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振動インテンシティ計測法の基礎的検討沖津, 昭慶, Okitsu, Akiyoshi, 畔上, 秀幸, Azegami, Hideyuki, 寺本, 雅博, Teramoto, Masahiro, 小林, 秀孝, Kobayashi, Hidetaka 05 1900 (has links)
No description available.
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Numerical Collision Analysis of Concrete Guard Fences for Performance-Based Design服部, 良平, Hattori, Ryouhei, 伊藤, 義人, Itoh, Yoshito, Kusama, Ryuichi, 劉, 斌, Liu, Bin 12 1900 (has links)
No description available.
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Integrating-factor-based 2-additive Runge-Kutta methods for advection-reaction-diffusion equationsKroshko, Andrew 30 May 2011 (has links)
There are three distinct processes that are predominant in models of flowing
media with interacting components: advection, reaction, and diffusion.
Collectively, these processes are typically modelled with partial differential
equations (PDEs) known as advection-reaction-diffusion (ARD) equations.<p>
To solve most PDEs in practice, approximation methods known as numerical methods
are used. The method of lines is used to approximate PDEs with systems of
ordinary differential equations (ODEs) by a process known as
semi-discretization. ODEs are more readily analysed and benefit from
well-developed numerical methods and software. Each term of an ODE that
corresponds to one of the processes of an ARD equation benefits from particular
mathematical properties in a numerical method. These properties are often
mutually exclusive for many basic numerical methods.<p>
A limitation to the widespread use of more complex numerical methods is that the
development of the appropriate software to provide comparisons to existing
numerical methods is not straightforward. Scientific and numerical software is
often inflexible, motivating the development of a class of software known as
problem-solving environments (PSEs). Many existing PSEs such as Matlab have
solvers for ODEs and PDEs but lack specific features, beyond a scripting
language, to readily experiment with novel or existing solution methods. The PSE
developed during the course of this thesis solves ODEs known as initial-value
problems, where only the initial state is fully known. The PSE is used to assess
the performance of new numerical methods for ODEs that integrate each term of a
semi-discretized ARD equation. This PSE is part of the PSE pythODE that uses
object-oriented and software-engineering techniques to allow implementations of
many existing and novel solution methods for ODEs with minimal effort spent on
code modification and integration.<p>
The new numerical methods use a commutator-free exponential Runge-Kutta (CFERK)
method to solve the advection term of an ARD equation. A matrix exponential is
used as the exponential function, but CFERK methods can use other numerical
methods that model the flowing medium. The reaction term is solved separately
using an explicit Runge-Kutta method because solving it along with the
diffusion term can result in stepsize restrictions and hence inefficiency. The
diffusion term is solved using a Runge-Kutta-Chebyshev method that takes
advantage of the spatially symmetric nature of the diffusion process to avoid
stepsize restrictions from a property known as stiffness. The resulting methods,
known as Integrating-factor-based 2-additive Runge-Kutta methods, are shown to be able to find higher-accuracy
solutions in less computational time than competing methods for certain
challenging semi-discretized ARD equations. This demonstrates the practical
viability both of using CFERK methods for advection and a 3-splitting in
general.
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Approximation Techniques for Incompressible Flows with Heterogeneous PropertiesSalgado Gonzalez, Abner Jonatan 2010 August 1900 (has links)
We study approximation techniques for incompressible
flows with heterogeneous
properties. Speci cally, we study two types of phenomena. The first is the flow of a
viscous incompressible fluid through a rigid porous medium, where the permeability
of the medium depends on the pressure. The second is the
ow of a viscous incompressible fluid with variable density. The heterogeneity is the permeability and the
density, respectively.
For the first problem, we propose a finite element discretization and, in the case
where the dependence on the pressure is bounded from above and below, we prove its
convergence to the solution and propose an algorithm to solve the discrete system. In
the case where the dependence is exponential, we propose a splitting scheme which
involves solving only two linear systems.
For the second problem, we introduce a fractional time-stepping scheme which,
as opposed to other existing techniques, requires only the solution of a Poisson equation
for the determination of the pressure. This simpli cation greatly reduces the
computational cost. We prove the stability of first and second order schemes, and
provide error estimates for first order schemes.
For all the introduced discretization schemes we present numerical experiments,
which illustrate their performance on model problems, as well as on realistic ones.
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Numerical Analysis of Force Convection for NotebookLiou, Rong-tai 21 July 2004 (has links)
With development and advancement of notebook, at the same time it brings its cooling problem, it is very important that use outside surface cooling except inside.
The main in study is simulate of electronic cooling in Notebook outside surface, design force convection models and placed them under the Notebook, force convection has immediate effect on the surface and produce heat dissipation. The simulation uses software FLUENT 6.0 to analysis the result of heat dissipation, the models are constructed and described by use turbulent field of three dimensions. The study has two main parameters¡GThe form of force convection models and controlled airflow. The result of numerical analysis use Nusselt number to determine the effect of heat dissipation.
According to the result of numerical analysis to increase effect of heat dissipation for the following methods¡G1. Increase airflow across the designed models, 2. Decrease the angle of elevation when using notebook, 3. Airflow enter the designed models by one entrance and leave by the side exports, 4. When airflow pass through the designed models smoothly, 5. Airflow can influence the notebook surface immediately.
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Redesign and Stress Analysis of Composite Bicycle FrameSung, Yi-Chun 27 July 2005 (has links)
The positions of high stress concentration in a bicycle frame structure made in composite materials and a way to strengthen them were investigated via SolidWorks and ANSYS, 3D picture plotting software, and numerical simulation software, respectively. The capability of productivity will be improved indirectly due to the shortening of the time in the process of customers¡¦ order, research, development and mass production.
In experiment, prepreg tape (TOHO UT500 carbon fiber/AD. Group matrix) which were produced by AD. Group were made into laminates by hot-pressing machine. The material constants of the laminate and the stress-strain diagram were obtained according to the stander of ASTM D3039. The received material constants are E11 =151.55 GPa and E22 = 7.654 GPa, respectively.
In simulation, the experimental data E11 and E22 were used in the numerical analysis, and obtained the stress and deformation fields of the bicycle frame structure and the front fork were plotted based on the standards provided by AD. Group. Reinforcements were made according to the positions of stress concentration in the diagrams. The results of improvements of the front fork after reinforcement include¡G the deformation of normal rigidity was improved to 9.45mm from 12.89mm, and the lateral deformation was significantly improved to 0.97mm from 13mm. Other improvements of the frame structure after reinforcement contain the deformation: dual-side rigidity was improved to 6.6mm from 11.7mm, and the deformation of single-side rigidity was improved to 12.5mm. The rigidity of the head lug was 0.46mm and there is no need to reinforce it because it was meets requirements.
Keywords: Numerical analysis, bicycle frame, prepreg, stress concentration.
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Numerical Analysis of Residual Strength in AS-4/PEEK Composite LaminatesLee, Chin-Fa 24 June 2001 (has links)
The purpose of thesis is aimed to predict the residual stiffness and residual strength of a composite laminate by adopting the method of cumulative damage theories numerically. In association with the experimental work the numerical result can be verified in comparison. The fatigue data in composites are well known more scattered than those in conventional metals, because the material properties are complicated due to nonhomogeneity and anisotropy. Until now there exists very few unified theories to model composite fatigue properties. Most of them are semi-empirical expressions fitted by selecting material characteristic values. This work tries to make a precise prediction with hopefully saving time, money and manpower in future experiments.
On the aspect of numerical analysis, we employ finite element method incorporated with the software of ANSYS to generate 3-D finite element model and obtain the ultimate stress of cross-ply [0/90]4s and quasi-isotropic [0/+45/90/-45] laminates by Tsai-Wu failure criterion. It is assumed that the damage due to fatigue cycles is equal to the damage of stiffness and strength, in association with Miner¡¦s Rule and cumulative damage theories we obtain the residual stiffness and strength. The numerical result in comparison with the available empirical data is found acceptably well.
Finally, this study can be concluded as follows. The error of ultimate stress is 3.84 % in cross-ply[0/90]4s , and 8.38 % in quasi-isotropic[0/45/90/-45]2s laminates. The error of ultimate stress in centrally notched cross-ply[0/90]4s is 0.4 %, and 22.4 % in centrally notched quasi-isotropic laminates. As the fatigue cycles increasing, the residual stiffness and residual strength of the laminates are all decreasing. The decreasing rate is very slight at first and intermediate stages, whilst it is much faster near the last stage. It is found that the prediction of residual strength is more accurate in the case of maximum stress of 60% ultimate stress than that of 80% ultimate stress.
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An application of the Malliavin calculus in financeFordred, Gordon Ian. January 2009 (has links)
Thesis (M. Sc.(Mathematics and Applied Mathematics))--University of Pretoria, 2009. / Summary in English. Includes bibliographical references.
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A volumetric mesh-free deformation method for surgical simulation in virtual environmentsWang, Shuang. January 2009 (has links)
Thesis (M.S.)--University of Delaware, 2009. / Principal faculty advisors: Kenneth E. Barner and Karl V. Steiner, Dept. of Electrical & Computer Engineering. Includes bibliographical references.
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Application of Higdon non-reflecting boundary conditions to shallow water models /van Joolen, Vincent J. January 2003 (has links) (PDF)
Thesis (Ph. D. in Applied Mathematics)--Naval Postgraduate School, June 2003. / Dissertation supervisors: Beny Neta, Dan Givoli. Includes bibliographical references (p. 131-133). Also available online.
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