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1دورية أكاديمية
المؤلفون: Shyue, Keh-Ming
المساهمون: 國立臺灣大學數學系
مصطلحات موضوعية: Volume tracking, Wave propagation method, Multicomponent flows, Mie-Gruneisen equation of state, Impact problem
الوصف: We present a simple volume-of- uid approach to interface tracking for inviscid compressible multicomponent ow problems in two space dimensions. The algorithm uses a uniform Carte- sian grid with some grid cells subdivided by tracked interfaces, approximately aligned with the material interfaces in the ow field. A standard volume-moving procedure that consists of two basic steps: (1) the update of a discrete set of volume fractions from the current time to the next, and (2) the reconstruction of interfaces from the resulting volume fractions, is employed to find the new location of the tracked interfaces in piecewise linear form at the end of a time step. As in the previous work by LeVeque and the author to front tracking based on a surface- moving procedure (J. Comput. Phys., 123 (1996), pp. 354-368), a conservative high-resolution wave propagation method is applied on the resulting slightly nonuniform grid to update all the cell values, while the stability of the method is maintained by using a large time step idea even in the presence of small cells and the use of a time step with respect to the uniform grid cells. We validate our algorithm by performing the simulation of a Mach 1 . 22 shock wave in air over a circular R22 gas bubble, where sensible agreement of some key ow features of the computed solutions are observed when direct comparison of our results are made with the existing experimental and numerical ones appeared in the literature. Other computations are also presented that show the feasibility of the algorithm together with a mixture type of the model equations developed by the author (J. Comput. Phys., 171 (2001), pp. 678-707) for practical multicomponent problems with general compressible materials characterized by a Mie-Gr¨ uneisen form of the equation of state.
وصف الملف: application/pdf; 2575908 bytes
العلاقة: Journal of Computational Physics 215(1),219-244; 20060927121127789779; http://ntur.lib.ntu.edu.tw/handle/246246/20060927121127789779Test; http://ntur.lib.ntu.edu.tw/bitstream/246246/20060927121127789779/1/vof2d.pdfTest
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2تقرير
المؤلفون: 吳光鐘
المساهمون: 國立臺灣大學應用力學研究所
مصطلحات موضوعية: 彈性波傳, 異向性材料, 掩埋波源, 雙材料, elastic wave propagation, anisotropic material, buried source, bimaterial
جغرافية الموضوع: 計畫年度：93, 起迄日期：2004-08-01/2005-07-31
الوصف: 本計劃分析在均勻半空間或雙材料無 限域內之集中力或差排的暫態反應。以Wu (2000)所提求解異向動彈力的方法為基礎 來推廣處理該問題。此法之優點在於不需 利用積分轉換即可求得顯式解。除此之 外，顯式解中各個反射波及透射波亦可一 目了然。本計劃第二年度考慮雙材料的問 題。 ; A transient analysis of a line force or dislocation in an anisotropic elastic homogeneous halfspace or a bimaterial infinite space is made in this project. A new method proposed by Wu (2000) for anisotropic elastodynamics is extended to treat the problem. A major advantage of the method is that explicit solution can be derived without the use of integral transforms. Furthermore, individual reflected and refracted waves can be clearly identified in the solution. In the second year a bimaterial problem is considered.
وصف الملف: application/pdf; 184602 bytes
العلاقة: 932212E002027; http://ntur.lib.ntu.edu.tw/handle/246246/21739Test; http://ntur.lib.ntu.edu.tw/bitstream/246246/21739/1/932212E002027.pdfTest
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3تقرير
المؤلفون: 吳光鐘
المساهمون: 國立臺灣大學應用力學研究所
مصطلحات موضوعية: 彈性波傳, 異向性材料, 掩埋波源, 半空間, elastic wave propagation, anisotropic material, buried source, half-space
جغرافية الموضوع: 計畫年度：92, 起迄日期：2003-08-01/2004-07-31
الوصف: 本計劃分析在均勻半空間或雙材料無 限域內之集中力或差排的暫態反應。本計 劃推廣一個Wu (2000)所提求解異向動彈 力的方法來處理該問題。此法之優點在於 不需利用積分轉換即可求得顯式解。除此 之外，顯式解中各個反射波及透射波亦可 一目了然。本計劃第一年度考慮半空間的 問題。 ; A transient analysis of a line force or dislocation in an anisotropic elastic homogeneous halfspace or a bimaterial infinite space is made in this project. A new method proposed by Wu (2000) for anisotropic elastodynamics is extended to treat the problem. A major advantage of the method is that explicit solution can be derived without the use of integral transforms. Furthermore, individual reflected and refracted waves can be clearly identified in the solution. In the first year a halfspace is considered.
وصف الملف: application/pdf; 212006 bytes
العلاقة: 922212E002067; http://ntur.lib.ntu.edu.tw/handle/246246/21711Test; http://ntur.lib.ntu.edu.tw/bitstream/246246/21711/1/922212E002067.pdfTest
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4تقرير
المؤلفون: 吳光鐘
المساهمون: 國立臺灣大學應用力學研究所
مصطلحات موضوعية: 異向彈性材料, 彈性波傳, 動態集中載重, anisotropic elastic material, elastic wave propagation, dynamic concentrated loading
جغرافية الموضوع: 計畫年度：92, 起迄日期：2003-08-01/2004-07-31
الوصف: 本計劃研究動態點集中載重作用於無 限異向彈性體內的三維全域或半無窮域暫 態反應。本計劃利用雷登轉換來發展一個 新的計算方法。新法之效率及準確性將以 實際算例來驗證。 ; The three-dimensional full-field transient response to a dynamic point force in an infinite or a semi-infnite anisotropic elastic body is studied. A new method based on the Radon transform is developed. The efficiency and accuracy of the proposed method will be verified by numerical examples.
وصف الملف: application/pdf; 248199 bytes
العلاقة: 922211E002077; http://ntur.lib.ntu.edu.tw/handle/246246/21697Test; http://ntur.lib.ntu.edu.tw/bitstream/246246/21697/1/922211E002077.pdfTest
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5تقرير
المؤلفون: 洪淑蕙
مصطلحات موضوعية: parallel computation, seismic wave propagation, anisotropy, mantle plume
جغرافية الموضوع: 計畫年度：91, 起迄日期：2002-08-01/2003-07-31
الوصف: Mid-ocean ridges and surface hotspots are two places where active volcanisms occur on our planet. Using seismological observations as constraints, the goal of our study is to understand the form of mantle upwelling and melt production at a possible deep-rooted mantle plume and beneath a slow-spreading ridge segment which are responsible for magma eruption on the earth’s surface. Seismic experiments on the fast-spreading East-Pacific Rise and ridge-centered Icelandic hotspot generated numerous high-quality records which indicate the underlying structures are partially-molten, elastically heterogeneous and anisotropic as well as attenuated. In these geodynamically-interesting but structurally-complicated environments expected under discontinuous ridge segments and hotspot tracks, many of the usual approximation employed in modeling finite-frequency seismic wave propagation break down. This study explores the effects of velocity heterogeneity and anisotropy associated with temperature and compositional variations in the upwelling mantle on seismic waveforms by virtue of direct solution method. Fully understanding of seismic wave behaviors in a complicated structure like the earth will help data acquisition accusation and interpretation to image the deep mantle structure.
وصف الملف: application/pdf; 289572 bytes
العلاقة: 912611M002025; http://ntur.lib.ntu.edu.tw/handle/246246/11832Test; http://ntur.lib.ntu.edu.tw/bitstream/246246/11832/1/912611M002025.pdfTest
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6تقرير
المؤلفون: 許銘熙
مصطلحات موضوعية: wave propagation, boundary fitted coordinate, free surface, darn break, 波傳, 邊界閉合座標, 自由水面潰壩
جغرافية الموضوع: 計畫年度：89 第二期, 起迄日期：2000-08-01/2001-07-31
الوصف: The wave propagation of darn break flows in a sloping smooth channel was simulated by numerical model in this paper. In order to obtain movable boundaries on the free surface, the techniques of the moving grids and boundary-fitted coordinate system presented by Thompson are adopted. The solutions were obtained by transforming the irregular physical domain into regular computational domain. The governing equations of the two-dimensional momentum and continuity equations were solved simulataneously by using the finite difference scheme on nonstaggered grids. The arbitrary Lagrangian ¡X Eulerian (ALE) kinematic description was applied in the procedure of calculation. The numerical model was verified by experimental data of wave propagation due to a darn failure. As a result, the model was used to simulate and analyse the wave propagation of dam break in different sloping channel ; 本文主要在以數值方法模擬斜坡渠道上潰壩流場之波傳。為掌握自由水面不規則移動邊界之變化，採用動格網方式配合邊界閉合座標法，並將不規則物理平面座標轉換成規則之計算平面上進行求解。對於二維動量及連續方程之控制方程式之求解，探用非交錯格網系統以有限差分法離做控制方程式，並以交替拉格蘭吉‧尤拉運動描述法來模擬自由水面之波傳現象。本文利用潰壩流場之實驗資料作為模式之驗證，進而模擬各渠床坡度之潰壩流場。
وصف الملف: application/pdf; 1762721 bytes
العلاقة: 892211E002141; http://ntur.lib.ntu.edu.tw/handle/246246/10685Test; http://ntur.lib.ntu.edu.tw/bitstream/246246/10685/1/892211E002141.pdfTest
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7تقرير
المؤلفون: 吳光鐘
المساهمون: 國立臺灣大學應用力學研究所
مصطلحات موضوعية: 異向彈性, 彈性波傳, 格林函數, Anisotropic Elasticity, Elastic Wave Propagation, Green Function
جغرافية الموضوع: 計畫年度：89 第一期, 起迄日期：1999-08-01/2000-07-31
الوصف: 本計畫將史磋法延伸於二維異向動彈 力問題。傳統動彈力分析方法是以積分轉 換為基礎，本計畫發展之方法則無此需要, 應用上甚為方便。利用新法，本計劃求得 無限域反平面應變問題之動態格林函數。 此格林函數反比於時間及一有效動態剪力 模數。其所對應在通過源點之平面上之曳 引力為零。以無限域格林函數為基礎，本 計畫並求得楔形體，半無線域及無限板之 格林函數。 ; The project extends the Stroh formalism to two-dimensional anisotropic elastodynamic problems. Conventional methods of analysis are based on integral transforms. The method developed in this project does not require such procedure. The dynamic Green’s function due to an impulse in an infinite anisotropic medium under antiplane deformation is derived using the extended Stroh formalism method. The Green’s function is inversely proportional to the time t and an effective dynamic shear modulus. It is shown that the tractions on the planes passing through the source point vanish identically. Based on the free-space Green’s function, the Green’s functions for wedges, semi-infinite media and strips are obtained.
وصف الملف: application/pdf; 42394 bytes
العلاقة: 892212E002007; http://ntur.lib.ntu.edu.tw/handle/246246/21573Test; http://ntur.lib.ntu.edu.tw/bitstream/246246/21573/1/892212E002007.pdfTest
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8رسالة جامعية
المؤلفون: 林珈樺, Lin, Chia-Hua
المساهمون: 理學院: 地質科學研究所, 指導教授: 胡植慶, 李憲忠, 林珈樺, Lin, Chia-Hua
مصطلحات موضوعية: 1951年花東縱谷地震序列, 縱谷斷層, 震源逆推, 隨機滑移分布模型, 三維地震波傳模擬, 1951 Longitudinal Valley earthquake sequence, Longitudinal Valley Fault, source rupture model, stochastic slip model, 3D wave propagation simulation
الوقت: 44
الوصف: 台灣東部花東縱谷被視為歐亞板塊與菲律賓海板塊的縫合帶，而花東縱谷斷層系統由北到南貫穿整個花東縱谷，屬於台灣地區活躍的斷層系統。在1951年10月到12月的期間，四個規模大於6.9的地震陸續發生在花蓮外海及花東縱谷斷層沿線，且記錄到數千個餘震，餘震震源隨時間由北往南傳遞，此地震事件被稱為「花東縱谷地震序列」，當時在縱谷沿線觀察到總共約90公里的同震地表破裂。本研究針對此的震序列做進一步的探討，以期了解縱谷斷層的滑移特性。本文主要分為兩大部份，第一部分藉由同震地表變形量以非負最小平方法(Non-Negative Least Square, NNLS)對三個不同斷層模型進行反演，求得斷層面上之滑移分布(slip pattern)，再透過譜元素法(Spectral Element Method, SEM)計算縱谷斷層分段破裂之地震波傳遞情形，並以模擬之地動分布圖(ShakeMap)和瞬時速度波場(snapshot)之結果，討論其波傳特性；第二部分則以台灣地震模型(Taiwan Earthquake Model)的縱谷斷層幾何作為基礎，考慮地震發生時，斷層滑移分布的不確定與隨機性，透過隨機滑移分布模型(stochastic slip model)建立出十個隨機滑移分布，並模擬縱谷斷層全段破裂在不同震源破裂情境下的地震波傳情形，最後統計不同破裂起始點的平均地動分布與地動極值分布。數值模擬的統計結果顯示，當縱谷斷層發生破裂，花東縱谷地區在各種震源破裂模型中，受到影響最為顯著，地表加速度值大多超過250 cm/s2。若破裂起始點在縱谷斷層中段，全台的地表加速度量值皆會大於80 cm/s2，而儘管距離縱谷斷層較遠的台北盆地、宜蘭平原、台灣南部地區，因受到破裂方向性與場址效應的影響，在特定的破裂分布情形下，會產生超過預期的地表加速度量值。藉由逆推而得的同震滑移分布與隨機滑移分布模型所建立之震源破裂模型的波傳模擬結果，我們可以了解當縱谷斷層發生破裂時，對台灣的影響範圍，並以統計的方式降低斷層面的滑移不確定性對地動分布的影響，期望更接近未來可能的地震情境，作為未來地震防災的參考依據。 ; The Longitudinal Valley (LV) in the eastern Taiwan is considered as the suture zone between the Eurasia Plate and the Philippine Sea Plate. Thousands of earthquakes are occur in this area every year. The Longitudinal Valley Fault (LVF) is a seismically active structure, which is located along the LV. During the time period from October to December in 1951, lots of large earthquakes occurred between Hualien and Taitung area, including four major earthquakes (M > 6.9) and thousands of aftershocks. This earthquake series is known as the Longitudinal Valley Earthquake sequence. Coseismic surface rupture with a total length of approximate 90 km were observed along LV. In order to understand the characteristics of source rupture and resultant strong ground motion, this study is comprised of two different parts. In first part, we reconstructed the source model and strong ground motion time history of this earthquake sequence. Inversion of the coseismic displacement data was first conducted. Based on the inverted slip distribution, we performed 3D forward simulation using the Spectral Element Method. Therefore, the second part of the ...
وصف الملف: 4448878 bytes; application/pdf
العلاقة: http://ntur.lib.ntu.edu.tw/handle/246246/273010Test; http://ntur.lib.ntu.edu.tw/bitstream/246246/273010/1/ntu-105-R02224105-1.pdfTest
الإتاحة: https://doi.org/10.6342/NTU201601658Test
http://ntur.lib.ntu.edu.tw/handle/246246/273010Test
http://ntur.lib.ntu.edu.tw/bitstream/246246/273010/1/ntu-105-R02224105-1.pdfTest -
9رسالة جامعية
المؤلفون: 林詩珊, Lin, Shih-Shan
المساهمون: 工學院: 工程科學及海洋工程學研究所, 指導教授: 黃心豪, 林詩珊, Lin, Shih-Shan
مصطلحات موضوعية: 聲學超穎材料, 拉脹性, 頻散關係, 能帶結構, 波傳行為, 可調頻, Acoustic metamaterial, Auxetic, Dispersion relation, Band structure, Wave propagation, Tunable
الوقت: 15
الوصف: 本文主要探討可調頻平面超穎材料之聲波傳遞行為。首先透過商用有限元素分析軟體進行分析模擬，針對一具拉脹性薄膜結構之超穎材料作週期性排列設定，分析其單元之能帶結構，因其結構拉脹特性，利用幾何變形將可能阻擋某些特定頻率下聲波通過，達到可調頻的效果。另外，亦透過聲學實驗觀察該特定頻率下的波傳衰減行為，並與模擬進行比較與相互映證，結果顯示該結構將能阻隔特定頻率範圍內的聲波傳遞。 ; A tunable planar auxetic metamaterial for controlling and filtering acoustic waves was investigated. In the study, the commercial finite element software package was utilized for numerical simulations. A planar auxetic structure was placed periodically, and its acoustic band structure was obtained. It was found that the bandages may appear in certain frequency range because of the geometric deformation of the auxetic structure. In addition, the wave attenuation behavior at a specific frequency was investigated experimentally, and the experimental results were compared with those obtained from numerical simulations. Both the numerical and experimental results showed that the planar auxetic structure is tunable for controlling the sound wave propagation and filtering the waves within a specific frequency range. ; 工程科學及海洋工程學系 ; 工學院 ; 博碩士論文
وصف الملف: 7387613 bytes; application/pdf
العلاقة: http://ntur.lib.ntu.edu.tw/handle/246246/271525Test; http://ntur.lib.ntu.edu.tw/bitstream/246246/271525/1/ntu-105-R03525025-1.pdfTest
الإتاحة: https://doi.org/10.6342/NTU201602850Test
http://ntur.lib.ntu.edu.tw/handle/246246/271525Test
http://ntur.lib.ntu.edu.tw/bitstream/246246/271525/1/ntu-105-R03525025-1.pdfTest -
10رسالة جامعية
المؤلفون: 柯秉良, Ko, Ping-Liang
المساهمون: 工學院: 機械工程學研究所, 指導教授: 馬劍清, 柯秉良, Ko, Ping-Liang
مصطلحات موضوعية: 布拉格光纖光柵, 數位影像相關法, 應變, 能量調變法, 壓力感測器, 模態耦合理論, 暫態波傳, Fiber Bragg Grating, Digital Image Correlation, strain, power modulated method, pressure sensors, coupled mode theory, transient wave propagation
الوقت: 96
الوصف: 光纖感測器具有良好的機械性質以及幾何形狀特質、高靈敏度以及不受電磁波干擾等優點，因此近年來以光纖感測器做為感測器的相關研究發展相當迅速，其中又以布拉格光纖光柵感測器（Fiber Bragg Grating, FBG）最為受到重視，而其應用於量測時可搭配波長解調器進行靜態訊號的監測或是以能量調變型光纖光柵架設進行動態訊號量測，上述兩種方式若再結合分波多工器則可實現多點同時量測的技術。而數位影像相關法（Digital Image Correlation, DIC）可進行非接觸之全域量測，進年來也被廣泛應用於精密的位移及應變量測問題上，而這些量測技術本實驗室過去已投入相當多的研究，並擁有相當成熟之技術，而本文中將利用這些技術進行高精度壓力感測器之設計與開發，同時也對已有之量測技術進行改良。 本文主要應用FBG製作微小壓力感測的系統，利用薄板理論及光纖模態耦合理論模型設計FBG壓力感測器，使其可針對氣壓及液體壓力進行精密量測，並搭配實驗室過去以及新開發之波長解調技術，對微小之壓力變化進行量測與測試，可與市售之商用壓力感測器進行比較，並將其應用於液體之壓力波量測、音箱導音管之微小壓力變化量測以及風扇系統之氣壓變化量測。此外，也將理論模擬之結果與量測結果進行比較。在布拉格光纖光柵的實驗量測上，本文針對實驗室新引進之波長解調器進行詳細的測試並與其他感測技術量測之結果互相驗證比較，確認其量測結果之正確性，並引進大頻寬之傾斜式光纖光柵做為能量調變型光纖光柵之濾波器，並將其應用於大振幅波長飄移之暫態訊號量測。在本文末段則是針對FBG應用於車削加工時刀具狀態與壽命監測進行初步的評估，並提出其可行性與改良之建議。 ; Recently, the optical fiber sensors, especially the fiber Bragg grating (FBG) sensors, have been rapidly developed due to the advantages such as excellent mechanical properties, thin geometries, high sensitivity and electromagnetics immunity. It can be applied to static analysis by demodulating the FBG central wavelength or dynamic measurement by power modulated system, and both of them can measure multiple points in the same time with wavelength division multiplexer. On the other hand, digital image correlation (DIC), which is a non-contact and full field measurement technique, has also been used widely for measurement of displacement and strain problems. Both of them are developed in our laboratory and this thesis is going to use these techniques to design the high precision pressure sensors and improve these developed measurement techniques. The main object of this research is focused on the application of FBG on measuring small pressure changes due to the disturbance of fluid. We also use the theory of thin plate and the coupled mode theory to design FBG pressure sensors. The FBG pressure sensor we designed and manufactured can be used for measuring not only the air pressure but also the water pressure. It can detect the small pressure change by the I-MON system or the dynamic pressure change from power modulated ...
وصف الملف: 26279819 bytes; application/pdf
العلاقة: http://ntur.lib.ntu.edu.tw/handle/246246/278259Test; http://ntur.lib.ntu.edu.tw/bitstream/246246/278259/1/ntu-104-R02522518-1.pdfTest
