying hypotheses in homogeneous and composite solids, as well as generate small dimensional discrete models and numerical solutions with a high accuracy.

  19. 3D Finite Element Modeling of Single Bolt Connections under Static and Dynamic Tension Loading

    Directory of Open Access Journals (Sweden)

    Emily Guzas

    2015-01-01

    Full Text Available The Naval Undersea Warfare Center has funded research to examine a range of finite element approaches used for modeling bolted connections subjected to various loading conditions. Research focused on developing finite element bolt representations that were accurate and computationally efficient. A variety of finite element modeling approaches, from detailed models to simplified ones, were used to represent the behavior of single solid bolts under static and dynamic tension loading. Test cases utilized models of bolted connection test arrangements (static tension and dynamic tension developed for previous research and validated against test data for hollow bore bolts (Behan et al., 2013. Simulation results for solid bolts are validated against experimental data from physical testing of bolts in these load configurations.

  20. Simulation of 3D tumor cell growth using nonlinear finite element method.

    Science.gov (United States)

    Dong, Shoubing; Yan, Yannan; Tang, Liqun; Meng, Junping; Jiang, Yi

    2016-01-01

    We propose a novel parallel computing framework for a nonlinear finite element method (FEM)-based cell model and apply it to simulate avascular tumor growth. We derive computation formulas to simplify the simulation and design the basic algorithms. With the increment of the proliferation generations of tumor cells, the FEM elements may become larger and more distorted. Then, we describe a remesh and refinement processing of the distorted or over large finite elements and the parallel implementation based on Message Passing Interface to improve the accuracy and efficiency of the simulation. We demonstrate the feasibility and effectiveness of the FEM model and the parallelization methods in simulations of early tumor growth.

  1. A 3D analysis of reinforced concrete structures by the finite element method

    International Nuclear Information System (INIS)

    Claure, J.D.; Campos Filho, A.

    1995-01-01

    Fundamental features of a computational model, based on the finite element methods, for the analysis of concrete structure are presented. The study comprehends short and long-term loading situations, where creep and shrinkage in concrete are considered. The reinforcement is inserted in the finite element model using an embedded model. A smeared crack model is used for the concrete cracking, which considers the contribution of concrete between cracks and allows the closing the cracks closing. The computational code MPGS (Multi-Purpose Graphic System) is used, to make easy the analysis and interpretation of the numeric results. (author). 8 refs., 4 figs

  2. Comparison of finite element and finite difference methods for 2D and 3D calculations with Monte Carlo method results for idealized cases of a heavy water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Grant, Carlos; Marconi, Javier; Serra, Oscar [Comision Nacional de Energia Atomica, Buenos Aires (Argentina)]. E-mail: grant@cnea.gov.ar; Mollerach, Ricardo; Fink, Jose [Nucleoelectrica Argentina S.A., Buenos Aires (Argentina)]. E-mail: RMollerach@na-sa.com.ar; JFink@na-sa.com.ar

    2005-07-01

    Nowadays, the increased calculation capacity of modern computers allows us to evaluate the 2D and 3D flux and power distribution of nuclear reactor in a reasonable amount of time using a Monte Carlo method. This method gives results that can be considered the most reliable evaluation of flux and power distribution with a great amount of detail. This is the reason why these results can be considered as benchmark cases that can be used for the validation of other methods. For this purpose, idealized models were calculated using Monte Carlo (code MCNP5) for the ATUCHA I reactor. 2D and 3D cases with and without control rods and channels without fuel element were analyzed. All of them were modeled using a finite element code (DELFIN) and a finite difference code (PUMA). In both cases two energy groups were use. (author)

  3. Accurate Modeling of a Transverse Flux Permanent Magnet Generator Using 3D Finite Element Analysis

    DEFF Research Database (Denmark)

    Hosseini, Seyedmohsen; Moghani, Javad Shokrollahi; Jensen, Bogi Bech

    2011-01-01

    This paper presents an accurate modeling method that is applied to a single-sided outer-rotor transverse flux permanent magnet generator. The inductances and the induced electromotive force for a typical generator are calculated using the magnetostatic three-dimensional finite element method. A n...

  4. Multilevel iterative solvers for the edge finite element solution of the 3D Maxwell equation

    NARCIS (Netherlands)

    Nechaev, O.V.; Shurina, E.P.; Bochev, Mikhail A.

    2008-01-01

    In the edge vector finite element solution of the frequency domain Maxwell equations, the presence of a large kernel of the discrete rotor operator is known to ruin convergence of standard iterative solvers. We extend the approach of [R. Hiptmair, Multigrid method for Maxwell’s equations, SIAM J.

  5. Multilevel iterative solvers for the edge finite element solution of the 3D Maxwell equation

    NARCIS (Netherlands)

    Nechaev, O.V.; Shurina, E.P.; Bochev, Mikhail A.

    In the edge vector finite element solution of the frequency domain Maxwell equations, the presence of a large kernel of the discrete rotor operator is known to ruin convergence of standard iterative solvers. We extend the approach of [1] and, using domain decomposition ideas, construct a multilevel

  6. Generation of 3-D finite element models of restored human teeth using micro-CT techniques.

    NARCIS (Netherlands)

    Verdonschot, N.J.J.; Fennis, W.M.M.; Kuys, R.H.; Stolk, J.; Kreulen, C.M.; Creugers, N.H.J.

    2001-01-01

    PURPOSE: This article describes the development of a three-dimensional finite element model of a premolar based on a microscale computed tomographic (CT) data-acquisition technique. The development of the model is part of a project studying the optimal design and geometry of adhesive tooth-colored

  7. 3D finite element analysis of the frictional behavior of the human fingertip.

    Science.gov (United States)

    Yoshida, Hiroaki; Tada, Mitsunori; Mochimaru, Masaaki

    2006-01-01

    Although the tactile sensation is one of the most important senses, little quantitative research has been carried out to investigate the sense of the touch of the fingertip. We developed a three-dimensional finite element model of the fingertip and performed a determination of material properties using an optimization technique so that the contact area of finite element analysis corresponded with that of the experiment when a rigid plane was indented. The estimated material properties agreed with published data and the optimization method is considered to be effective. The finite element model slid on the rigid plane while indented using determined material properties and ABAQUS subroutine based on the rubber friction. At the low indentation depth, the stick-slip behavior of the finite element analysis mostly agreed with the experimental. However, when the indentation depth was increased, the frictional behavior in the tangential direction of the analysis was not consistent with that of the experiment because of the anisotropic in the shear direction. This study is an approach to understanding the friction and tactile sensation of the fingertip.

  8. Superconvergence of mixed finite element approximations to 3-D Maxwell's equations in metamaterials

    KAUST Repository

    Huang, Yunqing

    2011-09-01

    Numerical simulation of metamaterials has attracted more and more attention since 2000, after the first metamaterial with negative refraction index was successfully constructed. In this paper we construct a fully-discrete leap-frog type finite element scheme to solve the three-dimensional time-dependent Maxwell\\'s equations when metamaterials are involved. First, we obtain some superclose results between the interpolations of the analytical solutions and finite element solutions obtained using arbitrary orders of Raviart-Thomas-Nédélec mixed spaces on regular cubic meshes. Then we prove the superconvergence result in the discrete l2 norm achieved for the lowest-order Raviart-Thomas-Nédélec space. To our best knowledge, such superconvergence results have never been obtained elsewhere. Finally, we implement the leap-frog scheme and present numerical results justifying our theoretical analysis. © 2011 Elsevier Inc.

  9. Study of a 3D-Finite Element Calculation of Bucket Foundation

    DEFF Research Database (Denmark)

    André Larsen, Kim; Ibsen, Lars Bo

    2004-01-01

    The bucket foundation is a new type of foundation, which has been developed over the past 3 years and today it is used for a Vestas V90-3.0 MW offshore wind turbine as a prototype. Ibsen et al.(2003). The bucket foundation is believed to have great potential in the future offshore wind parks...... as the wind turbines are getting larger and more effective. The behaviour of bucket foundations located in saturated dense sand has been investigated by use of model tests. One of the methods to predict the response of a full size bucket foundation is the Finite Element Method, FEM. This method has been used...... to back calculate the response of the model tests in the laboratory. It has been shown that a three-dimensional Finite Element model is a useful method to predict the behaviour of bucket foundations for offshore wind turbines installed in saturated sand....

  10. 3-D finite element method for micromechanical analysis in fibrous composite material

    OpenAIRE

    Cheng, Chun-Chung

    1995-01-01

    The objective of this thesis was to study whether simplified three dimensional finite element models could be used as a micromechanical model for analysis of stresses at the fiber and matrix level while providing smeared composite properties for the global structural analysis. The mathematical model was programmed using the MATLAB engineering software. For considering interface cracks between the fiber and matrix, springs were modeled in the connecting nodes between the fiber and matrix on ea...

  11. 3D finite element model of the chinchilla ear for characterizing middle ear functions

    OpenAIRE

    Wang, Xuelin; Gan, Rong Z.

    2016-01-01

    Chinchilla is a commonly used animal model for research of sound transmission through the ear. Experimental measurements of the middle ear transfer function in chinchillas have shown that the middle ear cavity greatly affects the tympanic membrane (TM) and stapes footplate (FP) displacements. However, there is no finite element (FE) model of the chinchilla ear available in the literature to characterize the middle ear functions with the anatomical features of the chinchilla ear. This paper re...

  12. Modeling 3D PCMI using the Extended Finite Element Method with higher order elements

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Spencer, Benjamin W. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-03-31

    This report documents the recent development to enable XFEM to work with higher order elements. It also demonstrates the application of higher order (quadratic) elements to both 2D and 3D models of PCMI problems, where discrete fractures in the fuel are represented using XFEM. The modeling results demonstrate the ability of the higher order XFEM to accurately capture the effects of a crack on the response in the vicinity of the intersecting surfaces of cracked fuel and cladding, as well as represent smooth responses in the regions away from the crack.

  13. ON FINITE DIFFERENCE SCHEMES FOR THE 3-D WAVE EQUATION USING NON-CARTESIAN GRIDS

    OpenAIRE

    B. Hamilton; S. Bilbao

    2013-01-01

    In this paper, we investigate finite difference schemes forthe 3-D wave equation using 27-point stencils on the cubiclattice, a 13-point stencil on the face-centered cubic (FCC)lattice, and a 9-point stencil on the body-centered cubic(BCC) lattice. The tiling of the wavenumber space for nonCartesian grids is considered in order to analyse numericaldispersion. Schemes are compared for computational effi-ciency in terms of minimising numerical wave speed error.It is shown that the 13-point scheme...

  14. Plastic Limit Loads for Slanted Circumferential Through-Wall Cracked Pipes Using 3D Finite-Element Limit Analyses

    International Nuclear Information System (INIS)

    Jang, Hyun Min; Cho, Doo Ho; Kim, Young Jin; Huh, Nam Su; Shim, Do Jun; Choi, Young Hwan; Park, Jung Soon

    2011-01-01

    On the basis of detailed 3D finite-element (FE) limit analyses, the plastic limit load solutions for pipes with slanted circumferential through-wall cracks (TWCs) subjected to axial tension, global bending, and internal pressure are reported. The FE model and analysis procedure employed in the present numerical study were validated by comparing the present FE results with existing solutions for plastic limit loads of pipes with idealized TWCs. For the quantification of the effect of slanted crack on plastic limit load, slant correction factors for calculating the plastic limit loads of pipes with slanted TWCs from pipes with idealized TWCs are newly proposed from extensive 3D FE calculations. These slant-correction factors are presented in tabulated form for practical ranges of geometry and for each set of loading conditions

  15. 3D controlled-source electromagnetic modeling in anisotropic medium using edge-based finite element method

    DEFF Research Database (Denmark)

    Cai, Hongzhu; Xiong, Bin; Han, Muran

    2014-01-01

    This paper presents a linear edge-based finite element method for numerical modeling of 3D controlled-source electromagnetic data in an anisotropic conductive medium. We use a nonuniform rectangular mesh in order to capture the rapid change of diffusive electromagnetic field within the regions...... of anomalous conductivity and close to the location of the source. In order to avoid the source singularity, we solve Maxwell's equation with respect to anomalous electric field. The nonuniform rectangular mesh can be transformed to hexahedral mesh in order to simulate the bathymetry effect. The sparse system...

  16. Simulation of 3D parachute fluid–structure interaction based on nonlinear finite element method and preconditioning finite volume method

    Directory of Open Access Journals (Sweden)

    Fan Yuxin

    2014-12-01

    Full Text Available A fluid–structure interaction method combining a nonlinear finite element algorithm with a preconditioning finite volume method is proposed in this paper to simulate parachute transient dynamics. This method uses a three-dimensional membrane–cable fabric model to represent a parachute system at a highly folded configuration. The large shape change during parachute inflation is computed by the nonlinear Newton–Raphson iteration and the linear system equation is solved by the generalized minimal residual (GMRES method. A membrane wrinkling algorithm is also utilized to evaluate the special uniaxial tension state of membrane elements on the parachute canopy. In order to avoid large time expenses during structural nonlinear iteration, the implicit Hilber–Hughes–Taylor (HHT time integration method is employed. For the fluid dynamic simulations, the Roe and HLLC (Harten–Lax–van Leer contact scheme has been modified and extended to compute flow problems at all speeds. The lower–upper symmetric Gauss–Seidel (LU-SGS approximate factorization is applied to accelerate the numerical convergence speed. Finally, the test model of a highly folded C-9 parachute is simulated at a prescribed speed and the results show similar characteristics compared with experimental results and previous literature.

  17. Probabilistic Fatigue Damage Prognosis Using a Surrogate Model Trained Via 3D Finite Element Analysis

    Science.gov (United States)

    Leser, Patrick E.; Hochhalter, Jacob D.; Newman, John A.; Leser, William P.; Warner, James E.; Wawrzynek, Paul A.; Yuan, Fuh-Gwo

    2015-01-01

    Utilizing inverse uncertainty quantification techniques, structural health monitoring can be integrated with damage progression models to form probabilistic predictions of a structure's remaining useful life. However, damage evolution in realistic structures is physically complex. Accurately representing this behavior requires high-fidelity models which are typically computationally prohibitive. In the present work, a high-fidelity finite element model is represented by a surrogate model, reducing computation times. The new approach is used with damage diagnosis data to form a probabilistic prediction of remaining useful life for a test specimen under mixed-mode conditions.

  18. An explicit ''ALE'' finite element formulation for 3D transient dynamic fluid-structure interaction problems

    International Nuclear Information System (INIS)

    Donea, J.; Giuliani, S.

    1989-01-01

    Finite element models, implemented in the computed code EURDYN-3M, are presented for the prediction of the non-linear response of three-dimensional fluid-structure systems exposed to transient dynamic loading. An arbitrary Lagrangian-Eulerian kinematical description of the fluid domain is adopted in which the grid points can be displaced independently of the fluid motion. This formulation leads to an easy and accurate treatment of fluid-structure interfaces and permits significant fluid sloshing and swirling to occur without producing excessive distorsions of the computational mesh. Two numerical examples are presented to illustrate the potential of the proposed modelling procedures

  19. 3D Finite Elements Modelling for Design and Performance Analysis of UO Pellets

    Directory of Open Access Journals (Sweden)

    Gustavo L. Demarco

    2011-01-01

    Full Text Available The geometry of a fuel pellet is a compromise among the intention to maximize UO2 content and minimize the temperature gradient taking into account the thermomechanical behaviour, the economy, and the safety of the fuel management during and after irradiation. “Dishings”, “shoulders”, “chamfers”, and/or “a central hole” on a cylinder with an improved l/d relation (length of the pellet/diameter are introduced in order to optimize the shape of the pellet. The MeCom tools coupled with the BaCo code constitutes a complete system for the 3D analysis of the stress strain state of the pellet under irradiation. CANDU and PHWR MOX fuel will be used to illustrate the excellent qualitative agreement between experimental data and calculations by using these computational tools.

  20. Solution of 3D inverse scattering problems by combined inverse equivalent current and finite element methods

    International Nuclear Information System (INIS)

    Kılıç, Emre; Eibert, Thomas F.

    2015-01-01

    An approach combining boundary integral and finite element methods is introduced for the solution of three-dimensional inverse electromagnetic medium scattering problems. Based on the equivalence principle, unknown equivalent electric and magnetic surface current densities on a closed surface are utilized to decompose the inverse medium problem into two parts: a linear radiation problem and a nonlinear cavity problem. The first problem is formulated by a boundary integral equation, the computational burden of which is reduced by employing the multilevel fast multipole method (MLFMM). Reconstructed Cauchy data on the surface allows the utilization of the Lorentz reciprocity and the Poynting's theorems. Exploiting these theorems, the noise level and an initial guess are estimated for the cavity problem. Moreover, it is possible to determine whether the material is lossy or not. In the second problem, the estimated surface currents form inhomogeneous boundary conditions of the cavity problem. The cavity problem is formulated by the finite element technique and solved iteratively by the Gauss–Newton method to reconstruct the properties of the object. Regularization for both the first and the second problems is achieved by a Krylov subspace method. The proposed method is tested against both synthetic and experimental data and promising reconstruction results are obtained

  1. Mapping 3D breast lesions from full-field digital mammograms using subject-specific finite element models

    Science.gov (United States)

    García, E.; Oliver, A.; Diaz, O.; Diez, Y.; Gubern-Mérida, A.; Martí, R.; Martí, J.

    2017-03-01

    Patient-specific finite element (FE) models of the breast have received increasing attention due to the potential capability of fusing images from different modalities. During the Magnetic Resonance Imaging (MRI) to X-ray mammography registration procedure, the FE model is compressed mimicking the mammographic acquisition. Subsequently, suspicious lesions in the MRI volume can be projected into the 2D mammographic space. However, most registration algorithms do not provide the reverse information, avoiding to obtain the 3D geometrical information from the lesions localized in the mammograms. In this work we introduce a fast method to localize the 3D position of the lesion within the MRI, using both cranio-caudal (CC) and medio-lateral oblique (MLO) mammographic projections, indexing the tetrahedral elements of the biomechanical model by means of an uniform grid. For each marked lesion in the Full-Field Digital Mammogram (FFDM), the X-ray path from source to the marker is calculated. Barycentric coordinates are computed in the tetrahedrons traversed by the ray. The list of elements and coordinates allows to localize two curves within the MRI and the closest point between both curves is taken as the 3D position of the lesion. The registration errors obtained in the mammographic space are 9.89 +/- 3.72 mm in CC- and 8.04 +/- 4.68 mm in MLO-projection and the error in the 3D MRI space is equal to 10.29 +/- 3.99 mm. Regarding the uniform grid, it is computed spending between 0.1 and 0.7 seconds. The average time spent to compute the 3D location of a lesion is about 8 ms.

  2. A holistic 3D finite element simulation model for thermoelectric power generator element

    International Nuclear Information System (INIS)

    Wu, Guangxi; Yu, Xiong

    2014-01-01

    Highlights: • Development of a holistic simulation model for the thermoelectric energy harvester. • Account for delta Seebeck coefficient and carrier charge densities variations. • Solution of thermo-electric coupling problem with finite element method. • Model capable of predicting phenomena not captured by traditional models. • A simulation tool for design of innovative TEM materials and structures. - Abstract: Harvesting the thermal energy stored in the ambient environment provides a potential sustainable energy source. Thermoelectric power generators have advantages of having no moving parts, being durable, and light-weighted. These unique features are advantageous for many applications (i.e., carry-on medical devices, embedded infrastructure sensors, aerospace, transportation, etc.). To ensure the efficient applications of thermoelectric energy harvesting system, the behaviors of such systems need to be fully understood. Finite element simulations provide important tools for such purpose. Although modeling the performance of thermoelectric modules has been conducted by many researchers, due to the complexity in solving the coupled problem, the influences of the effective Seebeck coefficient and carrier density variations on the performance of thermoelectric system are generally neglected. This results in an overestimation of the power generator performance under strong-ionization temperature region. This paper presents an advanced simulation model for thermoelectric elements that considers the effects of both factors. The mathematical basis of this model is firstly presented. Finite element simulations are then implemented on a thermoelectric power generator unit. The characteristics of the thermoelectric power generator and their relationship to its performance are discussed under different working temperature regions. The internal physics processes of the TEM harvester are analyzed from the results of computational simulations. The new model

  3. How Can Stress Be Controlled in Endodontically Treated Teeth? A 3D Finite Element Analysis

    Directory of Open Access Journals (Sweden)

    İhsan Yıkılgan

    2013-01-01

    Full Text Available The aim of this study was to analyze the stresses that develop by oblique and vertical forces in endodontically treated maxillary second premolars that were restored with resin composite. Additionally, in our study the effects of the different restorative approaches and use of different base materials on stress formation were analyzed using three-dimensional finite element stress analysis. For restoration, the models representing both cusp capping, palatinal cusp capping, standard MOD restoration, and use of woven fiber in occlusal part were prepared. In all models, oblique forces caused more stress than did vertical forces. Materials with low elastic moduli cause high amounts of stress, whereas materials with elastic moduli similar to that of dental tissues cause low amounts of stress. Additional approaches such as cusp capping, functional cusp capping, and woven fiber use do not affect stress formation on the tooth after endodontic treatment.

  4. Biomechanical analysis and comparison of 12 dental implant systems using 3D finite element study.

    Science.gov (United States)

    Liang, Rui; Guo, Weihua; Qiao, Xiangchen; Wen, Hailin; Yu, Mei; Tang, Wei; Liu, Lei; Wei, Yongtao; Tian, Weidong

    2015-01-01

    Finite element analysis plays an important role in dental implant design. The objective of this study was to show the effect of the overall geometry of dental implants on their biomechanics after implantation. In this study, 12 dental implants, with the same length, diameter and screw design, were simulated from different implant systems. Numerical model of right mandibular incisor bone segment was generated from CT data. The von-Mises stress distributions and the total deformation distributions under vertical/lateral load were compared for each implant by scores ranking method. The implants with cylindrical shapes had highest scores. Results indicated that cylindrical shape represented better geometry over taper implant. This study is helpful in choosing the optimal dental implant for clinical application and also contributes to individual implant design. Our study could also provide reference for choice and modification of dental implant in any other insertion sites and bone qualities.

  5. Finite-difference method Stokes solver (FDMSS) for 3D pore geometries: Software development, validation and case studies

    KAUST Repository

    Gerke, Kirill M.

    2018-01-17

    Permeability is one of the fundamental properties of porous media and is required for large-scale Darcian fluid flow and mass transport models. Whilst permeability can be measured directly at a range of scales, there are increasing opportunities to evaluate permeability from pore-scale fluid flow simulations. We introduce the free software Finite-Difference Method Stokes Solver (FDMSS) that solves Stokes equation using a finite-difference method (FDM) directly on voxelized 3D pore geometries (i.e. without meshing). Based on explicit convergence studies, validation on sphere packings with analytically known permeabilities, and comparison against lattice-Boltzmann and other published FDM studies, we conclude that FDMSS provides a computationally efficient and accurate basis for single-phase pore-scale flow simulations. By implementing an efficient parallelization and code optimization scheme, permeability inferences can now be made from 3D images of up to 109 voxels using modern desktop computers. Case studies demonstrate the broad applicability of the FDMSS software for both natural and artificial porous media.

  6. A new heat transfer analysis in machining based on two steps of 3D finite element modelling and experimental validation

    Science.gov (United States)

    Haddag, B.; Kagnaya, T.; Nouari, M.; Cutard, T.

    2013-01-01

    Modelling machining operations allows estimating cutting parameters which are difficult to obtain experimentally and in particular, include quantities characterizing the tool-workpiece interface. Temperature is one of these quantities which has an impact on the tool wear, thus its estimation is important. This study deals with a new modelling strategy, based on two steps of calculation, for analysis of the heat transfer into the cutting tool. Unlike the classical methods, considering only the cutting tool with application of an approximate heat flux at the cutting face, estimated from experimental data (e.g. measured cutting force, cutting power), the proposed approach consists of two successive 3D Finite Element calculations and fully independent on the experimental measurements; only the definition of the behaviour of the tool-workpiece couple is necessary. The first one is a 3D thermomechanical modelling of the chip formation process, which allows estimating cutting forces, chip morphology and its flow direction. The second calculation is a 3D thermal modelling of the heat diffusion into the cutting tool, by using an adequate thermal loading (applied uniform or non-uniform heat flux). This loading is estimated using some quantities obtained from the first step calculation, such as contact pressure, sliding velocity distributions and contact area. Comparisons in one hand between experimental data and the first calculation and at the other hand between measured temperatures with embedded thermocouples and the second calculation show a good agreement in terms of cutting forces, chip morphology and cutting temperature.

  7. Detachments of the subducted Indian continental lithosphere based on 3D finite-frequency tomographic images

    Science.gov (United States)

    Liang, X.; Tian, X.; Wang, M.

    2017-12-01

    Indian plate collided with Eurasian plate at 60 Ma and there are about 3000 km crustal shortening since the continental-continental collision. At least one third of the total amount of crustal shortening between Indian and Eurasian plates could not be accounted by thickened Tibetan crust and surface erosion. It will need a combination of possible transfer of lower crust to the mantle by eclogitization and lateral extrusion. Based on the lithosphere-asthenosphere boundary images beneath the Tibetan plateau, there is also at least the same amount deficit for lithospheric mantle subducted into upper/lower mantle or lateral extrusion with the crust. We have to recover a detailed Indian continental lithosphere image beneath the plateau in order to explain this deficit of mass budget. Combining the new teleseismic body waves recorded by SANDWICH passive seismic array with waveforms from several previous temporary seismic arrays, we carried out finite-frequency tomographic inversions to image three-dimensional velocity structures beneath southern and central Tibetan plateau to examine the possible image of subducted Indian lithosphere in the Tibetan upper mantle. We have recovered a continuous high velocity body in upper mantle and piece-wised high velocity anomalies in the mantle transition zone. Based on their geometry and relative locations, we interpreted these high velocity anomalies as the subducted and detached Indian lithosphere at different episodes of the plateau evolution. Detachments of the subducted Indian lithosphere should have a crucial impact on the volcanism activities and uplift history of the plateau.

  8. Comparative Analysis of Bulge Deformation between 2D and 3D Finite Element Models

    Directory of Open Access Journals (Sweden)

    Qin Qin

    2014-02-01

    Full Text Available Bulge deformation of the slab is one of the main factors that affect slab quality in continuous casting. This paper describes an investigation into bulge deformation using ABAQUS to model the solidification process. A three-dimensional finite element analysis model of the slab solidification process has been first established because the bulge deformation is closely related to slab temperature distributions. Based on slab temperature distributions, a three-dimensional thermomechanical coupling model including the slab, the rollers, and the dynamic contact between them has also been constructed and applied to a case study. The thermomechanical coupling model produces outputs such as the rules of bulge deformation. Moreover, the three-dimensional model has been compared with a two-dimensional model to discuss the differences between the two models in calculating the bulge deformation. The results show that the platform zone exists in the wide side of the slab and the bulge deformation is affected strongly by the ratio of width-to-thickness. The indications are also that the difference of the bulge deformation for the two modeling ways is little when the ratio of width-to-thickness is larger than six.

  9. 3D Finite Element Electrical Model of Larval Zebrafish ECG Signals.

    Directory of Open Access Journals (Sweden)

    James Crowcombe

    Full Text Available Assessment of heart function in zebrafish larvae using electrocardiography (ECG is a potentially useful tool in developing cardiac treatments and the assessment of drug therapies. In order to better understand how a measured ECG waveform is related to the structure of the heart, its position within the larva and the position of the electrodes, a 3D model of a 3 days post fertilisation (dpf larval zebrafish was developed to simulate cardiac electrical activity and investigate the voltage distribution throughout the body. The geometry consisted of two main components; the zebrafish body was modelled as a homogeneous volume, while the heart was split into five distinct regions (sinoatrial region, atrial wall, atrioventricular band, ventricular wall and heart chambers. Similarly, the electrical model consisted of two parts with the body described by Laplace's equation and the heart using a bidomain ionic model based upon the Fitzhugh-Nagumo equations. Each region of the heart was differentiated by action potential (AP parameters and activation wave conduction velocities, which were fitted and scaled based on previously published experimental results. ECG measurements in vivo at different electrode recording positions were then compared to the model results. The model was able to simulate action potentials, wave propagation and all the major features (P wave, R wave, T wave of the ECG, as well as polarity of the peaks observed at each position. This model was based upon our current understanding of the structure of the normal zebrafish larval heart. Further development would enable us to incorporate features associated with the diseased heart and hence assist in the interpretation of larval zebrafish ECGs in these conditions.

  10. 3D Finite Element Electrical Model of Larval Zebrafish ECG Signals

    Science.gov (United States)

    Crowcombe, James; Dhillon, Sundeep Singh; Hurst, Rhiannon Mary; Egginton, Stuart; Müller, Ferenc; Sík, Attila; Tarte, Edward

    2016-01-01

    Assessment of heart function in zebrafish larvae using electrocardiography (ECG) is a potentially useful tool in developing cardiac treatments and the assessment of drug therapies. In order to better understand how a measured ECG waveform is related to the structure of the heart, its position within the larva and the position of the electrodes, a 3D model of a 3 days post fertilisation (dpf) larval zebrafish was developed to simulate cardiac electrical activity and investigate the voltage distribution throughout the body. The geometry consisted of two main components; the zebrafish body was modelled as a homogeneous volume, while the heart was split into five distinct regions (sinoatrial region, atrial wall, atrioventricular band, ventricular wall and heart chambers). Similarly, the electrical model consisted of two parts with the body described by Laplace’s equation and the heart using a bidomain ionic model based upon the Fitzhugh-Nagumo equations. Each region of the heart was differentiated by action potential (AP) parameters and activation wave conduction velocities, which were fitted and scaled based on previously published experimental results. ECG measurements in vivo at different electrode recording positions were then compared to the model results. The model was able to simulate action potentials, wave propagation and all the major features (P wave, R wave, T wave) of the ECG, as well as polarity of the peaks observed at each position. This model was based upon our current understanding of the structure of the normal zebrafish larval heart. Further development would enable us to incorporate features associated with the diseased heart and hence assist in the interpretation of larval zebrafish ECGs in these conditions. PMID:27824910

  11. 3D visualization and finite element mesh formation from wood anatomy samples, Part II – Algorithm approach

    Directory of Open Access Journals (Sweden)

    Petr Koňas

    2009-01-01

    Full Text Available Paper presents new original application WOOD3D in form of program code assembling. The work extends the previous article “Part I – Theoretical approach” in detail description of implemented C++ classes of utilized projects Visualization Toolkit (VTK, Insight Toolkit (ITK and MIMX. Code is written in CMake style and it is available as multiplatform application. Currently GNU Linux (32/64b and MS Windows (32/64b platforms were released. Article discusses various filter classes for image filtering. Mainly Otsu and Binary threshold filters are classified for anatomy wood samples thresholding. Registration of images series is emphasized for difference of colour spaces compensation is included. Resulted work flow of image analysis is new methodological approach for images processing through the composition, visualization, filtering, registration and finite element mesh formation. Application generates script in ANSYS parametric design language (APDL which is fully compatible with ANSYS finite element solver and designer environment. The script includes the whole definition of unstructured finite element mesh formed by individual elements and nodes. Due to simple notation, the same script can be used for generation of geometrical entities in element positions. Such formed volumetric entities are prepared for further geometry approximation (e.g. by boolean or more advanced methods. Hexahedral and tetrahedral types of mesh elements are formed on user request with specified mesh options. Hexahedral meshes are formed both with uniform element size and with anisotropic character. Modified octree method for hexahedral mesh with anisotropic character was declared in application. Multicore CPUs in the application are supported for fast image analysis realization. Visualization of image series and consequent 3D image are realized in VTK format sufficiently known and public format, visualized in GPL application Paraview. Future work based on mesh

  12. Incorporating higher order WINKLER springs with 3-D finite element model of a reactor building for seismic SSI analysis

    International Nuclear Information System (INIS)

    Ermutlu, H.E.

    1993-01-01

    In order to fulfill the seismic safety requirements, in the frame of seismic requalification activities for NPP Muehleberg, Switzerland, detailed seismic analysis performed on the Reactor Building and the results are presented previously. The primary objective of the present investigation is to assess the seismic safety of the reinforced concrete structures of reactor building. To achieve this objective requires a rather detailed 3-D finite element modeling for the outer shell structures, the drywell, the reactor pools, the floor decks and finally, the basemat. This already is a complicated task, which enforces need for simplifications in modelling the reactor internals and the foundation soil. Accordingly, all internal parts are modelled by vertical sticks and the Soil Structure Interaction (SSI) effects are represented by sets of transitional and higher order rotational WINKLER springs, i.e. avoiding complicated finite element SSI analysis. As a matter of fact, the availability of the results of recent investigations carried out on the reactor building using diversive finite element SSI analysis methods allow to calibrate the WINKLER springs, ensuring that the overall SSI behaviour of the reactor building is maintained

  13. A 3D Finite Element Model with Improved Spatial Resolution to Investigate the Effect of Varying Viscosity on Antarctica

    Science.gov (United States)

    Blank, B.; van der Wal, W.; Pappa, F.; Ebbing, J.

    2017-12-01

    B. Blank1, H. Hu1, W. van der Wal1, F Pappa2, J. Ebbing21Delft University of Technology 2Christian-Albrechts-University of KielSince the beginning of the 2000's time-variable gravity data from GRACE has proved to be an effective method for mapping ice mass loss in Antarctica. However, Glacial Isostatic Adjustment (GIA) models are required to correct for GIA induced mass changes. While most GIA models have adopted an Earth model that only varies radially in parameters, it has long been clear that the Earth structure also varies with longitude and latitude. For this study a new global 3D GIA model has been developed within the finite element software package ABAQUS, which can be modified to operate on a spatial resolution down to 50 km locally. The model is being benchmarked against normal model models for surface loading. It will be used to investigate the effects of a 3D varying lithosphere and upper asthenosphere in Antarctica. Viscosity which will be computed from temperature estimates with laboratory based flow laws. A new 3D temperature map of the Antarctic lithosphere has been developed within ESA's GOCE+ project based on seismic data as well as on GOCE and GRACE inferred gravity gradients. Output from the GIA model with this new temperature estimates will be compared to that of 1D viscosity profiles and other recent 3D viscosity models based on seismic data. From these side to side comparisons we want to investigate the influence of the viscosity map on uplift rates and horizontal movement. Finally the results can be compared to GPS measurement to investigate the validity of all models.

  14. Soil-blade orientation effect on tillage forces determined by 3D finite element models

    Directory of Open Access Journals (Sweden)

    Ayadi Ibrahmi

    2014-10-01

    Full Text Available This paper investigated the effect of the cutting parameters of a blade on the tillage force components using finite element modeling. A three-dimensional model was carried out with Abaqus Explicit in order to study the interaction between the tool and soil. The soil was modeled with linear forms of the Drucker-Pager model, while the tool was considered as a rigid body with a reference point taken at its tip. The effect of tillage depth and the width of a vertical blade were studied. It was found that the amounts of the draught and vertical forces increase linearly with a slope of 0.037 and 0.0143 respectively when the width increases. The narrow tool (width< 60mm has a greater effect on the specific draught force than a larger tool. Draught and specific draught force increase with polynomial and linear curve respectively versus the depth. However, this effect was reduced for the vertical force. These results were in a good agreement with previously published works. The second part of this paper is focused on the oblique position of the blade to evaluate the effect of the attack angles on both the tillage forces (draught, lateral and vertical and the cutting process of the soil during and after its failure. For all considered angles, the draught force presents the highest values compared to the vertical and lateral forces. Results showed that working with small cutting and an average rake angles (30° to 60° and 45° respectively can produce a good soil inversion.

  15. An induction-based magnetohydrodynamic 3D code for finite magnetic Reynolds number liquid-metal flows in fusion blankets

    Energy Technology Data Exchange (ETDEWEB)

    Kawczynski, Charlie; Smolentsev, Sergey, E-mail: sergey@fusion.ucla.edu; Abdou, Mohamed

    2016-11-01

    Highlights: • A new induction-based magnetohydrodynamic code was developed using a finite difference method. • The code was benchmarked against purely hydrodynamic and MHD flows for low and finite magnetic Reynolds number. • Possible applications of the new code include liquid-metal MHD flows in the breeder blanket during unsteady events in the plasma. - Abstract: Most numerical analysis performed in the past for MHD flows in liquid-metal blankets were based on the assumption of low magnetic Reynolds number and involved numerical codes that utilized electric potential as the main electromagnetic variable. One limitation of this approach is that such codes cannot be applied to truly unsteady processes, for example, MHD flows of liquid-metal breeder/coolant during unsteady events in plasma, such as major plasma disruptions, edge-localized modes and vertical displacements, when changes in plasmas occur at millisecond timescales. Our newly developed code MOONS (Magnetohydrodynamic Object-Oriented Numerical Solver) uses the magnetic field as the main electromagnetic variable to relax the limitations of the low magnetic Reynolds number approximation for more realistic fusion reactor environments. The new code, written in Fortran, implements a 3D finite-difference method and is capable of simulating multi-material domains. The constrained transport method was implemented to evolve the magnetic field in time and assure that the magnetic field remains solenoidal within machine accuracy at every time step. Various verification tests have been performed including purely hydrodynamic flows and MHD flows at low and finite magnetic Reynolds numbers. Test results have demonstrated very good accuracy against known analytic solutions and other numerical data.

  16. 3D Finite Element Modelling of Cutting Forces in Drilling Fibre Metal Laminates and Experimental Hole Quality Analysis

    Science.gov (United States)

    Giasin, Khaled; Ayvar-Soberanis, Sabino; French, Toby; Phadnis, Vaibhav

    2017-02-01

    Machining Glass fibre aluminium reinforced epoxy (GLARE) is cumbersome due to distinctively different mechanical and thermal properties of its constituents, which makes it challenging to achieve damage-free holes with the acceptable surface quality. The proposed work focuses on the study of the machinability of thin ( 2.5 mm) GLARE laminate. Drilling trials were conducted to analyse the effect of feed rate and spindle speed on the cutting forces and hole quality. The resulting hole quality metrics (surface roughness, hole size, circularity error, burr formation and delamination) were assessed using surface profilometry and optical scanning techniques. A three dimensional (3D) finite-element (FE) model of drilling GLARE laminate was also developed using ABAQUS/Explicit to help understand the mechanism of drilling GLARE. The homogenised ply-level response of GLARE laminate was considered in the FE model to predict cutting forces in the drilling process.

  17. 3D finite element model for writing long-period fiber gratings by CO2 laser radiation.

    Science.gov (United States)

    Coelho, João M P; Nespereira, Marta; Abreu, Manuel; Rebordão, José

    2013-08-12

    In the last years, mid-infrared radiation emitted by CO2 lasers has become increasing popular as a tool in the development of long-period fiber gratings. However, although the development and characterization of the resulting sensing devices have progressed quickly, further research is still necessary to consolidate functional models, especially regarding the interaction between laser radiation and the fiber's material. In this paper, a 3D finite element model is presented to simulate the interaction between laser radiation and an optical fiber and to determine the resulting refractive index change. Dependence with temperature of the main parameters of the optical fiber materials (with special focus on the absorption of incident laser radiation) is considered, as well as convection and radiation losses. Thermal and residual stress analyses are made for a standard single mode fiber, and experimental results are presented.

  18. Experimental Investigation and 3D Finite Element Prediction of Temperature Distribution during Travelling Heat Sourced from Oxyacetylene Flame

    International Nuclear Information System (INIS)

    Alkali, Adam Umar; Ginta, Turnad Lenggo; Abdul-Rani, Ahmad Majdi

    2015-01-01

    This paper presents a 3D transient finite element modelling of the workpiece temperature field produced during the travelling heat sourced from oxyacetylene flame. The proposed model was given in terms of preheat-only test applicable during thermally enhanced machining using the oxyacetylene flame as a heat source. The FEA model as well as the experimental test investigated the surface temperature distribution on 316L stainless steel at scanning speed of 100mm/min, 125mm/min 160mm/min, 200mm/min and 250mm/min. The parametric properties of the heat source maintained constant are; lead distance L d =10mm, focus height F h =7.5mm, oxygen gas pressure P oxy =15psi and acetylene gas pressure P acty =25psi. An experimental validation of the temperature field induced on type 316L stainless steel reveal that temperature distribution increases when the travelling speed decreases. (paper)

  19. 3D Finite Element Model for Writing Long-Period Fiber Gratings by CO2 Laser Radiation

    Directory of Open Access Journals (Sweden)

    José Rebordão

    2013-08-01

    Full Text Available In the last years, mid-infrared radiation emitted by CO2 lasers has become increasing popular as a tool in the development of long-period fiber gratings. However, although the development and characterization of the resulting sensing devices have progressed quickly, further research is still necessary to consolidate functional models, especially regarding the interaction between laser radiation and the fiber’s material. In this paper, a 3D finite element model is presented to simulate the interaction between laser radiation and an optical fiber and to determine the resulting refractive index change. Dependence with temperature of the main parameters of the optical fiber materials (with special focus on the absorption of incident laser radiation is considered, as well as convection and radiation losses. Thermal and residual stress analyses are made for a standard single mode fiber, and experimental results are presented.

  20. Electromagnetic characteristics and static torque of a solid salient poles synchronous motor computed by 3D-finite element method magnetics

    International Nuclear Information System (INIS)

    Popnikolova Radevska, Mirka; Cundev, Milan; Petkovska, Lidija

    2002-01-01

    In these paper is presented a methodology for numerical determination and complex analysis of the electromagnetic characteristics of the Solid Salient Poles Synchronous Motor, with rated data: 2.5 kW, 240 V and 1500 r.p.m.. A mathematical model and original algorithm for the nonlinear and iterative calculations by using Finite Element Method in 3D domain will be given. The program package FEM-3D will be used to perform automatically mesh generation of the finite elements in the 3D domain, calculation of the magnetic field distribution, as well as electromagnetic characteristics and Static torque in SSPSM. (Author)

  1. High Resolution 3-D Finite-Volume Coastal Ocean Modeling in Lower Campbell River and Discovery Passage, British Columbia, Canada

    Directory of Open Access Journals (Sweden)

    Yuehua Lin

    2014-03-01

    Full Text Available The 3-D unstructured-grid, Finite-Volume Coastal Ocean Model (FVCOM was used to simulate the flows in Discovery Passage including the adjoining Lower Campbell River, British Columbia, Canada. Challenges in the studies include the strong tidal currents (e.g., up to 7.8 m/s in Seymour Narrows and tailrace discharges, small-scale topographic features and steep bottom slopes, and stratification affected by the Campbell River freshwater discharges. Two applications of high resolution 3-D FVCOM modeling were conducted. One is for the Lower Campbell River extending upstream as far as the John Hart Hydroelectric dam. The horizontal resolution varies from 0.27 m to 32 m in the unstructured triangular mesh to resolve the tailrace flow. The bottom elevation decreases ~14 m within the distance of ~1.4 km along the river. This pioneering FVCOM river modeling demonstrated a very good performance in simulating the river flow structures. The second application is to compute ocean currents immediately above the seabed along the present underwater electrical cable crossing routes across Discovery Passage. Higher resolution was used near the bottom with inter-layer spacing ranging from 0.125 to 0.0005 of total water depth. The model behaves very well in simulating the strong tidal currents in the area at high resolution in both the horizontal and vertical. One year maximum near bottom tidal current along the routes was then analyzed using the model results.

  2. Finite element code FENIA verification and application for 3D modelling of thermal state of radioactive waste deep geological repository

    Science.gov (United States)

    Butov, R. A.; Drobyshevsky, N. I.; Moiseenko, E. V.; Tokarev, U. N.

    2017-11-01

    The verification of the FENIA finite element code on some problems and an example of its application are presented in the paper. The code is being developing for 3D modelling of thermal, mechanical and hydrodynamical (THM) problems related to the functioning of deep geological repositories. Verification of the code for two analytical problems has been performed. The first one is point heat source with exponential heat decrease, the second one - linear heat source with similar behavior. Analytical solutions have been obtained by the authors. The problems have been chosen because they reflect the processes influencing the thermal state of deep geological repository of radioactive waste. Verification was performed for several meshes with different resolution. Good convergence between analytical and numerical solutions was achieved. The application of the FENIA code is illustrated by 3D modelling of thermal state of a prototypic deep geological repository of radioactive waste. The repository is designed for disposal of radioactive waste in a rock at depth of several hundred meters with no intention of later retrieval. Vitrified radioactive waste is placed in the containers, which are placed in vertical boreholes. The residual decay heat of radioactive waste leads to containers, engineered safety barriers and host rock heating. Maximum temperatures and corresponding times of their establishment have been determined.

  3. Iterative methods for 3D implicit finite-difference migration using the complex Padé approximation

    International Nuclear Information System (INIS)

    Costa, Carlos A N; Campos, Itamara S; Costa, Jessé C; Neto, Francisco A; Schleicher, Jörg; Novais, Amélia

    2013-01-01

    Conventional implementations of 3D finite-difference (FD) migration use splitting techniques to accelerate performance and save computational cost. However, such techniques are plagued with numerical anisotropy that jeopardises the correct positioning of dipping reflectors in the directions not used for the operator splitting. We implement 3D downward continuation FD migration without splitting using a complex Padé approximation. In this way, the numerical anisotropy is eliminated at the expense of a computationally more intensive solution of a large-band linear system. We compare the performance of the iterative stabilized biconjugate gradient (BICGSTAB) and that of the multifrontal massively parallel direct solver (MUMPS). It turns out that the use of the complex Padé approximation not only stabilizes the solution, but also acts as an effective preconditioner for the BICGSTAB algorithm, reducing the number of iterations as compared to the implementation using the real Padé expansion. As a consequence, the iterative BICGSTAB method is more efficient than the direct MUMPS method when solving a single term in the Padé expansion. The results of both algorithms, here evaluated by computing the migration impulse response in the SEG/EAGE salt model, are of comparable quality. (paper)

  4. 3-D DC resistivity modelling with arbitrary long electrode sources using finite element method on unstructured grids

    Science.gov (United States)

    Yang, Jun; Liu, Yuanying; Wu, Xiaoping

    2017-11-01

    We present a 3-D electrical resistivity modelling with long electrode sources using finite element method on unstructured tetrahedral grids. The radius and resistivity of the electrode is neglected and the electrode can be regarded as a line source with finite length in our modelling. An approximated equation for determining the current density along the electrode is derived for current density correction in heterogeneous media. Electrical fields excited by arbitrary long electrode sources in heterogeneous conductive media can be simulated. Both total- and secondary-potential methods are implemented in the simulation. The analytic electrical potentials of an arbitrary long electrode source in a conductive half-space is derived and used for accuracy analysis in the numerical simulations. The apparent resistivities for survey arrays with long electrode sources are proposed based on the analytic solution of the half-space model. The responses of electrical fields excited by point electrode and long electrode sources to resistivity anomalies are compared with ground and borehole simulations, which shows that the arrays with long electrode sources are more sensitive to the anomalies than those with point electrode sources. A time-lapsed monitoring for hydraulic fracturing in oil field using the production wells as long electrode sources is also simulated, which indicates that the borehole potential data of the long electrode source array can help assess the location of the fracture zone.

  5. 3D finite element analysis of immediate loading of single wide versus double implants for replacing mandibular molar

    Directory of Open Access Journals (Sweden)

    Shrikar R Desai

    2013-01-01

    Full Text Available Purpose: The purpose of this finite element study was to compare the stresses, strains, and displacements of double versus single implant in immediate loading for replacing mandibular molar. Materials and Methods: Two 3D FEM (finite element method models were made to simulate implant designs. The first model used 5-mm-wide diameter implant to support a single molar crown. The second model used 3.75-3.75 double implant design. Anisotropic properties were assigned to bone model. Each model was analyzed with single force magnitude (100 N in vertical axis. Results: This FEM study suggested that micromotion can be controlled better for double implants compared to single wide-diameter implants. The Von Mises stress for double implant showed 74.44% stress reduction compared to that of 5-mm implant. The Von Mises elastic strain was reduced by 61% for double implant compared to 5-mm implant. Conclusion: Within the limitations of the study, when the mesiodistal space for artificial tooth is more than 12.5 mm, under immediate loading, the double implant support should be considered.

  6. 3D finite element analysis of immediate loading of single wide versus double implants for replacing mandibular molar

    Science.gov (United States)

    Desai, Shrikar R.; Karthikeyan, I.; Gaddale, Reetika

    2013-01-01

    Purpose: The purpose of this finite element study was to compare the stresses, strains, and displacements of double versus single implant in immediate loading for replacing mandibular molar. Materials and Methods: Two 3D FEM (finite element method) models were made to simulate implant designs. The first model used 5-mm-wide diameter implant to support a single molar crown. The second model used 3.75-3.75 double implant design. Anisotropic properties were assigned to bone model. Each model was analyzed with single force magnitude (100 N) in vertical axis. Results: This FEM study suggested that micromotion can be controlled better for double implants compared to single wide-diameter implants. The Von Mises stress for double implant showed 74.44% stress reduction compared to that of 5-mm implant. The Von Mises elastic strain was reduced by 61% for double implant compared to 5-mm implant. Conclusion: Within the limitations of the study, when the mesiodistal space for artificial tooth is more than 12.5 mm, under immediate loading, the double implant support should be considered. PMID:24554890

  7. 3D visualization and finite element mesh formation from wood anatomy samples, Part I – Theoretical approach

    Directory of Open Access Journals (Sweden)

    Petr Koňas

    2009-01-01

    Full Text Available The work summarizes created algorithms for formation of finite element (FE mesh which is derived from bitmap pattern. Process of registration, segmentation and meshing is described in detail. C++ library of STL from Insight Toolkit (ITK Project together with Visualization Toolkit (VTK were used for base processing of images. Several methods for appropriate mesh output are discussed. Multiplatform application WOOD3D for the task under GNU GPL license was assembled. Several methods of segmentation and mainly different ways of contouring were included. Tetrahedral and rectilinear types of mesh were programmed. Improving of mesh quality in some simple ways is mentioned. Testing and verification of final program on wood anatomy samples of spruce and walnut was realized. Methods of microscopic anatomy samples preparation are depicted. Final utilization of formed mesh in the simple structural analysis was performed.The article discusses main problems in image analysis due to incompatible colour spaces, samples preparation, thresholding and final conversion into finite element mesh. Assembling of mentioned tasks together and evaluation of the application are main original results of the presented work. In presented program two thresholding filters were used. By utilization of ITK two following filters were included. Otsu filter based and binary filter based were used. The most problematic task occurred in a production of wood anatomy samples in the unique light conditions with minimal or zero co­lour space shift and the following appropriate definition of thresholds (corresponding thresholding parameters and connected methods (prefiltering + registration which influence the continuity and mainly separation of wood anatomy structure. Solution in samples staining is suggested with the following quick image analysis realization. Next original result of the work is complex fully automated application which offers three types of finite element mesh

  8. An Investigation of Three types of Tooth Implant Supported Fixed Prosthesis Designs with 3D Finite Element Analysis

    Directory of Open Access Journals (Sweden)

    Sara Koosha

    2013-01-01

    Full Text Available Objective: Tooth/implant supported fixed prostheses may present biomechanical design problems, as the implant is rigidly anchored within the alveolus, whereas the tooth is attached by the periodontal ligament to the bone allowing movement. Many clinicians prefer tooth/implant supported fixed prosthesis designs with rigid connectors. However, there are some doubts about the effect of attachment placement in different prosthesis designs. The purpose of this study was to examine the stresses accumulated around the implant and natural teeth under occlusal forces using three dimensional finite element analysis (3D FEA.Materials and Methods: In this study, different connection designs of tooth/implant fixed prosthesis in distal extension situations were investigated by 3D FEA. Three models with various connection designs were studied; in the first model an implant rigidly connected to an abutment, in the second and third models an implant connected to abutment tooth with nonrigid connector in the distal part of the tooth and mesial part of the implant. In each model, a screw type implant (5×11mm and a mandibular second premolar were used. The stress values of these models loaded with vertical forces (250N were analyzed.Results: There was no difference in stress distribution around the bone support of the implant. Maximum stress values were observed at the crestal bone of the implant. In all models, tooth movement was higher than implant movement.Conclusion: There is no difference in using a rigid connector, non rigid connector in the distal surface of the tooth or in the mesial surface of an implant.

  9. Comparison of Short and Standard Implants in the Posterior Mandible: A 3D Analysis Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Allahyar Geramy

    2018-02-01

    Full Text Available Objectives: This study aimed to analyze functional stresses around short and long implant-supported prostheses with different crown heights.Materials and Methods: Four three-dimensional (3D models were designed with SolidWorks 2015. In models 1 (control and 2, three dental implants (second premolar 4.1x8 mm, molars: 4.8x8 mm were placed. In models 3 and 4, three dental implants (second premolar 4.1x4 mm, molars: 4.8x4 were placed. Residual bone height was 10 mm in groups 1 and 2 (grafted bone models and 6 mm in groups 3 and 4. The crown heights were modeled at 11.5 mm for groups 1 to 3, and 15 mm for group 4. The applied oblique force was 220 N to simulate chewing movements. The maximum von Mises and principal stresses on the implants and the supporting tissues were compared using the 3D finite element method.Results: In all models, the highest stress value was seen within the most coronal part of bone (crestal bone, which was cortical or grafted bone. The highest stress values in the bone supporting the implant neck were seen in the premolar region of each model, especially in model 4 (291.16 MPa. The lowest stress values were demonstrated in the molar region of model 3 (48.066 MPa. The model 2 implants showed the highest von Mises stress concentrated at their neck (424.44 MPa.Conclusions: In atrophic posterior mandible with increased crown height space, short implants with wider diameter seem to be a more feasible approach compared to grafting methods.

  10. Torque Control During Intrusion on Upper Central Incisor in Labial and Lingual bracket System - A 3D Finite Element Study.

    Science.gov (United States)

    Pol, Tejas R; Vandekar, Meghna; Patil, Anuradha; Desai, Sanjana; Shetty, Vikram; Hazarika, Saptarshi

    2018-01-01

    The aim of present study was to investigate the difference of torque control during intrusive force on upper central incisors with normal, under and high torque in lingual and labial orthodontic systems through 3D finite element analysis. Six 3D models of an upper right central incisor with different torque were designed in Solid Works 2006. Software ANSYS Version 16.0 was used to evaluate intrusive force on upper central incisor model . An intrusive force of 0.15 N was applied to the bracket slot in different torque models and the displacements along a path of nodes in the upper central incisor was assessed. On application of Intrusive force on under torqued upper central incisor in Labial system produce labial crown movement but in Lingual system caused lingual movement in the apical and incisal parts. The same intrusive force in normal-torqued central incisor led to a palatal movement in apical and labial displacement of incisal edge in Lingual system and a palatal displacement in apical area and a labial movement in the incisal edge in Labial systemin. In overtorqued upper central incisor, the labial crown displacement in Labial system is more than Lingual system. In labial and lingual system on application of the same forces in upper central incisor with different inclinations showed different responses. The magnitudes of torque Loss during intrusive loads in incisors with normal, under and over-torque were higher in Labial system than Lingual orthodontic appliances. Key words: FEM, lingual orthodontics, intrusion, torque control, labial bracket systems.

  11. Effect of Endocrown Restorations with Different CAD/CAM Materials: 3D Finite Element and Weibull Analyses

    Directory of Open Access Journals (Sweden)

    Laden Gulec

    2017-01-01

    Full Text Available The aim of this study was to evaluate the effects of two endocrown designs and computer aided design/manufacturing (CAD/CAM materials on stress distribution and failure probability of restorations applied to severely damaged endodontically treated maxillary first premolar tooth (MFP. Two types of designs without and with 3 mm intraradicular extensions, endocrown (E and modified endocrown (ME, were modeled on a 3D Finite element (FE model of the MFP. Vitablocks Mark II (VMII, Vita Enamic (VE, and Lava Ultimate (LU CAD/CAM materials were used for each type of design. von Mises and maximum principle values were evaluated and the Weibull function was incorporated with FE analysis to calculate the long term failure probability. Regarding the stresses that occurred in enamel, for each group of material, ME restoration design transmitted less stress than endocrown. During normal occlusal function, the overall failure probability was minimum for ME with VMII. ME restoration design with VE was the best restorative option for premolar teeth with extensive loss of coronal structure under high occlusal loads. Therefore, ME design could be a favorable treatment option for MFPs with missing palatal cusp. Among the CAD/CAM materials tested, VMII and VE were found to be more tooth-friendly than LU.

  12. Stress analysis in bone tissue around single implants with different diameters and veneering materials: a 3-D finite element study.

    Science.gov (United States)

    Santiago Junior, Joel Ferreira; Pellizzer, Eduardo Piza; Verri, Fellippo Ramos; de Carvalho, Paulo Sérgio Perri

    2013-12-01

    The aim of this study was to evaluate the stress distribution on bone tissue with a single prosthesis supported by implants of large and conventional diameter and presenting different veneering materials using the 3-D finite element method. Sixteen models were fabricated to reproduce a bone block with implants, using two diameters (3.75×10 mm and 5.00×10 mm), four different veneering materials (composite resin, acrylic resin, porcelain, and NiCr crown), and two loads (axial (200 N) and oblique (100 N)). For data analysis, the maximum principal stress and von Mises criterion were used. For the axial load, the cortical bone in all models did not exhibit significant differences, and the trabecular bone presented higher tensile stress with reduced implant diameter. For the oblique load, the cortical bone presented a significant increase in tensile stress on the same side as the loading for smaller implant diameters. The trabecular bone showed a similar but more discreet trend. There was no difference in bone tissue with different veneering materials. The veneering material did not influence the stress distribution in the supporting tissues of single implant-supported prostheses. The large-diameter implants improved the transference of occlusal loads to bone tissue and decreased stress mainly under oblique loads. Oblique loading was more detrimental to distribution stresses than axial loading. © 2013.

  13. Object-oriented philosophy in designing adaptive finite-element package for 3D elliptic deferential equations

    Science.gov (United States)

    Zhengyong, R.; Jingtian, T.; Changsheng, L.; Xiao, X.

    2007-12-01

    Although adaptive finite-element (AFE) analysis is becoming more and more focused in scientific and engineering fields, its efficient implementations are remain to be a discussed problem as its more complex procedures. In this paper, we propose a clear C++ framework implementation to show the powerful properties of Object-oriented philosophy (OOP) in designing such complex adaptive procedure. In terms of the modal functions of OOP language, the whole adaptive system is divided into several separate parts such as the mesh generation or refinement, a-posterior error estimator, adaptive strategy and the final post processing. After proper designs are locally performed on these separate modals, a connected framework of adaptive procedure is formed finally. Based on the general elliptic deferential equation, little efforts should be added in the adaptive framework to do practical simulations. To show the preferable properties of OOP adaptive designing, two numerical examples are tested. The first one is the 3D direct current resistivity problem in which the powerful framework is efficiently shown as only little divisions are added. And then, in the second induced polarization£¨IP£©exploration case, new adaptive procedure is easily added which adequately shows the strong extendibility and re-usage of OOP language. Finally we believe based on the modal framework adaptive implementation by OOP methodology, more advanced adaptive analysis system will be available in future.

  14. Effect of Endocrown Restorations with Different CAD/CAM Materials: 3D Finite Element and Weibull Analyses.

    Science.gov (United States)

    Gulec, Laden; Ulusoy, Nuran

    2017-01-01

    The aim of this study was to evaluate the effects of two endocrown designs and computer aided design/manufacturing (CAD/CAM) materials on stress distribution and failure probability of restorations applied to severely damaged endodontically treated maxillary first premolar tooth (MFP). Two types of designs without and with 3 mm intraradicular extensions, endocrown (E) and modified endocrown (ME), were modeled on a 3D Finite element (FE) model of the MFP. Vitablocks Mark II (VMII), Vita Enamic (VE), and Lava Ultimate (LU) CAD/CAM materials were used for each type of design. von Mises and maximum principle values were evaluated and the Weibull function was incorporated with FE analysis to calculate the long term failure probability. Regarding the stresses that occurred in enamel, for each group of material, ME restoration design transmitted less stress than endocrown. During normal occlusal function, the overall failure probability was minimum for ME with VMII. ME restoration design with VE was the best restorative option for premolar teeth with extensive loss of coronal structure under high occlusal loads. Therefore, ME design could be a favorable treatment option for MFPs with missing palatal cusp. Among the CAD/CAM materials tested, VMII and VE were found to be more tooth-friendly than LU.

  15. Stress-strain distribution at bone-implant interface of two splinted overdenture systems using 3D finite element analysis

    Science.gov (United States)

    2013-01-01

    PURPOSE This study was accomplished to assess the biomechanical state of different retaining methods of bar implant-overdenture. MATERIALS AND METHODS Two 3D finite element models were designed. The first model included implant overdenture retained by Hader-clip attachment, while the second model included two extracoronal resilient attachment (ERA) studs added distally to Hader splint bar. A non-linear frictional contact type was assumed between overdentures and mucosa to represent sliding and rotational movements among different attachment components. A 200 N was applied at the molar region unilaterally and perpendicular to the occlusal plane. Additionally, the mandible was restrained at their ramus ends. The maximum equivalent stress and strain (von Mises) were recorded and analyzed at the bone-implant interface level. RESULTS The values of von Mises stress and strain of the first model at bone-implant interface were higher than their counterparts of the second model. Stress concentration and high value of strain were recognized surrounding implant of the unloaded side in both models. CONCLUSION There were different patterns of stress-strain distribution at bone-implant interface between the studied attachment designs. Hader bar-clip attachment showed better biomechanical behavior than adding ERA studs distal to hader bar. PMID:24049576

  16. 3D Quantification of Wall Shear Stress and Oscillatory Shear Index Using a Finite-Element Method in 3D CINE PC-MRI Data of the Thoracic Aorta.

    Science.gov (United States)

    Sotelo, Julio; Urbina, Jesus; Valverde, Israel; Tejos, Cristian; Irarrazaval, Pablo; Andia, Marcelo E; Uribe, Sergio; Hurtado, Daniel E

    2016-06-01

    Several 2D methods have been proposed to estimate WSS and OSI from PC-MRI, neglecting the longitudinal velocity gradients that typically arise in cardiovascular flow, particularly on vessel geometries whose cross section and centerline orientation strongly vary in the axial direction. Thus, the contribution of longitudinal velocity gradients remains understudied. In this work, we propose a 3D finite-element method for the quantification of WSS and OSI from 3D-CINE PC-MRI that accounts for both in-plane and longitudinal velocity gradients. We demonstrate the convergence and robustness of the method on cylindrical geometries using a synthetic phantom based on the Poiseuille flow equation. We also show that, in the presence of noise, the method is both stable and accurate. Using computational fluid dynamics simulations, we show that the proposed 3D method results in more accurate WSS estimates than those obtained from a 2D analysis not considering out-of-plane velocity gradients. Further, we conclude that for irregular geometries the accurate prediction of WSS requires the consideration of longitudinal gradients in the velocity field. Additionally, we compute 3D maps of WSS and OSI for 3D-CINE PC-MRI data sets from an aortic phantom and sixteen healthy volunteers and two patients. The OSI values show a greater dispersion than WSS, which is strongly dependent on the PC-MRI resolution. We envision that the proposed 3D method will improve the estimation of WSS and OSI from 3D-CINE PC-MRI images, allowing for more accurate estimates in vessels with pathologies that induce high longitudinal velocity gradients, such as coarctations and aneurisms.

  17. Intraplate Strain and the Seismic Cycle: Inferences from 3D Finite-Element Spherical Viscoelastic Models and GPS Data

    Science.gov (United States)

    Fleitout, L.; Klein, E.; Vigny, C.; Garaud, J. D.

    2017-12-01

    The postseismic deformations affecting the subducting and overiding plates over thousands of kilometers after the Sumatra, Tohoku and Maule megaearthquakes have been measured precisely by GPS positioning. The characteristics of the postseismic deformation are very similar for the three earthquakes. Modeling using 3D finite element methodsleads to the conclusion that only viscous relaxation in an asthenosphere a few hundred kilometers thick with a viscosity of some 3. 1018Pas, can explain the far-field GPS data. A low viscosity channel along thedeep part of the slab interface helps to explain uplift over the volcanic arc. Viscoelastic models of the seismic cycle based on the mechanical models compatible with the postseismic data predict a continuous transitionbetween postseismic extension andthe compensating interseismic compression. The transition between the two regimes occurs sooner in areas close to the trench. The predictions of the models are compared to GPS data in South-America before Maule earthquake. The GPS time-series are corrected for deformations induced by hydrological loading deduced from the GRACE mission.A slight but welldefined general compression of the South American plate is evidenced between20 and 40 degrees south.Postseismic extension several decades after Valdivia earthquake is also conspicuous south of 40° South.At shorter distances from the trench, the zone of strong compression rate isbroader thanpredicted by elastic back-slip models.Although Chile appears like an ideal place to study deformations through the seismic cycle, similar patterns seem to prevail in other areas affected by megaearthquakes: In Asia, the Northward motion of the 'Sunda block' with respect to South China, or the convergence ratebetween Amour and Okhotsk plates infered from GPS data collected before the megaearthquake, are, at least in part, due to interseismic elastic compression of the lithosphere.

  18. The Distributed Lambda (?) Model (DLM): A 3-D, Finite-Element Muscle Model Based on Feldman's ? Model; Assessment of Orofacial Gestures

    Science.gov (United States)

    Nazari, Mohammad Ali; Perrier, Pascal; Payan, Yohan

    2013-01-01

    Purpose: The authors aimed to design a distributed lambda model (DLM), which is well adapted to implement three-dimensional (3-D), finite-element descriptions of muscles. Method: A muscle element model was designed. Its stress-strain relationships included the active force-length characteristics of the ? model along the muscle fibers, together…

  19. Biomechanical assessment and 3D finite element analysis of the treatment of tibial fractures using minimally invasive percutaneous plates

    Science.gov (United States)

    Hu, Xin-Jia; Wang, Hua

    2017-01-01

    The aim of the present study was to investigate the biomechanical effects of varying the length of a limited contact-dynamic compression plate (LC-DCP) and the number and position of screws on middle tibial fractures, and to provide biomechanical evidence regarding minimally invasive plate osteosynthesis (MIPO). For biomechanical testing, 60 tibias from cadavers (age at mortality, 20–40 years) were used to create middle and diagonal fracture models without defects. Tibias were randomly grouped and analyzed by biomechanic and three-dimensional (3D) finite element analysis. The differences among LC-DCPs of different lengths (6-, 10- and 14-hole) with 6 screws, 14-hole LC-DCPs with different numbers of screws (6, 10 and 14), and 14-hole LC-DCPs with 6 screws at different positions with regard to mechanical characteristics, including compressing, torsion and bending, were examined. The 6-hole LC-DCP had greater vertical compression strain compared with the 10- and 14-hole LC-DCPs (P0.05). However, plates with 14 screws had greater vertical strain compared with those fixed with 6 or 10 screws (P<0.01). For 4-hole LC-DCPs with screws at different positions, vertical compression strain values were lowest for plates with screws at positions 1, 4, 7, 8, 11 and 14 (P<0.01). The lateral strain values and vertical strain values for plates with screws at positions 1, 3, 6, 9, 12 and 14 were significantly lower compared with those at the other positions (P<0.01), and torque values were also low. Thus, the 14-hole LC-DCP was the most stable against vertical compression, torsion and bending, and the 6-hole LC-DCP was the least stable. However, the use of 14 screws with a 14-hole LC-DCP provided less stability against bending than did 6 or 10 screws. Furthermore, fixation with distributed screws, in which some screws were close to the fracture line, provided good stability against compression and torsion, while fixation with screws at the ends of the LC-DCP provided poor

  20. BOPACE 3-D addendum: The Boeing plastic analysis capabilities for 3-dimensional solids using isoparametric finite elements

    Science.gov (United States)

    Vos, R. G.; Straayer, J. W.

    1975-01-01

    Modifications and additions incorporated into the BOPACE 3-D program are described. Updates to the program input data formats, error messages, file usage, size limitations, and overlay schematic are included.

  1. Kinematic finite fault and 3D seismic wave propagation of the 24 August, 2016, Mw 6.0 central Italy earthquake

    Directory of Open Access Journals (Sweden)

    Federica Magnoni

    2016-12-01

    Full Text Available The magnitude Mw 6.0 earthquake of 24th August 2016 caused severe damages and nearly 300 fatalities in the central Italy region. Initial reports revealed an asymmetrical distribution of damage and coseismic effects, suggesting a major role of heterogeneities, both in the rupture history and in the geological structure of the region. Near realtime availability of seismological data afforded a timely determination of a finite fault model (Tinti et al., 2016. Here we test this source model by performing a 3D simulation of seismic wave propagation within a 3D structural model containing the major geological features of the region. Agreement between modeled seismograms and observed seismograms suggests that some complexities in the waveforms, such as high amplification in the region of the Mt. Vettore fault system, can be accounted for by complexities in the fault rupture and 3D structural models. Finally, the consistency of the hypothesis of two distinct events has been analyzed.

  2. 3D reconstruction of bony elements of the knee joint and finite element analysis of total knee prosthesis obtained from the reconstructed model.

    Science.gov (United States)

    Djoudi, Farid

    2013-01-01

    Two separate themes are presented in this paper. The first theme is to present a graphical modeling approach of human anatomical structures namely, the femur and the tibia. The second theme involves making a finite element analysis of stresses, displacements and deformations in prosthetic implants (the femoral implant and the polyethylene insert). The graphical modeling approach comes in two parts. The first is the segmentation of MRI scanned images, retrieved in DICOM format for edge detection. In the second part, 3D-CAD models are generated from the results of the segmentation stage. The finite element analysis is done by first extracting the prosthetic implants from the reconstructed 3D-CAD model, then do a finite element analysis of these implants under objectively determined conditions such as; forces, allowed displacements, the materials composing implant, and the coefficient of friction. The objective of this work is to implement an interface for exchanging data between 2D MRI images obtained from a medical diagnosis of a patient and the 3D-CAD model used in various applications, such as; the extraction of the implants, stress analysis at the knee joint and can serve as an aid to surgery, also predict the behavior of the prosthetic implants vis-a-vis the forces acting on the knee joints.

  3. Feasibility of rapid and automated importation of 3D echocardiographic left ventricular (LV) geometry into a finite element (FEM) analysis model.

    Science.gov (United States)

    Verhey, Janko F; Nathan, Nadia S

    2004-10-08

    Finite element method (FEM) analysis for intraoperative modeling of the left ventricle (LV) is presently not possible. Since 3D structural data of the LV is now obtainable using standard transesophageal echocardiography (TEE) devices intraoperatively, the present study describes a method to transfer this data into a commercially available FEM analysis system: ABAQUS. In this prospective study TomTec LV Analysis TEE Software was used for semi-automatic endocardial border detection, reconstruction, and volume-rendering of the clinical 3D echocardiographic data. A newly developed software program MVCP FemCoGen, written in Delphi, reformats the TomTec file structures in five patients for use in ABAQUS and allows visualization of regional deformation of the LV. This study demonstrates that a fully automated importation of 3D TEE data into FEM modeling is feasible and can be efficiently accomplished in the operating room. For complete intraoperative 3D LV finite element analysis, three input elements are necessary: 1. time-gaited, reality-based structural information, 2. continuous LV pressure and 3. instantaneous tissue elastance. The first of these elements is now available using the methods presented herein.

  4. Feasibility of rapid and automated importation of 3D echocardiographic left ventricular (LV geometry into a finite element (FEM analysis model

    Directory of Open Access Journals (Sweden)

    Nathan Nadia S

    2004-10-01

    Full Text Available Abstract Background Finite element method (FEM analysis for intraoperative modeling of the left ventricle (LV is presently not possible. Since 3D structural data of the LV is now obtainable using standard transesophageal echocardiography (TEE devices intraoperatively, the present study describes a method to transfer this data into a commercially available FEM analysis system: ABAQUS©. Methods In this prospective study TomTec LV Analysis TEE© Software was used for semi-automatic endocardial border detection, reconstruction, and volume-rendering of the clinical 3D echocardiographic data. A newly developed software program MVCP FemCoGen©, written in Delphi, reformats the TomTec file structures in five patients for use in ABAQUS and allows visualization of regional deformation of the LV. Results This study demonstrates that a fully automated importation of 3D TEE data into FEM modeling is feasible and can be efficiently accomplished in the operating room. Conclusion For complete intraoperative 3D LV finite element analysis, three input elements are necessary: 1. time-gaited, reality-based structural information, 2. continuous LV pressure and 3. instantaneous tissue elastance. The first of these elements is now available using the methods presented herein.

  5. Phase structure of 3D Z(N) lattice gauge theories at finite temperature: Large-N and continuum limits

    Energy Technology Data Exchange (ETDEWEB)

    Borisenko, O., E-mail: oleg@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine, 03680 Kiev (Ukraine); Chelnokov, V., E-mail: chelnokov@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine, 03680 Kiev (Ukraine); Gravina, M., E-mail: gravina@fis.unical.it [Dipartimento di Fisica, Università della Calabria, and Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Cosenza, I-87036 Arcavacata di Rende, Cosenza (Italy); Papa, A., E-mail: papa@fis.unical.it [Dipartimento di Fisica, Università della Calabria, and Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Cosenza, I-87036 Arcavacata di Rende, Cosenza (Italy)

    2014-11-15

    We study numerically three-dimensional Z(N) lattice gauge theories at finite temperature, for N=5,6,8,12,13 and 20 on lattices with temporal extension N{sub t}=2,4,8. For each model, we locate phase transition points and determine critical indices. We propose also the scaling of critical points with N. The data obtained enable us to verify the scaling near the continuum limit for the Z(N) models at finite temperatures.

  6. Phase structure of 3D Z(N) lattice gauge theories at finite temperature: Large-N and continuum limits

    International Nuclear Information System (INIS)

    Borisenko, O.; Chelnokov, V.; Gravina, M.; Papa, A.

    2014-01-01

    We study numerically three-dimensional Z(N) lattice gauge theories at finite temperature, for N=5,6,8,12,13 and 20 on lattices with temporal extension N t =2,4,8. For each model, we locate phase transition points and determine critical indices. We propose also the scaling of critical points with N. The data obtained enable us to verify the scaling near the continuum limit for the Z(N) models at finite temperatures

  7. Systematic design of 3D auxetic lattice materials with programmable Poisson’s ratio for finite strains

    DEFF Research Database (Denmark)

    Wang, Fengwen

    2018-01-01

    This paper presents a systematic approach for designing 3D auxetic lattice materials, which exhibit constant negative Poisson’s ratios over large strain intervals. A unit cell model mimicking tensile tests is established and based on the proposed model, the secant Poisson’s ratio is defined...... as the negative ratio between the lateral and the longitudinal engineering strains. The optimization problem for designing a material unit cell with a target Poisson’s ratio is formulated to minimize the average lateral engineering stresses under the prescribed deformations. Numerical results demonstrate that 3D......, material architectures for any Poisson’s ratio in the interval of ν∈[−0.78,0.00] are explicitly presented. Numerical evaluations show that interpolated auxetic lattice materials exhibit constant Poisson’s ratios in the target strain interval of [0.00, 0.20] and that 3D auxetic lattice material...

  8. 3D finite compartment modeling of formation and healing of bruises may identify methods for age determination of bruises

    NARCIS (Netherlands)

    Stam, B.; van Gemert, M.J.C.; van Leeuwen, T.G.; Aalders, M.C.G.

    2010-01-01

    Simulating the spatial and temporal behavior of bruises may identify methods that allow accurate age determination of bruises to assess child abuse. We developed a numerical 3D model to simulate the spatial kinetics of hemoglobin and bilirubin during the formation and healing of bruises. Using this

  9. 3d Finite Element Modelling of Non-Crimp Fabric Based Fibre Composite Based on X-Ray Ct Data

    DEFF Research Database (Denmark)

    Jespersen, Kristine Munk; Asp, Leif; Mikkelsen, Lars Pilgaard

    2017-01-01

    initiation and progression in the material. In the current study, the real bundle structure inside a non-crimp fabric based fibre composite is extracted from 3D X-ray CT images and imported into ABAQUS for numerical modelling.The local stress concentrations when loaded in tension caused by the fibre bundle...

  10. Enriched finite element method for 2-D and 3-D blunt crack problems in a viscoelastic medium

    International Nuclear Information System (INIS)

    Duan, Jingbo; Lei, Yongjun; Li, Daokui

    2012-01-01

    The analysis of two-dimensional and three-dimensional blunt crack problems in a linear viscoelastic medium is numerically investigated using the enriched finite element method. The enriched crack-tip elements are established by enriching the asymptotic displacement fields at the blunt crack front to the regular elements. The corresponding transition elements are formulated to eliminate displacement field incompatibility. The viscoelastic incremental formulations for the enriched finite element method in time domain are derived according to the Boltzmann superposition principle. The time-dependent deformations of crack are presented and the stress intensity factors are directly obtained from the enriched degree of freedoms. The numerical examples indicate that the enriched finite element method is extremely suitable for dealing with complicated blunt crack problems

  11. A practical method for computation of ductile crack growth by means of finite elements and parametric 3D-modelling

    International Nuclear Information System (INIS)

    Baumjohann, F.; Kroening, J.

    1999-01-01

    The present paper originates from a contribution to the safety assessment of a reactor pressure vessel (RPV). Investigations evaluating the safety against brittle fracture (exclosure of crack initiation and arrest assessments) are completed by calculations concerning ductile crack extension. Crack geometries including the expected crack extension are generated parametrically by a computer code and are used for further calculations with finite element programs. J-integrals of ductile growing cracks located between two comparative contours are determined by interpolation. The comparative contours are loaded by instationary temperature and pressure fields and are evaluated in advance. Taking the stability condition into consideration, the ductile crack extension is determined by pursuing the equilibrium between loading and crack resistance. The automatic modelling and a mathematical program processing the finite element results evaluate the crack growth of the finite element results very effectively. (orig.)

  12. Free Tools and Strategies for the Generation of 3D Finite Element Meshes: Modeling of the Cardiac Structures

    Directory of Open Access Journals (Sweden)

    E. Pavarino

    2013-01-01

    Full Text Available The Finite Element Method is a well-known technique, being extensively applied in different areas. Studies using the Finite Element Method (FEM are targeted to improve cardiac ablation procedures. For such simulations, the finite element meshes should consider the size and histological features of the target structures. However, it is possible to verify that some methods or tools used to generate meshes of human body structures are still limited, due to nondetailed models, nontrivial preprocessing, or mainly limitation in the use condition. In this paper, alternatives are demonstrated to solid modeling and automatic generation of highly refined tetrahedral meshes, with quality compatible with other studies focused on mesh generation. The innovations presented here are strategies to integrate Open Source Software (OSS. The chosen techniques and strategies are presented and discussed, considering cardiac structures as a first application context.

  13. Visualization of 2-D and 3-D fields from its value in a finite number of points

    International Nuclear Information System (INIS)

    Dari, E.A.; Venere, M.J.

    1990-01-01

    This work describes a method for the visualization of two- and three-dimensional fields, given its value in a finite number of points. These data can be originated in experimental measurements, numerical results, or any other source. For the field interpolation, the space is divided into simplices (triangles or tetrahedrons), using the Watson algorithm to obtain the Delaunay triangulation. Inside each simplex, linear interpolation is assumed. The visualization is accomplished by means of Finite Elements post-processors, capable of handling unstructured meshes, which were also developed by the authors. (Author) [es

  14. 3D adaptive finite element method for a phase field model for the moving contact line problems

    KAUST Repository

    Shi, Yi

    2013-08-01

    In this paper, we propose an adaptive finite element method for simulating the moving contact line problems in three dimensions. The model that we used is the coupled Cahn-Hilliard Navier-Stokes equations with the generalized Navier boundary condition(GNBC) proposed in [18]. In our algorithm, to improve the efficiency of the simulation, we use the residual type adaptive finite element algorithm. It is well known that the phase variable decays much faster away from the interface than the velocity variables. There- fore we use an adaptive strategy that will take into account of such difference. Numerical experiments show that our algorithm is both efficient and reliable. © 2013 American Institute of Mathematical Sciences.

  15. Combined magnetic vector-scalar potential finite element computation of 3D magnetic field and performance of modified Lundell alternators in Space Station applications. Ph.D. Thesis

    Science.gov (United States)

    Wang, Ren H.

    1991-01-01

    A method of combined use of magnetic vector potential (MVP) based finite element (FE) formulations and magnetic scalar potential (MSP) based FE formulations for computation of three-dimensional (3D) magnetostatic fields is developed. This combined MVP-MSP 3D-FE method leads to considerable reduction by nearly a factor of 3 in the number of unknowns in comparison to the number of unknowns which must be computed in global MVP based FE solutions. This method allows one to incorporate portions of iron cores sandwiched in between coils (conductors) in current-carrying regions. Thus, it greatly simplifies the geometries of current carrying regions (in comparison with the exclusive MSP based methods) in electric machinery applications. A unique feature of this approach is that the global MSP solution is single valued in nature, that is, no branch cut is needed. This is again a superiority over the exclusive MSP based methods. A Newton-Raphson procedure with a concept of an adaptive relaxation factor was developed and successfully used in solving the 3D-FE problem with magnetic material anisotropy and nonlinearity. Accordingly, this combined MVP-MSP 3D-FE method is most suited for solution of large scale global type magnetic field computations in rotating electric machinery with very complex magnetic circuit geometries, as well as nonlinear and anisotropic material properties.

  16. Numerical Simulation of Fragment Separation during Rock Cutting Using a 3D Dynamic Finite Element Analysis Code

    Directory of Open Access Journals (Sweden)

    Zhenguo Lu

    2017-01-01

    Full Text Available To predict fragment separation during rock cutting, previous studies on rock cutting interactions using simulation approaches, experimental tests, and theoretical methods were considered in detail. This study used the numerical code LS-DYNA (3D to numerically simulate fragment separation. In the simulations, a damage material model and erosion criteria were used for the base rock, and the conical pick was designated a rigid material. The conical pick moved at varying linear speeds to cut the fixed base rock. For a given linear speed of the conical pick, numerical studies were performed for various cutting depths and mechanical properties of rock. The numerical simulation results demonstrated that the cutting forces and sizes of the separated fragments increased significantly with increasing cutting depth, compressive strength, and elastic modulus of the base rock. A strong linear relationship was observed between the mean peak cutting forces obtained from the numerical, theoretical, and experimental studies with correlation coefficients of 0.698, 0.8111, 0.868, and 0.768. The simulation results also showed an exponential relationship between the specific energy and cutting depth and a linear relationship between the specific energy and compressive strength. Overall, LS-DYNA (3D is effective and reliable for predicting the cutting performance of a conical pick.

  17. High-Fidelity RF Gun Simulations with the Parallel 3D Finite Element Particle-In-Cell Code Pic3P

    Energy Technology Data Exchange (ETDEWEB)

    Candel, A; Kabel, A.; Lee, L.; Li, Z.; Limborg, C.; Ng, C.; Schussman, G.; Ko, K.; /SLAC

    2009-06-19

    SLAC's Advanced Computations Department (ACD) has developed the first parallel Finite Element 3D Particle-In-Cell (PIC) code, Pic3P, for simulations of RF guns and other space-charge dominated beam-cavity interactions. Pic3P solves the complete set of Maxwell-Lorentz equations and thus includes space charge, retardation and wakefield effects from first principles. Pic3P uses higher-order Finite Elementmethods on unstructured conformal meshes. A novel scheme for causal adaptive refinement and dynamic load balancing enable unprecedented simulation accuracy, aiding the design and operation of the next generation of accelerator facilities. Application to the Linac Coherent Light Source (LCLS) RF gun is presented.

  18. Dynamic analysis of centrifugal machines rotors supported on ball bearings by combined application of 3D and beam finite element models

    Science.gov (United States)

    Pavlenko, I. V.; Simonovskiy, V. I.; Demianenko, M. M.

    2017-08-01

    This research paper is aimed to investigating rotor dynamics of multistage centrifugal machines with ball bearings by using the computer programs “Critical frequencies of the rotor” and “Forced oscillations of the rotor,” which are implemented the mathematical model based on the use of beam finite elements. Free and forces oscillations of the rotor for the multistage centrifugal oil pump NPS 200-700 are observed by taking into account the analytical dependence of bearing stiffness on rotor speed, which is previously defined on the basis of results’ approximation for the numerical simulation in ANSYS by applying 3D finite elements. The calculations found that characteristic and constrained oscillations of rotor and corresponded to them forms of vibrations, as well as the form of constrained oscillation on the actual frequency for acceptable residual unbalance are determined.

  19. Dynamic pulse buckling of cylindrical shells under axial impact: A benchmark study of 2D and 3D finite element calculations

    International Nuclear Information System (INIS)

    Hoffman, E.L.; Ammerman, D.J.

    1995-01-01

    A series of tests investigating dynamic pulse buckling of a cylindrical shell under axial impact is compared to several 2D and 3D finite element simulations of the event. The purpose of the work is to investigate the performance of various analysis codes and element types on a problem which is applicable to radioactive material transport packages, and ultimately to develop a benchmark problem to qualify finite element analysis codes for the transport package design industry. During the pulse buckling tests, a buckle formed at each end of the cylinder, and one of the two buckles became unstable and collapsed. Numerical simulations of the test were performed using PRONTO, a Sandia developed transient dynamics analysis code, and ABAQUS/Explicit with both shell and continuum elements. The calculations are compared to the tests with respect to deformed shape and impact load history

  20. 3D Viscoelastic Finite Element Modelling of Polymer Flow in the Fiber Drawing Process for Microstructured Polymer Optical Fiber Fabrication

    DEFF Research Database (Denmark)

    Fasano, Andrea; Rasmussen, Henrik K.; Marín, J. M. R.

    2015-01-01

    The process of drawing an optical fiber from a polymer preform is still not completely understood,although it represents one of the most critical steps in the process chain for the fabrication of microstructuredpolymer optical fibers (mPOFs). Here we present a new approach for the numerical...... modelling of the fiber drawingprocess using a fully three-dimensional and time-dependent finite element method, giving significant insightinto this widely spread mPOF production technique. Our computational predictions are physically based on theviscoelastic fluid dynamics of polymers. Until now...

  1. Comparative analysis of nodal and edge finite element method for numerical analysis of 3-D magnetostatic systems

    International Nuclear Information System (INIS)

    Mintchev, Pavel; Dimitrov, Marin; Balinov, Stoimen

    2002-01-01

    The possibilities for applying the Finite Element Method (FEM) with gauged magnetic vector potential and the Edge Element Method (EEM) for three-dimensional numerical analysis of magnetostatic systems are analyzed. It is established that the EEM ensures sufficient accuracy for engineering calculations but in some cases its use results in bad convergence. The use of the FEM with gauged magnetic vector potential instead of the EEM is recommended for preliminary calculations of devices with complex geometry and large air gaps between the ferromagnetic parts. (Author)

  2. Finite-element-method (FEM model generation of time-resolved 3D echocardiographic geometry data for mitral-valve volumetry

    Directory of Open Access Journals (Sweden)

    Kikinis Ron

    2006-03-01

    Full Text Available Abstract Introduction Mitral Valve (MV 3D structural data can be easily obtained using standard transesophageal echocardiography (TEE devices but quantitative pre- and intraoperative volume analysis of the MV is presently not feasible in the cardiac operation room (OR. Finite element method (FEM modelling is necessary to carry out precise and individual volume analysis and in the future will form the basis for simulation of cardiac interventions. Method With the present retrospective pilot study we describe a method to transfer MV geometric data to 3D Slicer 2 software, an open-source medical visualization and analysis software package. A newly developed software program (ROIExtract allowed selection of a region-of-interest (ROI from the TEE data and data transformation for use in 3D Slicer. FEM models for quantitative volumetric studies were generated. Results ROI selection permitted the visualization and calculations required to create a sequence of volume rendered models of the MV allowing time-based visualization of regional deformation. Quantitation of tissue volume, especially important in myxomatous degeneration can be carried out. Rendered volumes are shown in 3D as well as in time-resolved 4D animations. Conclusion The visualization of the segmented MV may significantly enhance clinical interpretation. This method provides an infrastructure for the study of image guided assessment of clinical findings and surgical planning. For complete pre- and intraoperative 3D MV FEM analysis, three input elements are necessary: 1. time-gated, reality-based structural information, 2. continuous MV pressure and 3. instantaneous tissue elastance. The present process makes the first of these elements available. Volume defect analysis is essential to fully understand functional and geometrical dysfunction of but not limited to the valve. 3D Slicer was used for semi-automatic valve border detection and volume-rendering of clinical 3D echocardiographic

  3. A 3D FINITE ELEMENT ANALYSIS OF INCOMPRESSIBLE FLUID FLOW AND CONTAMINANT TRANSPORT THROUGH A POROUS LANDFILL

    Directory of Open Access Journals (Sweden)

    ADEGUN, I. K.

    2014-08-01

    Full Text Available The paper investigated the flow of incompressible fluid and contaminant transport through a Porous Landfill using a numerical technique. A threedimensional finite element analysis technique was adopted for the solution. The problem was based on the Darcy’s Law and the Advection-Dispersion equation. The solutions of the Darcy’s and Advection-Dispersion equations were generated using Finite Element Analysis Software known as COMSOL Multiphysics. This simulation tool tracked the contaminant transport in the Landfill for 360 days at 10 days interval. It first modeled steady-state fluid flow by employing the Darcy’s Law Application Mode and then followed up with a transient solute-transport simulation by employing the Solute-Transport Application Mode from the Earth Science Module of COMSOL. The solution results obtained from this model were found to be in close agreement with reallife data obtained at the 130- million ton Bukit Tagar Mega Sanitary Landfill site, Selangor near Kuala Lumpur, Malaysia. This showed that the model can effectively predict the trends in the distributions of pollutants from a Municipal Solid Waste Landfill into nearby land and water sources. The model is thus applicable to the issues of environmental protection and safety of groundwater.

  4. Comparison of 2D Finite Element Modeling Assumptions with Results From 3D Analysis for Composite Skin-Stiffener Debonding

    Science.gov (United States)

    Krueger, Ronald; Paris, Isbelle L.; OBrien, T. Kevin; Minguet, Pierre J.

    2004-01-01

    The influence of two-dimensional finite element modeling assumptions on the debonding prediction for skin-stiffener specimens was investigated. Geometrically nonlinear finite element analyses using two-dimensional plane-stress and plane-strain elements as well as three different generalized plane strain type approaches were performed. The computed skin and flange strains, transverse tensile stresses and energy release rates were compared to results obtained from three-dimensional simulations. The study showed that for strains and energy release rate computations the generalized plane strain assumptions yielded results closest to the full three-dimensional analysis. For computed transverse tensile stresses the plane stress assumption gave the best agreement. Based on this study it is recommended that results from plane stress and plane strain models be used as upper and lower bounds. The results from generalized plane strain models fall between the results obtained from plane stress and plane strain models. Two-dimensional models may also be used to qualitatively evaluate the stress distribution in a ply and the variation of energy release rates and mixed mode ratios with delamination length. For more accurate predictions, however, a three-dimensional analysis is required.

  5. Polymorphism of iron at high pressure: A 3D phase-field model for displacive transitions with finite elastoplastic deformations

    Science.gov (United States)

    Vattré, A.; Denoual, C.

    2016-07-01

    A thermodynamically consistent framework for combining nonlinear elastoplasticity and multivariant phase-field theory is formulated at large strains. In accordance with the Clausius-Duhem inequality, the Helmholtz free energy and time-dependent constitutive relations give rise to displacive driving forces for pressure-induced martensitic phase transitions in materials. Inelastic forces are obtained by using a representation of the energy landscape that involves the concept of reaction pathways with respect to the point group symmetry operations of crystal lattices. On the other hand, additional elastic forces are derived for the most general case of large strains and rotations, as well as nonlinear, anisotropic, and different elastic pressure-dependent properties of phases. The phase-field formalism coupled with finite elastoplastic deformations is implemented into a three-dimensional Lagrangian finite element approach and is applied to analyze the iron body-centered cubic (α-Fe) into hexagonal close-packed (ɛ-Fe) phase transitions under high hydrostatic compression. The simulations exhibit the major role played by the plastic deformation in the morphological and microstructure evolution processes. Due to the strong long-range elastic interactions between variants without plasticity, a forward α → ɛ transition is energetically unfavorable and remains incomplete. However, plastic dissipation releases considerably the stored strain energy, leading to the α ↔ ɛ ↔α‧ (forward and reverse) polymorphic phase transformations with an unexpected selection of variants.

  6. Goal-Oriented Self-Adaptive hp Finite Element Simulation of 3D DC Borehole Resistivity Simulations

    KAUST Repository

    Calo, Victor M.

    2011-05-14

    In this paper we present a goal-oriented self-adaptive hp Finite Element Method (hp-FEM) with shared data structures and a parallel multi-frontal direct solver. The algorithm automatically generates (without any user interaction) a sequence of meshes delivering exponential convergence of a prescribed quantity of interest with respect to the number of degrees of freedom. The sequence of meshes is generated from a given initial mesh, by performing h (breaking elements into smaller elements), p (adjusting polynomial orders of approximation) or hp (both) refinements on the finite elements. The new parallel implementation utilizes a computational mesh shared between multiple processors. All computational algorithms, including automatic hp goal-oriented adaptivity and the solver work fully in parallel. We describe the parallel self-adaptive hp-FEM algorithm with shared computational domain, as well as its efficiency measurements. We apply the methodology described to the three-dimensional simulation of the borehole resistivity measurement of direct current through casing in the presence of invasion.

  7. Application of an unstructured 3D finite volume numerical model to flows and salinity dynamics in the San Francisco Bay-Delta

    Science.gov (United States)

    Martyr-Koller, R.C.; Kernkamp, H.W.J.; Van Dam, Anne A.; Mick van der Wegen,; Lucas, Lisa; Knowles, N.; Jaffe, B.; Fregoso, T.A.

    2017-01-01

    A linked modeling approach has been undertaken to understand the impacts of climate and infrastructure on aquatic ecology and water quality in the San Francisco Bay-Delta region. The Delft3D Flexible Mesh modeling suite is used in this effort for its 3D hydrodynamics, salinity, temperature and sediment dynamics, phytoplankton and water-quality coupling infrastructure, and linkage to a habitat suitability model. The hydrodynamic model component of the suite is D-Flow FM, a new 3D unstructured finite-volume model based on the Delft3D model. In this paper, D-Flow FM is applied to the San Francisco Bay-Delta to investigate tidal, seasonal and annual dynamics of water levels, river flows and salinity under historical environmental and infrastructural conditions. The model is driven by historical winds, tides, ocean salinity, and river flows, and includes federal, state, and local freshwater withdrawals, and regional gate and barrier operations. The model is calibrated over a 9-month period, and subsequently validated for water levels, flows, and 3D salinity dynamics over a 2 year period.Model performance was quantified using several model assessment metrics and visualized through target diagrams. These metrics indicate that the model accurately estimated water levels, flows, and salinity over wide-ranging tidal and fluvial conditions, and the model can be used to investigate detailed circulation and salinity patterns throughout the Bay-Delta. The hydrodynamics produced through this effort will be used to drive affiliated sediment, phytoplankton, and contaminant hindcast efforts and habitat suitability assessments for fish and bivalves. The modeling framework applied here will serve as a baseline to ultimately shed light on potential ecosystem change over the current century.

  8. Application of an unstructured 3D finite volume numerical model to flows and salinity dynamics in the San Francisco Bay-Delta

    Science.gov (United States)

    Martyr-Koller, R. C.; Kernkamp, H. W. J.; van Dam, A.; van der Wegen, M.; Lucas, L. V.; Knowles, N.; Jaffe, B.; Fregoso, T. A.

    2017-06-01

    A linked modeling approach has been undertaken to understand the impacts of climate and infrastructure on aquatic ecology and water quality in the San Francisco Bay-Delta region. The Delft3D Flexible Mesh modeling suite is used in this effort for its 3D hydrodynamics, salinity, temperature and sediment dynamics, phytoplankton and water-quality coupling infrastructure, and linkage to a habitat suitability model. The hydrodynamic model component of the suite is D-Flow FM, a new 3D unstructured finite-volume model based on the Delft3D model. In this paper, D-Flow FM is applied to the San Francisco Bay-Delta to investigate tidal, seasonal and annual dynamics of water levels, river flows and salinity under historical environmental and infrastructural conditions. The model is driven by historical winds, tides, ocean salinity, and river flows, and includes federal, state, and local freshwater withdrawals, and regional gate and barrier operations. The model is calibrated over a 9-month period, and subsequently validated for water levels, flows, and 3D salinity dynamics over a 2 year period. Model performance was quantified using several model assessment metrics and visualized through target diagrams. These metrics indicate that the model accurately estimated water levels, flows, and salinity over wide-ranging tidal and fluvial conditions, and the model can be used to investigate detailed circulation and salinity patterns throughout the Bay-Delta. The hydrodynamics produced through this effort will be used to drive affiliated sediment, phytoplankton, and contaminant hindcast efforts and habitat suitability assessments for fish and bivalves. The modeling framework applied here will serve as a baseline to ultimately shed light on potential ecosystem change over the current century.

  9. Numerical simulations of eddy current testing signals of steam generator tubes by 3-D finite element method

    International Nuclear Information System (INIS)

    Sakai, Takayuki; Soneda, Naoki

    1996-01-01

    In every inspection of Japanese PWR plants, all of steam generator tubes are inspected using Eddy Current Testing (ECT) method. However, the relationships between the ECT signals and the defect shapes are known only for the representative shapes of defects. In order to improve the reliability of inspections and the capability of ECT probes, development of numerical simulation technique of the ECT signals for arbitrarily shaped defects is essential. In this study, three-dimensional finite element code is developed to simulate the ECT signals for any kinds of defects in the SG tubes. The code is fully vectorized so that it runs on the supercomputers very efficiently. The simulation results agree very well with the experimental results. Sensitivity analyses are performed to investigate the relationships between the defect shapes and the ECT signals. (author)

  10. [3D finite-element study on displacement of craniofacial complex with retractive forces parallel to the occlusion plane on the maxilla of rhesus monkeys].

    Science.gov (United States)

    Huang, Jiaxin; Zhang, Xiaorong; Yao, Ji

    2014-04-01

    To construct a 3D finite-element model of the craniofacial complex with the original DICOM data of CT and to investigate the preliminary biomechanical characteristics with different directions and magnitudes of retractive forces to the maxilla of rhesus monkeys. A male rhesus monkey with mixed dentition was used. Spiral CT was performed to establish a 3D finite-element model of the craniofacial complex. The ANSYS 12.1 software was used to analyze craniofacial complex displacement. Each landmark showed larger displacement with increasing force value. The displacement values and force size exhibited a linear relationship. In the x-axis direction, all displacements were small. In the y-axis direction, all displacements showed significantly higher changes with increasing force value displacement. In the z-axis direction, the A-point and ANS point moved downward, but PNS moved upward. Loading retractive force resultes in an apparent backward and clockwise rotation on the maxilla with no obvious effects on the width of the upper jaw.

  11. Efficacy of adding a supporting implant in stress distribution of long-span fixed partial dentures: a 3D finite element analysis

    Directory of Open Access Journals (Sweden)

    Rami

    2016-06-01

    Full Text Available Background. Long span is seen in many clinical situations. Treatmentplanning options of these cases are difficult and may require FPD, RPD or ISP. Each option has its own disadvantages, including mechanical problems, patient comfort and cost. This article will evaluate the stress distribution of a different treatment option, which consists of adding a single supporting implant to the FPD by using 3D finite element analysis. Methods. Three models, each consisting of 5 units, were created as follows: 1. Tooth Pontic Pontic Pontic Tooth; 2. Tooth Pontic Implant Pontic Tooth; 3. Tooth Pontic Pontic Implant Tooth. An axial force was applied to the prostheses by using 3D finite element method and stresses were evaluated. Results. The maximum stress was found in the prostheses in all the models; the highest stress values in all the shared components of the models were almost similar. Stress in implants was lower in the second model than the third one. Conclusion. Adding a supporting implant in long-span FPD has no advantages while it has the disadvantages of complicating treatment and the complications that may occur to the implant and surrounding bone.

  12. Comparison of 3D Adaptive Remeshing Strategies for Finite Element Simulations of Electromagnetic Heating of Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Fadhil Mezghani

    2015-01-01

    Full Text Available The optical properties of metallic nanoparticles are well known, but the study of their thermal behavior is in its infancy. However the local heating of surrounding medium, induced by illuminated nanostructures, opens the way to new sensors and devices. Consequently the accurate calculation of the electromagnetically induced heating of nanostructures is of interest. The proposed multiphysics problem cannot be directly solved with the classical refinement method of Comsol Multiphysics and a 3D adaptive remeshing process based on an a posteriori error estimator is used. In this paper the efficiency of three remeshing strategies for solving the multiphysics problem is compared. The first strategy uses independent remeshing for each physical quantity to reach a given accuracy. The second strategy only controls the accuracy on temperature. The third strategy uses a linear combination of the two normalized targets (the electric field intensity and the temperature. The analysis of the performance of each strategy is based on the convergence of the remeshing process in terms of number of elements. The efficiency of each strategy is also characterized by the number of computation iterations, the number of elements, the CPU time, and the RAM required to achieve a given target accuracy.

  13. Stress distribution in the cervical region of an upper central incisor in a 3D finite element model

    Directory of Open Access Journals (Sweden)

    Isis Andréa Venturini Pola Poiate

    2009-06-01

    Full Text Available The aim of this study was to evaluate the stress distribution in the cervical region of a sound upper central incisor in two clinical situations, standard and maximum masticatory forces, by means of a 3D model with the highest possible level of fidelity to the anatomic dimensions. Two models with 331,887 linear tetrahedral elements that represent a sound upper central incisor with periodontal ligament, cortical and trabecular bones were loaded at 45º in relation to the tooth's long axis. All structures were considered to be homogeneous and isotropic, with the exception of the enamel (anisotropic. A standard masticatory force (100 N was simulated on one of the models, while on the other one a maximum masticatory force was simulated (235.9 N. The software used were: PATRAN for pre- and post-processing and Nastran for processing. In the cementoenamel junction area, tensile forces reached 14.7 MPa in the 100 N model, and 40.2 MPa in the 235.9 N model, exceeding the enamel's tensile strength (16.7 MPa. The fact that the stress concentration in the amelodentinal junction exceeded the enamel's tensile strength under simulated conditions of maximum masticatory force suggests the possibility of the occurrence of non-carious cervical lesions such as abfractions.

  14. Solid modeling techniques to build 3D finite element models of volcanic systems: An example from the Rabaul Caldera system, Papua New Guinea

    Science.gov (United States)

    Ronchin, Erika; Masterlark, Timothy; Molist, Joan Martí; Saunders, Steve; Tao, Wei

    2013-03-01

    Simulating the deformation of active volcanoes is challenging due to inherent mechanical complexities associated with heterogeneous distributions of rheologic properties and irregular geometries associated with the topography and bathymetry. From geologic and tomographic studies we know that geologic bodies naturally have complex 3D shapes. Finite element models (FEMs) are capable of simulating the pressurization of magma intrusions into mechanical domains with arbitrary geometric and geologic complexity. We construct FEMs comprising pressurization (due to magma intrusion) within an assemblage of 3D parts having common mechanical properties for Rabaul Caldera, Papua New Guinea. We use information of material properties distributed on discrete points mainly deduced from topography, geology, seismicity, and tomography of Rabaul Caldera to first create contours of each part and successively to generate each 3D part shape by lofting the volume through the contours. The implementation of Abaqus CAE with Python scripts allows for automated execution of hundreds of commands necessary for the construction of the parts having substantial geometric complexity. The lofted solids are then assembled to form the composite model of Rabaul Caldera, having a geometrically complex loading configuration and distribution of rheologic properties. Comparison between predicted and observed deformation led us to identify multiple deformation sources (0.74 MPa change in pressure in the magma chamber and 0.17 m slip along the ring fault) responsible for the displacements measured at Matupit Island between August 1992 and August 1993.

  15. A gauged finite-element potential formulation for accurate inductive and galvanic modelling of 3-D electromagnetic problems

    Science.gov (United States)

    Ansari, S. M.; Farquharson, C. G.; MacLachlan, S. P.

    2017-07-01

    In this paper, a new finite-element solution to the potential formulation of the geophysical electromagnetic (EM) problem that explicitly implements the Coulomb gauge, and that accurately computes the potentials and hence inductive and galvanic components, is proposed. The modelling scheme is based on using unstructured tetrahedral meshes for domain subdivision, which enables both realistic Earth models of complex geometries to be considered and efficient spatially variable refinement of the mesh to be done. For the finite-element discretization edge and nodal elements are used for approximating the vector and scalar potentials respectively. The issue of non-unique, incorrect potentials from the numerical solution of the usual incomplete-gauged potential system is demonstrated for a benchmark model from the literature that uses an electric-type EM source, through investigating the interface continuity conditions for both the normal and tangential components of the potential vectors, and by showing inconsistent results obtained from iterative and direct linear equation solvers. By explicitly introducing the Coulomb gauge condition as an extra equation, and by augmenting the Helmholtz equation with the gradient of a Lagrange multiplier, an explicitly gauged system for the potential formulation is formed. The solution to the discretized form of this system is validated for the above-mentioned example and for another classic example that uses a magnetic EM source. In order to stabilize the iterative solution of the gauged system, a block diagonal pre-conditioning scheme that is based upon the Schur complement of the potential system is used. For all examples, both the iterative and direct solvers produce the same responses for the potentials, demonstrating the uniqueness of the numerical solution for the potentials and fixing the problems with the interface conditions between cells observed for the incomplete-gauged system. These solutions of the gauged system also

  16. Finite Element Modeling of CNS White Matter Kinematics: Use of a 3D RVE to Determine Material Properties.

    Science.gov (United States)

    Pan, Yi; Sullivan, Daniel; Shreiber, David I; Pelegri, Assimina A

    2013-01-01

    Axonal injury represents a critical target area for the prevention and treatment of traumatic brain and spinal cord injuries. Finite element (FE) models of the head and/or brain are often used to predict brain injury caused by external mechanical loadings, such as explosive waves and direct impact. The accuracy of these numerical models depends on correctly determining the material properties and on the precise depiction of the tissues' microstructure (microscopic level). Moreover, since the axonal microstructure for specific regions of the brain white matter is locally oriented, the stress, and strain fields are highly anisotropic and axon orientation dependent. Additionally, mechanical strain has been identified as the proximal cause of axonal injury, which further demonstrates the importance of this multi-scale relationship. In this study, our previously developed FE and kinematic axonal models are coupled and applied to a pseudo 3-dimensional representative volume element of central nervous system white matter to investigate the multi-scale mechanical behavior. An inverse FE procedure was developed to identify material parameters of spinal cord white matter by combining the results of uniaxial testing with FE modeling. A satisfactory balance between simulation and experiment was achieved via optimization by minimizing the squared error between the simulated and experimental force-stretch curve. The combination of experimental testing and FE analysis provides a useful analysis tool for soft biological tissues in general, and specifically enables evaluations of the axonal response to tissue-level loading and subsequent predictions of axonal damage.

  17. Cancer cell mechanics with altered cytoskeletal behavior and substrate effects: A 3D finite element modeling study.

    Science.gov (United States)

    Katti, Dinesh R; Katti, Kalpana S

    2017-12-01

    A robust computational model of a cancer cell is presented using finite element modeling. The model accurately captures nuances of the various components of the cellular substructure. The role of degradation of cytoskeleton on overall elastic properties of the cancer cell is reported. The motivation for degraded cancer cellular substructure, the cytoskeleton is the observation that the innate mechanics of cytoskeleton is disrupted by various anti-cancer drugs as therapeutic treatments for the destruction of the cancer tumors. We report a significant influence on the degradation of the cytoskeleton on the mechanics of cancer cell. Further, a simulations based study is reported where we evaluate mechanical properties of the cancer cell attached to a variety of substrates. The loading of the cancer cell is less influenced by nature of the substrate, but low modulus substrates such as osteoblasts and hydrogels indicate a significant change in unloading behavior and also the plastic deformation. Overall, softer substrates such as osteoblasts and other bone cells result in a much altered unloading response as well as significant plastic deformation. These substrates are relevant to metastasis wherein certain type of cancers such as prostate and breast cancer cells migrate to the bone and colonize through mesenchymal to epithelial transition. The modeling study presented here is an important first step in the development of strong predictive methodologies for cancer progression. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. A Comprehensive 3D Finite Element Model of a Thermoelectric Module Used in a Power Generator: A Transient Performance Perspective

    Science.gov (United States)

    Wu, Guangxi; Yu, Xiong

    2015-06-01

    Thermoelectric power generator has potential for small-scale and distributed power generation because of its high durability and scalability. It is very important to realize that the transient behavior of thermoelectric modules (TEM) affects a thermoelectric generator's response to dynamic working environments. Traditionally, researchers have used simplified models to describe the behavior of thermoelectric modules. In this paper we propose a comprehensive mathematical model that considers the effect of variations of chemical potential and carrier density, which are ignored by traditional models. Finite element models based on this new model are used to simulate the transient behavior of a thermoelectric module subjected to rapid changes in boundary temperature or working load. Simulation results show that transition times of thermoelectric modules affected by temperature change are much longer than those of modules affected by changes in electrical load resistance. Sudden changes in working temperature cause voltage overshoot of the TEM output, which, however, is not observed in responses to sudden changes of load resistance. Comparisons also show there are significant differences between the behavior of TEM predicted by use of this new comprehensive model and that predicted by use of traditional models, particularly for the high-temperature intrinsic ionization region and the low-temperature weak ionization region. This implies that chemical potential and carrier density variations, which are taken into account by this new model but ignored by traditional models, have major effects on the performance of TEM.

  19. Framework design of an anterior fiber-reinforced hybrid composite fixed partial denture: a 3D finite element study.

    Science.gov (United States)

    Yokoyama, Daiichiro; Shinya, Akikazu; Lassila, Lippo V J; Gomi, Harunori; Nakasone, Yuji; Vallittu, Pekka K; Shinya, Akiyoshi

    2009-01-01

    The aim of this study was to investigate the optimal design of a fiber-reinforced composite (FRC) framework to obtain the maximum reinforcement for fixed partial dentures (FPDs) under three different loading conditions using three-dimensional finite element (FE) analysis. materials and methods: A three-unit FPD replacing the maxillary right lateral incisor was constructed using FE analysis software (ANSYS 10.0, ANSYS). A fiber framework of the pontic was designed with three variations: with the main framework curved labially (FRC1), located in the center (FRC2), or curved lingually (FRC3). Each framework was compared with a hybrid composite FPD without any fiber reinforcement (C-FPD). A lateral load was applied to the three different loading points of the pontic 0 mm, 3 mm, and 6 mm from the incisal edge, each representing loading conditions 1, 2, and 3, respectively. Localized high stress concentration was observed around the connectors under all loading conditions. In all FRC-FPD models, the FRC framework showed stress-bearing capacity for the FPD. The highest stress reduction ratio under all loading conditions was obtained using the FRC1 model. The FRC1 framework also best reduced displacement of the framework. This study suggests that the optimum design of an FRC framework is to labially curve the FRC of the main framework at the region of the pontic.

  20. Stress analysis of a complete maxillary denture under various drop impact conditions: a 3D finite element study.

    Science.gov (United States)

    Sunbuloglu, Emin

    2015-01-01

    Complete maxillary dentures are one of the most economic and easy ways of treatment for edentulous patients and are still widely used. However, their survival rate is slightly above three years. It is presumed that the failure reasons are not only due to normal fatigue but also emerge from damage based on unavoidable improper usage. Failure types other than long-term fatigue, such as over-deforming, also influence the effective life span of dentures. A hypothesis is presumed, stating that the premature/unexpected failures may be initiated by impact on dentures, which can be related to dropping them on the ground or other effects such as biting crispy food. Thus, the behavior of a complete maxillary denture under impact loading due to drop on a rigid surface was investigated using the finite element method utilizing explicit time integration and a rate-sensitive elastoplastic material model of polymethylmethacrylate (PMMA). Local permanent deformations have been observed along with an emphasis on frenulum region of the denture, regardless of the point of impact. Contact stresses at the tooth-denture base were also investigated. The spread of energy within the structure via wave propagation is seen to play a critical role in this fact. Stress-wave propagation is also seen to be an important factor that decreases the denture's fatigue life.

  1. Calibration of 3D ALE finite element model from experiments on friction stir welding of lap joints

    Science.gov (United States)

    Fourment, Lionel; Gastebois, Sabrina; Dubourg, Laurent

    2016-10-01

    In order to support the design of such a complex process like Friction Stir Welding (FSW) for the aeronautic industry, numerical simulation software requires (1) developing an efficient and accurate Finite Element (F.E.) formulation that allows predicting welding defects, (2) properly modeling the thermo-mechanical complexity of the FSW process and (3) calibrating the F.E. model from accurate measurements from FSW experiments. This work uses a parallel ALE formulation developed in the Forge® F.E. code to model the different possible defects (flashes and worm holes), while pin and shoulder threads are modeled by a new friction law at the tool / material interface. FSW experiments require using a complex tool with scroll on shoulder, which is instrumented for providing sensitive thermal data close to the joint. Calibration of unknown material thermal coefficients, constitutive equations parameters and friction model from measured forces, torques and temperatures is carried out using two F.E. models, Eulerian and ALE, to reach a satisfactory agreement assessed by the proper sensitivity of the simulation to process parameters.

  2. Dynamic and static analysis of FGM skew plates with 3D elasticity based graded finite element modeling

    Directory of Open Access Journals (Sweden)

    Kamran Asemi

    Full Text Available The present article deals with static and dynamic behavior of functionally graded skew plates based on the three-dimensional theory of elasticity. On the basis of the principle of minimum potential energy and the Rayleigh Ritz method, the equations of motion are derived in conjunction with the graded finite element approach. Solution of the resulted system of equations in time domain is carried out via Newmark's time integration method. Calculations are applied for fully clamped boundary condition. In the present paper, two different sets of distributions for material properties are considered. For the static analysis, material properties are considered to vary through the thickness direction according to an exponential law. In the case of dynamic analysis, variations of the volume fractions through the thickness are assumed to obey a power law function. Thus, the effective material properties at each point are determined by the Mori-Tanaka scheme. In case of dynamic analysis, the results are obtained for uniform step loadings. The effects of material gradient index and skew angle on displacement components and stress response are studied. Results of present formulations are verified by available results of a functionally graded rectangular plate for different boundary conditions and also compared with result of a homogenous skew plate by commercial FEM software.

  3. 3D finite element simulation of temperature distribution, residual stress and distortion on 304 stainless steel plates using GTA welding

    Energy Technology Data Exchange (ETDEWEB)

    Venkatkumar, D.; Ravindran, D. [National Engineering College, Tamilnadu (India)

    2016-01-15

    In the present study, the distortion induced in rectangular plate of AISI 304 SS during autogenous GTA welding process is measured experimentally and further validated using Finite element (FE) analysis. The thermal histories are measured at fixed locations over the surface of the plate and the results are compared with FE analysis. The Gaussian surface and Volumetric heat source models are simulated and transient heat transfer analysis is performed. The heat source models have been tested with two different speeds. The effectiveness of change in thermal histories of the heat sources have been studied and reported. In FE analysis, the sequentially coupled thermomechanical analysis is performed using the thermal histories as input and the distortion of the plates are predicted and compared with experimental measurements. The large and small displacement theories are employed for the above purpose and the effectiveness of the theories are reported. The edge deformation of the plates have been measured and validated for both the theories. The residual stress and distortion at the mid span are predicted and discussed. The results predicted using large displacement theory is in good agreement with measured values.

  4. Analytical study of performance evaluation for seismic retrofitting of reinforced concrete building using 3D dynamic nonlinear finite element analysis

    Science.gov (United States)

    Sato, Yuichi; Kajihara, Shinichi; Kaneko, Yoshio

    2011-06-01

    This paper presents three-dimensional finite element (FE) analyses of an all-frame model of a three-story reinforced concrete (RC) building damaged in the 1999 Taiwan Chi-Chi Earthquake. Non-structural brick walls of the building acted as a seismic resistant element although their contributions were neglected in the design. Hence, the entire structure of a typical frame was modeled and static and dynamic nonlinear analyses were conducted to evaluate the contributions of the brick walls. However, the results of the analyses were considerably overestimated due to coarse mesh discretizations, which were unavoidable due to limited computer resources. This study corrects the overestimations by modifying (1) the tensile strengths and (2) shear stiffness reduction factors of concrete and brick. The results indicate that brick walls improve frame strength although shear failures are caused in columns shortened by spandrel walls. Then, the effectiveness of three types of seismic retrofits is evaluated. The maximum drift of the first floor is reduced by 89.3%, 94.8%, and 27.5% by Steel-confined, Full-RC, and Full-brick models, respectively. Finally, feasibility analyses of models with soils were conducted. The analyses indicated that the soils elongate the natural period of building models although no significant differences were observed.

  5. Investigating the Mechanical Function of the Cervix during Pregnancy using Finite Element Models derived from High Resolution 3D MRI

    Science.gov (United States)

    Fernandez, M.; House, M.; Jambawalikar, S.; Zork, N.; Vink, J.; Wapner, R.; Myers, K.

    2015-01-01

    Preterm birth is a strong contributor to perinatal mortality, and preterm infants that survive are at risk for long-term morbidities. During most of pregnancy appropriate mechanical function of the cervix is required to maintain the developing fetus in utero. Premature cervical softening and subsequent cervical shortening are hypothesized to cause preterm birth. Presently, there is a lack of understanding of the structural and material factors that influence the mechanical function of the cervix during pregnancy. In this study we build finite element (FE) models of the pregnant uterus, cervix, and fetal membrane based on magnetic resonance imagining (MRI) data in order to examine the mechanical function of the cervix under the physiologic loading conditions of pregnancy. We calculate the mechanical loading state of the cervix for two pregnant patients: 22 weeks gestational age with a normal cervical length and 28 weeks with a short cervix. We investigate the influence of 1) anatomical geometry 2) cervical material properties, and 3) fetal membrane material properties, including its adhesion properties, on the mechanical loading state of the cervix under physiologically relevant intrauterine pressures. Our study demonstrates that membrane-uterus interaction, cervical material modeling, and membrane mechanical properties are factors that must be deliberately and carefully handled in order to construct a high quality mechanical simulation of pregnancy. PMID:25970655

  6. Wakefield Simulation of CLIC PETS Structure Using Parallel 3D Finite Element Time-Domain Solver T3P

    CERN Document Server

    Candel, A; Lee, L; Li, Z; Ng, C; Schussman, G; Ko, K; Syratchev, I

    2010-01-01

    In re­cent years, SLAC's Ad­vanced Com­pu­ta­tions De­part­ment (ACD) has de­vel­oped the par­al­lel 3D Fi­nite El­e­ment elec­tro­mag­net­ic time-do­main code T3P. High­er-or­der Fi­nite El­e­ment meth­ods on con­for­mal un­struc­tured mesh­es and mas­sive­ly par­al­lel pro­cess­ing allow un­prece­dent­ed sim­u­la­tion ac­cu­ra­cy for wake­field com­pu­ta­tions and sim­u­la­tions of tran­sient ef­fects in re­al­is­tic ac­cel­er­a­tor struc­tures. Ap­pli­ca­tions in­clude sim­u­la­tion of wake­field damp­ing in the Com­pact Lin­ear Col­lid­er (CLIC) Power Ex­trac­tion and Trans­fer Struc­ture (PETS).

  7. Strain-rate sensitivity of foam materials: A numerical study using 3D image-based finite element model

    Directory of Open Access Journals (Sweden)

    Sun Yongle

    2015-01-01

    Full Text Available Realistic simulations are increasingly demanded to clarify the dynamic behaviour of foam materials, because, on one hand, the significant variability (e.g. 20% scatter band of foam properties and the lack of reliable dynamic test methods for foams bring particular difficulty to accurately evaluate the strain-rate sensitivity in experiments; while on the other hand numerical models based on idealised cell structures (e.g. Kelvin and Voronoi may not be sufficiently representative to capture the actual structural effect. To overcome these limitations, the strain-rate sensitivity of the compressive and tensile properties of closed-cell aluminium Alporas foam is investigated in this study by means of meso-scale realistic finite element (FE simulations. The FE modelling method based on X-ray computed tomography (CT image is introduced first, as well as its applications to foam materials. Then the compression and tension of Alporas foam at a wide variety of applied nominal strain-rates are simulated using FE model constructed from the actual cell geometry obtained from the CT image. The stain-rate sensitivity of compressive strength (collapse stress and tensile strength (0.2% offset yield point are evaluated when considering different cell-wall material properties. The numerical results show that the rate dependence of cell-wall material is the main cause of the strain-rate hardening of the compressive and tensile strengths at low and intermediate strain-rates. When the strain-rate is sufficiently high, shock compression is initiated, which significantly enhances the stress at the loading end and has complicated effect on the stress at the supporting end. The plastic tensile wave effect is evident at high strain-rates, but shock tension cannot develop in Alporas foam due to the softening associated with single fracture process zone occurring in tensile response. In all cases the micro inertia of individual cell walls subjected to localised deformation

  8. JAC3D -- A three-dimensional finite element computer program for the nonlinear quasi-static response of solids with the conjugate gradient method

    International Nuclear Information System (INIS)

    Biffle, J.H.

    1993-02-01

    JAC3D is a three-dimensional finite element program designed to solve quasi-static nonlinear mechanics problems. A set of continuum equations describes the nonlinear mechanics involving large rotation and strain. A nonlinear conjugate gradient method is used to solve the equation. The method is implemented in a three-dimensional setting with various methods for accelerating convergence. Sliding interface logic is also implemented. An eight-node Lagrangian uniform strain element is used with hourglass stiffness to control the zero-energy modes. This report documents the elastic and isothermal elastic-plastic material model. Other material models, documented elsewhere, are also available. The program is vectorized for efficient performance on Cray computers. Sample problems described are the bending of a thin beam, the rotation of a unit cube, and the pressurization and thermal loading of a hollow sphere

  9. Simulation of the enhancement factor from an individual 3D hemisphere-on-post field emitter by using finite elements method.

    Science.gov (United States)

    Roveri, D S; Sant'Anna, G M; Bertan, H H; Mologni, J F; Alves, M A R; Braga, E S

    2016-01-01

    This paper presents a 3D computational framework for evaluating electrostatic properties of a single field emitter characterized by the hemisphere-on-post geometry. Numerical simulations employed the finite elements method by using Ansys-Maxwell software. Extensive parametric simulations were focused on the threshold distance from which the emitter field enhancement factor (γ) becomes independent from the anode-substrate gap (G). This investigation allowed demonstrating that the ratio between G and the emitter height (h) is a reliable reference for a broad range of emitter dimensions; furthermore, results permitted establishing G/h ≥ 2.2 as the threshold condition for setting the anode without affecting γ. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Biomechanical Assessment of Restored Mandibular Molar by Endocrown in Comparison to a Glass Fiber Post-Retained Conventional Crown: 3D Finite Element Analysis.

    Science.gov (United States)

    Helal, Mohammed Abu; Wang, Zhigang

    2017-10-25

    To compare equivalent and contact stresses in a mandibular molar restored by all-ceramic crowns through two methods: ceramic endocrowns and ceramic crowns supported by fiber-reinforced composite (FRC) posts and core, by using 3D finite element analysis during normal masticatory load. Three 3D models of a mandibular first molar were made and labeled as such: intact molar with no restoration (A); ceramic endocrown-restored molar (B); ceramic crown supported by FRC posts and core restored molar (C). By using 3D FE analysis with contact components, normal masticatory load was simulated. The mvM stresses in all models were calculated. Maximal mvM stresses in the ceramic of restorations, dentin, and luting cement were contrasted among models and to values of materials' strength. Contact shear and tensile stresses in the restoration/tooth interface around restorations were also calculated. The highest mvM stress levels in the enamel and dentin for the tooth restored by ceramic endocrown were lower in the crown ceramic than in tooth restored with FRC posts and all-ceramic crowns; however, in the resin adhesive cement interface it was lower for ceramic crown supported by FRC posts than the in ceramic endocrown restoration. The maximum contact shear and tensile stress values along the restoration/tooth interface of ceramic endocrowns were lower than those with ceramic crowns supported by FRC posts. Ceramic endocrown restorations presented a lower mvM stress level in dentin than the conventional ceramic crowns supported by FRC posts and core. Ceramic endocrown restorations in molars are less susceptible to damage than those with conventional ceramic crowns retained by FRC posts. Ceramic endocrowns properly cemented in molars must not be fractured or loosen during normal masticatory load. Therefore, ceramic endocrowns are advised as practicable, minimally invasive, and esthetic restorations for root canal treated mandibular molars. © 2017 by the American College of

  11. A line-by-line hybrid unstructured finite volume/Monte Carlo method for radiation transfer in 3D non-gray medium

    Science.gov (United States)

    Sun, Hai-Feng; Sun, Feng-Xian; Xia, Xin-Lin

    2018-01-01

    A hybrid method combing the unstructured finite volume method and the Monte Carlo method and incorporating the line-by-line model has been developed to simulate the radiative transfer in highly spectral and inhomogeneous medium. In this method, the unstructured finite volume method is adopted to solve the spectral radiative transfer equation at wave numbers or spectral locations determined by the Monte Carlo method. The Monte Carlo method takes effects by firstly defining the monotonic random number relations corresponding to the spectral emitted power density of every discretized element of the concerning medium, and then by reversing the spectral location through comparison of these relations with predefined random numbers. Through this Monte Carlo method, the actual number of spectral locations on which the spectral radiative transfer equations are solved may be reduced: only the spectral locations that have higher spectral emissive powers would be more possibly selected. To increase the performance of the presented method, the total variation diminishing scheme on unstructured grids is adopted in treating the spectral radiative intensity at interface between control volumes. And, the discretized radiative transfer equation is implicitly and iteratively solved by an algebraic multi-grid solution approach to accelerate the convergence of the equation. The presented method was applied to 3D homogeneous and inhomogeneous cases for the validation and performance studies. Results show that for both cases, the presented method agree well with pure Monte Carlo benchmark solutions with acceptable number of spectral locations and computing time.

  12. Dynamic pulse buckling of cylindrical shells under axial impact: A comparison of 2D and 3D finite element calculations with experimental data

    International Nuclear Information System (INIS)

    Hoffman, E.L.; Ammerman, D.J.

    1995-04-01

    A series of tests investigating dynamic pulse buckling of a cylindrical shell under axial impact is compared to several 2D and 3D finite element simulations of the event. The purpose of the work is to investigate the performance of various analysis codes and element types on a problem which is applicable to radioactive material transport packages, and ultimately to develop a benchmark problem to qualify finite element analysis codes for the transport package design industry. Four axial impact tests were performed on 4 in-diameter, 8 in-long, 304 L stainless steel cylinders with a 3/16 in wall thickness. The cylinders were struck by a 597 lb mass with an impact velocity ranging from 42.2 to 45.1 ft/sec. During the impact event, a buckle formed at each end of the cylinder, and one of the two buckles became unstable and collapsed. The instability occurred at the top of the cylinder in three tests and at the bottom in one test. Numerical simulations of the test were performed using the following codes and element types: PRONTO2D with axisymmetric four-node quadrilaterals; PRONTO3D with both four-node shells and eight-node hexahedrons; and ABAQUS/Explicit with axisymmetric two-node shells and four-node quadrilaterals, and 3D four-node shells and eight-node hexahedrons. All of the calculations are compared to the tests with respect to deformed shape and impact load history. As in the tests, the location of the instability is not consistent in all of the calculations. However, the calculations show good agreement with impact load measurements with the exception of an initial load spike which is proven to be the dynamic response of the load cell to the impact. Finally, the PRONIT02D calculation is compared to the tests with respect to strain and acceleration histories. Accelerometer data exhibited good qualitative agreement with the calculations. The strain comparisons show that measurements are very sensitive to gage placement

  13. Patient-specific geometrical modeling of orthopedic structures with high efficiency and accuracy for finite element modeling and 3D printing.

    Science.gov (United States)

    Huang, Huajun; Xiang, Chunling; Zeng, Canjun; Ouyang, Hanbin; Wong, Kelvin Kian Loong; Huang, Wenhua

    2015-12-01

    We improved the geometrical modeling procedure for fast and accurate reconstruction of orthopedic structures. This procedure consists of medical image segmentation, three-dimensional geometrical reconstruction, and assignment of material properties. The patient-specific orthopedic structures reconstructed by this improved procedure can be used in the virtual surgical planning, 3D printing of real orthopedic structures and finite element analysis. A conventional modeling consists of: image segmentation, geometrical reconstruction, mesh generation, and assignment of material properties. The present study modified the conventional method to enhance software operating procedures. Patient's CT images of different bones were acquired and subsequently reconstructed to give models. The reconstruction procedures were three-dimensional image segmentation, modification of the edge length and quantity of meshes, and the assignment of material properties according to the intensity of gravy value. We compared the performance of our procedures to the conventional procedures modeling in terms of software operating time, success rate and mesh quality. Our proposed framework has the following improvements in the geometrical modeling: (1) processing time: (femur: 87.16 ± 5.90 %; pelvis: 80.16 ± 7.67 %; thoracic vertebra: 17.81 ± 4.36 %; P modeling requires less operating time and workload, but the orthopedic structures were generated at a higher rate of success as compared with the conventional method. It is expected to benefit the surgical planning of orthopedic structures with less operating time and high accuracy of modeling.

  14. Comparison between Experimental and 3D Finite Element Analysis of Reinforced and Partially Pre-Stressed Concrete Solid Beams Subjected to Combined Load of Bending, Torsion and Shear

    Directory of Open Access Journals (Sweden)

    A. S. Alnuaimi

    2008-12-01

    Full Text Available This paper presents a non-linear analysis of three reinforced and two partially prestressed concrete solid beams based on a 20 node isoparametric element using an in-house 3D finite element program. Anon linear elastic isotropic model, proposed by Kotsovos, was used to model concrete behaviour, while steel was modelled as an embedded element exhibiting elastic-perfectly plastic response. Allowance was made for shear retention and for tension stiffening in concrete after cracking. Only in a fixed direction, smeared cracking modelling was adopted. The beams dimensions were 300x300 mm cross section, 3800 mm length and were subjected to combined bending, torsion and shear. Experimental results were compared with the non-linear predictions. The comparison was judged by load displacement relationship, steel strain, angle of twist, failure load, crack pattern and mode of failure. Good agreement was observed between the predicted ultimate load and the experimentally measured loads. It was concluded that the present program can confidently be used to predict the behaviour and failure load of reinforced and partially prestressed concrete solid beams subjected to a combined load of bending, torsion and shear.

  15. An Efficient Framework For Fast Computer Aided Design of Microwave Circuits Based on the Higher-Order 3D Finite-Element Method

    Directory of Open Access Journals (Sweden)

    A. Lamecki

    2014-12-01

    Full Text Available In this paper, an efficient computational framework for the full-wave design by optimization of complex microwave passive devices, such as antennas, filters, and multiplexers, is described. The framework consists of a computational engine, a 3D object modeler, and a graphical user interface. The computational engine, which is based on a finite element method with curvilinear higher-order tetrahedral elements, is coupled with built-in or external gradient-based optimization procedures. For speed, a model order reduction technique is used and the gradient computation is achieved by perturbation with geometry deformation, processed on the level of the individual mesh nodes. To maximize performance, the framework is targeted to multicore CPU architectures and its extended version can also use multiple GPUs. To illustrate the accuracy and high efficiency of the framework, we provide examples of simulations of a dielectric resonator antenna and full-wave design by optimization of two diplexers involving tens of unknowns, and show that the design can be completed within the duration of a few simulations using industry-standard FEM solvers. The accuracy of the design is confirmed by measurements.

  16. A 3D finite element model of prophylactic vertebroplasty in the metastatic spine: Vertebral stability and stress distribution on adjacent vertebrae.

    Science.gov (United States)

    Berton, Alessandra; Salvatore, Giuseppe; Giambini, Hugo; Ciuffreda, Mauro; Longo, Umile Giuseppe; Denaro, Vincenzo; Thoreson, Andrew; An, Kai-Nan

    2018-02-15

    Background and Objective Patients with metastatically compromised vertebra can experience pathologic fracture with relevant neurological complications. Vertebroplasty is a low cost procedure and it can potentially prevent neurologic impairment if performed at an early stage. The aim of this study is to evaluate the effects of prophylactic vertebroplasty on stability of the metastatic spine and analyze load distribution at adjacent vertebrae. Setting A 3D finite element model of two spinal motion segments (L3-L5) was developed. A central core of elements was selected in L4 vertebral body and material properties of a lytic metastasis and successively PMMA were assigned. The model was settled in order to simulate a non-osteoporotic spine and an osteoporotic spine. Outcome Measures Vertebral stability was assessed by the measurement of vertebral bulge (VB) and vertebral height (VH) on L4. Load transfer on adjacent vertebrae was evaluated by observing the distribution of the von Mises stress on L3 and L5 endplates. Results The metastasis increased VB by 424% and VH by 626%, while prophylactic vertebroplasty decreased VB and VH by 99% and 95%, respectively, when compared to the normal/non-metastatic model. Prophylactic vertebroplasty increased the average von Mises stress of L3 lower endplate by 1.33% in the non-osteoporotic spine, while it increased to 16% in the osteoporotic model. Conclusions Prophylactic vertebroplasty could represent an interesting option to improve vertebral strength of metastatically compromised spine without excessively increasing the stresses on adjacent vertebrae in non-osteoporotic spine.

  17. Simulation of hip fracture in sideways fall using a 3D finite element model of pelvis-femur-soft tissue complex with simplified representation of whole body.

    Science.gov (United States)

    Majumder, Santanu; Roychowdhury, Amit; Pal, Subrata

    2007-12-01

    Hip fractures due to sideways falls are a worldwide health problem, especially among the elderly population. The objective of this study was to simulate a real life sideways fall leading to hip fracture. To achieve this a computed tomography (CT) scan based three-dimensional (3D) finite element (FE) model of the pelvis-femur complex was developed using a wide range of mechanical properties in the bone of the complex. For impact absorption through large deformation, surrounding soft tissue was also included in the FE model from CT scan data. To incorporate the inertia effect, the whole body was represented by a spring-mass-dashpot system. For trochanteric soft tissue thickness of 14 mm, body weight of 77.47 kg and average hip impact velocity of 3.17 m/s, this detailed FE model could approximately simulate a sideways fall configuration and examine femoral fracture situation. At the contact surface, the peak impact load was 8331 N. In spite of the presence of 14 mm thick trochanteric soft tissue, within the trochanteric zone the most compressive peak principal strain was 3.5% which exceeds ultimate compressive strain. The modeled trochanteric fracture was consistent with clinical findings and with the findings of previous studies. Further, this detailed FE model may be used to find the effect of trochanteric soft tissue thickness variations on peak impact force, peak strain in sideways fall, and to simulate automobile side impact and backward fall situations.

  18. A comparison of 1D analytical model and 3D finite element analysis with experiments for a rosen-type piezoelectric transformer.

    Science.gov (United States)

    Boukazouha, F; Poulin-Vittrant, G; Tran-Huu-Hue, L P; Bavencoffe, M; Boubenider, F; Rguiti, M; Lethiecq, M

    2015-07-01

    This article is dedicated to the study of Piezoelectric Transformers (PTs), which offer promising solutions to the increasing need for integrated power electronics modules within autonomous systems. The advantages offered by such transformers include: immunity to electromagnetic disturbances; ease of miniaturisation for example, using conventional micro fabrication processes; and enhanced performance in terms of voltage gain and power efficiency. Central to the adequate description of such transformers is the need for complex analytical modeling tools, especially if one is attempting to include combined contributions due to (i) mechanical phenomena owing to the different propagation modes which differ at the primary and secondary sides of the PT; and (ii) electrical phenomena such as the voltage gain and power efficiency, which depend on the electrical load. The present work demonstrates an original one-dimensional (1D) analytical model, dedicated to a Rosen-type PT and simulation results are successively compared against that of a three-dimensional (3D) Finite Element Analysis (COMSOL Multiphysics software) and experimental results. The Rosen-type PT studied here is based on a single layer soft PZT (P191) with corresponding dimensions 18 mm × 3 mm × 1.5 mm, which operated at the second harmonic of 176 kHz. Detailed simulational and experimental results show that the presented 1D model predicts experimental measurements to within less than 10% error of the voltage gain at the second and third resonance frequency modes. Adjustment of the analytical model parameters is found to decrease errors relative to experimental voltage gain to within 1%, whilst a 2.5% error on the output admittance magnitude at the second resonance mode were obtained. Relying on the unique assumption of one-dimensionality, the present analytical model appears as a useful tool for Rosen-type PT design and behavior understanding. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. A 3D finite element-based model order reduction method for parametric resonance and whirling analysis of anisotropic rotor-bearing systems

    Science.gov (United States)

    Wang, Shuai; Wang, Yu; Zi, Yanyang; He, Zhengjia

    2015-12-01

    A generalized and efficient model for rotating anisotropic rotor-bearing systems is presented in this paper with full considerations of the system's anisotropy in stiffness, inertia and damping. Based on the 3D finite element model and the model order reduction method, the effects of anisotropy in shaft and bearings on the forced response and whirling of anisotropic rotor-bearing systems are systematically investigated. First, the coefficients of journal bearings are transformed from the fixed frame to the rotating one. Due to the anisotropy in shaft and bearings, the motion is governed by differential equations with periodically time-variant coefficients. Then, a free-interface complex component mode synthesis (CMS) method is employed to generate efficient reduced-order models (ROM) for the periodically time-variant systems. In order to solve the obtained equations, a variant of Hill's method for systems with multiple harmonic excitations is developed. Four dimensionless parameters are defined to quantify the types and levels of anisotropy of bearings. Finally, the effects of the four types of anisotropy on the forced response and whirl orbits are studied. Numerical results show that the anisotropy of bearings in stiffness splits the sole resonant peak into two isolated ones, but the anisotropy of bearings in damping coefficients mainly affect the response amplitudes. Moreover, the whirl orbits become much more complex when the shaft and bearings are both anisotropic. In addition, the cross-coupling stiffness coefficients of bearings significantly affect the dynamic behaviors of the systems and cannot be neglected, though they are often much smaller than the principle stiffness terms.

  20. Effect of type of luting agents on stress distribution in the bone surrounding implants supporting a three-unit fixed dental prosthesis: 3D finite element analysis

    Science.gov (United States)

    Ghasemi, Ehsan; Abedian, Alireza; Iranmanesh, Pedram; Khazaei, Saber

    2015-01-01

    Background: Osseointegration of dental implants is influenced by many biomechanical factors that may be related to stress distribution. The aim of this study was to evaluate the effect of type of luting agent on stress distribution in the bone surrounding implants, which support a three-unit fixed dental prosthesis (FDP) using finite element (FE) analysis. Materials and Methods: A 3D FE model of a three-unit FDP was designed replacing the maxillary first molar with maxillary second premolar and second molar as the abutments using CATIA V5R18 software and analyzed with ABAQUS/CAE 6.6 version. The model was consisted of 465108 nodes and 86296 elements and the luting agent thickness was considered 25 μm. Three load conditions were applied on eight points in each functional cusp in horizontal (57.0 N), vertical (200.0 N) and oblique (400.0 N, θ = 120°) directions. Five different luting agents were evaluated. All materials were assumed to be linear elastic, homogeneous, time independent and isotropic. Results: For all luting agent types, the stress distribution pattern in the cortical bone, connectors, implant and abutment regions was almost uniform among the three loads. Furthermore, the maximum von Mises stress of the cortical bone was at the palatal side of second premolar. Likewise, the maximum von Mises stress in the connector region was in the top and bottom of this part. Conclusion: Luting agents transfer the load to cortical bone and different types of luting agents do not affect the pattern of load transfer. PMID:25709676

  1. 2D and 3D transonic flow computation using finite volume method and model of Euler and Navier-Stokes equations

    Energy Technology Data Exchange (ETDEWEB)

    Fialova, M.; Fuerst, J.; Horak, J.; Kozel, K. [Czech Technical Univ., Faculty of Mechanical Engineering, Dept. of Technical Mathematics, Prague (Czech Republic)

    1997-12-31

    The work deals with numerical solution of 2D and 3D transonic flows using mathematical models of Euler and Navier-Stokes equations. For inviscid flows with a shock wave we tested modern TVD upwind and central methods. For computations of 2D and 3D compressible viscous laminar flows multistage Runge-Kutta methods were used. (orig.)

  2. A benchmark study of 2D and 3D finite element calculations simulating dynamic pulse buckling tests of cylindrical shells under axial impact

    International Nuclear Information System (INIS)

    Hoffman, E.L.; Ammerman, D.J.

    1993-01-01

    A series of tests investigating dynamic pulse buckling of a cylindrical shell under axial impact is compared to several finite element simulations of the event. The purpose of the study is to compare the performance of the various analysis codes and element types with respect to a problem which is applicable to radioactive material transport packages, and ultimately to develop a benchmark problem to qualify finite element analysis codes for the transport package design industry

  3. Influence of the worn tool affected by built-up edge (BUE) on micro end-milling process performance: A 3D finite element modeling investigation

    DEFF Research Database (Denmark)

    Davoudinejad, Ali; Tosello, Guido; Annoni, Massimiliano

    2017-01-01

    for the micro end-milling process of Aluminum material (Al6082-T6). 3D FEM simulations are carried out in full slot micro end-milling and contour up milling. The model first implements the actual tool geometry and then the effect of typical built-up edge (BUE) on the milling tool. The influence of BUE...

  4. Computation of the flash-temperature at the wheel-rail contact using a 3D finite element model and its comparison with analytical methods

    NARCIS (Netherlands)

    Naeimi, M.; Li, Z.; Dollevoet, R.P.B.J.; Wu, J.; Petrov, R.H.; Sietsma, J.

    2015-01-01

    The coupled mechanical–thermal behaviour of wheel and rail materials under rolling contact is studied to determine the temperature rise due to the frictional heat. The wheel–rail frictional rolling contact problem is solved using the three–dimensional finite element (FE) method. The FE model

  5. Trade-off between seismic source detail and crustal heterogeneities in spherical 3D finite element modeling: a 2004 Sumatra earthquake case study

    Directory of Open Access Journals (Sweden)

    Antonio Piersanti

    2011-04-01

    Full Text Available Finite-element methods are a powerful numerical simulation tool for modeling seismic events, as they allow three-dimensional complex models to be solved. We used a three-dimensional finite-element approach to evaluate the co-seismic displacement field produced by the devastating 2004 Sumatra–Andaman earthquake, which caused permanent deformations that were recorded by continuously operating GPS networks in a region of unprecedented area. Previous analysis of the static displacement fields have focused on the heterogeneous distribution of moment release on the fault plane; our intention here is to investigate how much the presence of crustal heterogeneities trades-off seismic source details. To achieve this aim, we adopted a quite simple source model in modeling the event. The key feature of our analysis is the generation of a complex three-dimensional spherical domain. Moreover, we also carried out an accurate analysis concerning the boundary conditions, which are crucial for finite-element simulations.

  6. The Sound Attenuation Coefficient Optimization in Case of a Three Parameter Impedance Model for a Rectangular 3D Straight Lined Duct of Finite Dimensions

    Directory of Open Access Journals (Sweden)

    Stefan BALINT

    2015-09-01

    Full Text Available A method for the minimization of the ratio of the sound pressure level at the exit to that at the entrance is presented for a rectangular 3D straight lined duct carrying a uniform gas flow. The duct dimensions, the incident sound wave as well as the frequency of the sound wave propagation are assumed to be known. It is assumed also that the liner impedance model is the mass-spring–damper model. The idea is to compute the considered ratio for a large number of combinations of the values of the inertance, resistance and stiffness of the liner and, by fitting the obtained data, to establish a formula for the dependence of the ratio in discussion on these three parameters of the liner. Using the obtained formula, the minimum value of the ratio, as well as the values of the inertance, resistance and stiffness, for which the minimum is obtained, are found.

  7. A 3-D Finite Element Analytical Study to Evaluate the Effects of Newer Variable Implant Thread Pattern in Different Bone Densities

    Directory of Open Access Journals (Sweden)

    Abhijeet Ramchandra Kore

    2017-10-01

    Full Text Available Introduction: Success of dental implant treatment depends on number of patient related and procedure dependent parameters. Various studies have shown that bone quality and implant design are two important factors in the success of dental implant treatment. Today, many implant systems are coming up with variable thread patterns. There is not much literature available on the effects of such variable thread patterns within different bone densities. Aim: The study was conducted to evaluate the effect of two different implant thread patterns in two different bone densities using three dimensional finite element analyses. Materials and Methods: A three-dimensional finite element model of a mandibular section of bone and an implant was developed. 4.2x12 mm screw type dental implants with two different thread designs (buttress thread design and variable thread design and a metal ceramic crown using Co-Cr and feldspathic porcelain were modelled. The model was developed with finite element software and two types of bone qualities were prepared (D2 and D4. A load of 450 N was applied in a vertical direction and in an oblique direction to the central fossa, buccal cusp and distal fossa of the mandibular first molar crown. Results: For the variable thread design, von Mises stresses developed within bone were 109.89 MPa and 257.46 MPa for vertical and oblique loading respectively, in D2 type of bone. While in D4, the stresses were 243.91 MPa and 371.81 MPa for vertical and oblique loading respectively. Similarly, for buttress thread design, stresses were 113.51 MPa and 176.14 MPa for vertical and oblique loading respectively in D2 type of bone; while in D4 type of bone the stresses were 290.99 MPa and 481.27 MPa respectively within the bone. Conclusion: The results of the present study showed that the von Mises stresses were more in D4 type of bone as compared to D2 type of bone for both, the variable and buttress thread designs. The study also compared the

  8. Finite Element Modeling in 3D of the Impact of Superfluid Helium Filled Micro-channels on the Heat Transfer through LHC Type Cable Insulation

    CERN Document Server

    Bielert, E; ten Kate, H

    2012-01-01

    For a future luminosity upgrade of CERN’s Large Hadron Collider, a drastically improved heat removal in the inner triplet quadrupole magnets is required. One of the necessary improvements involves the cable insulation. A porous all-polyimide insulation scheme has been proposed recently. Essentially the insulation features a network of micro channels filled with superfluid helium that significantly increases the heat transfer through the insulation layer. A three dimensional Finite Element model required to simulate and study the enhanced heat transfer through the micro channels is presented here. The thermal coupling between heated cable and helium as well as the heat flux through the micro-channels are investigated. The model is validated by comparison of results with published measured data. Finally a sensitivity analysis is performed concerning the stability of the cables in magnet windings.

  9. Advancement of the Eddy Current Testing using neural network technique. Development of 3-D finite element analysis sytem of elctro-magnetic field

    International Nuclear Information System (INIS)

    Sakai, Takayuki; Soneda, Naoki

    1994-01-01

    In PWR plants, an automatic recognition system of Eddy Current Testing (ECT) signals of steam generator tubes are strongly required to reduce inspectors' labor and to improve the reliability of the testing. Although the neural-network technique is very promising for this kind of system, it is necessary to evaluate its applicability to ECT signals throughly, where a database of the relationship of the defects and ECT signals plays a very important role. In this paper, a three dimensional finite element analysis system of electromagnetic field, which consists of an FEM code and pre/post processor, is developed to generate a database of ECT signals. T-Ω method and the edge element are employed in the FEM code to reduce the required computer memory. The code is verified through some comparisons with experiments and other calculations. (author)

  10. A 3D Finite-Difference BiCG Iterative Solver with the Fourier-Jacobi Preconditioner for the Anisotropic EIT/EEG Forward Problem

    Directory of Open Access Journals (Sweden)

    Sergei Turovets

    2014-01-01

    Full Text Available The Electrical Impedance Tomography (EIT and electroencephalography (EEG forward problems in anisotropic inhomogeneous media like the human head belongs to the class of the three-dimensional boundary value problems for elliptic equations with mixed derivatives. We introduce and explore the performance of several new promising numerical techniques, which seem to be more suitable for solving these problems. The proposed numerical schemes combine the fictitious domain approach together with the finite-difference method and the optimally preconditioned Conjugate Gradient- (CG- type iterative method for treatment of the discrete model. The numerical scheme includes the standard operations of summation and multiplication of sparse matrices and vector, as well as FFT, making it easy to implement and eligible for the effective parallel implementation. Some typical use cases for the EIT/EEG problems are considered demonstrating high efficiency of the proposed numerical technique.

  11. Comparative evaluation of stresses in tooth implant connected fixed partial denture by varying the implant design and position: A 3D finite element study

    Directory of Open Access Journals (Sweden)

    K V Pratheep

    2013-01-01

    Full Text Available Aim: This study aims at evaluating stresses generated in a fixed tooth to implant connected fixed partial denture (FPD by finite element method by varying implant design and position, in unilateral distal extension cases, i.e. for replacing mandibular 1 st and 2 nd molars. Materials and Methods: Four models were created, Model 1-A finite element model (FEA model of a crestal implant-tooth connected metal ceramic FPD with pontic in 36 region. The 35 region simulated the second premolar. Model 2-A FEA model of a basal implant-tooth connected metal ceramic FPD. Model 3-A FEA model of a crestal implant in 36 region connected to tooth 35 and cantilevered posteriorly with pontic in 37 region, made of metal ceramic. Model 4-A FEA model of a basal implant in 36 region connected to tooth 35 and cantilevered posteriorly with pontic in 37 region, made of metal ceramic. A vertical force of 100N directed evenly on the nodes on the occlusal surface of each of the three crowns. The models displayed stress both numerically and by color coding. Results: On comparing models 1 and 2, the model 1 showed comparatively more stresses in crestal bone area of the implant. On comparing models 3 and 4, model 3 showed lesser von misses stress values. Conclusion: In case of tooth implant connected FPDs without any cantilevers, basal implants show better stress distribution when compared to crestal implants. In case of cantilever designs, crestal implant design showed lower stress values, but the difference in stresses were less.

  12. Form finding and analysis of extensible membranes attached to 2-D and 3-D frames intended for micro air vehicles via experimentally validated finite element methods

    Science.gov (United States)

    Abudaram, Yaakov Jack

    This work is concerned with a new method to apply consistent and known pretension to silicone rubber membranes intended for micro air vehicles as well as an understanding in the science of developed pre-tension in membranes constrained by 2- D and 3-D frames and structures. Pre-tension has a marked effect on the static and dynamic response of membrane wings and controls the overall deflections, as such control and measurement of the membrane pre-tension is important. Two different 2-D frame geometries were fabricated to evaluate the technique. For open-cell frames, the pretension was not uniform, whereas it was for closed-cell frames. Results show developed full-field stress and strain fields as a function of membrane attachment temperature and frame geometry along with experimental iterations to prove repeatability. The membranes can be stretched to a specific pretension according to the temperature at which it adheres to frames. Strain fields in membranes attached to 3-D frames at various temperatures are modeled through FEA utilizing Abaqus to be able to predict the developed membrane deformations, stresses, and strains. Rigid frames with various curvatures are built via appropriate molds and then adhered to silicone rubber membranes and elevated to various temperatures to achieve different pre-strains for experimental validation. Additional experiments are conducted for more complex frame geometries involving both convex and concave topologies embedded within frames. Results are then compared with the Abaqus outputs to validate the accuracy of the FEA model. Highly compliant wings have been used for MAV platforms, where the wing structure is determined by some combination of carbon fiber composites and a membrane skin, adhered in between the layers of composite material. Another new technique of attaching membranes firmly on wing structures is introduced, which involves the application of a technology known as corona treatment coupled with another method of

  13. Effect of attachment types and number of implants supporting mandibular overdentures on stress distribution: a computed tomography-based 3D finite element analysis.

    Science.gov (United States)

    Arat Bilhan, Selda; Baykasoglu, Cengiz; Bilhan, Hakan; Kutay, Omer; Mugan, Ata

    2015-01-02

    The objective of this study was to calculate stresses in bone tissue surrounding uncoupled and splinted implants that are induced by a bite force applied to the mandible and to determine whether the number of mandibular overdenture supporting implants in mandibular bone influence the stress distribution. A human adult edentulous mandible retrieved from a formalin fixed cadaver was used to define the geometry of finite element (FE) model and the FE model was verified with experimental measurements. Following the FE model validation, three different biting situations were simulated for the 2-, 3- and 4-implant retentive anchor as well as bar attachment overdentures under vertical loading of 100 N. As a result of the analyses, it was concluded that an increment in implant number and the splinted attachment type tended to cause lower stresses and the use of two single attachments seems to be a safe and sufficient solution for the treatment of mandibular edentulism with overdentures. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Influence of Implant Position on Stress Distribution in Implant-Assisted Distal Extension Removable Partial Dentures: A 3D Finite Element Analysis.

    Directory of Open Access Journals (Sweden)

    Yeganeh Memari

    2014-10-01

    Full Text Available Distal extension removable partial denture is a prosthesis with lack of distal dental support with a 13-fold difference in resiliency between the mucosa and the periodontal ligament, resulting in leverage during compression forces. It may be potentially destructive to the abutments and the surrounding tissues. The aim of this study was to assess the effect of implant location on stress distribution, in distal extension implant assisted removable partial dentures.Three-dimensional models of a bilateral distal extension partially edentulous mandible containing anterior teeth and first premolar in both sides of the arch, a partial removable denture and an implant (4×10mm were designed. With the aid of the finite element program ANSYS 8.0, the models were meshed and strictly vertical forces of 10 N were applied to each cusp tip. Displacement and von Mises Maps were plotted for visualization of results.When an implant was placed in the second premolar region, the highest stress on implant, abutment tooth and cancellous bone was shown. The lowest stress was shown on implant and bone in the 1(st molar area.Implants located in the first molar area showed the least distribution of stresses in the analyzed models.

  15. Influence of Implant Position on Stress Distribution in Implant-Assisted Distal Extension Removable Partial Dentures: A 3D Finite Element Analysis.

    Science.gov (United States)

    Memari, Yeganeh; Geramy, Allahyar; Fayaz, Amir; Rezvani Habib Abadi, Shirin; Mansouri, Yasaman

    2014-09-01

    Distal extension removable partial denture is a prosthesis with lack of distal dental support with a 13-fold difference in resiliency between the mucosa and the periodontal ligament, resulting in leverage during compression forces. It may be potentially destructive to the abutments and the surrounding tissues. The aim of this study was to assess the effect of implant location on stress distribution, in distal extension implant assisted removable partial dentures. Three-dimensional models of a bilateral distal extension partially edentulous mandible containing anterior teeth and first premolar in both sides of the arch, a partial removable denture and an implant (4×10mm) were designed. With the aid of the finite element program ANSYS 8.0, the models were meshed and strictly vertical forces of 10 N were applied to each cusp tip. Displacement and von Mises Maps were plotted for visualization of results. When an implant was placed in the second premolar region, the highest stress on implant, abutment tooth and cancellous bone was shown. The lowest stress was shown on implant and bone in the 1(st) molar area. Implants located in the first molar area showed the least distribution of stresses in the analyzed models.

  16. Effect of Dynamic Center Region on the Flow and Mixing Efficiency in a New Tri-Screw Extruder Using 3D Finite Element Modeling

    Directory of Open Access Journals (Sweden)

    X. Z. Zhu

    2013-01-01

    Full Text Available Three-dimensional finite element modeling of polymer melt flowing in a new co-rotating tri-screw extruder was established with mesh superposition technique. Based on the particle tracking technology, three typical particle trajectories in the tri-screw extruder were calculated using a 4th-order-Runge-Kutta method to study the dynamic motions of the particles. Then the flow visualizations in the local center region were carried out. Moreover, the dispersive, distributive and stretching mixing efficiencies of the tri-screw and twin-screw extruders were compared, respectively. The results show that when the particles move from one screw to another, there are great abrupt changes in the velocities and displacements, which induce the abrupt change in the stress magnitude. Most of particles, which are initially distributed in the inlet plane of the center region, fast flow out the outlet and don’t pass through any screw. This special phenomenon induces a series of new characteristics in the residence time distribution (RTD, flow number, segregation scale and time averaged efficiency. In comparison with the twin-screw extruder, the tri-screw extruder has better mixing efficiency.

  17. A Novel Rat Model of Orthodontic Tooth Movement Using Temporary Skeletal Anchorage Devices: 3D Finite Element Analysis and In Vivo Validation

    Directory of Open Access Journals (Sweden)

    Neelambar Kaipatur

    2014-01-01

    Full Text Available The aim of this animal study was to develop a model of orthodontic tooth movement using a microimplant as a TSAD in rodents. A finite element model of the TSAD in alveolar bone was built using μCT images of rat maxilla to determine the von Mises stresses and displacement in the alveolar bone surrounding the TSAD. For in vivo validation of the FE model, Sprague-Dawley rats (n=25 were used and a Stryker 1.2 × 3 mm microimplant was inserted in the right maxilla and used to protract the right first permanent molar using a NiTi closed coil spring. Tooth movement measurements were taken at baseline, 4 and 8 weeks. At 8 weeks, animals were euthanized and tissues were analyzed by histology and EPMA. FE modeling showed maximum von Mises stress of 45 Mpa near the apex of TSAD but the average von Mises stress was under 25 Mpa. Appreciable tooth movement of 0.62 ± 0.04 mm at 4 weeks and 1.99 ± 0.14 mm at 8 weeks was obtained. Histological and EPMA results demonstrated no active bone remodeling around the TSAD at 8 weeks depicting good secondary stability. This study provided evidence that protracted tooth movement is achieved in small animals using TSADs.

  18. A Novel Rat Model of Orthodontic Tooth Movement Using Temporary Skeletal Anchorage Devices: 3D Finite Element Analysis and In Vivo Validation.

    Science.gov (United States)

    Kaipatur, Neelambar; Wu, Yuchin; Adeeb, Samer; Stevenson, Thomas; Major, Paul; Doschak, Michael

    2014-01-01

    The aim of this animal study was to develop a model of orthodontic tooth movement using a microimplant as a TSAD in rodents. A finite element model of the TSAD in alveolar bone was built using μCT images of rat maxilla to determine the von Mises stresses and displacement in the alveolar bone surrounding the TSAD. For in vivo validation of the FE model, Sprague-Dawley rats (n = 25) were used and a Stryker 1.2 × 3 mm microimplant was inserted in the right maxilla and used to protract the right first permanent molar using a NiTi closed coil spring. Tooth movement measurements were taken at baseline, 4 and 8 weeks. At 8 weeks, animals were euthanized and tissues were analyzed by histology and EPMA. FE modeling showed maximum von Mises stress of 45 Mpa near the apex of TSAD but the average von Mises stress was under 25 Mpa. Appreciable tooth movement of 0.62 ± 0.04 mm at 4 weeks and 1.99 ± 0.14 mm at 8 weeks was obtained. Histological and EPMA results demonstrated no active bone remodeling around the TSAD at 8 weeks depicting good secondary stability. This study provided evidence that protracted tooth movement is achieved in small animals using TSADs.

  19. Simultaneous 3D measurement of the translation and rotation of finite-size particles and the flow field in a fully developed turbulent water flow

    Science.gov (United States)

    Klein, Simon; Gibert, Mathieu; Bérut, Antoine; Bodenschatz, Eberhard

    2013-02-01

    We report a novel experimental technique that measures simultaneously in three dimensions the trajectories, the translation and the rotation of finite-size inertial particles together with the turbulent flow. The flow field is analyzed by tracking the temporal evolution of small fluorescent tracer particles. The inertial particles consist of a super-absorbent polymer that renders them index and density matched with water and thus invisible. The particles are marked by inserting at various locations tracer particles into the polymer. Translation and rotation, as well as the flow field around the particle are recovered dynamically from the analysis of the marker and tracer particle trajectories. We apply this technique to study the dynamics of inertial particles much larger in size (Rp/η ≈ 100) than the Kolmogorov length scale η in a von Kármán swirling water flow (Rλ ≈ 400). We show, using the mixed (particle/fluid) Eulerian second-order velocity structure function, that the interaction zone between the particle and the flow develops in a spherical shell of width 2Rp around the particle of radius Rp. This we interpret as an indication of a wake induced by the particle. This measurement technique has many additional advantages that will make it useful to address other problems such as particle collisions, dynamics of non-spherical solid objects, or even of wet granular matter.

  20. Simultaneous 3D measurement of the translation and rotation of finite size particles and the flow field in a fully developed turbulent water flow

    Science.gov (United States)

    Gibert, Mathieu; Klein, Simon; Bodenschatz, Eberhard

    2012-11-01

    We report a novel experimental technique that measures simultaneously in three dimensions the trajectories, the translation, and the rotation of finite size inertial particles together with the turbulent flow. The flow field is analyzed by tracking the temporal evolution of small fluorescent tracer particles. The inertial particles consist of a super-absorbent polymer that renders them index and density matched with water and thus invisible. The particles are marked by inserting at various locations tracer particles into the polymer. Translation and rotation, as well as the flow field around the particle are recovered dynamically from the analysis of the marker and tracer particle trajectories. We apply this technique to study the dynamics of inertial particles much larger in size (Rp / η ~ 100) than the Kolmogorov length scale η in a von Kármán swirling water flow (Rλ ~ 400). We show, using the mixed (particle/fluid) Eulerian second order velocity structure function, that the interaction zone between the particle and the flow develops in a spherical shell of width 2Rp around the particle of radius Rp. This we interpret as an indication of a wake induced by the particle. (http://arxiv.org/abs/1205.2181) This work was funded generously by the Max Planck Society and the Marie Curie Fellowship, Program PEOPLE - Call FP7-PEOPLE-IEF-2008 Proposal No 237521. Support from COST Action MP0806 is kindly acknowledged.

  1. Investigating the mechanical function of the cervix during pregnancy using finite element models derived from high-resolution 3D MRI.

    Science.gov (United States)

    Fernandez, M; House, M; Jambawalikar, S; Zork, N; Vink, J; Wapner, R; Myers, K

    2016-01-01

    Preterm birth is a strong contributor to perinatal mortality, and preterm infants that survive are at risk for long-term morbidities. During most of pregnancy, appropriate mechanical function of the cervix is required to maintain the developing fetus in utero. Premature cervical softening and subsequent cervical shortening are hypothesized to cause preterm birth. Presently, there is a lack of understanding of the structural and material factors that influence the mechanical function of the cervix during pregnancy. In this study we build finite element models of the pregnant uterus, cervix, and fetal membrane based on magnetic resonance imagining data in order to examine the mechanical function of the cervix under the physiologic loading conditions of pregnancy. We calculate the mechanical loading state of the cervix for two pregnant patients: 22 weeks gestational age with a normal cervical length and 28 weeks with a short cervix. We investigate the influence of (1) anatomical geometry, (2) cervical material properties, and (3) fetal membrane material properties, including its adhesion properties, on the mechanical loading state of the cervix under physiologically relevant intrauterine pressures. Our study demonstrates that membrane-uterus interaction, cervical material modeling, and membrane mechanical properties are factors that must be deliberately and carefully handled in order to construct a high quality mechanical simulation of pregnancy.

  2. Effect of Implant Height Differences on Different Attachment Types and Peri-Implant Bone in Mandibular Two-Implant Overdentures: 3D Finite Element Study.

    Science.gov (United States)

    Ozan, Oguz; Ramoglu, Serhat

    2015-06-01

    Implant-supported overdentures with self-aligning attachment systems are preferred to improve the stability and retention of complete dentures. The positioning of the implant attachments is a very important aspect of two-implant overdentures in obtaining better stress distribution. Therefore, the objective of this study was to compare two different attachment systems in a two-implant overdenture by evaluating the stress distributions in peri-implant bone and stresses on the attachments with positioning at different height levels using the 3D FEA method. Six models with ball attachments and 6 models with locator attachments-totaling 12 models (including 2 controls)-with the left implant positioned unilaterally at different height levels were subjected to 3 loading conditions (anterior, right posterior, and left posterior). Data for Von Misses stresses were produced numerically, color coded, and compared among the models for attachments and peri-implant cortical bone. The configurations in which implants presented 3 mm height differences in the bone level showed the most successful results in the peri-implant bone. When stresses on the attachments were compared, greater stress values were obtained from the ball attachments. As a conclusion, the configurations with a considerable (3 mm) height difference between quadrants of the mandible in the anterior segment showed the most successful results in the peri-implant bone. On the contrary, peak stress values around the implant observed from the models with less (1 mm) bone height difference may require leveling of the bone during surgery. However, these findings should be corroborated with clinical studies.

  3. QUESTIONNAIRES PRETESTING IN MARKETING RESEARCH

    Directory of Open Access Journals (Sweden)

    ALINA-MIHAELA BABONEA

    2011-04-01

    Full Text Available Designing the perfect survey questionnaire is impossible. However, researchers can still create an effective research. To make your questionnaire effective, it is necessary to pretest it before actually using it. The following paper reveals some general guidelines on pretesting and what to do for a more effective marketing research giving the fact that the existing literature highlights the importance and indispensability of pretesting and on the other hand, does not provide sufficient information in terms of methodology about it. Also, we have tried to explain the importance of questionnaires pretesting before applying them in order to obtain the best results in marketing research and we’ve kept in mind that high quality in this domain means using new tools and improving the existing ones if one searches for efficient results.

  4. 3D video

    CERN Document Server

    Lucas, Laurent; Loscos, Céline

    2013-01-01

    While 3D vision has existed for many years, the use of 3D cameras and video-based modeling by the film industry has induced an explosion of interest for 3D acquisition technology, 3D content and 3D displays. As such, 3D video has become one of the new technology trends of this century.The chapters in this book cover a large spectrum of areas connected to 3D video, which are presented both theoretically and technologically, while taking into account both physiological and perceptual aspects. Stepping away from traditional 3D vision, the authors, all currently involved in these areas, provide th

  5. 3D Animation Essentials

    CERN Document Server

    Beane, Andy

    2012-01-01

    The essential fundamentals of 3D animation for aspiring 3D artists 3D is everywhere--video games, movie and television special effects, mobile devices, etc. Many aspiring artists and animators have grown up with 3D and computers, and naturally gravitate to this field as their area of interest. Bringing a blend of studio and classroom experience to offer you thorough coverage of the 3D animation industry, this must-have book shows you what it takes to create compelling and realistic 3D imagery. Serves as the first step to understanding the language of 3D and computer graphics (CG)Covers 3D anim

  6. 3D Finite Element Modeling for Possible Creeping Behavior of Gas Hydrate-related Slipstream Submarine Slide, offshore Vancouver Island, Canada

    Science.gov (United States)

    LONG, S.; He, T.; Lan, K.; Spence, G.; Yelisetti, S.

    2017-12-01

    Natural gas hydrate-related submarine landslides have been identified on worldwide continental slope. Being a potential risk for marine environment and engineering projects, it has been a hot topic of hydrate research in recent decades. The study target is Slipstream submarine landslide, one of the slope failures on the frontal ridges of the Northern Cascadia accretionary margin, off Vancouver Island, Canada. The previous studies of P- & S-wave velocity structure based on OBS (Ocean Bottom Seismometer) data of SeaJade (Seafloor Earthquake Array - Japan Canada Cascadia Experiment) project indicated that there are two high concentration gas-hydrate layers within the ridge, one is at a depth of 100 mbsf (meter beneath the seafloor) with anomalous high P-wave velocities and the other is just above the prominent BSR (bottom-simulating reflector) at a depth of 265-275 mbsf. In this study we investigated the possible creeping behavior of gas hydrate layer to examine the critical instability of the ridge slope using the finite element method for self weight and additional stress (e.g., mega earthquake) conditions. The elastic and elasticoplasticity moduli of gas hydrate layer were obtained from laboratory measurements for different uniaxial pressure tests, which indicated that the sediments behave elastically for uniaxial pressures below 6 MPa, but elasticoplastically between 6-6.77 MPa. The modeled shear stress distribution indicated that the current sliding surface is more likely connected with the shallow high-velocity gas hydrate layer and sliding process related with gas hydrate starts from the toe of the slope and then progressively retreats to the place of current headwall, in a series of triangular blocks or wedges. Since the study area is in the earthquake belt, the large seismic acceleration will greatly affect the stress field and pore pressure distribution within the ridge, and the landslide is going to happen and supposedly at the shallow high-velocity gas

  7. 3D packaging for integrated circuit systems

    Energy Technology Data Exchange (ETDEWEB)

    Chu, D.; Palmer, D.W. [eds.

    1996-11-01

    A goal was set for high density, high performance microelectronics pursued through a dense 3D packing of integrated circuits. A {open_quotes}tool set{close_quotes} of assembly processes have been developed that enable 3D system designs: 3D thermal analysis, silicon electrical through vias, IC thinning, mounting wells in silicon, adhesives for silicon stacking, pretesting of IC chips before commitment to stacks, and bond pad bumping. Validation of these process developments occurred through both Sandia prototypes and subsequent commercial examples.

  8. Displacement and force distribution of splinted and tilted mandibular anterior teeth under occlusal loads: an in silico 3D finite element analysis

    Directory of Open Access Journals (Sweden)

    Allahyar Gerami

    2016-06-01

    Full Text Available Abstract Background Fixed orthodontic retainers have numerous advantages, but it is not known whether they can exert pathological forces on supporting tissues around the splinted teeth. The purpose of this study was to investigate how the inclination of the lower anterior teeth can affect dental displacement and also change the direction of occlusal loads exerted to dental and its supporting tissues. Methods Four three-dimensional finite element models of the anterior part of the mandible were designed. All the models contained the incisors and canines, their periodontal ligament layers (PDLs, the supporting bone (both spongy and cortical, and a pentaflex splinting wire placed in the lingual side of the teeth. Teeth inclination was considered to be 80° (model 1, 90° (model 2, 100° (model 3, and 110° (model 4 to the horizontal plane. The lower incisors were loaded with a 187-N vertical force. Their displacement patterns and the stress in their PDLs were evaluated. Results In incisors with 80° of inclination, less than a 0.1-mm lingual displacement was seen on the incisal edge and a similar distance of displacement towards the labial was seen on their root apices. However, in models with 90°–110° of inclination, the incisal edge displaced labially between about 0.01 and 0.45 mm, while root apices displaced lingually instead. By increasing the angle of the teeth, the strain in the periodontal ligament increased from about 37 to 58 mJ. The von Mises stresses around the cervical and apical areas differed for each tooth and each model, without a similar pattern. Increasing the angle of the teeth resulted in much higher cervical stresses in the incisors, but not in the canines. In the lateral incisor, cervical stress increased until 100° of inclination but reduced to about half by increasing the angle to 110°. Apical stress increased rather consistently in the incisor and lateral incisors, by increasing the inclination. However, in the

  9. JAC3D -- A three-dimensional finite element computer program for the nonlinear quasi-static response of solids with the conjugate gradient method; Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Biffle, J.H.

    1993-02-01

    JAC3D is a three-dimensional finite element program designed to solve quasi-static nonlinear mechanics problems. A set of continuum equations describes the nonlinear mechanics involving large rotation and strain. A nonlinear conjugate gradient method is used to solve the equation. The method is implemented in a three-dimensional setting with various methods for accelerating convergence. Sliding interface logic is also implemented. An eight-node Lagrangian uniform strain element is used with hourglass stiffness to control the zero-energy modes. This report documents the elastic and isothermal elastic-plastic material model. Other material models, documented elsewhere, are also available. The program is vectorized for efficient performance on Cray computers. Sample problems described are the bending of a thin beam, the rotation of a unit cube, and the pressurization and thermal loading of a hollow sphere.

  10. Finite element micro-modelling of a human ankle bone reveals the importance of the trabecular network to mechanical performance: new methods for the generation and comparison of 3D models.

    Science.gov (United States)

    Parr, W C H; Chamoli, U; Jones, A; Walsh, W R; Wroe, S

    2013-01-04

    Most modelling of whole bones does not incorporate trabecular geometry and treats bone as a solid non-porous structure. Some studies have modelled trabecular networks in isolation. One study has modelled the performance of whole human bones incorporating trabeculae, although this required considerable computer resources and purpose-written code. The difference between mechanical behaviour in models that incorporate trabecular geometry and non-porous models has not been explored. The ability to easily model trabecular networks may shed light on the mechanical consequences of bone loss in osteoporosis and remodelling after implant insertion. Here we present a Finite Element Analysis (FEA) of a human ankle bone that includes trabecular network geometry. We compare results from this model with results from non-porous models and introduce protocols achievable on desktop computers using widely available softwares. Our findings show that models including trabecular geometry are considerably stiffer than non-porous whole bone models wherein the non-cortical component has the same mass as the trabecular network, suggesting inclusion of trabecular geometry is desirable. We further present new methods for the construction and analysis of 3D models permitting: (1) construction of multi-property, non-porous models wherein cortical layer thickness can be manipulated; (2) maintenance of the same triangle network for the outer cortical bone surface in both 3D reconstruction and non-porous models allowing exact replication of load and restraint cases; and (3) creation of an internal landmark point grid allowing direct comparison between 3D FE Models (FEMs). Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Europeana and 3D

    Science.gov (United States)

    Pletinckx, D.

    2011-09-01

    The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  12. EUROPEANA AND 3D

    Directory of Open Access Journals (Sweden)

    D. Pletinckx

    2012-09-01

    Full Text Available The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  13. Open 3D Projects

    Directory of Open Access Journals (Sweden)

    Felician ALECU

    2010-01-01

    Full Text Available Many professionals and 3D artists consider Blender as being the best open source solution for 3D computer graphics. The main features are related to modeling, rendering, shading, imaging, compositing, animation, physics and particles and realtime 3D/game creation.

  14. Open 3D Projects

    OpenAIRE

    Felician ALECU

    2010-01-01

    Many professionals and 3D artists consider Blender as being the best open source solution for 3D computer graphics. The main features are related to modeling, rendering, shading, imaging, compositing, animation, physics and particles and realtime 3D/game creation.

  15. IZDELAVA TISKALNIKA 3D

    OpenAIRE

    Brdnik, Lovro

    2015-01-01

    Diplomsko delo analizira trenutno stanje 3D tiskalnikov na trgu. Prikazan je razvoj in principi delovanja 3D tiskalnikov. Predstavljeni so tipi 3D tiskalnikov, njihove prednosti in slabosti. Podrobneje je predstavljena zgradba in delovanje koračnih motorjev. Opravljene so meritve koračnih motorjev. Opisana je programska oprema za rokovanje s 3D tiskalniki in komponente, ki jih potrebujemo za izdelavo. Diploma se oklepa vprašanja, ali je izdelava 3D tiskalnika bolj ekonomična kot pa naložba v ...

  16. Peak stresses shift from femoral tunnel aperture to tibial tunnel aperture in lateral tibial tunnel ACL reconstructions: a 3D graft-bending angle measurement and finite-element analysis.

    Science.gov (United States)

    Van Der Bracht, Hans; Tampere, Thomas; Beekman, Pieter; Schepens, Alexander; Devriendt, Wouter; Verdonk, Peter; Victor, Jan

    2018-02-01

    To investigate the effect of tibial tunnel orientation on graft-bending angle and stress distribution in the ACL graft. Eight cadaveric knees were scanned in extension, 45°, 90°, and full flexion. 3D reconstructions with anatomically placed anterior cruciate ligament (ACL) grafts were constructed with Mimics 14.12 ® . 3D graft-bending angles were measured for classic medial tibial tunnels (MTT) and lateral tibial tunnels (LTT) with different drill-guide angles (DGA) (45°, 55°, 65°, and 75°). A pivot shift was performed on 1 knee in a finite-element analysis. The peak stresses in the graft were calculated for eight different tibial tunnel orientations. In a classic anatomical ACL repair, the largest graft-bending angle and peak stresses are seen at the femoral tunnel aperture. The use of a different DGA at the tibial side does not change the graft-bending angle at the femoral side or magnitude of peak stresses significantly. When using LTT, the largest graft-bending angles and peak stresses are seen at the tibial tunnel aperture. In a classic anatomical ACL repair, peak stresses in the ACL graft are found at the femoral tunnel aperture. When an LTT is used, peak stresses are similar compared to classic ACL repairs, but the location of the peak stress will shift from the femoral tunnel aperture towards the tibial tunnel aperture. the risk of graft rupture is similar for both MTTs and LTTs, but the location of graft rupture changes from the femoral tunnel aperture towards the tibial tunnel aperture, respectively. I.

  17. Refined 3d-3d correspondence

    Science.gov (United States)

    Alday, Luis F.; Genolini, Pietro Benetti; Bullimore, Mathew; van Loon, Mark

    2017-04-01

    We explore aspects of the correspondence between Seifert 3-manifolds and 3d N = 2 supersymmetric theories with a distinguished abelian flavour symmetry. We give a prescription for computing the squashed three-sphere partition functions of such 3d N = 2 theories constructed from boundary conditions and interfaces in a 4d N = 2∗ theory, mirroring the construction of Seifert manifold invariants via Dehn surgery. This is extended to include links in the Seifert manifold by the insertion of supersymmetric Wilson-'t Hooft loops in the 4d N = 2∗ theory. In the presence of a mass parameter cfor the distinguished flavour symmetry, we recover aspects of refined Chern-Simons theory with complex gauge group, and in particular construct an analytic continuation of the S-matrix of refined Chern-Simons theory.

  18. A 3d-3d appetizer

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Du; Ye, Ke [Walter Burke Institute for Theoretical Physics, California Institute of Technology, Pasadena, CA, 91125 (United States)

    2016-11-02

    We test the 3d-3d correspondence for theories that are labeled by Lens spaces. We find a full agreement between the index of the 3d N=2 “Lens space theory” T[L(p,1)] and the partition function of complex Chern-Simons theory on L(p,1). In particular, for p=1, we show how the familiar S{sup 3} partition function of Chern-Simons theory arises from the index of a free theory. For large p, we find that the index of T[L(p,1)] becomes a constant independent of p. In addition, we study T[L(p,1)] on the squashed three-sphere S{sub b}{sup 3}. This enables us to see clearly, at the level of partition function, to what extent G{sub ℂ} complex Chern-Simons theory can be thought of as two copies of Chern-Simons theory with compact gauge group G.

  19. From 3D view to 3D print

    Science.gov (United States)

    Dima, M.; Farisato, G.; Bergomi, M.; Viotto, V.; Magrin, D.; Greggio, D.; Farinato, J.; Marafatto, L.; Ragazzoni, R.; Piazza, D.

    2014-08-01

    In the last few years 3D printing is getting more and more popular and used in many fields going from manufacturing to industrial design, architecture, medical support and aerospace. 3D printing is an evolution of bi-dimensional printing, which allows to obtain a solid object from a 3D model, realized with a 3D modelling software. The final product is obtained using an additive process, in which successive layers of material are laid down one over the other. A 3D printer allows to realize, in a simple way, very complex shapes, which would be quite difficult to be produced with dedicated conventional facilities. Thanks to the fact that the 3D printing is obtained superposing one layer to the others, it doesn't need any particular work flow and it is sufficient to simply draw the model and send it to print. Many different kinds of 3D printers exist based on the technology and material used for layer deposition. A common material used by the toner is ABS plastics, which is a light and rigid thermoplastic polymer, whose peculiar mechanical properties make it diffusely used in several fields, like pipes production and cars interiors manufacturing. I used this technology to create a 1:1 scale model of the telescope which is the hardware core of the space small mission CHEOPS (CHaracterising ExOPlanets Satellite) by ESA, which aims to characterize EXOplanets via transits observations. The telescope has a Ritchey-Chrétien configuration with a 30cm aperture and the launch is foreseen in 2017. In this paper, I present the different phases for the realization of such a model, focusing onto pros and cons of this kind of technology. For example, because of the finite printable volume (10×10×12 inches in the x, y and z directions respectively), it has been necessary to split the largest parts of the instrument in smaller components to be then reassembled and post-processed. A further issue is the resolution of the printed material, which is expressed in terms of layers

  20. 3D virtuel udstilling

    DEFF Research Database (Denmark)

    Tournay, Bruno; Rüdiger, Bjarne

    2006-01-01

    3d digital model af Arkitektskolens gård med virtuel udstilling af afgangsprojekter fra afgangen sommer 2006. 10 s.......3d digital model af Arkitektskolens gård med virtuel udstilling af afgangsprojekter fra afgangen sommer 2006. 10 s....

  1. 3D Ground Mapping

    OpenAIRE

    Poverud, Therese Tokle; Christensen, Ole Petter; Jacop, Asadullah; Mpoyi, Giresse Kadima; Mann, Harjit Laly Singh; Albert, Ngenzi; Dalset, Bjørnar

    2015-01-01

    Utført i samarbeid med Cube AS Cube AS wants a system for 3D mapping of terrain using an UAV (unmanned aerial vehicle). We chose to equip the UAV with a camera to take aerial photos that are processed through image processing software to produce detailed, digital 3D maps.

  2. Underwater 3D filming

    Directory of Open Access Journals (Sweden)

    Roberto Rinaldi

    2014-12-01

    Full Text Available After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space (“Gravity” and the underwater realm look perfect to be reproduced in 3D. “Filming in space” was possible in “Gravity” using special effects and computer graphic. The underwater realm is still difficult to be handled. Underwater filming in 3D was not that easy and effective as filming in 2D, since not long ago. After almost 3 years of research, a French, Austrian and Italian team realized a perfect tool to film underwater, in 3D, without any constrains. This allows filmmakers to bring the audience deep inside an environment where they most probably will never have the chance to be.

  3. Finite

    Directory of Open Access Journals (Sweden)

    W.R. Azzam

    2015-08-01

    Full Text Available This paper reports the application of using a skirted foundation system to study the behavior of foundations with structural skirts adjacent to a sand slope and subjected to earthquake loading. The effect of the adopted skirts to safeguard foundation and slope from collapse is studied. The skirts effect on controlling horizontal soil movement and decreasing pore water pressure beneath foundations and beside the slopes during earthquake is investigated. This technique is investigated numerically using finite element analysis. A four story reinforced concrete building that rests on a raft foundation is idealized as a two-dimensional model with and without skirts. A two dimensional plain strain program PLAXIS, (dynamic version is adopted. A series of models for the problem under investigation were run under different skirt depths and lactation from the slope crest. The effect of subgrade relative density and skirts thickness is also discussed. Nodal displacement and element strains were analyzed for the foundation with and without skirts and at different studied parameters. The research results showed a great effectiveness in increasing the overall stability of the slope and foundation. The confined soil footing system by such skirts reduced the foundation acceleration therefore it can be tended to damping element and relieved the transmitted disturbance to the adjacent slope. This technique can be considered as a good method to control the slope deformation and decrease the slope acceleration during earthquakes.

  4. Blender 3D cookbook

    CERN Document Server

    Valenza, Enrico

    2015-01-01

    This book is aimed at the professionals that already have good 3D CGI experience with commercial packages and have now decided to try the open source Blender and want to experiment with something more complex than the average tutorials on the web. However, it's also aimed at the intermediate Blender users who simply want to go some steps further.It's taken for granted that you already know how to move inside the Blender interface, that you already have 3D modeling knowledge, and also that of basic 3D modeling and rendering concepts, for example, edge-loops, n-gons, or samples. In any case, it'

  5. TISKALNIK 3D DLP

    OpenAIRE

    Debeljak, Mitja

    2016-01-01

    Diplomska naloga opisuje različne vrste 3D tiskalnikov in izdelavo 3D tiskalnika s tehnologijo digitalnega svetlobnega procesa (Digital Light Processing ali DLP) za potrebe podjetja Doorson d.o.o. V nalogi je opisan postopek izdelave, deljen na mehanski, elektro in programski del ter podrobnejša predstavitev komponent, med katere kot pomembnejše sodijo Raspberry Pi in koračni motor. Prikazana je primerjava obstoječega 3D tiskalnika s tehnologijo ciljnega nalaganja (Fused Deposition Modeling a...

  6. DELTA 3D PRINTER

    Directory of Open Access Journals (Sweden)

    ȘOVĂILĂ Florin

    2016-07-01

    Full Text Available 3D printing is a very used process in industry, the generic name being “rapid prototyping”. The essential advantage of a 3D printer is that it allows the designers to produce a prototype in a very short time, which is tested and quickly remodeled, considerably reducing the required time to get from the prototype phase to the final product. At the same time, through this technique we can achieve components with very precise forms, complex pieces that, through classical methods, could have been accomplished only in a large amount of time. In this paper, there are presented the stages of a 3D model execution, also the physical achievement after of a Delta 3D printer after the model.

  7. Radiochromic 3D Detectors

    Science.gov (United States)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  8. Impresora 3D

    OpenAIRE

    Moreno, Iveth; Serracín, Pilar

    2017-01-01

    La idea de llevar a la realidad un objeto dibujado en un software de diseño asistido por computadora, da lugar a la creación de las impresoras 3D. Los orígenes de la impresión 3D se dieron para los años 80, y desde aquella época hasta hoy en día, este tipo de impresión ha contribuido en diversos campos del saber, que van desde la ingeniería hasta la medicina. En sus inicios las impresoras 3D además de costosas, eran de uso exclusivo para la creación de piezas de prototipado con una fuerte apl...

  9. 3D Digital Modelling

    DEFF Research Database (Denmark)

    Hundebøl, Jesper

    wave of new building information modelling tools demands further investigation, not least because of industry representatives' somewhat coarse parlance: Now the word is spreading -3D digital modelling is nothing less than a revolution, a shift of paradigm, a new alphabet... Research qeustions. Based...... on empirical probes (interviews, observations, written inscriptions) within the Danish construction industry this paper explores the organizational and managerial dynamics of 3D Digital Modelling. The paper intends to - Illustrate how the network of (non-)human actors engaged in the promotion (and arrest) of 3...... important to appreciate the analysis. Before turning to the presentation of preliminary findings and a discussion of 3D digital modelling, it begins, however, with an outline of industry specific ICT strategic issues. Paper type. Multi-site field study...

  10. 3D Projection Installations

    DEFF Research Database (Denmark)

    Halskov, Kim; Johansen, Stine Liv; Bach Mikkelsen, Michelle

    2014-01-01

    contributes to the understanding of the distinctive characteristics of such a new medium, and identifies three strategies for designing 3-D projection installations: establishing space; interplay between the digital and the physical; and transformation of materiality. The principal empirical case, From......Three-dimensional projection installations are particular kinds of augmented spaces in which a digital 3-D model is projected onto a physical three-dimensional object, thereby fusing the digital content and the physical object. Based on interaction design research and media studies, this article...

  11. Herramientas SIG 3D

    Directory of Open Access Journals (Sweden)

    Francisco R. Feito Higueruela

    2010-04-01

    Full Text Available Applications of Geographical Information Systems on several Archeology fields have been increasing during the last years. Recent avances in these technologies make possible to work with more realistic 3D models. In this paper we introduce a new paradigm for this system, the GIS Thetrahedron, in which we define the fundamental elements of GIS, in order to provide a better understanding of their capabilities. At the same time the basic 3D characteristics of some comercial and open source software are described, as well as the application to some samples on archeological researchs

  12. DELTA 3D PRINTER

    OpenAIRE

    ȘOVĂILĂ Florin; ȘOVĂILĂ Claudiu; BAROIU Nicuşor

    2016-01-01

    3D printing is a very used process in industry, the generic name being “rapid prototyping”. The essential advantage of a 3D printer is that it allows the designers to produce a prototype in a very short time, which is tested and quickly remodeled, considerably reducing the required time to get from the prototype phase to the final product. At the same time, through this technique we can achieve components with very precise forms, complex pieces that, through classical methods, could have been...

  13. Tangible 3D Modelling

    DEFF Research Database (Denmark)

    Hejlesen, Aske K.; Ovesen, Nis

    2012-01-01

    This paper presents an experimental approach to teaching 3D modelling techniques in an Industrial Design programme. The approach includes the use of tangible free form models as tools for improving the overall learning. The paper is based on lecturer and student experiences obtained through...

  14. A Pretest for Introductory Crops Students.

    Science.gov (United States)

    Elkins, Donald M.

    1987-01-01

    Discusses the advantages of using a pretest in introductory agronomy courses. Provides a pretest that has been developed for use in an introductory crops course taught at Southern Illinois University. Includes 25 definitions, 17 true-false and multiple choice questions, and 6 short answer questions. (TW)

  15. Twin Peaks - 3D

    Science.gov (United States)

    1997-01-01

    The two hills in the distance, approximately one to two kilometers away, have been dubbed the 'Twin Peaks' and are of great interest to Pathfinder scientists as objects of future study. 3D glasses are necessary to identify surface detail. The white areas on the left hill, called the 'Ski Run' by scientists, may have been formed by hydrologic processes.The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  16. Shaping 3-D boxes

    DEFF Research Database (Denmark)

    Stenholt, Rasmus; Madsen, Claus B.

    2011-01-01

    Enabling users to shape 3-D boxes in immersive virtual environments is a non-trivial problem. In this paper, a new family of techniques for creating rectangular boxes of arbitrary position, orientation, and size is presented and evaluated. These new techniques are based solely on position data......F) docking experiment against an existing technique, which requires the user to perform the rotation and scaling of the box explicitly. The precision of the users' box construction is evaluated by a novel error metric measuring the difference between two boxes. The results of the experiment strongly indicate...

  17. 3D Audio System

    Science.gov (United States)

    1992-01-01

    Ames Research Center research into virtual reality led to the development of the Convolvotron, a high speed digital audio processing system that delivers three-dimensional sound over headphones. It consists of a two-card set designed for use with a personal computer. The Convolvotron's primary application is presentation of 3D audio signals over headphones. Four independent sound sources are filtered with large time-varying filters that compensate for motion. The perceived location of the sound remains constant. Possible applications are in air traffic control towers or airplane cockpits, hearing and perception research and virtual reality development.

  18. 3D Surgical Simulation

    Science.gov (United States)

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

  19. 3D Model Optimization of Four-Facet Drill for 3D Drilling Simulation

    Science.gov (United States)

    Buranský, Ivan; Necpal, Martin; Bračík, Matej

    2016-09-01

    The article is focused on optimization of four-facet drill for 3D drilling numerical modelling. For optimization, the process of reverse engineering by PowerShape software was used. The design of four-facet drill was created in NumrotoPlus software. The modified 3D model of the drill was used in the numerical analysis of cutting forces. Verification of the accuracy of 3D models for reverse engineering was implemented using the colour deviation maps. The CAD model was in the STEP format. For simulation software, 3D model in the STEP format is ideal. STEP is a solid model. Simulation software automatically splits the 3D model into finite elements. The STEP model was therefore more suitable than the STL model.

  20. 3D Model Optimization of Four-Facet Drill for 3D Drilling Simulation

    Directory of Open Access Journals (Sweden)

    Buranský Ivan

    2016-09-01

    Full Text Available The article is focused on optimization of four-facet drill for 3D drilling numerical modelling. For optimization, the process of reverse engineering by PowerShape software was used. The design of four-facet drill was created in NumrotoPlus software. The modified 3D model of the drill was used in the numerical analysis of cutting forces. Verification of the accuracy of 3D models for reverse engineering was implemented using the colour deviation maps. The CAD model was in the STEP format. For simulation software, 3D model in the STEP format is ideal. STEP is a solid model. Simulation software automatically splits the 3D model into finite elements. The STEP model was therefore more suitable than the STL model.

  1. 3D Wire 2015

    DEFF Research Database (Denmark)

    Jordi, Moréton; F, Escribano; J. L., Farias

    , therefore, we’ve drawn conclusions and recommendations for future editions of the event, also generalizable to other experiences of gamification especially in events. This report details the methodology and working elements from the design phase, human resources and organization of production......This document is a general report on the implementation of gamification in 3D Wire 2015 event. As the second gamification experience in this event, we have delved deeply in the previous objectives (attracting public areas less frequented exhibition in previous years and enhance networking) and have...... proposed new ones (viralization of the event on social networks and improvement of the integration of international attendees). On the other hand we defined a set of research objectives related to the study of gamification in an eminently social place like an event. Most of the goals have been met and...

  2. [Digital modeling for the individual mandibular 3D mesh scaffold based on 3D printing technology].

    Science.gov (United States)

    Yan, Rongzeng; Luo, Danmei; Qin, Xiaoyu; Li, Runxin; Rong, Qiguo; Hu, Min

    2016-05-01

    To investigate an ideal modeling method of designing 3D mesh scaffold substitutes based on tissue engineering to restore mandibular bone defects. By analyzing the theoretical model from titanium scaffolds fabricated by 3D printing, the feasibility and effectiveness of the proposed methodology were verified. Based on the CT scanned data of a subject, the Mimics 15.0 and Geomagic studio 12.0 reverse engineering software were adopted to generate surface model of mandibular bone and the defect area was separated from the 3D model of bone. Then prosthesis was designed via mirror algorithm, in which outer shape was used as the external shape of scaffold. Unigraphics software NX 8.5 was applied on Boolean calculation of subtraction between prosthesis and regular microstructure structure and ANSYS 14.0 software was used to design the inner construction of 3D mesh scaffolds. The topological structure and the geometrical parameters of 3D mesh titanium scaffolds were adjusted according to the aim of optimized structure and maximal strength with minimal weight. The 3D mesh scaffolds solid model through two kinds of computer-aided methods was input into 3D printing equipment to fabricate titanium scaffolds. Individual scaffolds were designed successfully by two modeling methods. The finite element optimization made 10% decrease of the stress peak and volume decrease of 43%, and the porosity increased to 76.32%. This modeling method was validated by 3D printing titanium scaffold to be feasible and effective. 3D printing technology combined with finite element topology optimization to obtain the ideal mandibular 3D mesh scaffold is feasible and effective.

  3. 3D Printing and 3D Bioprinting in Pediatrics

    OpenAIRE

    Vijayavenkataraman, Sanjairaj; Fuh, Jerry Y H; Lu, Wen Feng

    2017-01-01

    Additive manufacturing, commonly referred to as 3D printing, is a technology that builds three-dimensional structures and components layer by layer. Bioprinting is the use of 3D printing technology to fabricate tissue constructs for regenerative medicine from cell-laden bio-inks. 3D printing and bioprinting have huge potential in revolutionizing the field of tissue engineering and regenerative medicine. This paper reviews the application of 3D printing and bioprinting in the field of pediatrics.

  4. 3D Printing and 3D Bioprinting in Pediatrics.

    Science.gov (United States)

    Vijayavenkataraman, Sanjairaj; Fuh, Jerry Y H; Lu, Wen Feng

    2017-07-13

    Additive manufacturing, commonly referred to as 3D printing, is a technology that builds three-dimensional structures and components layer by layer. Bioprinting is the use of 3D printing technology to fabricate tissue constructs for regenerative medicine from cell-laden bio-inks. 3D printing and bioprinting have huge potential in revolutionizing the field of tissue engineering and regenerative medicine. This paper reviews the application of 3D printing and bioprinting in the field of pediatrics.

  5. 3D printing for dummies

    CERN Document Server

    Hausman, Kalani Kirk

    2014-01-01

    Get started printing out 3D objects quickly and inexpensively! 3D printing is no longer just a figment of your imagination. This remarkable technology is coming to the masses with the growing availability of 3D printers. 3D printers create 3-dimensional layered models and they allow users to create prototypes that use multiple materials and colors.  This friendly-but-straightforward guide examines each type of 3D printing technology available today and gives artists, entrepreneurs, engineers, and hobbyists insight into the amazing things 3D printing has to offer. You'll discover methods for

  6. Eigenfrequency optimized 3D continua, with possibility for cavities

    DEFF Research Database (Denmark)

    Pedersen, Pauli; Pedersen, Niels Leergaard

    2015-01-01

    Eigenfrequency optimization for 3D continua is formulated and exemplified by the geometry and boundary conditions of a thick plate. Numerical finite element models are based on four node tetrahedra and results from subspace iterations give directly the basis for the continuum redesign. The 3D...

  7. 3D game environments create professional 3D game worlds

    CERN Document Server

    Ahearn, Luke

    2008-01-01

    The ultimate resource to help you create triple-A quality art for a variety of game worlds; 3D Game Environments offers detailed tutorials on creating 3D models, applying 2D art to 3D models, and clear concise advice on issues of efficiency and optimization for a 3D game engine. Using Photoshop and 3ds Max as his primary tools, Luke Ahearn explains how to create realistic textures from photo source and uses a variety of techniques to portray dynamic and believable game worlds.From a modern city to a steamy jungle, learn about the planning and technological considerations for 3D modelin

  8. Lunaserv Global Explorer, 3D

    Science.gov (United States)

    Miconi, C. E.; Estes, N. M.; Bowman-Cisneros, E.; Robinson, M. S.

    2015-06-01

    Lunaserv Global Explorer 3D is a platform independent, planetary data visualization application, which serves high resolution base-map imagery and terrain from web map service data sources, and displays it on a 3D spinning-globe interface.

  9. 3D cellular automata finite element (CAFE) modelling and experimental observation of damage in quasi-brittle nuclear materials: Indentation of a SiC-SiC-fibre ceramic matrix composite

    International Nuclear Information System (INIS)

    Saucedo Mora, Luis; Mostafavi, Mahmoud; Marrow, T. James; Khoshkhou, Danial; Connolly, Brian; Reinhard, Christina; Atwood, Robert; Zhao, Shuang

    2015-01-01

    Cellular automata integrated with finite elements (CAFE) have been used to develop a method to account for the effect of microstructure on quasi-brittle damage development. The microstructure is simulated explicitly by subdividing a finite element into smaller cells. A heterogeneous structure is created from key cells (seeds) using defined characteristics; the influence of the initial finite element mesh is effectively removed during the development of the microstructure. Graded microstructures, textures, particle anisotropy and multiple phases can be readily simulated, such as those in composites and porous materials. A mesh-free framework has been developed to compute the damage development through the microstructure, using cellular automata. With this method, we can study the development of discontinuous cracking and damage coalescence, and its sensitivity to microstructure. Experiments have been carried out to observe the three-dimensional development of damage, using high-resolution synchrotron X-ray computed tomography and digital volume correlation to observe Hertzian indentation of a SiC-SiC fibre composite, quantifying damage by measurement of the displacement fields within the material. The results demonstrate the applicability of the modelling strategy to damage development, and show how model input data may be obtained from small specimen tests, which could be performed at elevated temperatures with irradiated materials. (authors)

  10. The Future Is 3D

    Science.gov (United States)

    Carter, Luke

    2015-01-01

    3D printers are a way of producing a 3D model of an item from a digital file. The model builds up in successive layers of material placed by the printer controlled by the information in the computer file. In this article the author argues that 3D printers are one of the greatest technological advances of recent times. He discusses practical uses…

  11. The 3D additivist cookbook

    NARCIS (Netherlands)

    Allahyari, Morehshin; Rourke, Daniel; Rasch, Miriam

    The 3D Additivist Cookbook, devised and edited by Morehshin Allahyari & Daniel Rourke, is a free compendium of imaginative, provocative works from over 100 world-leading artists, activists and theorists. The 3D Additivist Cookbook contains .obj and .stl files for the 3D printer, as well as critical

  12. 3-D contextual Bayesian classifiers

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    distribution for the pixel values as well as a prior distribution for the configuration of class variables within the cross that is made of a pixel and its four nearest neighbours. We will extend these algorithms to 3-D, i.e. we will specify a simultaneous Gaussian distribution for a pixel and its 6 nearest 3......-D neighbours, and generalise the class variable configuration distributions within the 3-D cross given in 2-D algorithms. The new 3-D algorithms are tested on a synthetic 3-D multivariate dataset....

  13. Size and power of pretest procedures

    NARCIS (Netherlands)

    Albers, Willem/Wim; Boon, P.C.; Kallenberg, W.C.M.

    2000-01-01

    A pre-test procedure consists of a preliminary test on a nuisance parameter, investigating whether it equals a given value or not, followed by the main testing problem on the parameter of interest. In case of acceptance of the preliminary test, the main test is applied in the restricted family with

  14. Using 3D in Visualization

    DEFF Research Database (Denmark)

    Wood, Jo; Kirschenbauer, Sabine; Döllner, Jürgen

    2005-01-01

    to display 3D imagery. The extra cartographic degree of freedom offered by using 3D is explored and offered as a motivation for employing 3D in visualization. The use of VR and the construction of virtual environments exploit navigational and behavioral realism, but become most usefil when combined...... with abstracted representations embedded in a 3D space. The interactions between development of geovisualization, the technology used to implement it and the theory surrounding cartographic representation are explored. The dominance of computing technologies, driven particularly by the gaming industry...

  15. 3D for Graphic Designers

    CERN Document Server

    Connell, Ellery

    2011-01-01

    Helping graphic designers expand their 2D skills into the 3D space The trend in graphic design is towards 3D, with the demand for motion graphics, animation, photorealism, and interactivity rapidly increasing. And with the meteoric rise of iPads, smartphones, and other interactive devices, the design landscape is changing faster than ever.2D digital artists who need a quick and efficient way to join this brave new world will want 3D for Graphic Designers. Readers get hands-on basic training in working in the 3D space, including product design, industrial design and visualization, modeling, ani

  16. 3-D printers for libraries

    CERN Document Server

    Griffey, Jason

    2014-01-01

    As the maker movement continues to grow and 3-D printers become more affordable, an expanding group of hobbyists is keen to explore this new technology. In the time-honored tradition of introducing new technologies, many libraries are considering purchasing a 3-D printer. Jason Griffey, an early enthusiast of 3-D printing, has researched the marketplace and seen several systems first hand at the Consumer Electronics Show. In this report he introduces readers to the 3-D printing marketplace, covering such topics asHow fused deposition modeling (FDM) printing workBasic terminology such as build

  17. 3D Bayesian contextual classifiers

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    2000-01-01

    We extend a series of multivariate Bayesian 2-D contextual classifiers to 3-D by specifying a simultaneous Gaussian distribution for the feature vectors as well as a prior distribution of the class variables of a pixel and its 6 nearest 3-D neighbours.......We extend a series of multivariate Bayesian 2-D contextual classifiers to 3-D by specifying a simultaneous Gaussian distribution for the feature vectors as well as a prior distribution of the class variables of a pixel and its 6 nearest 3-D neighbours....

  18. A 3-D Contextual Classifier

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    1997-01-01

    . This includes the specification of a Gaussian distribution for the pixel values as well as a prior distribution for the configuration of class variables within the cross that is m ade of a pixel and its four nearest neighbours. We will extend this algorithm to 3-D, i.e. we will specify a simultaneous Gaussian...... distr ibution for a pixel and its 6 nearest 3-D neighbours, and generalise the class variable configuration distribution within the 3-D cross. The algorithm is tested on a synthetic 3-D multivariate dataset....

  19. Using 3D in Visualization

    DEFF Research Database (Denmark)

    Wood, Jo; Kirschenbauer, Sabine; Döllner, Jürgen

    2005-01-01

    The notion of three-dimensionality is applied to five stages of the visualization pipeline. While 3D visulization is most often associated with the visual mapping and representation of data, this chapter also identifies its role in the management and assembly of data, and in the media used...... to display 3D imagery. The extra cartographic degree of freedom offered by using 3D is explored and offered as a motivation for employing 3D in visualization. The use of VR and the construction of virtual environments exploit navigational and behavioral realism, but become most usefil when combined...

  20. Qademah Fault 3D Survey

    KAUST Repository

    Hanafy, Sherif M.

    2014-01-01

    Objective: Collect 3D seismic data at Qademah Fault location to 1. 3D traveltime tomography 2. 3D surface wave migration 3. 3D phase velocity 4. Possible reflection processing Acquisition Date: 26 – 28 September 2014 Acquisition Team: Sherif, Kai, Mrinal, Bowen, Ahmed Acquisition Layout: We used 288 receiver arranged in 12 parallel lines, each line has 24 receiver. Inline offset is 5 m and crossline offset is 10 m. One shot is fired at each receiver location. We use the 40 kgm weight drop as seismic source, with 8 to 15 stacks at each shot location.

  1. 3D modeling of metallic grain growth

    Energy Technology Data Exchange (ETDEWEB)

    George, D.; Carlson, N.; Gammel, J.T.; Kuprat, A.

    1999-06-01

    This paper will describe simulating metallic grain growth using the Gradient Weighted Moving Finite Elements code, GRAIN3D. The authors also describe the set of mesh topology change operations developed to respond to changes in the physical topology such as the collapse of grains and to maintain uniform calculational mesh quality. Validation of the method is demonstrated by comparison to analytic calculations. The authors present results of multigrain simulations where grain boundaries evolve by mean curvature motion and include results which incorporate grain boundary orientation dependence.

  2. Market study: 3-D eyetracker

    Science.gov (United States)

    1977-01-01

    A market study of a proposed version of a 3-D eyetracker for initial use at NASA's Ames Research Center was made. The commercialization potential of a simplified, less expensive 3-D eyetracker was ascertained. Primary focus on present and potential users of eyetrackers, as well as present and potential manufacturers has provided an effective means of analyzing the prospects for commercialization.

  3. Euro3D Science Conference

    Science.gov (United States)

    Walsh, J. R.

    2004-02-01

    The Euro3D RTN is an EU funded Research Training Network to foster the exploitation of 3D spectroscopy in Europe. 3D spectroscopy is a general term for spectroscopy of an area of the sky and derives its name from its two spatial + one spectral dimensions. There are an increasing number of instruments which use integral field devices to achieve spectroscopy of an area of the sky, either using lens arrays, optical fibres or image slicers, to pack spectra of multiple pixels on the sky (``spaxels'') onto a 2D detector. On account of the large volume of data and the special methods required to reduce and analyse 3D data, there are only a few centres of expertise and these are mostly involved with instrument developments. There is a perceived lack of expertise in 3D spectroscopy spread though the astronomical community and its use in the armoury of the observational astronomer is viewed as being highly specialised. For precisely this reason the Euro3D RTN was proposed to train young researchers in this area and develop user tools to widen the experience with this particular type of data in Europe. The Euro3D RTN is coordinated by Martin M. Roth (Astrophysikalisches Institut Potsdam) and has been running since July 2002. The first Euro3D science conference was held in Cambridge, UK from 22 to 23 May 2003. The main emphasis of the conference was, in keeping with the RTN, to expose the work of the young post-docs who are funded by the RTN. In addition the team members from the eleven European institutes involved in Euro3D also presented instrumental and observational developments. The conference was organized by Andy Bunker and held at the Institute of Astronomy. There were over thirty participants and 26 talks covered the whole range of application of 3D techniques. The science ranged from Galactic planetary nebulae and globular clusters to kinematics of nearby galaxies out to objects at high redshift. Several talks were devoted to reporting recent observations with newly

  4. 3D printing in dentistry.

    Science.gov (United States)

    Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A

    2015-12-01

    3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery.

  5. AxiSEM3D: broadband seismic wavefields in 3-D aspherical Earth models

    Science.gov (United States)

    Leng, K.; Nissen-Meyer, T.; Zad, K. H.; van Driel, M.; Al-Attar, D.

    2017-12-01

    Seismology is the primary tool for data-informed inference of Earth structure and dynamics. Simulating seismic wave propagation at a global scale is fundamental to seismology, but remains as one of most challenging problems in scientific computing, because of both the multiscale nature of Earth's interior and the observable frequency band of seismic data. We present a novel numerical method to simulate global seismic wave propagation in realistic 3-D Earth models. Our method, named AxiSEM3D, is a hybrid of spectral element method and pseudospectral method. It reduces the azimuthal dimension of wavefields by means of a global Fourier series parameterization, of which the number of terms can be locally adapted to the inherent azimuthal smoothness of the wavefields. AxiSEM3D allows not only for material heterogeneities, such as velocity, density, anisotropy and attenuation, but also for finite undulations on radial discontinuities, both solid-solid and solid-fluid, and thereby a variety of aspherical Earth features such as ellipticity, topography, variable crustal thickness, and core-mantle boundary topography. Such interface undulations are equivalently interpreted as material perturbations of the contiguous media, based on the "particle relabelling transformation". Efficiency comparisons show that AxiSEM3D can be 1 to 3 orders of magnitude faster than conventional 3-D methods, with the speedup increasing with simulation frequency and decreasing with model complexity, but for all realistic structures the speedup remains at least one order of magnitude. The observable frequency range of global seismic data (up to 1 Hz) has been covered for wavefield modelling upon a 3-D Earth model with reasonable computing resources. We show an application of surface wave modelling within a state-of-the-art global crustal model (Crust1.0), with the synthetics compared to real data. The high-performance C++ code is released at github.com/AxiSEM3D/AxiSEM3D.

  6. ADT-3D Tumor Detection Assistant in 3D

    Directory of Open Access Journals (Sweden)

    Jaime Lazcano Bello

    2008-12-01

    Full Text Available The present document describes ADT-3D (Three-Dimensional Tumor Detector Assistant, a prototype application developed to assist doctors diagnose, detect and locate tumors in the brain by using CT scan. The reader may find on this document an introduction to tumor detection; ADT-3D main goals; development details; description of the product; motivation for its development; result’s study; and areas of applicability.

  7. Handbook of 3D integration

    CERN Document Server

    Garrou , Philip; Ramm , Peter

    2014-01-01

    Edited by key figures in 3D integration and written by top authors from high-tech companies and renowned research institutions, this book covers the intricate details of 3D process technology.As such, the main focus is on silicon via formation, bonding and debonding, thinning, via reveal and backside processing, both from a technological and a materials science perspective. The last part of the book is concerned with assessing and enhancing the reliability of the 3D integrated devices, which is a prerequisite for the large-scale implementation of this emerging technology. Invaluable reading fo

  8. Exploration of 3D Printing

    OpenAIRE

    Lin, Zeyu

    2014-01-01

    3D printing technology is introduced and defined in this Thesis. Some methods of 3D printing are illustrated and their principles are explained with pictures. Most of the essential parts are presented with pictures and their effects are explained within the whole system. Problems on Up! Plus 3D printer are solved and a DIY product is made with this machine. The processes of making product are recorded and the items which need to be noticed during the process are the highlight in this th...

  9. 5-axis 3D Printer

    OpenAIRE

    Grutle, Øyvind Kallevik

    2015-01-01

    3D printers have in recent years become extremely popular. Even though 3D printing technology have existed since the late 1980's, it is now considered one of the most significant technological breakthroughs of the twenty-first century. Several different 3D printing processes have been invented during the years. But it is the fused deposition modeling (FDM) which was one of the first invented that is considered the most popular today. Even though the FDM process is the most popular, it still s...

  10. 3D Models of Immunotherapy

    Science.gov (United States)

    This collaborative grant is developing 3D models of both mouse and human biology to investigate aspects of therapeutic vaccination in order to answer key questions relevant to human cancer immunotherapy.

  11. 3D Face Appearance Model

    DEFF Research Database (Denmark)

    Lading, Brian; Larsen, Rasmus; Åström, Kalle

    2006-01-01

    We build a 3d face shape model, including inter- and intra-shape variations, derive the analytical jacobian of its resulting 2d rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations.}......We build a 3d face shape model, including inter- and intra-shape variations, derive the analytical jacobian of its resulting 2d rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations.}...

  12. 3D Face Apperance Model

    DEFF Research Database (Denmark)

    Lading, Brian; Larsen, Rasmus; Astrom, K

    2006-01-01

    We build a 3D face shape model, including inter- and intra-shape variations, derive the analytical Jacobian of its resulting 2D rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations......We build a 3D face shape model, including inter- and intra-shape variations, derive the analytical Jacobian of its resulting 2D rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations...

  13. An interface between I-DEAS and DYNA3D

    International Nuclear Information System (INIS)

    Andress, J.C.

    1986-01-01

    The I-DEAS software package can be used interactively to generate 3-dimensional finite element models for subsequent analysis. This memorandum describes techniques which allow I-DEAS to be used for the generation of finite element models for the code DYNA3D which is being used at Winfrith for impact analysis. In particular, it is shown how impacting and sliding interfaces can be defined conveniently even though the I-DEAS software does not directly support this feature of the DYNA3D code. A simple example is included to illustrate the use of the techniques described in this memorandum. (author)

  14. 3D imaging, 3D printing and 3D virtual planning in endodontics.

    Science.gov (United States)

    Shah, Pratik; Chong, B S

    2018-03-01

    The adoption and adaptation of recent advances in digital technology, such as three-dimensional (3D) printed objects and haptic simulators, in dentistry have influenced teaching and/or management of cases involving implant, craniofacial, maxillofacial, orthognathic and periodontal treatments. 3D printed models and guides may help operators plan and tackle complicated non-surgical and surgical endodontic treatment and may aid skill acquisition. Haptic simulators may assist in the development of competency in endodontic procedures through the acquisition of psycho-motor skills. This review explores and discusses the potential applications of 3D printed models and guides, and haptic simulators in the teaching and management of endodontic procedures. An understanding of the pertinent technology related to the production of 3D printed objects and the operation of haptic simulators are also presented.

  15. YouDash3D: exploring stereoscopic 3D gaming for 3D movie theaters

    Science.gov (United States)

    Schild, Jonas; Seele, Sven; Masuch, Maic

    2012-03-01

    Along with the success of the digitally revived stereoscopic cinema, events beyond 3D movies become attractive for movie theater operators, i.e. interactive 3D games. In this paper, we present a case that explores possible challenges and solutions for interactive 3D games to be played by a movie theater audience. We analyze the setting and showcase current issues related to lighting and interaction. Our second focus is to provide gameplay mechanics that make special use of stereoscopy, especially depth-based game design. Based on these results, we present YouDash3D, a game prototype that explores public stereoscopic gameplay in a reduced kiosk setup. It features live 3D HD video stream of a professional stereo camera rig rendered in a real-time game scene. We use the effect to place the stereoscopic effigies of players into the digital game. The game showcases how stereoscopic vision can provide for a novel depth-based game mechanic. Projected trigger zones and distributed clusters of the audience video allow for easy adaptation to larger audiences and 3D movie theater gaming.

  16. 3D future internet media

    CERN Document Server

    Dagiuklas, Tasos

    2014-01-01

    This book describes recent innovations in 3D media and technologies, with coverage of 3D media capturing, processing, encoding, and adaptation, networking aspects for 3D Media, and quality of user experience (QoE). The main contributions are based on the results of the FP7 European Projects ROMEO, which focus on new methods for the compression and delivery of 3D multi-view video and spatial audio, as well as the optimization of networking and compression jointly across the Future Internet (www.ict-romeo.eu). The delivery of 3D media to individual users remains a highly challenging problem due to the large amount of data involved, diverse network characteristics and user terminal requirements, as well as the user’s context such as their preferences and location. As the number of visual views increases, current systems will struggle to meet the demanding requirements in terms of delivery of constant video quality to both fixed and mobile users. ROMEO will design and develop hybrid-networking solutions that co...

  17. Novel 3D media technologies

    CERN Document Server

    Dagiuklas, Tasos

    2015-01-01

    This book describes recent innovations in 3D media and technologies, with coverage of 3D media capturing, processing, encoding, and adaptation, networking aspects for 3D Media, and quality of user experience (QoE). The contributions are based on the results of the FP7 European Project ROMEO, which focuses on new methods for the compression and delivery of 3D multi-view video and spatial audio, as well as the optimization of networking and compression jointly across the future Internet. The delivery of 3D media to individual users remains a highly challenging problem due to the large amount of data involved, diverse network characteristics and user terminal requirements, as well as the user’s context such as their preferences and location. As the number of visual views increases, current systems will struggle to meet the demanding requirements in terms of delivery of consistent video quality to fixed and mobile users. ROMEO will present hybrid networking solutions that combine the DVB-T2 and DVB-NGH broadcas...

  18. Materialedreven 3d digital formgivning

    DEFF Research Database (Denmark)

    Hansen, Flemming Tvede

    2010-01-01

    Formålet med forskningsprojektet er for det første at understøtte keramikeren i at arbejde eksperimenterende med digital formgivning, og for det andet at bidrage til en tværfaglig diskurs om brugen af digital formgivning. Forskningsprojektet fokuserer på 3d formgivning og derved på 3d digital...... formgivning og Rapid Prototyping (RP). RP er en fællesbetegnelse for en række af de teknikker, der muliggør at overføre den digitale form til 3d fysisk form. Forskningsprojektet koncentrerer sig om to overordnede forskningsspørgsmål. Det første handler om, hvordan viden og erfaring indenfor det keramiske...... fagområde kan blive udnyttet i forhold til 3d digital formgivning. Det andet handler om, hvad en sådan tilgang kan bidrage med, og hvordan den kan blive udnyttet i et dynamisk samspil med det keramiske materiale i formgivningen af 3d keramiske artefakter. Materialedreven formgivning er karakteriseret af en...

  19. 3D Imager and Method for 3D imaging

    NARCIS (Netherlands)

    Kumar, P.; Staszewski, R.; Charbon, E.

    2013-01-01

    3D imager comprising at least one pixel, each pixel comprising a photodetectorfor detecting photon incidence and a time-to-digital converter system configured for referencing said photon incidence to a reference clock, and further comprising a reference clock generator provided for generating the

  20. Pretest characterization of WIPP experimental waste

    International Nuclear Information System (INIS)

    Johnson, J.; Davis, H.

    1991-01-01

    The Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico, is an underground repository designed for the storage and disposal of transuranic (TRU) wastes from US Department of Energy (DOE) facilities across the country. The Performance Assessment (PA) studies for WIPP address compliance of the repository with applicable regulations, and include full-scale experiments to be performed at the WIPP site. These experiments are the bin-scale and alcove tests to be conducted by Sandia National Laboratories (SNL). Prior to conducting these experiments, the waste to be used in these tests needs to be characterized to provide data on the initial conditions for these experiments. This characterization is referred to as the Pretest Characterization of WIPP Experimental Waste, and is also expected to provide input to other programmatic efforts related to waste characterization. The purpose of this paper is to describe the pretest waste characterization activities currently in progress for the WIPP bin-scale waste, and to discuss the program plan and specific analytical protocols being developed for this characterization. The relationship between different programs and documents related to waste characterization efforts is also highlighted in this paper

  1. 3D vector flow imaging

    DEFF Research Database (Denmark)

    Pihl, Michael Johannes

    The main purpose of this PhD project is to develop an ultrasonic method for 3D vector flow imaging. The motivation is to advance the field of velocity estimation in ultrasound, which plays an important role in the clinic. The velocity of blood has components in all three spatial dimensions, yet...... conventional methods can estimate only the axial component. Several approaches for 3D vector velocity estimation have been suggested, but none of these methods have so far produced convincing in vivo results nor have they been adopted by commercial manufacturers. The basis for this project is the Transverse...... on the TO fields are suggested. They can be used to optimize the TO method. In the third part, a TO method for 3D vector velocity estimation is proposed. It employs a 2D phased array transducer and decouples the velocity estimation into three velocity components, which are estimated simultaneously based on 5...

  2. PLOT-3D/BARC, Interactive 3-D Colour Plotting

    International Nuclear Information System (INIS)

    Balhans Jayaswal

    1989-01-01

    1 - Description of program or function: PLOT3D is a general purpose, interactive program, designed to draw three dimensional graphs, histograms, maps and stereo 3D plots, in single or multicolour, from arrays of points (x,y,z) under various options such as clipping, smoothening, shading, etc. using a built-in 3D interpolation function, and after arbitrary rotations about the three coordinate axes. 2 - Method of solution: For plotting a two variables dependent function, z(x,y) the program reads its z values in form of a matrix, z(i,j), in which the indices i and j specify the values of x and y, respectively, either by direct proportionality or through array variables, X(i) and Y(j). Thereafter, the program normalizes the data coordinates, transforms them to effect the orientation of the figure, and then draws axonometric projection using single floating horizon method for hidden lines elimination. In addition, a built-in 3D interpolation function allows numerous intermediate points to be generated and immediately plotted and thus helps in drawing 3D histograms or smoothening the plotted surface, and in shading. The program has two modes of hidden lines removal, both based on single floating horizon method. There exist five versions of this program as listed in item 7. 3 - Restrictions on the complexity of the problem: The size of z data matrix cannot exceed 115 x 115. The number of interpolations cannot exceed 1001 x 1001. In versions 4 and 5, the number of colours cannot exceed 16. In layout diagrams, the items cannot be anything but orthorhombic in shape

  3. 3D Printed Bionic Nanodevices

    Science.gov (United States)

    Kong, Yong Lin; Gupta, Maneesh K.; Johnson, Blake N.; McAlpine, Michael C.

    2016-01-01

    Summary The ability to three-dimensionally interweave biological and functional materials could enable the creation of bionic devices possessing unique and compelling geometries, properties, and functionalities. Indeed, interfacing high performance active devices with biology could impact a variety of fields, including regenerative bioelectronic medicines, smart prosthetics, medical robotics, and human-machine interfaces. Biology, from the molecular scale of DNA and proteins, to the macroscopic scale of tissues and organs, is three-dimensional, often soft and stretchable, and temperature sensitive. This renders most biological platforms incompatible with the fabrication and materials processing methods that have been developed and optimized for functional electronics, which are typically planar, rigid and brittle. A number of strategies have been developed to overcome these dichotomies. One particularly novel approach is the use of extrusion-based multi-material 3D printing, which is an additive manufacturing technology that offers a freeform fabrication strategy. This approach addresses the dichotomies presented above by (1) using 3D printing and imaging for customized, hierarchical, and interwoven device architectures; (2) employing nanotechnology as an enabling route for introducing high performance materials, with the potential for exhibiting properties not found in the bulk; and (3) 3D printing a range of soft and nanoscale materials to enable the integration of a diverse palette of high quality functional nanomaterials with biology. Further, 3D printing is a multi-scale platform, allowing for the incorporation of functional nanoscale inks, the printing of microscale features, and ultimately the creation of macroscale devices. This blending of 3D printing, novel nanomaterial properties, and ‘living’ platforms may enable next-generation bionic systems. In this review, we highlight this synergistic integration of the unique properties of nanomaterials with

  4. Ideal 3D asymmetric concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Botella, Angel [Departamento Fisica Aplicada a los Recursos Naturales, Universidad Politecnica de Madrid, E.T.S.I. de Montes, Ciudad Universitaria s/n, 28040 Madrid (Spain); Fernandez-Balbuena, Antonio Alvarez; Vazquez, Daniel; Bernabeu, Eusebio [Departamento de Optica, Universidad Complutense de Madrid, Fac. CC. Fisicas, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2009-01-15

    Nonimaging optics is a field devoted to the design of optical components for applications such as solar concentration or illumination. In this field, many different techniques have been used for producing reflective and refractive optical devices, including reverse engineering techniques. In this paper we apply photometric field theory and elliptic ray bundles method to study 3D asymmetric - without rotational or translational symmetry - concentrators, which can be useful components for nontracking solar applications. We study the one-sheet hyperbolic concentrator and we demonstrate its behaviour as ideal 3D asymmetric concentrator. (author)

  5. PubChem3D: Biologically relevant 3-D similarity

    Directory of Open Access Journals (Sweden)

    Kim Sunghwan

    2011-07-01

    Full Text Available Abstract Background The use of 3-D similarity techniques in the analysis of biological data and virtual screening is pervasive, but what is a biologically meaningful 3-D similarity value? Can one find statistically significant separation between "active/active" and "active/inactive" spaces? These questions are explored using 734,486 biologically tested chemical structures, 1,389 biological assay data sets, and six different 3-D similarity types utilized by PubChem analysis tools. Results The similarity value distributions of 269.7 billion unique conformer pairs from 734,486 biologically tested compounds (all-against-all from PubChem were utilized to help work towards an answer to the question: what is a biologically meaningful 3-D similarity score? The average and standard deviation for the six similarity measures STST-opt, CTST-opt, ComboTST-opt, STCT-opt, CTCT-opt, and ComboTCT-opt were 0.54 ± 0.10, 0.07 ± 0.05, 0.62 ± 0.13, 0.41 ± 0.11, 0.18 ± 0.06, and 0.59 ± 0.14, respectively. Considering that this random distribution of biologically tested compounds was constructed using a single theoretical conformer per compound (the "default" conformer provided by PubChem, further study may be necessary using multiple diverse conformers per compound; however, given the breadth of the compound set, the single conformer per compound results may still apply to the case of multi-conformer per compound 3-D similarity value distributions. As such, this work is a critical step, covering a very wide corpus of chemical structures and biological assays, creating a statistical framework to build upon. The second part of this study explored the question of whether it was possible to realize a statistically meaningful 3-D similarity value separation between reputed biological assay "inactives" and "actives". Using the terminology of noninactive-noninactive (NN pairs and the noninactive-inactive (NI pairs to represent comparison of the "active/active" and

  6. Materialedreven 3d digital formgivning

    DEFF Research Database (Denmark)

    Hansen, Flemming Tvede

    2010-01-01

    formgivning og Rapid Prototyping (RP). RP er en fællesbetegnelse for en række af de teknikker, der muliggør at overføre den digitale form til 3d fysisk form. Forskningsprojektet koncentrerer sig om to overordnede forskningsspørgsmål. Det første handler om, hvordan viden og erfaring indenfor det keramiske...... animationsbaseret software Real Flow. Dynamics er en fællesbetegnelse for en række digitale redskaber i 3d software, der er beregnet til at simulere virkelighedsrelaterede fænomener som væsker, vind, tyngdekraft o. lign. For det første viser disse eksperimenter, at brugen af dynamics kan ses som et generativt og...... traditionel keramisk produktionssammenhæng. Problemstillingen opmuntrede endvidere til i et samarbejde med en programmør at udvikle et 3d digitalt redskab, der er blevet kaldt et digitalt interaktivt formgivningsredskab (DIF). Eksperimentet undersøger interaktive 3d digitale dynamiske systemer, der...

  7. Markerless 3D Face Tracking

    DEFF Research Database (Denmark)

    Walder, Christian; Breidt, Martin; Bulthoff, Heinrich

    2009-01-01

    We present a novel algorithm for the markerless tracking of deforming surfaces such as faces. We acquire a sequence of 3D scans along with color images at 40Hz. The data is then represented by implicit surface and color functions, using a novel partition-of-unity type method of efficiently combin...

  8. 3D Pit Stop Printing

    Science.gov (United States)

    Wright, Lael; Shaw, Daniel; Gaidds, Kimberly; Lyman, Gregory; Sorey, Timothy

    2018-01-01

    Although solving an engineering design project problem with limited resources or structural capabilities of materials can be part of the challenge, students making their own parts can support creativity. The authors of this article found an exciting solution: 3D printers are not only one of several tools for making but also facilitate a creative…

  9. 3D Printing: Exploring Capabilities

    Science.gov (United States)

    Samuels, Kyle; Flowers, Jim

    2015-01-01

    As 3D printers become more affordable, schools are using them in increasing numbers. They fit well with the emphasis on product design in technology and engineering education, allowing students to create high-fidelity physical models to see and test different iterations in their product designs. They may also help students to "think in three…

  10. A new algorithm for 3D reconstruction from support functions

    DEFF Research Database (Denmark)

    Gardner, Richard; Kiderlen, Markus

    2009-01-01

    We introduce a new algorithm for reconstructing an unknown shape from a finite number of noisy measurements of its support function. The algorithm, based on a least squares procedure, is very easy to program in standard software such as Matlab and allows, for the first time, good 3D reconstructio...

  11. 3D modellering af residualspændinger ved pulversvejsning

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær

    1998-01-01

    Der er opbygget en 3D finite element model i et general purpose FEM-program til beregning af henholdsvis temperaturfelter og de heraf inducerede spændinger ved pulversvejsning i 10mm ST37-2 plade.Til verifikation af de termiske felter er der foretaget temperaturmålinger på en serie...

  12. 3D, parallel fluid-structure interaction code

    CSIR Research Space (South Africa)

    Oxtoby, Oliver F

    2011-01-01

    Full Text Available The authors describe the development of a 3D parallel Fluid–Structure–Interaction (FSI) solver and its application to benchmark problems. Fluid and solid domains are discretised using and edge-based finite-volume scheme for efficient parallel...

  13. A Finite Element Removal Method for 3D Topology Optimization

    Directory of Open Access Journals (Sweden)

    M. Akif Kütük

    2013-01-01

    Full Text Available Topology optimization provides great convenience to designers during the designing stage in many industrial applications. With this method, designers can obtain a rough model of any part at the beginning of a designing stage by defining loading and boundary conditions. At the same time the optimization can be used for the modification of a product which is being used. Lengthy solution time is a disadvantage of this method. Therefore, the method cannot be widespread. In order to eliminate this disadvantage, an element removal algorithm has been developed for topology optimization. In this study, the element removal algorithm is applied on 3-dimensional parts, and the results are compared with the ones available in the related literature. In addition, the effects of the method on solution times are investigated.

  14. Shape corrections for 3D EIT

    Science.gov (United States)

    Paridis, Kyriakos; Lionheart, William R. B.

    2010-04-01

    Movement of the boundary in biomedical Electrical Impedance Tomography (EIT) has been always a source of error in image reconstruction. In the case of pulmonary EIT, where the patient's chest shape changes during respiration, this is inevitable, so it is essential to be able to correct for shape changes and consequently avoid artifacts. Assuming that the conductivity is isotropic, an assumption that is reasonable for lung tissue but admittedly violated for muscle, the boundary shape up to a Möbius transformation (conformal mapping) as well as the conductivity can theoretically be determined by 3D EIT data. While in two dimensions the space of conformal mappings are infinite dimensional, in the three dimensional case the Möbius transformations are given by a finite number of parameters. In this paper, we concentrate on the three dimensional case and take a linear approximation. We will give results of numerical studies analogous to the two dimensional work of Boyle et al on the effect of electrode movement and shape error in 3D EIT.

  15. 3D Printed Robotic Hand

    Science.gov (United States)

    Pizarro, Yaritzmar Rosario; Schuler, Jason M.; Lippitt, Thomas C.

    2013-01-01

    Dexterous robotic hands are changing the way robots and humans interact and use common tools. Unfortunately, the complexity of the joints and actuations drive up the manufacturing cost. Some cutting edge and commercially available rapid prototyping machines now have the ability to print multiple materials and even combine these materials in the same job. A 3D model of a robotic hand was designed using Creo Parametric 2.0. Combining "hard" and "soft" materials, the model was printed on the Object Connex350 3D printer with the purpose of resembling as much as possible the human appearance and mobility of a real hand while needing no assembly. After printing the prototype, strings where installed as actuators to test mobility. Based on printing materials, the manufacturing cost of the hand was $167, significantly lower than other robotic hands without the actuators since they have more complex assembly processes.

  16. Forensic 3D Scene Reconstruction

    International Nuclear Information System (INIS)

    LITTLE, CHARLES Q.; PETERS, RALPH R.; RIGDON, J. BRIAN; SMALL, DANIEL E.

    1999-01-01

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene

  17. Mortars for 3D printing

    Directory of Open Access Journals (Sweden)

    Demyanenko Olga

    2018-01-01

    Full Text Available The paper is aimed at developing scientifically proven compositions of mortars for 3D printing modified by a peat-based admixture with improved operational characteristics. The paper outlines the results of experimental research on hardened cement paste and concrete mixture with the use of modifying admixture MT-600 (thermally modified peat. It is found that strength of hardened cement paste increases at early age when using finely dispersed admixtures, which is the key factor for formation of construction and technical specifications of concrete for 3D printing technologies. The composition of new formations of hardened cement paste modified by MT-600 admixture were obtained, which enabled to suggest the possibility of their physico-chemical interaction while hardening.

  18. Automated 3-D Radiation Mapping

    International Nuclear Information System (INIS)

    Tarpinian, J. E.

    1991-01-01

    This work describes an automated radiation detection and imaging system which combines several state-of-the-art technologies to produce a portable but very powerful visualization tool for planning work in radiation environments. The system combines a radiation detection system, a computerized radiation imaging program, and computerized 3-D modeling to automatically locate and measurements are automatically collected and imaging techniques are used to produce colored, 'isodose' images of the measured radiation fields. The isodose lines from the images are then superimposed over the 3-D model of the area. The final display shows the various components in a room and their associated radiation fields. The use of an automated radiation detection system increases the quality of radiation survey obtained measurements. The additional use of a three-dimensional display allows easier visualization of the area and associated radiological conditions than two-dimensional sketches

  19. Conducting polymer 3D microelectrodes

    DEFF Research Database (Denmark)

    Sasso, Luigi; Vazquez, Patricia; Vedarethinam, Indumathi

    2010-01-01

    Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained...... showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared...

  20. 3D Printing A Survey

    Directory of Open Access Journals (Sweden)

    Muhammad Zulkifl Hasan

    2017-08-01

    Full Text Available Solid free fabrication SFF are produced to enhance the printing instrument utilizing distinctive strategies like Piezo spout control multi-spout injet printers or STL arrange utilizing cutting information. The procedure is utilized to diminish the cost and enhance the speed of printing. A few techniques take long at last because of extra process like dry the printing. This study will concentrate on SFFS utilizing UV gum for 3D printing.

  1. 3D printer electronics design

    OpenAIRE

    Cañete Vela, Isabel

    2014-01-01

    Nowadays, RepRap and Arduino communities have had an increasing progress. These terms are demarcated on the Open Source development model; the designs produced by these projects are released under the GNU General Public License, which promotes free universal access and distribution of it, allowing an exponential and rapid improvement. RepRap project uses Fused Additive manufacturing (FDM) technology, term used to refer to processes that make solid objects from 3D computer models. In particula...

  2. Wireless 3D Chocolate Printer

    OpenAIRE

    FROILAN G. DESTREZA; FRANCIS CARLO V. SOLLESTRE; MARJORIE V. VASQUEZ; FRANCIS B. MENDOZA

    2014-01-01

    This study is for the BSHRM Students of Batangas State University (BatStateU) ARASOF for the researchers believe that the Wireless 3D Chocolate Printer would be helpful in their degree program especially on making creative, artistic, personalized and decorative chocolate designs. The researchers used the Prototyping model as procedural method for the successful development and implementation of the hardware and software. This method has five phases which are the following: quick plan, quick d...

  3. [Real time 3D echocardiography

    Science.gov (United States)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  4. 3D silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Parzefall, Ulrich [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany)], E-mail: ulrich.parzefall@physik.uni-freiburg.de; Bates, Richard [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Boscardin, Maurizio [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy); Dalla Betta, Gian-Franco [INFN and Universita' di Trento, via Sommarive 14, 38050 Povo di Trento (Italy); Eckert, Simon [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Eklund, Lars; Fleta, Celeste [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Jakobs, Karl; Kuehn, Susanne [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Lozano, Manuel [Instituto de Microelectronica de Barcelona, IMB-CNM, CSIC, Barcelona (Spain); Pahn, Gregor [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Parkes, Chris [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Pellegrini, Giulio [Instituto de Microelectronica de Barcelona, IMB-CNM, CSIC, Barcelona (Spain); Pennicard, David [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Piemonte, Claudio; Ronchin, Sabina [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy); Szumlak, Tomasz [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Zoboli, Andrea [INFN and Universita' di Trento, via Sommarive 14, 38050 Povo di Trento (Italy); Zorzi, Nicola [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy)

    2009-06-01

    While the Large Hadron Collider (LHC) at CERN has started operation in autumn 2008, plans for a luminosity upgrade to the Super-LHC (sLHC) have already been developed for several years. This projected luminosity increase by an order of magnitude gives rise to a challenging radiation environment for tracking detectors at the LHC experiments. Significant improvements in radiation hardness are required with respect to the LHC. Using a strawman layout for the new tracker of the ATLAS experiment as an example, silicon strip detectors (SSDs) with short strips of 2-3 cm length are foreseen to cover the region from 28 to 60 cm distance to the beam. These SSD will be exposed to radiation levels up to 10{sup 15}N{sub eq}/cm{sup 2}, which makes radiation resistance a major concern for the upgraded ATLAS tracker. Several approaches to increasing the radiation hardness of silicon detectors exist. In this article, it is proposed to combine the radiation hard 3D-design originally conceived for pixel-style applications with the benefits of the established planar technology for strip detectors by using SSDs that have regularly spaced doped columns extending into the silicon bulk under the detector strips. The first 3D SSDs to become available for testing were made in the Single Type Column (STC) design, a technological simplification of the original 3D design. With such 3D SSDs, a small number of prototype sLHC detector modules with LHC-speed front-end electronics as used in the semiconductor tracking systems of present LHC experiments were built. Modules were tested before and after irradiation to fluences of 10{sup 15}N{sub eq}/cm{sup 2}. The tests were performed with three systems: a highly focused IR-laser with 5{mu}m spot size to make position-resolved scans of the charge collection efficiency, an Sr{sup 90}{beta}-source set-up to measure the signal levels for a minimum ionizing particle (MIP), and a beam test with 180 GeV pions at CERN. This article gives a brief overview of

  5. 3D print of polymer bonded rare-earth magnets, and 3D magnetic field scanning with an end-user 3D printer

    Science.gov (United States)

    Huber, C.; Abert, C.; Bruckner, F.; Groenefeld, M.; Muthsam, O.; Schuschnigg, S.; Sirak, K.; Thanhoffer, R.; Teliban, I.; Vogler, C.; Windl, R.; Suess, D.

    2016-10-01

    3D print is a recently developed technique, for single-unit production, and for structures that have been impossible to build previously. The current work presents a method to 3D print polymer bonded isotropic hard magnets with a low-cost, end-user 3D printer. Commercially available isotropic NdFeB powder inside a PA11 matrix is characterized, and prepared for the printing process. An example of a printed magnet with a complex shape that was designed to generate a specific stray field is presented, and compared with finite element simulation solving the macroscopic Maxwell equations. For magnetic characterization, and comparing 3D printed structures with injection molded parts, hysteresis measurements are performed. To measure the stray field outside the magnet, the printer is upgraded to a 3D magnetic flux density measurement system. To skip an elaborate adjusting of the sensor, a simulation is used to calibrate the angles, sensitivity, and the offset of the sensor. With this setup, a measurement resolution of 0.05 mm along the z-axes is achievable. The effectiveness of our calibration method is shown. With our setup, we are able to print polymer bonded magnetic systems with the freedom of having a specific complex shape with locally tailored magnetic properties. The 3D scanning setup is easy to mount, and with our calibration method we are able to get accurate measuring results of the stray field.

  6. NIKE3D, Static and Dynamic Response of 3-D Solids

    International Nuclear Information System (INIS)

    Hallquist, J.O.

    1996-01-01

    1 - Description of program or function: NIKE3D is a vectorized, fully implicit, three-dimensional, finite-element program for analyzing the finite-strain, static and dynamic response of inelastic solids, shells, and beams. Capabilities currently available include sliding interfaces, body force loads due to base acceleration, body force loads due to spinning (geometry dependent), concentrated nodal loads, pressure boundary conditions (geometry dependent), displacement boundary conditions, thermal stresses, plot-file generation, and problem restart. 2 - Method of solution: Spatial discretization is accomplished using eight-node solid elements that are integrated using a two-point Gauss quadrature rule, four-node shell elements that use a 2x2 Gauss integration in the surface and from 1 to 5 integration points through the thickness, and two-node thick beam elements using from 1 to 5 integration points in each local direction of the cross section at the center of the beam. Elastic, orthotropic elastic, elastic-plastic, thermo-elastic-plastic, soil and crushable foam, linear viscoelastic, thermo-orthotropic elastic, and thermo-elastic- creep material models are implemented. An incremental-interactive numerical algorithm, based on the Green-Naghdi and Jaumann stress rate formulations, is implemented in NIKE3D. Five iterative schemes are available including the BFGS quasi-Newton method, Broyden's quasi-Newton method, modified Newton-Raphson, full Newton, and full Newton with line search

  7. Fabrication and Deformation of 3D Multilayered Kirigami Microstructures.

    Science.gov (United States)

    Humood, Mohammad; Shi, Yan; Han, Mengdi; Lefebvre, Joseph; Yan, Zheng; Pharr, Matt; Zhang, Yihui; Huang, Yonggang; Rogers, John A; Polycarpou, Andreas A

    2018-03-01

    Mechanically guided 3D microassembly with controlled compressive buckling represents a promising emerging route to 3D mesostructures in a broad range of advanced materials, including single-crystalline silicon (Si), of direct relevance to microelectronic devices. During practical applications, the assembled 3D mesostructures and microdevices usually undergo external mechanical loading such as out-of-plane compression, which can induce damage in or failure of the structures/devices. Here, the mechanical responses of a few mechanically assembled 3D kirigami mesostructures under flat-punch compression are studied through combined experiment and finite element analyses. These 3D kirigami mesostructures consisting of a bilayer of Si and SU-8 epoxy are formed through integration of patterned 2D precursors with a prestretched elastomeric substrate at predefined bonding sites to allow controlled buckling that transforms them into desired 3D configurations. In situ scanning electron microscopy measurement enables detailed studies of the mechanical behavior of these structures. Analysis of the load-displacement curves allows the measurement of the effective stiffness and elastic recovery of various 3D structures. The compression experiments indicate distinct regimes in the compressive force/displacement curves and reveals different geometry-dependent deformation for the structures. Complementary computational modeling supports the experimental findings and further explains the geometry-dependent deformation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Interactive 3D Mars Visualization

    Science.gov (United States)

    Powell, Mark W.

    2012-01-01

    The Interactive 3D Mars Visualization system provides high-performance, immersive visualization of satellite and surface vehicle imagery of Mars. The software can be used in mission operations to provide the most accurate position information for the Mars rovers to date. When integrated into the mission data pipeline, this system allows mission planners to view the location of the rover on Mars to 0.01-meter accuracy with respect to satellite imagery, with dynamic updates to incorporate the latest position information. Given this information so early in the planning process, rover drivers are able to plan more accurate drive activities for the rover than ever before, increasing the execution of science activities significantly. Scientifically, this 3D mapping information puts all of the science analyses to date into geologic context on a daily basis instead of weeks or months, as was the norm prior to this contribution. This allows the science planners to judge the efficacy of their previously executed science observations much more efficiently, and achieve greater science return as a result. The Interactive 3D Mars surface view is a Mars terrain browsing software interface that encompasses the entire region of exploration for a Mars surface exploration mission. The view is interactive, allowing the user to pan in any direction by clicking and dragging, or to zoom in or out by scrolling the mouse or touchpad. This set currently includes tools for selecting a point of interest, and a ruler tool for displaying the distance between and positions of two points of interest. The mapping information can be harvested and shared through ubiquitous online mapping tools like Google Mars, NASA WorldWind, and Worldwide Telescope.

  9. Wireless 3D Chocolate Printer

    Directory of Open Access Journals (Sweden)

    FROILAN G. DESTREZA

    2014-02-01

    Full Text Available This study is for the BSHRM Students of Batangas State University (BatStateU ARASOF for the researchers believe that the Wireless 3D Chocolate Printer would be helpful in their degree program especially on making creative, artistic, personalized and decorative chocolate designs. The researchers used the Prototyping model as procedural method for the successful development and implementation of the hardware and software. This method has five phases which are the following: quick plan, quick design, prototype construction, delivery and feedback and communication. This study was evaluated by the BSHRM Students and the assessment of the respondents regarding the software and hardware application are all excellent in terms of Accuracy, Effecitveness, Efficiency, Maintainability, Reliability and User-friendliness. Also, the overall level of acceptability of the design project as evaluated by the respondents is excellent. With regard to the observation about the best raw material to use in 3D printing, the chocolate is good to use as the printed material is slightly distorted,durable and very easy to prepare; the icing is also good to use as the printed material is not distorted and is very durable but consumes time to prepare; the flour is not good as the printed material is distorted, not durable but it is easy to prepare. The computation of the economic viability level of 3d printer with reference to ROI is 37.14%. The recommendation of the researchers in the design project are as follows: adding a cooling system so that the raw material will be more durable, development of a more simplified version and improving the extrusion process wherein the user do not need to stop the printing process just to replace the empty syringe with a new one.

  10. A Localized Meshless Technique for Generating 3-D Wind Fields

    Directory of Open Access Journals (Sweden)

    Darrell W. Pepper

    2018-02-01

    Full Text Available A localized meshless method is used to simulate 3-D atmospheric wind fields for wind energy assessment and emergency response. The meshless (or mesh-free method with radial basis functions (RBFs alleviates the need to create a mesh required by finite difference, finite volume, and finite element methods. The method produces a fast solution that converges with high accuracy, establishing 3-D wind estimates over complex terrain. The method does not require discretization of the domain or boundary and removes the need for domain integration. The meshless method converges exponentially for smooth boundary shapes and boundary data, and is insensitive to dimensional constraints. Coding of the method is very easy and can be done using MATLAB or MAPLE. By employing a localized RBF procedure, 3-D wind fields can be established from sparse meteorological data. The meshless method can be easily run on PCs and hand-held mobile devices. This article summarizes previous work where the meshless method has successfully simulated 3D wind fields over various environments, along with the equations used to obtain the simulations.

  11. 3D Terahertz Beam Profiling

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Strikwerda, Andrew; Jepsen, Peter Uhd

    2013-01-01

    We present a characterization of THz beams generated in both a two-color air plasma and in a LiNbO3 crystal. Using a commercial THz camera, we record intensity images as a function of distance through the beam waist, from which we extract 2D beam profiles and visualize our measurements into 3D beam...... profiles. For the two-color air-plasma, we measure a conical beam profile that is focused to a bell-shape at the beam waist, whereas we observe a Gaussian beam profile for the THz beam generated from the LiNbO3 crystal....

  12. Virtual 3-D Facial Reconstruction

    Directory of Open Access Journals (Sweden)

    Martin Paul Evison

    2000-06-01

    Full Text Available Facial reconstructions in archaeology allow empathy with people who lived in the past and enjoy considerable popularity with the public. It is a common misconception that facial reconstruction will produce an exact likeness; a resemblance is the best that can be hoped for. Research at Sheffield University is aimed at the development of a computer system for facial reconstruction that will be accurate, rapid, repeatable, accessible and flexible. This research is described and prototypical 3-D facial reconstructions are presented. Interpolation models simulating obesity, ageing and ethnic affiliation are also described. Some strengths and weaknesses in the models, and their potential for application in archaeology are discussed.

  13. 3D Audio Acquisition and Reproduction Systems

    OpenAIRE

    Evrard, Marc; André, Cédric; Embrechts, Jean-Jacques; Verly, Jacques

    2011-01-01

    This presentation introduces two different research projects dealing with 3D audio for 3D-stereoscopic movies. The first project “3D audio acquisition for real time applications” studies the best method for acquiring a full 3D audio soundscape on location and for processing it in real-time for further reproduction. The second project “Adding 3D sound to 3D cinema” is aimed towards the study of reproducing a 3D soundscape consistent with the visual content of a 3D-stereoscopic movie. ...

  14. 3D Printable Graphene Composite

    Science.gov (United States)

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-07-01

    In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C-1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process.

  15. 3D printed bionic ears.

    Science.gov (United States)

    Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C

    2013-06-12

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing.

  16. LOTT RANCH 3D PROJECT

    International Nuclear Information System (INIS)

    Larry Lawrence; Bruce Miller

    2004-01-01

    The Lott Ranch 3D seismic prospect located in Garza County, Texas is a project initiated in September of 1991 by the J.M. Huber Corp., a petroleum exploration and production company. By today's standards the 126 square mile project does not seem monumental, however at the time it was conceived it was the most intensive land 3D project ever attempted. Acquisition began in September of 1991 utilizing GEO-SEISMIC, INC., a seismic data contractor. The field parameters were selected by J.M. Huber, and were of a radical design. The recording instruments used were GeoCor IV amplifiers designed by Geosystems Inc., which record the data in signed bit format. It would not have been practical, if not impossible, to have processed the entire raw volume with the tools available at that time. The end result was a dataset that was thought to have little utility due to difficulties in processing the field data. In 1997, Yates Energy Corp. located in Roswell, New Mexico, formed a partnership to further develop the project. Through discussions and meetings with Pinnacle Seismic, it was determined that the original Lott Ranch 3D volume could be vastly improved upon reprocessing. Pinnacle Seismic had shown the viability of improving field-summed signed bit data on smaller 2D and 3D projects. Yates contracted Pinnacle Seismic Ltd. to perform the reprocessing. This project was initiated with high resolution being a priority. Much of the potential resolution was lost through the initial summing of the field data. Modern computers that are now being utilized have tremendous speed and storage capacities that were cost prohibitive when this data was initially processed. Software updates and capabilities offer a variety of quality control and statics resolution, which are pertinent to the Lott Ranch project. The reprocessing effort was very successful. The resulting processed data-set was then interpreted using modern PC-based interpretation and mapping software. Production data, log data

  17. MAGNUS-3D: Accelerator magnet calculations in 3-dimensions

    Science.gov (United States)

    Pissanetzky, S.

    1988-12-01

    MAGNUS-3D is a professional finite element code for nonlinear magnetic engineering. MAGNUS-3D can solve numerically any general problem of linear or nonlinear magnetostatics in three dimensions. The problem is formulated in a domain with Dirichlet, Neumann or periodic boundary conditions, that can contain any combination of conductors of any shape in space, nonlinear magnetic materials with magnetic properties specified by magnetization tables, and nonlinear permanent magnets with any given demagnetization curve. MAGNUS-3D uses the two-scalar-potentials formulation of Magnetostatics and the finite element method, has an automatic 3D mesh generator, and advanced post-processing features that include graphics on a variety of supported devices, tabulation, and calculation of design quantities required in Magnetic Engineering. MAGNUS-3D is a general purpose 3D code, but it has been extensively used for accelerator work and many special features required for accelerator engineering have been incorporated into the code. One of such features is the calculation of field harmonic coefficients averaged in the direction of the beam, so important for the design of magnet ends. Another feature is its ability to calculate line integrals of any field component along the direction of the beam, or plot the field as a function of the z coordinate. MAGNUS-3D has found applications to the design of accelerator magnets and spectrometers, steering magnets, wigglers and undulators for free electron lasers, microtrons and magnets for synchrotron light sources, as well as magnets for NMR and medical applications, recording heads and various magnetic devices. There are three more programs closely associated with MAGNUS-3D. MAGNUS-GKS is the graphical postprocessor for the package; it supports a numer of output devices, including color vector or bit map devices. WIRE is an independent program that can calculate the field produced by any configuration of electric conductors in space, at any

  18. Use of 3D printed models in medical education: A randomized control trial comparing 3D prints versus cadaveric materials for learning external cardiac anatomy.

    Science.gov (United States)

    Lim, Kah Heng Alexander; Loo, Zhou Yaw; Goldie, Stephen J; Adams, Justin W; McMenamin, Paul G

    2016-05-06

    Three-dimensional (3D) printing is an emerging technology capable of readily producing accurate anatomical models, however, evidence for the use of 3D prints in medical education remains limited. A study was performed to assess their effectiveness against cadaveric materials for learning external cardiac anatomy. A double blind randomized controlled trial was undertaken on undergraduate medical students without prior formal cardiac anatomy teaching. Following a pre-test examining baseline external cardiac anatomy knowledge, participants were randomly assigned to three groups who underwent self-directed learning sessions using either cadaveric materials, 3D prints, or a combination of cadaveric materials/3D prints (combined materials). Participants were then subjected to a post-test written by a third party. Fifty-two participants completed the trial; 18 using cadaveric materials, 16 using 3D models, and 18 using combined materials. Age and time since completion of high school were equally distributed between groups. Pre-test scores were not significantly different (P = 0.231), however, post-test scores were significantly higher for 3D prints group compared to the cadaveric materials or combined materials groups (mean of 60.83% vs. 44.81% and 44.62%, P = 0.010, adjusted P = 0.012). A significant improvement in test scores was detected for the 3D prints group (P = 0.003) but not for the other two groups. The finding of this pilot study suggests that use of 3D prints do not disadvantage students relative to cadaveric materials; maximally, results suggest that 3D may confer certain benefits to anatomy learning and supports their use and ongoing evaluation as supplements to cadaver-based curriculums. Anat Sci Educ 9: 213-221. © 2015 American Association of Anatomists. © 2015 American Association of Anatomists.

  19. 3-D Vector Flow Imaging

    DEFF Research Database (Denmark)

    Holbek, Simon

    ultrasonic vector flow estimation and bring it a step closer to a clinical application. A method for high frame rate 3-D vector flow estimation in a plane using the transverse oscillation method combined with a 1024 channel 2-D matrix array is presented. The proposed method is validated both through phantom...... studies and in vivo. Phantom measurements are compared with their corresponding reference value, whereas the in vivo measurement is validated against the current golden standard for non-invasive blood velocity estimates, based on magnetic resonance imaging (MRI). The study concludes, that a high precision...... are introduced with the array. The major disadvantage with an RC transducer, is the limited field-of-view, which is restricted to the forward looking array. It is discussed, that this drawback may be solved with a diverging lens, providing a larger field-of-view, due the the dispersion of the energy. Based...

  20. Conducting Polymer 3D Microelectrodes

    Directory of Open Access Journals (Sweden)

    Jenny Emnéus

    2010-12-01

    Full Text Available Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described electrodes are possibly suitable for future in-vitro neurological measurements.

  1. 3D biometrics systems and applications

    CERN Document Server

    Zhang, David

    2013-01-01

    Includes discussions on popular 3D imaging technologies, combines them with biometric applications, and then presents real 3D biometric systems Introduces many efficient 3D feature extraction, matching, and fusion algorithms Techniques presented have been supported by experimental results using various 3D biometric classifications

  2. Supernova Remnant in 3-D

    Science.gov (United States)

    2009-01-01

    of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction. Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through. The blue filaments defining the blast wave were not mapped using the Doppler effect because they emit a different kind of light synchrotron radiation that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave. This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star. The flattened component that astronomers were unable to map into 3-D prior to these Spitzer observations consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as oxygen, neon, silicon, sulphur, argon and iron. High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of silicon appear in the northeast and southwest, while those of iron are seen in the southeast and north. These jets were already known and Doppler velocity measurements have been made for these structures, but their orientation and

  3. Embedding complex objects with 3d printing

    KAUST Repository

    Hussain, Muhammad Mustafa

    2017-10-12

    A CMOS technology-compatible fabrication process for flexible CMOS electronics embedded during additive manufacturing (i.e. 3D printing). A method for such a process may include printing a first portion of a 3D structure; pausing the step of printing the 3D structure to embed the flexible silicon substrate; placing the flexible silicon substrate in a cavity of the first portion of the 3D structure to embed the flexible silicon substrate in the 3D structure; and resuming the step of printing the 3D structure to form the second portion of the 3D structure.

  4. A non-conforming 3D spherical harmonic transport solver

    International Nuclear Information System (INIS)

    Van Criekingen, S.

    2006-01-01

    A new 3D transport solver for the time-independent Boltzmann transport equation has been developed. This solver is based on the second-order even-parity form of the transport equation. The angular discretization is performed through the expansion of the angular neutron flux in spherical harmonics (PN method). The novelty of this solver is the use of non-conforming finite elements for the spatial discretization. Such elements lead to a discontinuous flux approximation. This interface continuity requirement relaxation property is shared with mixed-dual formulations such as the ones based on Raviart-Thomas finite elements. Encouraging numerical results are presented. (authors)

  5. Interactive color display of 3-D engineering analysis results

    Science.gov (United States)

    Abel, John F.; Ingraffea, Anthony R.; Greenberg, Donald P.

    1987-01-01

    A general approach to three-dimensional postprocessing of engineering analyses is presented. The approach is versatile and may handle the results from a wide range of engineering analysis methods which involve the discretization of continua. To facilitate the understanding of complex three-dimensional numerical models, advanced interactive color postprocessing techniques are introduced. Finite element, finite difference, and boundary element models are evaluated with the prototype postprocessor. The existing color graphics program (POSTPRO3D) was ported to a high-resolution device. Interactive graphic tools were implemented to facilitate qualitative mesh evaluation from a single analysis. A postprocessing environment was design for workstation technology.

  6. Photopolymers in 3D printing applications

    OpenAIRE

    Pandey, Ramji

    2014-01-01

    3D printing is an emerging technology with applications in several areas. The flexibility of the 3D printing system to use variety of materials and create any object makes it an attractive technology. Photopolymers are one of the materials used in 3D printing with potential to make products with better properties. Due to numerous applications of photopolymers and 3D printing technologies, this thesis is written to provide information about the various 3D printing technologies with particul...

  7. Natural fibre composites for 3D Printing

    OpenAIRE

    Pandey, Kapil

    2015-01-01

    3D printing has been common option for prototyping. Not all the materials are suitable for 3D printing. Various studies have been done and still many are ongoing regarding the suitability of the materials for 3D printing. This thesis work discloses the possibility of 3D printing of certain polymer composite materials. The main objective of this thesis work was to study the possibility for 3D printing the polymer composite material composed of natural fibre composite and various different ...

  8. 3-D imaging with MDCT

    International Nuclear Information System (INIS)

    Rubin, Geoffrey D.

    2003-01-01

    Without doubt, the greatest challenge of multidetector-row CT is dealing with 'data explosion'. For our carotid/intracranial CT angiograms, we routinely have 375 images to review (300 mm coverage reconstructed every 0.8 mm); for aortic studies we have 450-500 images (∼600 mm coverage reconstructed every 1.3 mm); and for a study of the lower extremity inflow and run-off, we may generate 900-1000 transverse reconstructions. While we could reconstruct fewer images for these data, experience with single-detector row CT scanners indicates that longitudinal resolution and disease detection is improved when at least 50% overlap of cross-sections is generated [Radiology 200 (1996) 312]. If we are to optimize our clinical protocols and take full advantage of these CT scanners, we will need to change the way that we interpret, transfer, and store CT data. Film is no longer a viable option. Workstation based review of transverse reconstructions for interpretation is a necessity, but the workstations must improve to provide efficient access to these data, and we must have a way of providing our clinicians with images that can be transported to clinics and the operating room. Alternative visualization and analysis using volumetric tools, including 3-D visualization must evolve from luxury to necessity. We cannot rest on historical precedent to interpret these near isotropically sampled volumetric data using transverse reconstructions alone [Radiology 173 (1989) 527]. Although the tools for volumetric analysis on 3-D workstations have evolved over recent years, they have probably not yet evolved to a level that routine interpretation can be performed as efficiently and accurately as transverse section review. Both hardware and software developments must occur. While current computer workstations and visualization software are certainly adequate for assessing these MDCT data volumetrically, the process is very time consuming. What follows are a description of current

  9. 40 CFR 89.406 - Pre-test procedures.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Pre-test procedures. 89.406 Section 89.406 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Procedures § 89.406 Pre-test procedures. (a) Allow a minimum of 30 minutes warmup in the standby or operating...

  10. 3D Simulation of Nano-Imprint Lithography

    DEFF Research Database (Denmark)

    Román Marín, José Manuel; Rasmussen, Henrik K.; Hassager, Ole

    2010-01-01

    followed the line initiated by de Gennes, using a Molecular Stress Function model of the Doi and Edwards type. We have used a 3D Lagrangian Galerkin finite element methods implemented on a parallel computer architecture. In a Lagrangian techniques, the node point follows the particle movement, allowing...... for the movement of free surfaces or interfaces. We have extended the method to handle the dynamic movement of the contact line between the polymer melt and stamp during mold filling....

  11. CROWDSOURCING BASED 3D MODELING

    Directory of Open Access Journals (Sweden)

    A. Somogyi

    2016-06-01

    Full Text Available Web-based photo albums that support organizing and viewing the users’ images are widely used. These services provide a convenient solution for storing, editing and sharing images. In many cases, the users attach geotags to the images in order to enable using them e.g. in location based applications on social networks. Our paper discusses a procedure that collects open access images from a site frequently visited by tourists. Geotagged pictures showing the image of a sight or tourist attraction are selected and processed in photogrammetric processing software that produces the 3D model of the captured object. For the particular investigation we selected three attractions in Budapest. To assess the geometrical accuracy, we used laser scanner and DSLR as well as smart phone photography to derive reference values to enable verifying the spatial model obtained from the web-album images. The investigation shows how detailed and accurate models could be derived applying photogrammetric processing software, simply by using images of the community, without visiting the site.

  12. Numerical solution of 3D Stokes problems

    International Nuclear Information System (INIS)

    Zhou, R.Q.N.

    1993-01-01

    Preconditions conjugate gradient algorithms for solving 3D Stokes problems by stable piecewise discontinuous pressure finite elements are presented. The emphasis is on the preconditioning schemes and their numerical implementation for use with Hermitian-based discontinuous pressure elements. For the piecewise constant discontinuous pressure elements, a variant implementation of the preconditioner proposed by Cahouet and Chabard for the continuous pressure elements is employed. For the piecewise linear discontinuous pressure elements, a new preconditioner is presented. Numerical examples are presented for the cubic lid driven cavity problem with two representative elements (i.e., the Q2-P0 and the Q2-P1 brick elements). Numerical results show that the preconditioning schemes are very effective in reducing the number of pressure iterations at very reasonable costs. It is also shown that they are insensitive to the mesh Reynolds number, except for nearly steady flows (R em → 0), and are almost independent of mesh sizes. It is demonstrated that the schemes performed reasonably well on nonuniform meshes. 15 refs., 6 figs., 1 tab

  13. Laser Energy Deposition Model for the ICF3D Code

    Science.gov (United States)

    Kaiser, Thomas B.; Byers, Jack A.

    1996-11-01

    We have built a laser deposition module for the new ICF physics design code, ICF3D(``3D Unstructured Mesh ALE Hydrodynamics with the Upwind Discontinuous Finite Element Method,'' D. S. Kershaw, M. K. Prasad and M. J. Shaw,'' LLNL Report UCRL-JC-122104, (1995)), being developed at LLNL. The code uses a 3D unstructured grid on which hydrodynamic quantities are represented in terms of discontinuous linear finite elements (hexahedrons, prisms, tetrahedrons or pyramids). Because of the complex mesh geometry and (in general) non-uniform index of refraction (i.e., plasma density), the geometrical-optical ray-tracing problem is quite complicated. To solve it we have developed a grid-cell-face-crossing detection algorithm, an integrator for the ray equations of motion and a path-length calculator that are encapsulated in a C++ class that is used to create ray-bundle objects. Additional classes are being developed for inverse-bremsstrahlung and resonance-absorption heating models. A quasi-optical technique will be used to include diffractive effects. We use the ICF3D Python shell, a very flexible interface that allows command-line invocation of member functions.

  14. Vrste i tehnike 3D modeliranja

    OpenAIRE

    Bernik, Andrija

    2010-01-01

    Proces stvaranja 3D stvarnih ili imaginarnih objekata naziva se 3D modeliranje. Razvoj računalne tehnologije omogućuje korisniku odabir raznih metoda i tehnika kako bi se postigla optimalna učinkovitost. Odabir je vezan za klasično 3D modeliranje ili 3D skeniranje pomoću specijaliziranih programskih i sklopovskih rješenja. 3D tehnikama modeliranja korisnik može izraditi 3D model na nekoliko načina: koristi poligone, krivulje ili hibrid dviju spomenutih tehnika pod nazivom subdivizijsko modeli...

  15. Magma emplacement in 3D

    Science.gov (United States)

    Gorczyk, W.; Vogt, K.

    2017-12-01

    Magma intrusion is a major material transfer process in Earth's continental crust. Yet, the mechanical behavior of the intruding magma and its host are a matter of debate. In this study, we present a series of numerical thermo-mechanical experiments on mafic magma emplacement in 3D.In our model, we place the magmatic source region (40 km diameter) at the base of the mantle lithosphere and connect it to the crust by a 3 km wide channel, which may have evolved at early stages of magmatism during rapid ascent of hot magmatic fluids/melts. Our results demonstrate continental crustal response due to magma intrusion. We observe change in intrusion geometries between dikes, cone-sheets, sills, plutons, ponds, funnels, finger-shaped and stock-like intrusions as well as injection time. The rheology and temperature of the host-rock are the main controlling factors in the transition between these different modes of intrusion. Viscous deformation in the warm and deep crust favours host rock displacement and magma pools along the crust-mantle boundary forming deep-seated plutons or magma ponds in the lower to middle-crust. Brittle deformation in the cool and shallow crust induces cone-shaped fractures in the host rock and enables emplacement of finger- or stock-like intrusions at shallow or intermediate depth. A combination of viscous and brittle deformation forms funnel-shaped intrusions in the middle-crust. Low-density source magma results in T-shaped intrusions in cross-section with magma sheets at the surface.

  16. Single-sided sheet-to-tube spot welding investigated by 3D numerical simulations

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Chergui, Azeddine; Zhang, Wenqi

    The single-sided resistance spot welding process is analyzed by a 3D numerical study of sheet-to-tube joining. Finite element simulations are carried out in SORPAS® 3D. Two levels of electrode force and five levels of welding current are simulated. The overall effects of changing current and force...

  17. NASA-VOF3D, 3-D Transient, Free Surface, Incompressible Fluid Dynamic

    International Nuclear Information System (INIS)

    Torrey, M.D.

    1992-01-01

    1 - Description of program or function: NASA-VOF3D is a three- dimensional, transient, free surface, incompressible fluid dynamics program. It is specifically designed to calculate confined flows in a low gravity environment in which surface physics must be accurately treated. It allows multiple free surfaces with surface tension and wall adhesion and includes a partial cell treatment that allows curved boundaries and internal obstacles. Variable mesh spacing is permitted in all three coordinate directions. Boundary conditions available are rigid free-slip wall, rigid no-slip, wall, continuative, periodic, and specified pressure outflow boundary. 2 - Method of solution: NASA-VOF3D simulates incompressible flows with free surfaces using the volume-of-fluid (VOF) algorithm. This technique is based on the use of donor-acceptor differencing to track the free surface across an Eulerian grid. The free surfaces are treated by introducing a function defined to be unity at any point occupied by the fluid and zero elsewhere. The complete Navier- Stokes equations for an incompressible fluid are solved by finite differences with surface tension effects included. Wall adhesion may be included or neglected as a user option. The pressures (and velocities) are advanced in time throughout the computing mesh by either a conjugate residual method or the successive over-relaxation (SOR) method. The conjugate residual method is vectorized for the Cray and uses a scaled coefficient matrix. 3 - Restrictions on the complexity of the problem: NASA-VOF3D is restricted to cylindrical coordinate representation of the geometry. A three-dimensional wall-adhesion procedure is available only for straight-walled containers

  18. 3D ultrasound in fetal spina bifida.

    Science.gov (United States)

    Schramm, T; Gloning, K-P; Minderer, S; Tutschek, B

    2008-12-01

    3D ultrasound can be used to study the fetal spine, but skeletal mode can be inconclusive for the diagnosis of fetal spina bifida. We illustrate a diagnostic approach using 2D and 3D ultrasound and indicate possible pitfalls.

  19. Will 3D printers manufacture your meals?

    NARCIS (Netherlands)

    Bommel, K.J.C. van

    2013-01-01

    These days, 3D printers are laying down plastics, metals, resins, and other materials in whatever configurations creative people can dream up. But when the next 3D printing revolution comes, you'll be able to eat it.

  20. 3D Scanning technology for offshore purposes

    DEFF Research Database (Denmark)

    Christoffersen, Morten Thoft

    2005-01-01

    New scanning technology makes for construction of precision 3D models of production plants and offshore production facilities......New scanning technology makes for construction of precision 3D models of production plants and offshore production facilities...

  1. Eesti 3D jaoks kitsas / Virge Haavasalu

    Index Scriptorium Estoniae

    Haavasalu, Virge

    2009-01-01

    Produktsioonifirma Digitaalne Sputnik: Kaur ja Kaspar Kallas tegelevad filmide produtseerimise ning 3D digitaalkaamerate tootearendusega (Silicon Imaging LLC). Vendade Kallaste 3D-kaamerast. Kommenteerib Eesti Filmi Sihtasutuse direktor Marge Liiske

  2. Nanosensor Fabrication with 3D Manufacturing Techniques

    Data.gov (United States)

    National Aeronautics and Space Administration — We use 3D manufacturing techniques to fabricate sensors based on nanomaterials. We use 3D manufacturing techniques to fabricate sensors based on nanomaterials. This...

  3. 3D vizualizace budov kampusu Albertov

    OpenAIRE

    Peterková, Tereza

    2012-01-01

    3D vizualization campus buildings Albertov Abstract This work deals with theoretical and practical aspects of 3D countryside model creation and housing development with the help of geoinformation technologies, concretely programme equipment ESRI ArcGIS and Google SketchUp. The first part of the work brings a general overview concerning the problematics of 3D simulating and the possibilities of 3D information representation. It also includes a survey of already elaborated projects focused on v...

  4. 3D-Printed Millimeter Wave Structures

    Science.gov (United States)

    2016-03-14

    demonstrates the resolution of the printer with a 10 micron nozzle. Figure 2: Measured loss tangent of SEBS and SBS samples. 3D - Printed Millimeter... 3D printing of styrene-butadiene-styrene (SBS) and styrene ethylene/butylene-styrene (SEBS) is used to demonstrate the feasibility of 3D - printed ...Additionally, a dielectric lens is printed which improves the antenna gain of an open-ended WR-28 waveguide from 7 to 8.5 dBi. Keywords: 3D printing

  5. Digital Dentistry — 3D Printing Applications

    OpenAIRE

    Zaharia Cristian; Gabor Alin-Gabriel; Gavrilovici Andrei; Stan Adrian Tudor; Idorasi Laura; Sinescu Cosmin; Negruțiu Meda-Lavinia

    2017-01-01

    Three-dimensional (3D) printing is an additive manufacturing method in which a 3D item is formed by laying down successive layers of material. 3D printers are machines that produce representations of objects either planned with a CAD program or scanned with a 3D scanner. Printing is a method for replicating text and pictures, typically with ink on paper. We can print different dental pieces using different methods such as selective laser sintering (SLS), stereolithography, fused deposition mo...

  6. Beowulf 3D: a case study

    Science.gov (United States)

    Engle, Rob

    2008-02-01

    This paper discusses the creative and technical challenges encountered during the production of "Beowulf 3D," director Robert Zemeckis' adaptation of the Old English epic poem and the first film to be simultaneously released in IMAX 3D and digital 3D formats.

  7. 3D immersive and interactive learning

    CERN Document Server

    Cai, Yiyu

    2014-01-01

    This book reviews innovative uses of 3D for immersive and interactive learning, covering gifted programs, normal stream and special needs education. Reports on curriculum-based 3D learning in classrooms, and co-curriculum-based 3D student research projects.

  8. 3D-Printable Antimicrobial Composite Resins

    NARCIS (Netherlands)

    Yue, Jun; Zhao, Pei; Gerasimov, Jennifer Y.; van de Lagemaat, Marieke; Grotenhuis, Arjen; Rustema-Abbing, Minie; van der Mei, Henny C.; Busscher, Henk J.; Herrmann, Andreas; Ren, Yijin

    2015-01-01

    3D printing is seen as a game-changing manufacturing process in many domains, including general medicine and dentistry, but the integration of more complex functions into 3D-printed materials remains lacking. Here, it is expanded on the repertoire of 3D-printable materials to include antimicrobial

  9. 3D Printing and Its Urologic Applications.

    Science.gov (United States)

    Soliman, Youssef; Feibus, Allison H; Baum, Neil

    2015-01-01

    3D printing is the development of 3D objects via an additive process in which successive layers of material are applied under computer control. This article discusses 3D printing, with an emphasis on its historical context and its potential use in the field of urology.

  10. Expanding Geometry Understanding with 3D Printing

    Science.gov (United States)

    Cochran, Jill A.; Cochran, Zane; Laney, Kendra; Dean, Mandi

    2016-01-01

    With the rise of personal desktop 3D printing, a wide spectrum of educational opportunities has become available for educators to leverage this technology in their classrooms. Until recently, the ability to create physical 3D models was well beyond the scope, skill, and budget of many schools. However, since desktop 3D printers have become readily…

  11. Imaging a Sustainable Future in 3D

    Science.gov (United States)

    Schuhr, W.; Lee, J. D.; Kanngieser, E.

    2012-07-01

    It is the intention of this paper, to contribute to a sustainable future by providing objective object information based on 3D photography as well as promoting 3D photography not only for scientists, but also for amateurs. Due to the presentation of this article by CIPA Task Group 3 on "3D Photographs in Cultural Heritage", the presented samples are masterpieces of historic as well as of current 3D photography concentrating on cultural heritage. In addition to a report on exemplarily access to international archives of 3D photographs, samples for new 3D photographs taken with modern 3D cameras, as well as by means of a ground based high resolution XLITE staff camera and also 3D photographs taken from a captive balloon and the use of civil drone platforms are dealt with. To advise on optimum suited 3D methodology, as well as to catch new trends in 3D, an updated synoptic overview of the 3D visualization technology, even claiming completeness, has been carried out as a result of a systematic survey. In this respect, e.g., today's lasered crystals might be "early bird" products in 3D, which, due to lack in resolution, contrast and color, remember to the stage of the invention of photography.

  12. 3D Characterization of Recrystallization Boundaries

    DEFF Research Database (Denmark)

    Zhang, Yubin; Godfrey, Andrew William; MacDonald, A. Nicole

    2016-01-01

    A three-dimensional (3D) volume containing a recrystallizing grain and a deformed matrix in a partially recrystallized pure aluminum was characterized using the 3D electron backscattering diffraction technique. The 3D shape of a recrystallizing boundary, separating the recrystallizing grain...

  13. 3D modelling for multipurpose cadastre

    NARCIS (Netherlands)

    Abduhl Rahman, A.; Van Oosterom, P.J.M.; Hua, T.C.; Sharkawi, K.H.; Duncan, E.E.; Azri, N.; Hassan, M.I.

    2012-01-01

    Three-dimensional (3D) modelling of cadastral objects (such as legal spaces around buildings, around utility networks and other spaces) is one of the important aspects for a multipurpose cadastre (MPC). This paper describes the 3D modelling of the objects for MPC and its usage to the knowledge of 3D

  14. Recent progress in modelling 3D lithospheric deformation

    Science.gov (United States)

    Kaus, B. J. P.; Popov, A.; May, D. A.

    2012-04-01

    Modelling 3D lithospheric deformation remains a challenging task, predominantly because the variations in rock types, as well as nonlinearities due to for example plastic deformation result in sharp and very large jumps in effective viscosity contrast. As a result, there are only a limited number of 3D codes available, most of which are using direct solvers which are computationally and memory-wise very demanding. As a result, the resolutions for typical model runs are quite modest, despite the use of hundreds of processors (and using much larger computers is unlikely to bring much improvement in this situation). For this reason we recently developed a new 3D deformation code,called LaMEM: Lithosphere and Mantle Evolution Model. LaMEM is written on top of PETSc, and as a result it runs on massive parallel machines and we have a large number of iterative solvers available (including geometric and algebraic multigrid methods). As it remains unclear which solver combinations work best under which conditions, we have implemented most currently suggested methods (such as schur complement reduction or Fully coupled iterations). In addition, we can use either a finite element discretization (with Q1P0, stabilized Q1Q1 or Q2P-1 elements) or a staggered finite difference discretization for the same input geometry, which is based on a marker and cell technique). This gives us he flexibility to test various solver methodologies on the same model setup, in terms of accuracy, speed, memory usage etc. Here, we will report on some features of LaMEM, on recent code additions, as well as on some lessons we learned which are important for modelling 3D lithospheric deformation. Specifically we will discuss: 1) How we combine a particle-and-cell method to make it work with both a finite difference and a (lagrangian, eulerian or ALE) finite element formulation, with only minor code modifications code 2) How finite difference and finite element discretizations compare in terms of

  15. ALE3D: An Arbitrary Lagrangian-Eulerian Multi-Physics Code

    Energy Technology Data Exchange (ETDEWEB)

    Noble, Charles R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Anderson, Andrew T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Barton, Nathan R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bramwell, Jamie A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Capps, Arlie [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chang, Michael H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chou, Jin J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dawson, David M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Diana, Emily R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dunn, Timothy A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Faux, Douglas R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fisher, Aaron C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Greene, Patrick T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Heinz, Ines [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kanarska, Yuliya [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Khairallah, Saad A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Liu, Benjamin T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Margraf, Jon D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nichols, Albert L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nourgaliev, Robert N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Puso, Michael A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reus, James F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Robinson, Peter B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shestakov, Alek I. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Solberg, Jerome M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Taller, Daniel [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tsuji, Paul H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); White, Christopher A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); White, Jeremy L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-05-23

    ALE3D is a multi-physics numerical simulation software tool utilizing arbitrary-Lagrangian- Eulerian (ALE) techniques. The code is written to address both two-dimensional (2D plane and axisymmetric) and three-dimensional (3D) physics and engineering problems using a hybrid finite element and finite volume formulation to model fluid and elastic-plastic response of materials on an unstructured grid. As shown in Figure 1, ALE3D is a single code that integrates many physical phenomena.

  16. 2D and 3D Modeling Comparison

    OpenAIRE

    Gaidyte, Rita

    2010-01-01

    Many inventors and companies still use 2D drawings and are starting to realize a 3D design because 3D modeling can save time and money. In this project I am going to compare 2D and 3D drawings and modeling. 2D modeling and 3D modeling have advantages and disadvantages. For this comparison I made 2D and 3D models using AutoCAD, Autodesk Revit Architectural and Revit MEP software. So, I am going to compare CAD (Computer-aided design) and BIM (Building Information Modeling) technologies, beca...

  17. PRIPRAVA MODELOV ZA 3D - TISK

    OpenAIRE

    Črešnik, Igor

    2015-01-01

    V diplomskem delu predstavljamo pripravo modela na 3D-tisk. V prvem delu smo preleteli zgodovino tiska. Predstavili smo tehnologijo 3D-tiska ter različne tehnike tiskanja, ki jih uporabljajo določeni tiskalniki. V nadaljevanju smo pregledali različne tipe 3D-tiskalnikov, ki se uporabljajo za domačo ali komercialno uporabo ter izpostavili njihove prednosti in slabosti. V zadnjem delu diplomskega dela smo na praktičnem primeru 3D-modela hiše prikazali proces priprave modela za 3D-tisk. Pri delu...

  18. Wafer level 3-D ICs process technology

    CERN Document Server

    Tan, Chuan Seng; Reif, L Rafael

    2009-01-01

    This book focuses on foundry-based process technology that enables the fabrication of 3-D ICs. The core of the book discusses the technology platform for pre-packaging wafer lever 3-D ICs. However, this book does not include a detailed discussion of 3-D ICs design and 3-D packaging. This is an edited book based on chapters contributed by various experts in the field of wafer-level 3-D ICs process technology. They are from academia, research labs and industry.

  19. View-based 3-D object retrieval

    CERN Document Server

    Gao, Yue

    2014-01-01

    Content-based 3-D object retrieval has attracted extensive attention recently and has applications in a variety of fields, such as, computer-aided design, tele-medicine,mobile multimedia, virtual reality, and entertainment. The development of efficient and effective content-based 3-D object retrieval techniques has enabled the use of fast 3-D reconstruction and model design. Recent technical progress, such as the development of camera technologies, has made it possible to capture the views of 3-D objects. As a result, view-based 3-D object retrieval has become an essential but challenging res

  20. 3D Printing of Fluid Flow Structures

    OpenAIRE

    Taira, Kunihiko; Sun, Yiyang; Canuto, Daniel

    2017-01-01

    We discuss the use of 3D printing to physically visualize (materialize) fluid flow structures. Such 3D models can serve as a refreshing hands-on means to gain deeper physical insights into the formation of complex coherent structures in fluid flows. In this short paper, we present a general procedure for taking 3D flow field data and producing a file format that can be supplied to a 3D printer, with two examples of 3D printed flow structures. A sample code to perform this process is also prov...

  1. Case study: Beauty and the Beast 3D: benefits of 3D viewing for 2D to 3D conversion

    Science.gov (United States)

    Handy Turner, Tara

    2010-02-01

    From the earliest stages of the Beauty and the Beast 3D conversion project, the advantages of accurate desk-side 3D viewing was evident. While designing and testing the 2D to 3D conversion process, the engineering team at Walt Disney Animation Studios proposed a 3D viewing configuration that not only allowed artists to "compose" stereoscopic 3D but also improved efficiency by allowing artists to instantly detect which image features were essential to the stereoscopic appeal of a shot and which features had minimal or even negative impact. At a time when few commercial 3D monitors were available and few software packages provided 3D desk-side output, the team designed their own prototype devices and collaborated with vendors to create a "3D composing" workstation. This paper outlines the display technologies explored, final choices made for Beauty and the Beast 3D, wish-lists for future development and a few rules of thumb for composing compelling 2D to 3D conversions.

  2. Prediction of Student Performance Through Pretesting in Food and Nutrition

    Science.gov (United States)

    Carruth, Betty Ruth; Lamb, Mina W.

    1971-01-01

    Attempts to develop an objective pretest for identifying students' levels of knowledge in food and nutrition prior to class instruction and for predicting student performance on the final examination. (Editor/MU)

  3. Markerless 3D facial motion capture system

    Science.gov (United States)

    Hwang, Youngkyoo; Kim, Jung-Bae; Feng, Xuetao; Bang, Won-Chul; Rhee, Taehyun; Kim, James D. K.; Kim, ChangYeong

    2012-03-01

    We propose a novel markerless 3D facial motion capture system using only one common camera. This system is simple and easy to transfer facial expressions of a user's into virtual world. It has robustly tracking facial feature points associated with head movements. In addition, it estimates high accurate 3D points' locations. We designed novel approaches to the followings; Firstly, for precisely 3D head motion tracking, we applied 3D constraints using a 3D face model on conventional 2D feature points tracking approach, called Active Appearance Model (AAM). Secondly, for dealing with various expressions of a user's, we designed 2D face generic models from around 5000 images data and 3D shape data including symmetric and asymmetric facial expressions. Lastly, for accurately facial expression cloning, we invented a manifold space to successfully transfer 2D low dimensional feature points to 3D high dimensional points. The manifold space is defined by eleven facial expression bases.

  4. Application of 3D Laser Scanning Technology in Complex Rock Foundation Design

    Science.gov (United States)

    Junjie, Ma; Dan, Lu; Zhilong, Liu

    2017-12-01

    Taking the complex landform of Tanxi Mountain Landscape Bridge as an example, the application of 3D laser scanning technology in the mapping of complex rock foundations is studied in this paper. A set of 3D laser scanning technologies are formed and several key engineering problems are solved. The first is 3D laser scanning technology of complex landforms. 3D laser scanning technology is used to obtain a complete 3D point cloud data model of the complex landform. The detailed and accurate results of the surveying and mapping decrease the measuring time and supplementary measuring times. The second is 3D collaborative modeling of the complex landform. A 3D model of the complex landform is established based on the 3D point cloud data model. The super-structural foundation model is introduced for 3D collaborative design. The optimal design plan is selected and the construction progress is accelerated. And the last is finite-element analysis technology of the complex landform foundation. A 3D model of the complex landform is introduced into ANSYS for building a finite element model to calculate anti-slide stability of the rock, and provides a basis for the landform foundation design and construction.

  5. Accelerated 3D Upper Airway MRI using Compressed Sensing

    Science.gov (United States)

    Kim, Yoon-Chul; Narayanan, Shrikanth S.; Nayak, Krishna S.

    2014-01-01

    In speech-production research, 3D MRI of the upper airway has provided insights into vocal tract shaping and data for its modeling. Small movements of articulators can lead to large changes in the produced sound, therefore improving the resolution of these datasets, within the constraints of a sustained speech sound (6-12 seconds), is an important area for investigation. The purpose of the study is to provide a first application of compressed sensing (CS) to high-resolution 3D upper airway MRI using spatial finite difference as the sparsifying transform, and to experimentally determine the benefit of applying constraints on image phase. Estimates of image phase are incorporated into the CS reconstruction to improve the sparsity of the finite difference of the solution. In a retrospective sub-sampling experiment with no sound production, 5x and 4x were the highest acceleration factors that produced acceptable image quality when using a phase constraint and when not using a phase constraint, respectively. The prospective use of a 5x undersampled acquisition and phase-constrained CS reconstruction enabled 3D vocal tract MRI during sustained sound production of English consonants /s/, /∫/, /l/, and /r/ with 1.5 × 1.5 × 2.0 mm3 spatial resolution and 7 seconds of scan time. PMID:19353675

  6. 3-D Technology Approaches for Biological Ecologies

    Science.gov (United States)

    Liu, Liyu; Austin, Robert; U. S-China Physical-Oncology Sciences Alliance (PS-OA) Team

    Constructing three dimensional (3-D) landscapes is an inevitable issue in deep study of biological ecologies, because in whatever scales in nature, all of the ecosystems are composed by complex 3-D environments and biological behaviors. Just imagine if a 3-D technology could help complex ecosystems be built easily and mimic in vivo microenvironment realistically with flexible environmental controls, it will be a fantastic and powerful thrust to assist researchers for explorations. For years, we have been utilizing and developing different technologies for constructing 3-D micro landscapes for biophysics studies in in vitro. Here, I will review our past efforts, including probing cancer cell invasiveness with 3-D silicon based Tepuis, constructing 3-D microenvironment for cell invasion and metastasis through polydimethylsiloxane (PDMS) soft lithography, as well as explorations of optimized stenting positions for coronary bifurcation disease with 3-D wax printing and the latest home designed 3-D bio-printer. Although 3-D technologies is currently considered not mature enough for arbitrary 3-D micro-ecological models with easy design and fabrication, I hope through my talk, the audiences will be able to sense its significance and predictable breakthroughs in the near future. This work was supported by the State Key Development Program for Basic Research of China (Grant No. 2013CB837200), the National Natural Science Foundation of China (Grant No. 11474345) and the Beijing Natural Science Foundation (Grant No. 7154221).

  7. RT3D tutorials for GMS users

    Energy Technology Data Exchange (ETDEWEB)

    Clement, T.P. [Pacific Northwest National Lab., Richland, WA (United States); Jones, N.L. [Brigham Young Univ., Provo, UT (United States)

    1998-02-01

    RT3D (Reactive Transport in 3-Dimensions) is a computer code that solves coupled partial differential equations that describe reactive-flow and transport of multiple mobile and/or immobile species in a three dimensional saturated porous media. RT3D was developed from the single-species transport code, MT3D (DoD-1.5, 1997 version). As with MT3D, RT3D also uses the USGS groundwater flow model MODFLOW for computing spatial and temporal variations in groundwater head distribution. This report presents a set of tutorial problems that are designed to illustrate how RT3D simulations can be performed within the Department of Defense Groundwater Modeling System (GMS). GMS serves as a pre- and post-processing interface for RT3D. GMS can be used to define all the input files needed by RT3D code, and later the code can be launched from within GMS and run as a separate application. Once the RT3D simulation is completed, the solution can be imported to GMS for graphical post-processing. RT3D v1.0 supports several reaction packages that can be used for simulating different types of reactive contaminants. Each of the tutorials, described below, provides training on a different RT3D reaction package. Each reaction package has different input requirements, and the tutorials are designed to describe these differences. Furthermore, the tutorials illustrate the various options available in GMS for graphical post-processing of RT3D results. Users are strongly encouraged to complete the tutorials before attempting to use RT3D and GMS on a routine basis.

  8. Numerical solution of several 2D and 3D internal flow problems

    Science.gov (United States)

    Fialová, M.; Fořt, J.; Fürst, J.; Huněk, M.; Kozel, K.

    The work deals with numerical solution of 3D Euler and 2D or 3D Navier-Stokes equations. Incompressible, subsonic and transonic flow through a cascade or in a channel of constant cross-section is numerically solved. Two versions of Lax-Wendroff type finite volume schemes and Runge-Kutta scheme were developed for 3D computations. The work presents some 2D and 3D results of laminar viscous flows through a cascade or in a channel as well as 2D results achieved by ENO scheme. The results of cascade computation are compared with experimental measurement.

  9. Role of 3D animation in periodontal patient education: a randomized controlled trial.

    Science.gov (United States)

    Cleeren, Gertjan; Quirynen, Marc; Ozcelik, Onur; Teughels, Wim

    2014-01-01

    This randomized controlled parallel trial investigates the effect of 3D animation on the increase and recall of knowledge on periodontitis by patients with periodontitis. The effects of a 3D animation (3D animation group) were compared with narration and drawing (control group) for periodontal patient education. A total of 68 periodontitis patients were stratified according to educational level and then randomly allocated to control or 3D animation groups. All patients received: (1) a pre-test (baseline knowledge), (2) a patient education video (3D animation or control video), (3) a post-test (knowledge immediately after looking at the video), and (4) a follow-up test (knowledge recall after 2 weeks). Each test contained 10 multiple-choice questions. There was no significant difference in baseline knowledge. Patients receiving the 3D animations had significantly higher scores for both the post-test and the follow-up test, when compared with patients receiving sketch animations. 3D animations are more effective than real-time drawings for periodontal patient education in terms of knowledge recall. 3D animations may be a powerful tool for assisting in the information process. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Identification of the transition arrays 3d74s-3d74p in Br X and 3d64s-3d64p in Br XI

    International Nuclear Information System (INIS)

    Zeng, X.T.; Jupen, C.; Bengtsson, P.; Engstroem, L.; Westerlind, M.; Martinson, I.

    1991-01-01

    We report a beam-foil study of multiply ionized bromine in the region 400-1300A, performed with 6 and 8 MeV Br ions from a tandem accelerator. At these energies transitions belonging to Fe-like Br X and Mn-like Br XI are expected to be prominent. We have identified 31 lines as 3d 7 4s-3d 7 4p transitions in Br X, from which 16 levels of the previously unknown 3d 7 4s configuration could be established. We have also added 6 new 3d 7 4p levels to the 99 previously known. For Br XI we have classified 9 lines as 3d 6 4s-3d 6 4p combinations. The line identifications have been corroborated by isoelectronic comparisons and theoretical calculations using the superposition-of-configurations technique. (orig.)

  11. 3D PHOTOGRAPHS IN CULTURAL HERITAGE

    Directory of Open Access Journals (Sweden)

    W. Schuhr

    2013-07-01

    Full Text Available This paper on providing "oo-information" (= objective object-information on cultural monuments and sites, based on 3D photographs is also a contribution of CIPA task group 3 to the 2013 CIPA Symposium in Strasbourg. To stimulate the interest in 3D photography for scientists as well as for amateurs, 3D-Masterpieces are presented. Exemplary it is shown, due to their high documentary value ("near reality", 3D photography support, e.g. the recording, the visualization, the interpretation, the preservation and the restoration of architectural and archaeological objects. This also includes samples for excavation documentation, 3D coordinate calculation, 3D photographs applied for virtual museum purposes and as educational tools. In addition 3D photography is used for virtual museum purposes, as well as an educational tool and for spatial structure enhancement, which in particular holds for inscriptions and in rock arts. This paper is also an invitation to participate in a systematic survey on existing international archives of 3D photographs. In this respect it is also reported on first results, to define an optimum digitization rate for analog stereo views. It is more than overdue, in addition to the access to international archives for 3D photography, the available 3D photography data should appear in a global GIS(cloud-system, like on, e.g., google earth. This contribution also deals with exposing new 3D photographs to document monuments of importance for Cultural Heritage, including the use of 3D and single lense cameras from a 10m telescope staff, to be used for extremely low earth based airborne 3D photography, as well as for "underwater staff photography". In addition it is reported on the use of captive balloon and drone platforms for 3D photography in Cultural Heritage. It is liked to emphasize, the still underestimated 3D effect on real objects even allows, e.g., the spatial perception of extremely small scratches as well as of nuances in

  12. SALE-3D, 3-D Fluid Flow, Navier Stokes Equation Using Lagrangian or Eulerian Method

    International Nuclear Information System (INIS)

    Amsden, A.A.; Ruppel, H.M.

    1991-01-01

    1 - Description of problem or function: SALE-3D calculates three- dimensional fluid flows at all speeds, from the incompressible limit to highly supersonic. An implicit treatment of the pressure calculation similar to that in the Implicit Continuous-fluid Eulerian (ICE) technique provides this flow speed flexibility. In addition, the computing mesh may move with the fluid in a typical Lagrangian fashion, be held fixed in an Eulerian manner, or move in some arbitrarily specified way to provide a continuous rezoning capability. This latitude results from use of an Arbitrary Lagrangian-Eulerian (ALE) treatment of the mesh. The partial differential equations solved are the Navier-Stokes equations and the mass and internal energy equations. The fluid pressure is determined from an equation of state and supplemented with an artificial viscous pressure for the computation of shock waves. The computing mesh consists of a three-dimensional network of arbitrarily shaped, six-sided deformable cells, and a variety of user-selectable boundary conditions are provided in the program. 2 - Method of solution: SALE3D uses an ICED-ALE technique, which combines the ICE method of treating flow speeds and the ALE mesh treatment to calculate three-dimensional fluid flow. The finite- difference approximations to the conservation of mass, momentum, and specific internal energy differential equations are solved in a sequence of time steps on a network of deformable computational cells. The basic hydrodynamic part of each cycle is divided into three phases: (1) an explicit solution of the Lagrangian equations of motion updating the velocity field by the effects of all forces, (2) an implicit calculation using Newton-Raphson iterative scheme that provides time-advanced pressures and velocities, and (3) the addition of advective contributions for runs that are Eulerian or contain some relative motion of grid and fluid. A powerful feature of this three-phases approach is the ease with which

  13. 3D Systems” ‘Stuck in the Middle’ of the 3D Printer Boom?

    NARCIS (Netherlands)

    A. Hoffmann (Alan)

    2014-01-01

    textabstract3D Systems, the pioneer of 3D printing, predicted a future where "kids from 8 to 80" could design and print their ideas at home. By 2013, 9 years after the creation of the first working 3D printer, there were more than 30 major 3D printing companies competing for market share. 3DS and

  14. Educational Online 3D Workshop Simulations

    OpenAIRE

    Unver, Ertu; Taylor, Andrew

    2009-01-01

    This paper describes the stages in the development of an online 3D interactive virtual learning environment for use in art and design higher education. The 3D interactive environment enables users to experiment within virtual workshop and studio spaces independently or as multi-user groups. The environment will create opportunities for adding interactive 3D on-line teaching support materials, links to ‘live’ lectures and provides real-time distance communication learning and training experien...

  15. ERP system for 3D printing industry

    Directory of Open Access Journals (Sweden)

    Deaky Bogdan

    2017-01-01

    Full Text Available GOCREATE is an original cloud-based production management and optimization service which helps 3D printing service providers to use their resources better. The proposed Enterprise Resource Planning system can significantly increase income through improved productivity. With GOCREATE, the 3D printing service providers get a much higher production efficiency at a much lower licensing cost, to increase their competitiveness in the fast growing 3D printing market.

  16. 3D Face Modeling based on 3D Dense Morphable Face Shape Model

    OpenAIRE

    Yongsuk Jang Kim; Sun-Tae Chung; Boogyun Kim; Seongwon Cho

    2008-01-01

    Realistic 3D face model is more precise in representing pose, illumination, and expression of face than 2D face model so that it can be utilized usefully in various applications such as face recognition, games, avatars, animations, and etc. In this paper, we propose a 3D face modeling method based on 3D dense morphable shape model. The proposed 3D modeling method first constructs a 3D dense morphable shape model from 3D face scan data obtained using a 3D scanner. Next, th...

  17. 3-D Printed Habitat - Design Competition

    Data.gov (United States)

    National Aeronautics and Space Administration — The 3D-Printed Habitat Challenge seeks to develop the fundamental technologies necessary to manufacture habitats using indigenous materials, including recycled...

  18. Dimensional accuracy of 3D printed vertebra

    Science.gov (United States)

    Ogden, Kent; Ordway, Nathaniel; Diallo, Dalanda; Tillapaugh-Fay, Gwen; Aslan, Can

    2014-03-01

    3D printer applications in the biomedical sciences and medical imaging are expanding and will have an increasing impact on the practice of medicine. Orthopedic and reconstructive surgery has been an obvious area for development of 3D printer applications as the segmentation of bony anatomy to generate printable models is relatively straightforward. There are important issues that should be addressed when using 3D printed models for applications that may affect patient care; in particular the dimensional accuracy of the printed parts needs to be high to avoid poor decisions being made prior to surgery or therapeutic procedures. In this work, the dimensional accuracy of 3D printed vertebral bodies derived from CT data for a cadaver spine is compared with direct measurements on the ex-vivo vertebra and with measurements made on the 3D rendered vertebra using commercial 3D image processing software. The vertebra was printed on a consumer grade 3D printer using an additive print process using PLA (polylactic acid) filament. Measurements were made for 15 different anatomic features of the vertebral body, including vertebral body height, endplate width and depth, pedicle height and width, and spinal canal width and depth, among others. It is shown that for the segmentation and printing process used, the results of measurements made on the 3D printed vertebral body are substantially the same as those produced by direct measurement on the vertebra and measurements made on the 3D rendered vertebra.

  19. Getting started in 3D with Maya

    CERN Document Server

    Watkins, Adam

    2012-01-01

    Deliver professional-level 3D content in no time with this comprehensive guide to 3D animation with Maya. With over 12 years of training experience, plus several award winning students under his belt, author Adam Watkins is the ideal mentor to get you up to speed with 3D in Maya. Using a structured and pragmatic approach Getting Started in 3D with Maya begins with basic theory of fundamental techniques, then builds on this knowledge using practical examples and projects to put your new skills to the test. Prepared so that you can learn in an organic fashion, each chapter builds on the know

  20. 3D-tulostuksen viipalointiohjelmien vertailu

    OpenAIRE

    Virolainen, Ville

    2015-01-01

    Opinnäytetyön tavoitteena on selventää 3D-tulostamisen prosessia yksityisen käyttäjän näkökulmasta sekä luoda testitulostuksia, joiden perusteella pystytään vertailemaan prosessissa käytettävien viipalointiohjelmien toimintaa keskenään. Työssä perehdytään aluksi 3D-tulostuksen teoriataustaan, jonka jälkeen suoritetaan 3D-tulostimella testitulostukset käyttäen kolmea eri viipalointiohjelmaa. 3D-tulostamisella tarkoitetaan prosessia, jonka tarkoituksena on luoda kolmiulotteinen objekti käyt...

  1. Perspectives on Materials Science in 3D

    DEFF Research Database (Denmark)

    Juul Jensen, Dorte

    2016-01-01

    Materials characterization in 3D has opened a new era in materials science, which is discussed in this paper. The original motivations and visions behind the development of one of the new 3D techniques, namely the three dimensional x-ray diffraction (3DXRD) method, are presented and the route...... to its implementation is described. The present status of materials science in 3D is illustrated by examples related to recrystallization. Finally, challenges and suggestions for the future success for 3D Materials Science relating to hardware evolution, data analysis, data exchange and modeling...

  2. 3D PDF - a means of public access to geological 3D - objects, using the example of GTA3D

    Science.gov (United States)

    Slaby, Mark-Fabian; Reimann, Rüdiger

    2013-04-01

    In geology, 3D modeling has become very important. In the past, two-dimensional data such as isolines, drilling profiles, or cross-sections based on those, were used to illustrate the subsurface geology, whereas now, we can create complex digital 3D models. These models are produced with special software, such as GOCAD ®. The models can be viewed, only through the software used to create them, or through viewers available for free. The platform-independent PDF (Portable Document Format), enforced by Adobe, has found a wide distribution. This format has constantly evolved over time. Meanwhile, it is possible to display CAD data in an Adobe 3D PDF file with the free Adobe Reader (version 7). In a 3D PDF, a 3D model is freely rotatable and can be assembled from a plurality of objects, which can thus be viewed from all directions on their own. In addition, it is possible to create moveable cross-sections (profiles), and to assign transparency to the objects. Based on industry-standard CAD software, 3D PDFs can be generated from a large number of formats, or even be exported directly from this software. In geoinformatics, different approaches to creating 3D PDFs exist. The intent of the Authority for Mining, Energy and Geology to allow free access to the models of the Geotectonic Atlas (GTA3D), could not be realized with standard software solutions. A specially designed code converts the 3D objects to VRML (Virtual Reality Modeling Language). VRML is one of the few formats that allow using image files (maps) as textures, and to represent colors and shapes correctly. The files were merged in Acrobat X Pro, and a 3D PDF was generated subsequently. A topographic map, a display of geographic directions and horizontal and vertical scales help to facilitate the use.

  3. FastScript3D - A Companion to Java 3D

    Science.gov (United States)

    Koenig, Patti

    2005-01-01

    FastScript3D is a computer program, written in the Java 3D(TM) programming language, that establishes an alternative language that helps users who lack expertise in Java 3D to use Java 3D for constructing three-dimensional (3D)-appearing graphics. The FastScript3D language provides a set of simple, intuitive, one-line text-string commands for creating, controlling, and animating 3D models. The first word in a string is the name of a command; the rest of the string contains the data arguments for the command. The commands can also be used as an aid to learning Java 3D. Developers can extend the language by adding custom text-string commands. The commands can define new 3D objects or load representations of 3D objects from files in formats compatible with such other software systems as X3D. The text strings can be easily integrated into other languages. FastScript3D facilitates communication between scripting languages [which enable programming of hyper-text markup language (HTML) documents to interact with users] and Java 3D. The FastScript3D language can be extended and customized on both the scripting side and the Java 3D side.

  4. A Shell/3D Modeling Technique for the Analysis of Delaminated Composite Laminates

    Science.gov (United States)

    Krueger, Ronald; OBrien, T. Kevin

    2000-01-01

    A shell/3D modeling technique was developed for which a local solid finite element model is used only in the immediate vicinity of the delamination front. The goal was to combine the accuracy of the full three-dimensional solution with the computational efficiency of a shell finite element model. Multi-point constraints provided a kinematically compatible interface between the local 3D model and the global structural model which has been meshed with shell finite elements. Double Cantilever Beam, End Notched Flexure, and Single Leg Bending specimens were analyzed first using full 3D finite element models to obtain reference solutions. Mixed mode strain energy release rate distributions were computed using the virtual crack closure technique. The analyses were repeated using the shell/3D technique to study the feasibility for pure mode I, mode II and mixed mode I/II cases. Specimens with a unidirectional layup and with a multidirectional layup were simulated. For a local 3D model, extending to a minimum of about three specimen thicknesses on either side of the delamination front, the results were in good agreement with mixed mode strain energy release rates obtained from computations where the entire specimen had been modeled with solid elements. For large built-up composite structures the shell/3D modeling technique offers a great potential for reducing the model size, since only a relatively small section in the vicinity of the delamination front needs to be modeled with solid elements.

  5. Implementation of LDG method for 3D unstructured meshes

    Directory of Open Access Journals (Sweden)

    Filander A. Sequeira Chavarría

    2012-07-01

    Full Text Available This paper describes an implementation of the Local Discontinuous Galerkin method (LDG applied to elliptic problems in 3D. The implementation of the major operators is discussed. In particular the use of higher-order approximations and unstructured meshes. Efficient data structures that allow fast assembly of the linear system in the mixed formulation are described in detail. Keywords: Discontinuous finite element methods, high-order approximations, unstructured meshes, object-oriented programming. Mathematics Subject Classification: 65K05, 65N30, 65N55.

  6. Optimized designs for 2D and 3D thermoelastic structures

    DEFF Research Database (Denmark)

    Pedersen, Pauli; Pedersen, Niels Leergaard

    2011-01-01

    With design independent loads and only a constrained volume, the same optimal design does simultaneously lead to minimum compliance and maximum strength. However, for thermoelastic structures this is not the case and a maximum volume may not be an active constraint for minimum compliance...... energy density (or uniform von Mises stress) is presented and applied, and it is shown by examples that the obtained designs are close to fulfilling also strength maximization. Explicit formulas for equivalent thermoelastic loads in 2D and 3D finite element analysis are derived and applied, including...

  7. Shell Element Verification & Regression Problems for DYNA3D

    Energy Technology Data Exchange (ETDEWEB)

    Zywicz, E

    2008-02-01

    A series of quasi-static regression/verification problems were developed for the triangular and quadrilateral shell element formulations contained in Lawrence Livermore National Laboratory's explicit finite element program DYNA3D. Each regression problem imposes both displacement- and force-type boundary conditions to probe the five independent nodal degrees of freedom employed in the targeted formulation. When applicable, the finite element results are compared with small-strain linear-elastic closed-form reference solutions to verify select aspects of the formulations implementation. Although all problems in the suite depict the same geometry, material behavior, and loading conditions, each problem represents a unique combination of shell formulation, stabilization method, and integration rule. Collectively, the thirty-six new regression problems in the test suite cover nine different shell formulations, three hourglass stabilization methods, and three families of through-thickness integration rules.

  8. Authoring Adaptive 3D Virtual Learning Environments

    Science.gov (United States)

    Ewais, Ahmed; De Troyer, Olga

    2014-01-01

    The use of 3D and Virtual Reality is gaining interest in the context of academic discussions on E-learning technologies. However, the use of 3D for learning environments also has drawbacks. One way to overcome these drawbacks is by having an adaptive learning environment, i.e., an environment that dynamically adapts to the learner and the…

  9. 3D Printing. What's the Harm?

    Science.gov (United States)

    Love, Tyler S.; Roy, Ken

    2016-01-01

    Health concerns from 3D printing were first documented by Stephens, Azimi, Orch, and Ramos (2013), who found that commercially available 3D printers were producing hazardous levels of ultrafine particles (UFPs) and volatile organic compounds (VOCs) when plastic materials were melted through the extruder. UFPs are particles less than 100 nanometers…

  10. Wow! 3D Content Awakens the Classroom

    Science.gov (United States)

    Gordon, Dan

    2010-01-01

    From her first encounter with stereoscopic 3D technology designed for classroom instruction, Megan Timme, principal at Hamilton Park Pacesetter Magnet School in Dallas, sensed it could be transformative. Last spring, when she began pilot-testing 3D content in her third-, fourth- and fifth-grade classrooms, Timme wasn't disappointed. Students…

  11. 3D Printing of Molecular Models

    Science.gov (United States)

    Gardner, Adam; Olson, Arthur

    2016-01-01

    Physical molecular models have played a valuable role in our understanding of the invisible nano-scale world. We discuss 3D printing and its use in producing models of the molecules of life. Complex biomolecular models, produced from 3D printed parts, can demonstrate characteristics of molecular structure and function, such as viral self-assembly,…

  12. Pathways for Learning from 3D Technology

    Science.gov (United States)

    Carrier, L. Mark; Rab, Saira S.; Rosen, Larry D.; Vasquez, Ludivina; Cheever, Nancy A.

    2012-01-01

    The purpose of this study was to find out if 3D stereoscopic presentation of information in a movie format changes a viewer's experience of the movie content. Four possible pathways from 3D presentation to memory and learning were considered: a direct connection based on cognitive neuroscience research; a connection through "immersion"…

  13. Towards sustainable and clean 3D Geoinformation

    NARCIS (Netherlands)

    Stoter, J.E.; Ledoux, H.; Zlatanova, S.; Biljecki, F.; Kolbe, T.H.; Bill, R.; Donaubauer, A.

    2016-01-01

    This paper summarises the on going research activities of the 3D Geoinformation Group at the Delft University of Technology. The main challenge underpinning the research of this group is providing clean and appropriate 3D data about our environment in order to serve a wide variety of applications.

  14. Multiway calibration in 3D QSAR

    NARCIS (Netherlands)

    Nilsson, J.; DeJong, S.; Smilde, A. K.

    1997-01-01

    We have introduced multilinear PLS in 3D QSAR and applied it to GRID descriptors from a set of benzamides with affinity to the dopamine D-3 receptor subtype, synthesized as potential drugs against schizophrenia. The key issue in 3D QSAR modelling is to obtain a predictive model that is easy to

  15. Automatic balancing of 3D models

    DEFF Research Database (Denmark)

    Christiansen, Asger Nyman; Schmidt, Ryan; Bærentzen, Jakob Andreas

    2014-01-01

    3D printing technologies allow for more diverse shapes than are possible with molds and the cost of making just one single object is negligible compared to traditional production methods. However, not all shapes are suitable for 3D print. One of the remaining costs is therefore human time spent o...

  16. 3D Printed Block Copolymer Nanostructures

    Science.gov (United States)

    Scalfani, Vincent F.; Turner, C. Heath; Rupar, Paul A.; Jenkins, Alexander H.; Bara, Jason E.

    2015-01-01

    The emergence of 3D printing has dramatically advanced the availability of tangible molecular and extended solid models. Interestingly, there are few nanostructure models available both commercially and through other do-it-yourself approaches such as 3D printing. This is unfortunate given the importance of nanotechnology in science today. In this…

  17. Digital Dentistry — 3D Printing Applications

    Directory of Open Access Journals (Sweden)

    Zaharia Cristian

    2017-03-01

    Full Text Available Three-dimensional (3D printing is an additive manufacturing method in which a 3D item is formed by laying down successive layers of material. 3D printers are machines that produce representations of objects either planned with a CAD program or scanned with a 3D scanner. Printing is a method for replicating text and pictures, typically with ink on paper. We can print different dental pieces using different methods such as selective laser sintering (SLS, stereolithography, fused deposition modeling, and laminated object manufacturing. The materials are certified for printing individual impression trays, orthodontic models, gingiva mask, and different prosthetic objects. The material can reach a flexural strength of more than 80 MPa. 3D printing takes the effectiveness of digital projects to the production phase. Dental laboratories are able to produce crowns, bridges, stone models, and various orthodontic appliances by methods that combine oral scanning, 3D printing, and CAD/CAM design. Modern 3D printing has been used for the development of prototypes for several years, and it has begun to find its use in the world of manufacturing. Digital technology and 3D printing have significantly elevated the rate of success in dental implantology using custom surgical guides and improving the quality and accuracy of dental work.

  18. 3D printing of functional structures

    NARCIS (Netherlands)

    Krijnen, Gijsbertus J.M.

    The technology colloquial known as ‘3D printing’ has developed in such diversity in printing technologies and application fields that meanwhile it seems anything is possible. However, clearly the ideal 3D Printer, with high resolution, multi-material capability, fast printing, etc. is yet to be

  19. 3D-printed cereal foods

    NARCIS (Netherlands)

    Noort, M.; Bommel, K. van; Renzetti, S.

    2017-01-01

    Additive manufacturing, also known as 3D printing, is an up-and-coming production technology based on layer-by-layer deposition of material to reproduce a computer-generated 3D design. Additive manufacturing is a collective term used for a variety of technologies, such as fused deposition modeling

  20. User-centered 3D geovisualisation

    DEFF Research Database (Denmark)

    Nielsen, Anette Hougaard

    2004-01-01

    . In a broader perspective, the overall aim is to develop a language in 3D Geovisualisation gained through usability projects and the development of a theoretical background. A conceptual level of user-centered 3D Geovisualisation is introduced by applying a categorisation originating from Virtual Reality...... interact by navigating, browsing, manipulating and querying the system....

  1. Recognition of 3D facial expression dynamics

    NARCIS (Netherlands)

    Sandbach, G.; Zafeiriou, S.; Pantic, Maja; Rueckert, D.

    2012-01-01

    In this paper we propose a method that exploits 3D motion-based features between frames of 3D facial geometry sequences for dynamic facial expression recognition. An expressive sequence is modelled to contain an onset followed by an apex and an offset. Feature selection methods are applied in order

  2. Integrated modelling for 3D GIS

    NARCIS (Netherlands)

    Pilouk, M.

    1996-01-01


    A three dimensional (3D) model facilitates the study of the real world objects it represents. A geoinformation system (GIS) should exploit the 3D model in a digital form as a basis for answering questions pertaining to aspects of the real world. With respect to the earth sciences,

  3. Limited Feedback for 3D Massive MIMO under 3D-UMa and 3D-UMi Scenarios

    Directory of Open Access Journals (Sweden)

    Zheng Hu

    2015-01-01

    Full Text Available For three-dimensional (3D massive MIMO utilizing the uniform rectangular array (URA in the base station (BS, we propose a limited feedback transmission scheme in which the channel state information (CSI feedback operations for horizontal domain and vertical domain are separate. Compared to the traditional feedback scheme, the scheme can reduce the feedback overhead, code word index search complexity, and storage requirement. Also, based on the zenith of departure angle (ZoD distribution in 3D-Urban Macro Cell (3D-UMa and 3D-Urban Micro Cell (3D-UMi scenarios, we propose the angle quantization codebook for vertical domain, while the codebook of long term evolution-advanced (LTE-Advanced is still adopted in horizontal domain to preserve compatibility with the LTE-Advanced. Based on the angle quantization codebook, the subsampled 3-bit DFT codebook is designed for vertical domain. The system-level simulation results reveal that, to compromise the feedback overhead and system performance, 2-bit codebook for 3D-UMa scenario and 3-bit codebook for 3D-UMi scenario can meet requirements in vertical domain. The feedback period for vertical domain can also be extended appropriately to reduce the feedback overhead.

  4. LandSIM3D: modellazione in real time 3D di dati geografici

    Directory of Open Access Journals (Sweden)

    Lambo Srl Lambo Srl

    2009-03-01

    Full Text Available LandSIM3D: realtime 3D modelling of geographic data LandSIM3D allows to model in 3D an existing landscape in a few hours only and geo-referenced offering great landscape analysis and understanding tools. 3D projects can then be inserted into the existing landscape with ease and precision. The project alternatives and impact can then be visualized and studied into their immediate environmental. The complex evolution of the landscape in the future can also be simulated and the landscape model can be manipulated interactively and better shared with colleagues. For that reason, LandSIM3D is different from traditional 3D imagery solutions, normally reserved for computer graphics experts. For more information about LandSIM3D, go to www.landsim3d.com.

  5. BEAMS3D Neutral Beam Injection Model

    Energy Technology Data Exchange (ETDEWEB)

    Lazerson, Samuel

    2014-04-14

    With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.

  6. 6D Interpretation of 3D Gravity

    Science.gov (United States)

    Herfray, Yannick; Krasnov, Kirill; Scarinci, Carlos

    2017-02-01

    We show that 3D gravity, in its pure connection formulation, admits a natural 6D interpretation. The 3D field equations for the connection are equivalent to 6D Hitchin equations for the Chern-Simons 3-form in the total space of the principal bundle over the 3-dimensional base. Turning this construction around one gets an explanation of why the pure connection formulation of 3D gravity exists. More generally, we interpret 3D gravity as the dimensional reduction of the 6D Hitchin theory. To this end, we show that any \\text{SU}(2) invariant closed 3-form in the total space of the principal \\text{SU}(2) bundle can be parametrised by a connection together with a 2-form field on the base. The dimensional reduction of the 6D Hitchin theory then gives rise to 3D gravity coupled to a topological 2-form field.

  7. Inclined nanoimprinting lithography for 3D nanopatterning

    International Nuclear Information System (INIS)

    Liu Zhan; Bucknall, David G; Allen, Mark G

    2011-01-01

    We report a non-conventional shear-force-driven nanofabrication approach, inclined nanoimprint lithography (INIL), for producing 3D nanostructures of varying heights on planar substrates in a single imprinting step. Such 3D nanostructures are fabricated by exploiting polymer anisotropic dewetting where the degree of anisotropy can be controlled by the magnitude of the inclination angle. The feature size is reduced from micron scale of the template to a resultant nanoscale pattern. The underlying INIL mechanism is investigated both experimentally and theoretically. The results indicate that the shear force generated at a non-zero inclination angle induced by the INIL apparatus essentially leads to asymmetry in the polymer flow direction ultimately resulting in 3D nanopatterns with different heights. INIL removes the requirements in conventional nanolithography of either utilizing 3D templates or using multiple lithographic steps. This technique enables various 3D nanoscale devices including angle-resolved photonic and plasmonic crystals to be fabricated.

  8. Maintaining and troubleshooting your 3D printer

    CERN Document Server

    Bell, Charles

    2014-01-01

    Maintaining and Troubleshooting Your 3D Printer by Charles Bell is your guide to keeping your 3D printer running through preventive maintenance, repair, and diagnosing and solving problems in 3D printing. If you've bought or built a 3D printer such as a MakerBot only to be confounded by jagged edges, corner lift, top layers that aren't solid, or any of a myriad of other problems that plague 3D printer enthusiasts, then here is the book to help you get past all that and recapture the joy of creative fabrication. The book also includes valuable tips for builders and those who want to modify the

  9. Fabrication of 3D Silicon Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kok, A.; Hansen, T.E.; Hansen, T.A.; Lietaer, N.; Summanwar, A.; /SINTEF, Oslo; Kenney, C.; Hasi, J.; /SLAC; Da Via, C.; /Manchester U.; Parker, S.I.; /Hawaii U.

    2012-06-06

    Silicon sensors with a three-dimensional (3-D) architecture, in which the n and p electrodes penetrate through the entire substrate, have many advantages over planar silicon sensors including radiation hardness, fast time response, active edge and dual readout capabilities. The fabrication of 3D sensors is however rather complex. In recent years, there have been worldwide activities on 3D fabrication. SINTEF in collaboration with Stanford Nanofabrication Facility have successfully fabricated the original (single sided double column type) 3D detectors in two prototype runs and the third run is now on-going. This paper reports the status of this fabrication work and the resulted yield. The work of other groups such as the development of double sided 3D detectors is also briefly reported.

  10. Density-Based 3D Shape Descriptors

    Directory of Open Access Journals (Sweden)

    Schmitt Francis

    2007-01-01

    Full Text Available We propose a novel probabilistic framework for the extraction of density-based 3D shape descriptors using kernel density estimation. Our descriptors are derived from the probability density functions (pdf of local surface features characterizing the 3D object geometry. Assuming that the shape of the 3D object is represented as a mesh consisting of triangles with arbitrary size and shape, we provide efficient means to approximate the moments of geometric features on a triangle basis. Our framework produces a number of 3D shape descriptors that prove to be quite discriminative in retrieval applications. We test our descriptors and compare them with several other histogram-based methods on two 3D model databases, Princeton Shape Benchmark and Sculpteur, which are fundamentally different in semantic content and mesh quality. Experimental results show that our methodology not only improves the performance of existing descriptors, but also provides a rigorous framework to advance and to test new ones.

  11. 3D-grafiikka ja pelimoottorit

    OpenAIRE

    Sillanpää, Otto

    2014-01-01

    Tässä opinnäytetyössä tutkitaan miten 3D-mallit saadaan sellaiseen muotoon, että ne olisivat käytettävissä eri pelimoottoreissa. Tutkimuksen tarkoituksena on selvittää, miten luodaan 3D-malleja pelimoottoreihin, sekä miten 3D-mallinnusohjelmat ja pelimoottorit eroavat toisistaan, kun käsitellään 3D-malleja. Tässä työssä pelimoottoreina toimivat Valven Source sekä Epic Gamesin Unreal Engine 3. 3D-mallinnusohjelmista käytössä olivat Autodeskin 3ds Max 2014 ja Blender Foundationin Blender 2.7...

  12. The psychology of the 3D experience

    Science.gov (United States)

    Janicke, Sophie H.; Ellis, Andrew

    2013-03-01

    With 3D televisions expected to reach 50% home saturation as early as 2016, understanding the psychological mechanisms underlying the user response to 3D technology is critical for content providers, educators and academics. Unfortunately, research examining the effects of 3D technology has not kept pace with the technology's rapid adoption, resulting in large-scale use of a technology about which very little is actually known. Recognizing this need for new research, we conducted a series of studies measuring and comparing many of the variables and processes underlying both 2D and 3D media experiences. In our first study, we found narratives within primetime dramas had the power to shift viewer attitudes in both 2D and 3D settings. However, we found no difference in persuasive power between 2D and 3D content. We contend this lack of effect was the result of poor conversion quality and the unique demands of 3D production. In our second study, we found 3D technology significantly increased enjoyment when viewing sports content, yet offered no added enjoyment when viewing a movie trailer. The enhanced enjoyment of the sports content was shown to be the result of heightened emotional arousal and attention in the 3D condition. We believe the lack of effect found for the movie trailer may be genre-related. In our final study, we found 3D technology significantly enhanced enjoyment of two video games from different genres. The added enjoyment was found to be the result of an increased sense of presence.

  13. Advanced 3D Printers for Cellular Solids

    Science.gov (United States)

    2016-06-30

    searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send...created in commercially available finite element software ABAQUS . The geometry will be imported to SolidWorks, which will export the geometry file as an...in conjunction with the parent finite element geometry, which will be virtually compressed using the finite element method executed using the ABAQUS

  14. Medical 3D Printing for the Radiologist.

    Science.gov (United States)

    Mitsouras, Dimitris; Liacouras, Peter; Imanzadeh, Amir; Giannopoulos, Andreas A; Cai, Tianrun; Kumamaru, Kanako K; George, Elizabeth; Wake, Nicole; Caterson, Edward J; Pomahac, Bohdan; Ho, Vincent B; Grant, Gerald T; Rybicki, Frank J

    2015-01-01

    While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article. (©)RSNA, 2015.

  15. Digital relief generation from 3D models

    Science.gov (United States)

    Wang, Meili; Sun, Yu; Zhang, Hongming; Qian, Kun; Chang, Jian; He, Dongjian

    2016-09-01

    It is difficult to extend image-based relief generation to high-relief generation, as the images contain insufficient height information. To generate reliefs from three-dimensional (3D) models, it is necessary to extract the height fields from the model, but this can only generate bas-reliefs. To overcome this problem, an efficient method is proposed to generate bas-reliefs and high-reliefs directly from 3D meshes. To produce relief features that are visually appropriate, the 3D meshes are first scaled. 3D unsharp masking is used to enhance the visual features in the 3D mesh, and average smoothing and Laplacian smoothing are implemented to achieve better smoothing results. A nonlinear variable scaling scheme is then employed to generate the final bas-reliefs and high-reliefs. Using the proposed method, relief models can be generated from arbitrary viewing positions with different gestures and combinations of multiple 3D models. The generated relief models can be printed by 3D printers. The proposed method provides a means of generating both high-reliefs and bas-reliefs in an efficient and effective way under the appropriate scaling factors.

  16. 3D bioprinting of tissues and organs.

    Science.gov (United States)

    Murphy, Sean V; Atala, Anthony

    2014-08-01

    Additive manufacturing, otherwise known as three-dimensional (3D) printing, is driving major innovations in many areas, such as engineering, manufacturing, art, education and medicine. Recent advances have enabled 3D printing of biocompatible materials, cells and supporting components into complex 3D functional living tissues. 3D bioprinting is being applied to regenerative medicine to address the need for tissues and organs suitable for transplantation. Compared with non-biological printing, 3D bioprinting involves additional complexities, such as the choice of materials, cell types, growth and differentiation factors, and technical challenges related to the sensitivities of living cells and the construction of tissues. Addressing these complexities requires the integration of technologies from the fields of engineering, biomaterials science, cell biology, physics and medicine. 3D bioprinting has already been used for the generation and transplantation of several tissues, including multilayered skin, bone, vascular grafts, tracheal splints, heart tissue and cartilaginous structures. Other applications include developing high-throughput 3D-bioprinted tissue models for research, drug discovery and toxicology.

  17. 3D imaging in forensic odontology.

    Science.gov (United States)

    Evans, Sam; Jones, Carl; Plassmann, Peter

    2010-06-16

    This paper describes the investigation of a new 3D capture method for acquiring and subsequent forensic analysis of bite mark injuries on human skin. When documenting bite marks with standard 2D cameras errors in photographic technique can occur if best practice is not followed. Subsequent forensic analysis of the mark is problematic when a 3D structure is recorded into a 2D space. Although strict guidelines (BAFO) exist, these are time-consuming to follow and, due to their complexity, may produce errors. A 3D image capture and processing system might avoid the problems resulting from the 2D reduction process, simplifying the guidelines and reducing errors. Proposed Solution: a series of experiments are described in this paper to demonstrate that the potential of a 3D system might produce suitable results. The experiments tested precision and accuracy of the traditional 2D and 3D methods. A 3D image capture device minimises the amount of angular distortion, therefore such a system has the potential to create more robust forensic evidence for use in courts. A first set of experiments tested and demonstrated which method of forensic analysis creates the least amount of intra-operator error. A second set tested and demonstrated which method of image capture creates the least amount of inter-operator error and visual distortion. In a third set the effects of angular distortion on 2D and 3D methods of image capture were evaluated.

  18. Medical 3D Printing for the Radiologist

    Science.gov (United States)

    Mitsouras, Dimitris; Liacouras, Peter; Imanzadeh, Amir; Giannopoulos, Andreas A.; Cai, Tianrun; Kumamaru, Kanako K.; George, Elizabeth; Wake, Nicole; Caterson, Edward J.; Pomahac, Bohdan; Ho, Vincent B.; Grant, Gerald T.

    2015-01-01

    While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article. ©RSNA, 2015 PMID:26562233

  19. Extra Dimensions: 3D in PDF Documentation

    International Nuclear Information System (INIS)

    Graf, Norman A

    2012-01-01

    Experimental science is replete with multi-dimensional information which is often poorly represented by the two dimensions of presentation slides and print media. Past efforts to disseminate such information to a wider audience have failed for a number of reasons, including a lack of standards which are easy to implement and have broad support. Adobe's Portable Document Format (PDF) has in recent years become the de facto standard for secure, dependable electronic information exchange. It has done so by creating an open format, providing support for multiple platforms and being reliable and extensible. By providing support for the ECMA standard Universal 3D (U3D) and the ISO PRC file format in its free Adobe Reader software, Adobe has made it easy to distribute and interact with 3D content. Until recently, Adobe's Acrobat software was also capable of incorporating 3D content into PDF files from a variety of 3D file formats, including proprietary CAD formats. However, this functionality is no longer available in Acrobat X, having been spun off to a separate company. Incorporating 3D content now requires the additional purchase of a separate plug-in. In this talk we present alternatives based on open source libraries which allow the programmatic creation of 3D content in PDF format. While not providing the same level of access to CAD files as the commercial software, it does provide physicists with an alternative path to incorporate 3D content into PDF files from such disparate applications as detector geometries from Geant4, 3D data sets, mathematical surfaces or tesselated volumes.

  20. Educational Material for 3D Visualization of Spine Procedures: Methods for Creation and Dissemination.

    Science.gov (United States)

    Cramer, Justin; Quigley, Edward; Hutchins, Troy; Shah, Lubdha

    2017-06-01

    Spine anatomy can be difficult to master and is essential for performing spine procedures. We sought to utilize the rapidly expanding field of 3D technology to create freely available, interactive educational materials for spine procedures. Our secondary goal was to convey lessons learned about 3D modeling and printing. This project involved two parallel processes: the creation of 3D-printed physical models and interactive digital models. We segmented illustrative CT studies of the lumbar and cervical spine to create 3D models and then printed them using a consumer 3D printer and a professional 3D printing service. We also included downloadable versions of the models in an interactive eBook and platform-independent web viewer. We then provided these educational materials to residents with a pretest and posttest to assess efficacy. The "Spine Procedures in 3D" eBook has been downloaded 71 times as of October 5, 2016. All models used in the book are available for download and printing. Regarding test results, the mean exam score improved from 70 to 86%, with the most dramatic improvement seen in the least experienced trainees. Participants reported increased confidence in performing lumbar punctures after exposure to the material. We demonstrate the value of 3D models, both digital and printed, in learning spine procedures. Moreover, 3D printing and modeling is a rapidly expanding field with a large potential role for radiologists. We have detailed our process for creating and sharing 3D educational materials in the hopes of motivating and enabling similar projects.

  1. 3D face modeling, analysis and recognition

    CERN Document Server

    Daoudi, Mohamed; Veltkamp, Remco

    2013-01-01

    3D Face Modeling, Analysis and Recognition presents methodologies for analyzing shapes of facial surfaces, develops computational tools for analyzing 3D face data, and illustrates them using state-of-the-art applications. The methodologies chosen are based on efficient representations, metrics, comparisons, and classifications of features that are especially relevant in the context of 3D measurements of human faces. These frameworks have a long-term utility in face analysis, taking into account the anticipated improvements in data collection, data storage, processing speeds, and application s

  2. Participation and 3D Visualization Tools

    DEFF Research Database (Denmark)

    Mullins, Michael; Jensen, Mikkel Holm; Henriksen, Sune

    2004-01-01

    With a departure point in a workshop held at the VR Media Lab at Aalborg University , this paper deals with aspects of public participation and the use of 3D visualisation tools. The workshop grew from a desire to involve a broad collaboration between the many actors in the city through using new...... perceptions of architectural representation in urban design where 3D visualisation techniques are used. It is the authors? general finding that, while 3D visualisation media have the potential to increase understanding of virtual space for the lay public, as well as for professionals, the lay public require...

  3. 3D Printing the ATLAS' barrel toroid

    CERN Document Server

    Goncalves, Tiago Barreiro

    2016-01-01

    The present report summarizes my work as part of the Summer Student Programme 2016 in the CERN IR-ECO-TSP department (International Relations – Education, Communication & Outreach – Teacher and Student Programmes). Particularly, I worked closely with the S’Cool LAB team on a science education project. This project included the 3D designing, 3D printing, and assembling of a model of the ATLAS’ barrel toroid. A detailed description of the project' development is presented and a short manual on how to use 3D printing software and hardware is attached.

  4. Pharmacophore definition and 3D searches.

    Science.gov (United States)

    Langer, T; Wolber, G

    2004-12-01

    The most common pharmacophore building concepts based on either 3D structure of the target or ligand information are discussed together with the application of such models as queries for 3D database search. An overview of the key techniques available on the market is given and differences with respect to algorithms used and performance obtained are highlighted. Pharmacophore modelling and 3D database search are shown to be successful tools for enriching screening experiments aimed at the discovery of novel bio-active compounds.: © 2004 Elsevier Ltd . All rights reserved.

  5. 3D Bio-Printing Review

    Science.gov (United States)

    Du, Xianbin

    2018-01-01

    Ultimate goal of tissue engineering is to replace pathological or necrotic body tissue or organ by artificial tissue or organ and tissue engineering is a very promising research field. 3D bio-printing is a kind of emerging technologies and a branch of tissue engineering. It has made significant progress in the past decade. 3D bio-printing can realize tissue and organ construction in vitro and has wide application in basic research and pharmacy. This paper is to make an analysis and review on 3D bio-printing from the perspectives of bioink, printing technology and technology application.

  6. 3D radiative transfer in stellar atmospheres

    International Nuclear Information System (INIS)

    Carlsson, M

    2008-01-01

    Three-dimensional (3D) radiative transfer in stellar atmospheres is reviewed with special emphasis on the atmospheres of cool stars and applications. A short review of methods in 3D radiative transfer shows that mature methods exist, both for taking into account radiation as an energy transport mechanism in 3D (magneto-) hydrodynamical simulations of stellar atmospheres and for the diagnostic problem of calculating the emergent spectrum in more detail from such models, both assuming local thermodynamic equilibrium (LTE) and in non-LTE. Such methods have been implemented in several codes, and examples of applications are given.

  7. FUN3D Manual: 12.9

    Science.gov (United States)

    Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; hide

    2016-01-01

    This manual describes the installation and execution of FUN3D version 12.9, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  8. FUN3D Manual: 12.5

    Science.gov (United States)

    Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, William L.; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; hide

    2014-01-01

    This manual describes the installation and execution of FUN3D version 12.5, including optional dependent packages. FUN3D is a suite of computational uid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables ecient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  9. FUN3D Manual: 12.4

    Science.gov (United States)

    Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; hide

    2014-01-01

    This manual describes the installation and execution of FUN3D version 12.4, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixedelement unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  10. FUN3D Manual: 13.3

    Science.gov (United States)

    Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; hide

    2018-01-01

    This manual describes the installation and execution of FUN3D version 13.3, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  11. FUN3D Manual: 13.0

    Science.gov (United States)

    Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bill; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; hide

    2016-01-01

    This manual describes the installation and execution of FUN3D version 13.0, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  12. FUN3D Manual: 12.6

    Science.gov (United States)

    Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, William L.; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; hide

    2015-01-01

    This manual describes the installation and execution of FUN3D version 12.6, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  13. FUN3D Manual: 12.8

    Science.gov (United States)

    Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; hide

    2015-01-01

    This manual describes the installation and execution of FUN3D version 12.8, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  14. FUN3D Manual: 12.7

    Science.gov (United States)

    Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; hide

    2015-01-01

    This manual describes the installation and execution of FUN3D version 12.7, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  15. 3D printed magnetic polymer composite transformers

    Science.gov (United States)

    Bollig, Lindsey M.; Hilpisch, Peter J.; Mowry, Greg S.; Nelson-Cheeseman, Brittany B.

    2017-11-01

    The possibility of 3D printing a transformer core using fused deposition modeling methods is explored. With the use of additive manufacturing, ideal transformer core geometries can be achieved in order to produce a more efficient transformer. In this work, different 3D printed settings and toroidal geometries are tested using a custom integrated magnetic circuit capable of measuring the hysteresis loop of a transformer. These different properties are then characterized, and it was determined the most effective 3D printed transformer core requires a high fill factor along with a high concentration of magnetic particulate.

  16. 3D background aerodynamics using CFD

    DEFF Research Database (Denmark)

    Sørensen, Niels N.

    2002-01-01

    3D rotor computations for the Greek Geovilogiki (GEO) 44 meter rotor equipped with 19 meters blades are performed. The lift and drag polars are extracted at five spanvise locations r/R= (.37, .55, .71, .82, .93) based on identification of stagnationpoints between 2D and 3D computations. The inner...... most sections shows clear evidence of 3D radial pumping, with increased lift compared to 2D values. In contrast to earlier investigated airfoils a very limited impact on the drag values are observed....

  17. A high capacity 3D steganography algorithm.

    Science.gov (United States)

    Chao, Min-Wen; Lin, Chao-hung; Yu, Cheng-Wei; Lee, Tong-Yee

    2009-01-01

    In this paper, we present a very high-capacity and low-distortion 3D steganography scheme. Our steganography approach is based on a novel multilayered embedding scheme to hide secret messages in the vertices of 3D polygon models. Experimental results show that the cover model distortion is very small as the number of hiding layers ranges from 7 to 13 layers. To the best of our knowledge, this novel approach can provide much higher hiding capacity than other state-of-the-art approaches, while obeying the low distortion and security basic requirements for steganography on 3D models.

  18. 3D Immersive Visualization with Astrophysical Data

    Science.gov (United States)

    Kent, Brian R.

    2017-01-01

    We present the refinement of a new 3D immersion technique for astrophysical data visualization.Methodology to create 360 degree spherical panoramas is reviewed. The 3D software package Blender coupled with Python and the Google Spatial Media module are used together to create the final data products. Data can be viewed interactively with a mobile phone or tablet or in a web browser. The technique can apply to different kinds of astronomical data including 3D stellar and galaxy catalogs, images, and planetary maps.

  19. 40 CFR 90.408 - Pre-test procedures.

    Science.gov (United States)

    2010-07-01

    ....408 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... during service accumulation is allowed only in accordance with § 90.118. (b) Engine pre-test preparation... by § 90.324(a). If necessary, allow the heated sample line, filters, and pumps to reach operating...

  20. 40 CFR 91.408 - Pre-test procedures.

    Science.gov (United States)

    2010-07-01

    ....408 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... accordance with § 91.117. (b) Engine pre-test preparation. (1) Drain and charge the fuel tank(s) with the..., including the sample probe, using mode 1 from Table 2 in appendix A of this subpart. The emission sampling...

  1. Quasi 3D modeling of water flow in vadose zone and groundwater

    Science.gov (United States)

    Kuznetsov, M.; Yakirevich, A.; Pachepsky, Y. A.; Sorek, S.; Weisbrod, N.

    2012-07-01

    SummaryThe complexity of subsurface flow systems calls for a variety of concepts leading to the multiplicity of simplified flow models. One habitual simplification is based on the assumption that lateral flow and transport in unsaturated zone are not significant unless the capillary fringe is involved. In such cases the flow and transport in the unsaturated zone above groundwater level can be simulated as a 1D phenomenon, whereas the flow and transport through groundwater are viewed as 2D or 3D phenomena. A new approach for a numerical scheme for 3D variably saturated flow using quasi 3D Richards' equation and finite difference scheme is presented. The corresponding numerical algorithm and the QUASI-3D computer code were developed. Results of the groundwater level simulations were compared with transient laboratory experimental data for 2D data constant-flux infiltration, quasi-3D HYDRUS-MODFLOW numerical model and a FULL-3D numerical model using Richards' equation. Hypothetical 3D examples of infiltration, pumping and groundwater mound dissipation for different spatial-time scales are presented. Water flow simulation for the Alto Piura aquifer (Peru) demonstrates the QUASI-3D model application at the regional scale. Computationally the QUASI-3D code was found to be more efficient by an order of 10-300%, while being accurate with respect to the benchmark fully 3D variable saturation code, when the capillary fringe was considered.

  2. 3D Massive MIMO Systems: Modeling and Performance Analysis

    KAUST Repository

    Nadeem, Qurrat-Ul-Ain

    2015-07-30

    Multiple-input-multiple-output (MIMO) systems of current LTE releases are capable of adaptation in the azimuth only. Recently, the trend is to enhance system performance by exploiting the channel’s degrees of freedom in the elevation, which necessitates the characterization of 3D channels. We present an information-theoretic channel model for MIMO systems that supports the elevation dimension. The model is based on the principle of maximum entropy, which enables us to determine the distribution of the channel matrix consistent with the prior information on the angles. Based on this model, we provide analytical expression for the cumulative density function (CDF) of the mutual information (MI) for systems with a single receive and finite number of transmit antennas in the general signalto- interference-plus-noise-ratio (SINR) regime. The result is extended to systems with finite receive antennas in the low SINR regime. A Gaussian approximation to the asymptotic behavior of MI distribution is derived for the large number of transmit antennas and paths regime. We corroborate our analysis with simulations that study the performance gains realizable through meticulous selection of the transmit antenna downtilt angles, confirming the potential of elevation beamforming to enhance system performance. The results are directly applicable to the analysis of 5G 3D-Massive MIMO-systems.

  3. XML3D and Xflow: combining declarative 3D for the Web with generic data flows.

    Science.gov (United States)

    Klein, Felix; Sons, Kristian; Rubinstein, Dmitri; Slusallek, Philipp

    2013-01-01

    Researchers have combined XML3D, which provides declarative, interactive 3D scene descriptions based on HTML5, with Xflow, a language for declarative, high-performance data processing. The result lets Web developers combine a 3D scene graph with data flows for dynamic meshes, animations, image processing, and postprocessing.

  4. Do-It-Yourself: 3D Models of Hydrogenic Orbitals through 3D Printing

    Science.gov (United States)

    Griffith, Kaitlyn M.; de Cataldo, Riccardo; Fogarty, Keir H.

    2016-01-01

    Introductory chemistry students often have difficulty visualizing the 3-dimensional shapes of the hydrogenic electron orbitals without the aid of physical 3D models. Unfortunately, commercially available models can be quite expensive. 3D printing offers a solution for producing models of hydrogenic orbitals. 3D printing technology is widely…

  5. The 3D Object Mediator : Handling 3D Models on Internet

    NARCIS (Netherlands)

    Kok, A.J.F.; Lawick van Pabst, J. van; Afsarmanesh, H.

    1997-01-01

    The 3D Object MEdiator (3DOME 3) offers two services for handling 3D models: a modelshop and a renderfarm. These services can be consulted through the Internet. The modelshop meets the demands for brokerage of geometric descriptions of 3D models. People who create geometric models of objects can

  6. 3D Printing Electrically Small Spherical Antennas

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2013-01-01

    3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations....

  7. 3D Biomaterial Microarrays for Regenerative Medicine

    DEFF Research Database (Denmark)

    Gaharwar, Akhilesh K.; Arpanaei, Ayyoob; Andresen, Thomas Lars

    2015-01-01

    Three dimensional (3D) biomaterial microarrays hold enormous promise for regenerative medicine because of their ability to accelerate the design and fabrication of biomimetic materials. Such tissue-like biomaterials can provide an appropriate microenvironment for stimulating and controlling stem...

  8. Lightning fast animation in Element 3D

    CERN Document Server

    Audronis, Ty

    2014-01-01

    An easy-to-follow and all-inclusive guide, in which the underlying principles of 3D animation as well as their importance are explained in detail. The lessons are designed to teach you how to think of 3D animation in such a way that you can troubleshoot any problem, or animate any scene that comes your way.If you are a Digital Artist, Animation Artist, or a Game Programmer and you want to become an expert in Element 3D, this is the book for you. Although there are a lot of basics for beginners in this book, it includes some advanced techniques for both animating in Element 3D, and overcoming i

  9. Advances in 3D neuronal cell culture

    NARCIS (Netherlands)

    Frimat, Jean Philippe; Xie, Sijia; Bastiaens, Alex; Schurink, Bart; Wolbers, Floor; Den Toonder, Jaap; Luttge, Regina

    2015-01-01

    In this contribution, the authors present our advances in three-dimensional (3D) neuronal cell culture platform technology contributing to controlled environments for microtissue engineering and analysis of cellular physiological and pathological responses. First, a micromachined silicon sieving

  10. Eyes on the Earth 3D

    Science.gov (United States)

    Kulikov, anton I.; Doronila, Paul R.; Nguyen, Viet T.; Jackson, Randal K.; Greene, William M.; Hussey, Kevin J.; Garcia, Christopher M.; Lopez, Christian A.

    2013-01-01

    Eyes on the Earth 3D software gives scientists, and the general public, a realtime, 3D interactive means of accurately viewing the real-time locations, speed, and values of recently collected data from several of NASA's Earth Observing Satellites using a standard Web browser (climate.nasa.gov/eyes). Anyone with Web access can use this software to see where the NASA fleet of these satellites is now, or where they will be up to a year in the future. The software also displays several Earth Science Data sets that have been collected on a daily basis. This application uses a third-party, 3D, realtime, interactive game engine called Unity 3D to visualize the satellites and is accessible from a Web browser.

  11. Mobile 3D Viewer Supporting RFID System

    International Nuclear Information System (INIS)

    Kim, J. J.; Yang, S. W.; Choi, Y.

    2007-01-01

    As hardware capabilities of mobile devices are being rapidly enhanced, applications based upon mobile devices are also being developed in wider areas. In this paper, a prototype mobile 3D viewer with the object identification through RFID system is presented. To visualize 3D engineering data such as CAD data, we need a process to compute triangulated data from boundary based surface like B-rep solid or trimmed surfaces. Since existing rendering engines on mobile devices do not provide triangulation capability, mobile 3D programs have focused only on an efficient handling with pre-tessellated geometry. We have developed a light and fast triangulation process based on constrained Delaunay triangulation suitable for mobile devices in the previous research. This triangulation software is used as a core for the mobile 3D viewer on a PDA with RFID system that may have potentially wide applications in many areas

  12. Nonlaser-based 3D surface imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shin-yee; Johnson, R.K.; Sherwood, R.J. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    3D surface imaging refers to methods that generate a 3D surface representation of objects of a scene under viewing. Laser-based 3D surface imaging systems are commonly used in manufacturing, robotics and biomedical research. Although laser-based systems provide satisfactory solutions for most applications, there are situations where non laser-based approaches are preferred. The issues that make alternative methods sometimes more attractive are: (1) real-time data capturing, (2) eye-safety, (3) portability, and (4) work distance. The focus of this presentation is on generating a 3D surface from multiple 2D projected images using CCD cameras, without a laser light source. Two methods are presented: stereo vision and depth-from-focus. Their applications are described.

  13. Designing Biomaterials for 3D Printing.

    Science.gov (United States)

    Guvendiren, Murat; Molde, Joseph; Soares, Rosane M D; Kohn, Joachim

    2016-10-10

    Three-dimensional (3D) printing is becoming an increasingly common technique to fabricate scaffolds and devices for tissue engineering applications. This is due to the potential of 3D printing to provide patient-specific designs, high structural complexity, rapid on-demand fabrication at a low-cost. One of the major bottlenecks that limits the widespread acceptance of 3D printing in biomanufacturing is the lack of diversity in "biomaterial inks". Printability of a biomaterial is determined by the printing technique. Although a wide range of biomaterial inks including polymers, ceramics, hydrogels and composites have been developed, the field is still struggling with processing of these materials into self-supporting devices with tunable mechanics, degradation, and bioactivity. This review aims to highlight the past and recent advances in biomaterial ink development and design considerations moving forward. A brief overview of 3D printing technologies focusing on ink design parameters is also included.

  14. Measuring Visual Closeness of 3-D Models

    KAUST Repository

    Gollaz Morales, Jose Alejandro

    2012-09-01

    Measuring visual closeness of 3-D models is an important issue for different problems and there is still no standardized metric or algorithm to do it. The normal of a surface plays a vital role in the shading of a 3-D object. Motivated by this, we developed two applications to measure visualcloseness, introducing normal difference as a parameter in a weighted metric in Metro’s sampling approach to obtain the maximum and mean distance between 3-D models using 3-D and 6-D correspondence search structures. A visual closeness metric should provide accurate information on what the human observers would perceive as visually close objects. We performed a validation study with a group of people to evaluate the correlation of our metrics with subjective perception. The results were positive since the metrics predicted the subjective rankings more accurately than the Hausdorff distance.

  15. Intrinsic defects in 3D printed materials

    OpenAIRE

    Bolton, Christopher; Dagastine, Raymond

    2015-01-01

    We discuss the impact of bulk structural defects on the coherence, phase and polarisation of light passing through transparent 3D printed materials fabricated using a variety of commercial print technologies.

  16. 3D-printed bioanalytical devices

    Science.gov (United States)

    Bishop, Gregory W.; Satterwhite-Warden, Jennifer E.; Kadimisetty, Karteek; Rusling, James F.

    2016-07-01

    While 3D printing technologies first appeared in the 1980s, prohibitive costs, limited materials, and the relatively small number of commercially available printers confined applications mainly to prototyping for manufacturing purposes. As technologies, printer cost, materials, and accessibility continue to improve, 3D printing has found widespread implementation in research and development in many disciplines due to ease-of-use and relatively fast design-to-object workflow. Several 3D printing techniques have been used to prepare devices such as milli- and microfluidic flow cells for analyses of cells and biomolecules as well as interfaces that enable bioanalytical measurements using cellphones. This review focuses on preparation and applications of 3D-printed bioanalytical devices.

  17. 3D VISUALIZATION FOR VIRTUAL MUSEUM DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    M. Skamantzari

    2016-06-01

    Full Text Available The interest in the development of virtual museums is nowadays rising rapidly. During the last decades there have been numerous efforts concerning the 3D digitization of cultural heritage and the development of virtual museums, digital libraries and serious games. The realistic result has always been the main concern and a real challenge when it comes to 3D modelling of monuments, artifacts and especially sculptures. This paper implements, investigates and evaluates the results of the photogrammetric methods and 3D surveys that were used for the development of a virtual museum. Moreover, the decisions, the actions, the methodology and the main elements that this kind of application should include and take into consideration are described and analysed. It is believed that the outcomes of this application will be useful to researchers who are planning to develop and further improve the attempts made on virtual museums and mass production of 3D models.

  18. 3D HOLOGRAM PENGENALAN ALAT TRANSPORTASI

    Directory of Open Access Journals (Sweden)

    Muhammad Jumal Wahda

    2017-04-01

    Full Text Available Alat transportasi merupakan salah satu kebutuhan utama manusia untuk menunjang berbagai kegiatan sehari-hari. Alat transportasi dalam pengelompokannya dapat berupa alat transportasi darat, udara dan laut. Alat transportasi tersebut antara lain adalah : mobil, sepeda motor, bus umum, taksi, sepeda, becak, pesawat terbang, kapal laut dan lain-lain. Umumnya didaerah perkotaan alat transportasi lebih banyak dibandingkan dengan pedesaan. Oleh karena itu dibutuhkan sebuah edukasi yang menyenangkan untuk meningkatkan pengetahuan masyarakat mengenai alat transportasi. “3D Hologram Pengenalan Alat Transportasi” adalah sebuah 3D hologram tentang edukasi mengenai alat transportasi. Dengan adanya “3D Hologram Pengenalan Alat Transportasi”, diharapkan mampu membuat pengguna lebih mengenali alat transportasi khususnya di Indonesia. Dari hasil pengujian didapatkan bahwa “3D Hologram Pengenalan Alat Transportasi” mampu memberikan informasi dan pengetahuan kepada pengguna transportasi di Indonesia.

  19. 3D Printing Electrically Small Spherical Antennas

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2013-01-01

    3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations.......3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations....

  20. The Idaho Virtualization Laboratory 3D Pipeline

    Directory of Open Access Journals (Sweden)

    Nicholas A. Holmer

    2014-05-01

    Full Text Available Three dimensional (3D virtualization and visualization is an important component of industry, art, museum curation and cultural heritage, yet the step by step process of 3D virtualization has been little discussed. Here we review the Idaho Virtualization Laboratory’s (IVL process of virtualizing a cultural heritage item (artifact from start to finish. Each step is thoroughly explained and illustrated including how the object and its metadata are digitally preserved and ultimately distributed to the world.

  1. Making 3D movies of Northern Lights

    Science.gov (United States)

    Hivon, Eric; Mouette, Jean; Legault, Thierry

    2017-10-01

    We describe the steps necessary to create three-dimensional (3D) movies of Northern Lights or Aurorae Borealis out of real-time images taken with two distant high-resolution fish-eye cameras. Astrometric reconstruction of the visible stars is used to model the optical mapping of each camera and correct for it in order to properly align the two sets of images. Examples of the resulting movies can be seen at http://www.iap.fr/aurora3d

  2. Multifractal modelling and 3D lacunarity analysis

    International Nuclear Information System (INIS)

    Hanen, Akkari; Imen, Bhouri; Asma, Ben Abdallah; Patrick, Dubois; Hedi, Bedoui Mohamed

    2009-01-01

    This study presents a comparative evaluation of lacunarity of 3D grey level models with different types of inhomogeneity. A new method based on the 'Relative Differential Box Counting' was developed to estimate the lacunarity features of grey level volumes. To validate our method, we generated a set of 3D grey level multifractal models with random, anisotropic and hierarchical properties. Our method gives a lacunarity measurement correlated with the theoretical one and allows a better model classification compared with a classical approach.

  3. Signal and Noise in 3D Environments

    Science.gov (United States)

    2015-09-30

    complicated 3D environments. I have also been doing a great deal of work in modeling the noise field (the ocean soundscape ) due to various sources... soundscape to learn about the ocean environment. I distinguish this from geoacoustic inversion and ocean tomography, in that the methods envisioned will rely...on broader features of the soundscape . OBJECTIVES In the first phase of this effort we will focus on the 3D modeling solutions, documenting the

  4. Intracranial Volume Quantification from 3D Photography

    OpenAIRE

    Tu, Liyun; Porras, Antonio R.; Ensel, Scott; Tsering, Deki; Paniagua, Beatriz; Enquobahrie, Andinet; Oh, Albert; Keating, Robert; Rogers, Gary F.; Linguraru, Marius George

    2017-01-01

    3D photography offers non-invasive, radiation-free, and anesthetic-free evaluation of craniofacial morphology. However, intracranial volume (ICV) quantification is not possible with current non-invasive imaging systems in order to evaluate brain development in children with cranial pathology. The aim of this study is to develop an automated, radiation-free framework to estimate ICV. Pairs of computed tomography (CT) images and 3D photographs were aligned using registration. We used the real I...

  5. 3D-Printing Plates without "Support"

    OpenAIRE

    Yasusi Kanada

    2015-01-01

    When printing a plate (or dish) by an FDM 3D printer, the process normally requires support material, which causes several problems. This paper proposes a method for forming thin plates without using wasteful support material. This method requires several extraordinary parameter values when slicing plates. The experiments show that the plates can, for the most part, be successfully formed using a conventional slicer and a 3D printer; however, seams between layers spoil th...

  6. 3D Reconstruction of NMR Images

    Directory of Open Access Journals (Sweden)

    Peter Izak

    2007-01-01

    Full Text Available This paper introduces experiment of 3D reconstruction NMR images scanned from magnetic resonance device. There are described methods which can be used for 3D reconstruction magnetic resonance images in biomedical application. The main idea is based on marching cubes algorithm. For this task was chosen sophistication method by program Vision Assistant, which is a part of program LabVIEW.

  7. Recognition of Symmetric 3D Bodies

    Czech Academy of Sciences Publication Activity Database

    Suk, Tomáš; Flusser, Jan

    2014-01-01

    Roč. 6, č. 3 (2014), s. 722-757 ISSN 2073-8994 R&D Projects: GA ČR GAP103/11/1552 Institutional support: RVO:67985556 Keywords : rotation symmetry * reflection symmetry * 3D complex moments * 3D rotation invariants Subject RIV: JD - Computer Applications, Robotics Impact factor: 0.826, year: 2014 http://library.utia.cas.cz/separaty/2014/ZOI/suk-0431156.pdf

  8. Querying 3D Data by Adjacency Graphs

    OpenAIRE

    Bore, Nils; Jensfelt, Patric; Folkesson, John

    2015-01-01

    The need for robots to search the 3D data they have saved is becoming more apparent. We present an approach for finding structures in 3D models such as those built by robots of their environment. The method extracts geometric primitives from point cloud data. An attributed graph over these primitives forms our representation of the surface structures. Recurring substructures are found with frequent graph mining techniques. We investigate if a model invariant to changes in size and reflection ...

  9. 3D Guided Wave Motion Analysis on Laminated Composites

    Science.gov (United States)

    Tian, Zhenhua; Leckey, Cara; Yu, Lingyu

    2013-01-01

    Ultrasonic guided waves have proved useful for structural health monitoring (SHM) and nondestructive evaluation (NDE) due to their ability to propagate long distances with less energy loss compared to bulk waves and due to their sensitivity to small defects in the structure. Analysis of actively transmitted ultrasonic signals has long been used to detect and assess damage. However, there remain many challenging tasks for guided wave based SHM due to the complexity involved with propagating guided waves, especially in the case of composite materials. The multimodal nature of the ultrasonic guided waves complicates the related damage analysis. This paper presents results from parallel 3D elastodynamic finite integration technique (EFIT) simulations used to acquire 3D wave motion in the subject laminated carbon fiber reinforced polymer composites. The acquired 3D wave motion is then analyzed by frequency-wavenumber analysis to study the wave propagation and interaction in the composite laminate. The frequency-wavenumber analysis enables the study of individual modes and visualization of mode conversion. Delamination damage has been incorporated into the EFIT model to generate "damaged" data. The potential for damage detection in laminated composites is discussed in the end.

  10. 3-D discrete shearlet transform and video processing.

    Science.gov (United States)

    Negi, Pooran Singh; Labate, Demetrio

    2012-06-01

    In this paper, we introduce a digital implementation of the 3-D shearlet transform and illustrate its application to problems of video denoising and enhancement. The shearlet representation is a multiscale pyramid of well-localized waveforms defined at various locations and orientations, which was introduced to overcome the limitations of traditional multiscale systems in dealing with multidimensional data. While the shearlet approach shares the general philosophy of curvelets and surfacelets, it is based on a very different mathematical framework, which is derived from the theory of affine systems and uses shearing matrices rather than rotations. This allows a natural transition from the continuous setting to the digital setting and a more flexible mathematical structure. The 3-D digital shearlet transform algorithm presented in this paper consists in a cascade of a multiscale decomposition and a directional filtering stage. The filters employed in this decomposition are implemented as finite-length filters, and this ensures that the transform is local and numerically efficient. To illustrate its performance, the 3-D discrete shearlet transform is applied to problems of video denoising and enhancement, and compared against other state-of-the-art multiscale techniques, including curvelets and surfacelets.

  11. Reversible 3-D decorrelation of medical images.

    Science.gov (United States)

    Roos, P; Viergever, M A

    1993-01-01

    Two methods, namely, differential pulse code modulation (DPCM) and hierarchical interpolation (HINT), are considered. It is shown that HINT cannot be extended straightforwardly to 3-D images as contrasted with DPCM. A 3-D HINT is therefore proposed which is based on a combination of 2-D and 3-D filters. Both decorrelation methods were applied to three-dimensional computed tomography (CT), magnetic resonance (MR), and single-photon-emission CT (SPECT) images. It was found that a 3-D approach is optimal for some studies, while for other studies 2-D or even 1-D decorrelation performs better. The optimal dimensionality of DPCM is related to the magnitudes of the local correlation coefficients (CCs). However, the nonlocal nature of HINT makes the local correlation coefficients useless as indicators of the dimensionality; a better candidate is the image voxel size. For images with cubic or nearly cubic voxels 3-D HINT is generally optimal. For images in which the slice thickness is large compared to the pixel size a 2-D (intraslice) HINT is best. In general, the increase in efficiency obtained by extending 2-D decorrelation method to 3-D is small.

  12. Stereoscopic reconfiguration for 3D displays

    Science.gov (United States)

    Houde, Jean-Christophe; Jodoin, Pierre-Marc; Desch"nes, François

    2012-03-01

    In this paper, we present a method to reconfigure 3D movies in order to minimize distortion when seen on a different display than the one it has been configured for. By their very nature, 3D broadcasts come with a stereoscopic pair to be seen by the left and right eyes. However, according to reasons that we ought to explain in the paper, the cameras used to shoot a movie are calibrated according to specific viewing parameters such as the screen size, the viewing distance and the eye separation. As a consequence, a 3D broadcast seen on a different display (say a home theater or a PC screen) than the one it has been configured for (say an IMAX R screen) will suffer from noticeable distortions. In this paper, we describe the relationship between the size of the 3D display, the position of the observer, and the intrinsic and extrinsic parameters of the cameras. With this information, we propose a method to reorganize the stereoscopic pair in order to minimize distortion when seen on an arbitrary display. In addition to the raw video pair, our method uses the viewing distance, a rough estimate of the 3D scene, and some basic information on the 3D display. An inpainting technique is used to fill disoccluded areas.

  13. Endodontic applications of 3D printing.

    Science.gov (United States)

    Anderson, J; Wealleans, J; Ray, J

    2018-02-27

    Computer-aided design (CAD) and computer-aided manufacturing (CAM) technologies can leverage cone beam computed tomography data for production of objects used in surgical and nonsurgical endodontics and in educational settings. The aim of this article was to review all current applications of 3D printing in endodontics and to speculate upon future directions for research and clinical use within the specialty. A literature search of PubMed, Ovid and Scopus was conducted using the following terms: stereolithography, 3D printing, computer aided rapid prototyping, surgical guide, guided endodontic surgery, guided endodontic access, additive manufacturing, rapid prototyping, autotransplantation rapid prototyping, CAD, CAM. Inclusion criteria were articles in the English language documenting endodontic applications of 3D printing. Fifty-one articles met inclusion criteria and were utilized. The endodontic literature on 3D printing is generally limited to case reports and pre-clinical studies. Documented solutions to endodontic challenges include: guided access with pulp canal obliteration, applications in autotransplantation, pre-surgical planning and educational modelling and accurate location of osteotomy perforation sites. Acquisition of technical expertise and equipment within endodontic practices present formidable obstacles to widespread deployment within the endodontic specialty. As knowledge advances, endodontic postgraduate programmes should consider implementing 3D printing into their curriculums. Future research directions should include clinical outcomes assessments of treatments employing 3D printed objects. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

  14. Towards next generation 3D cameras

    Science.gov (United States)

    Gupta, Mohit

    2017-03-01

    We are in the midst of a 3D revolution. Robots enabled by 3D cameras are beginning to autonomously drive cars, perform surgeries, and manage factories. However, when deployed in the real-world, these cameras face several challenges that prevent them from measuring 3D shape reliably. These challenges include large lighting variations (bright sunlight to dark night), presence of scattering media (fog, body tissue), and optically complex materials (metal, plastic). Due to these factors, 3D imaging is often the bottleneck in widespread adoption of several key robotics technologies. I will talk about our work on developing 3D cameras based on time-of-flight and active triangulation that addresses these long-standing problems. This includes designing `all-weather' cameras that can perform high-speed 3D scanning in harsh outdoor environments, as well as cameras that recover shape of objects with challenging material properties. These cameras are, for the first time, capable of measuring detailed (<100 microns resolution) scans in extremely demanding scenarios with low-cost components. Several of these cameras are making a practical impact in industrial automation, being adopted in robotic inspection and assembly systems.

  15. ASSESSING 3D PHOTOGRAMMETRY TECHNIQUES IN CRANIOMETRICS

    Directory of Open Access Journals (Sweden)

    M. C. Moshobane

    2016-06-01

    Full Text Available Morphometrics (the measurement of morphological features has been revolutionized by the creation of new techniques to study how organismal shape co-varies with several factors such as ecophenotypy. Ecophenotypy refers to the divergence of phenotypes due to developmental changes induced by local environmental conditions, producing distinct ecophenotypes. None of the techniques hitherto utilized could explicitly address organismal shape in a complete biological form, i.e. three-dimensionally. This study investigates the use of the commercial software, Photomodeler Scanner® (PMSc® three-dimensional (3D modelling software to produce accurate and high-resolution 3D models. Henceforth, the modelling of Subantarctic fur seal (Arctocephalus tropicalis and Antarctic fur seal (Arctocephalus gazella skulls which could allow for 3D measurements. Using this method, sixteen accurate 3D skull models were produced and five metrics were determined. The 3D linear measurements were compared to measurements taken manually with a digital caliper. In addition, repetitive measurements were recorded by varying researchers to determine repeatability. To allow for comparison straight line measurements were taken with the software, assuming that close accord with all manually measured features would illustrate the model’s accurate replication of reality. Measurements were not significantly different demonstrating that realistic 3D skull models can be successfully produced to provide a consistent basis for craniometrics, with the additional benefit of allowing non-linear measurements if required.

  16. 3D numerical simulations of multiphase continental rifting

    Science.gov (United States)

    Naliboff, J.; Glerum, A.; Brune, S.

    2017-12-01

    Observations of rifted margin architecture suggest continental breakup occurs through multiple phases of extension with distinct styles of deformation. The initial rifting stages are often characterized by slow extension rates and distributed normal faulting in the upper crust decoupled from deformation in the lower crust and mantle lithosphere. Further rifting marks a transition to higher extension rates and coupling between the crust and mantle lithosphere, with deformation typically focused along large-scale detachment faults. Significantly, recent detailed reconstructions and high-resolution 2D numerical simulations suggest that rather than remaining focused on a single long-lived detachment fault, deformation in this phase may progress toward lithospheric breakup through a complex process of fault interaction and development. The numerical simulations also suggest that an initial phase of distributed normal faulting can play a key role in the development of these complex fault networks and the resulting finite deformation patterns. Motivated by these findings, we will present 3D numerical simulations of continental rifting that examine the role of temporal increases in extension velocity on rifted margin structure. The numerical simulations are developed with the massively parallel finite-element code ASPECT. While originally designed to model mantle convection using advanced solvers and adaptive mesh refinement techniques, ASPECT has been extended to model visco-plastic deformation that combines a Drucker Prager yield criterion with non-linear dislocation and diffusion creep. To promote deformation localization, the internal friction angle and cohesion weaken as a function of accumulated plastic strain. Rather than prescribing a single zone of weakness to initiate deformation, an initial random perturbation of the plastic strain field combined with rapid strain weakening produces distributed normal faulting at relatively slow rates of extension in both 2D and

  17. Local analytical sensitivity analysis for design of continua with optimized 3D buckling behavior

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard; Pedersen, Pauli

    2018-01-01

    The localized analytical sensitivity for eigenfrequency is extended to the non-linear problem of 3D continuum buckling analysis. Implemented in a finite element approach the inherent complexity of mode switching and multiple eigenvalues is found not to be a practical problem. The number of necess......The localized analytical sensitivity for eigenfrequency is extended to the non-linear problem of 3D continuum buckling analysis. Implemented in a finite element approach the inherent complexity of mode switching and multiple eigenvalues is found not to be a practical problem. The number...

  18. The NIH 3D Print Exchange: A Public Resource for Bioscientific and Biomedical 3D Prints

    OpenAIRE

    Coakley, Meghan F.; Hurt, Darrell E.; Weber, Nick; Mtingwa, Makazi; Fincher, Erin C.; Alekseyev, Vsevelod; Chen, David T.; Yun, Alvin; Gizaw, Metasebia; Swan, Jeremy; Yoo, Terry S.; Huyen, Yentram

    2014-01-01

    The National Institutes of Health (NIH) has launched the NIH 3D Print Exchange, an online portal for discovering and creating bioscientifically relevant 3D models suitable for 3D printing, to provide both researchers and educators with a trusted source to discover accurate and informative models. There are a number of online resources for 3D prints, but there is a paucity of scientific models, and the expertise required to generate and validate such models remains a barrier. The NIH 3D Print ...

  19. PRETVORBA 3D MODELOV IZ PROGRAMA BLENDER V BINARNI ZAPIS IGRALNEGA POGONA PRISM3D

    OpenAIRE

    Lušenc, Simon

    2014-01-01

    Magistrsko delo predstavi binarni zapis 3D modelov, uporabljenih v igralnem pogonu Prism3D in razvoj dodatka za pretvorbo 3D modelov s programskim orodjem Blender, ki ga tudi najprej na kratko opišemo. V nadaljevanju analiziramo zapise uporabljenih datotek, kar nam omogoči razvoj dodatka za uvoz in izvoz 3D modela, uporabljenega v igralnem pogonu Prism3D. Po predstavljeni izdelavi dodatka z vizualno primerjavo ocenimo njegovo uspešnosti in podamo možne izboljšave.

  20. 3D sound and 3D image interactions: a review of audio-visual depth perception

    Science.gov (United States)

    Berry, Jonathan S.; Roberts, David A. T.; Holliman, Nicolas S.

    2014-02-01

    There has been much research concerning visual depth perception in 3D stereoscopic displays and, to a lesser extent, auditory depth perception in 3D spatial sound systems. With 3D sound systems now available in a number of different forms, there is increasing interest in the integration of 3D sound systems with 3D displays. It therefore seems timely to review key concepts and results concerning depth perception in such display systems. We first present overviews of both visual and auditory depth perception, before focussing on cross-modal effects in audio-visual depth perception, which may be of direct interest to display and content designers.