具體描述
內容簡介
Finite Element Method and its Applications discusses the methods in a general frame and the performance on the computer, the variational formulations for elliptic boundary value problems, the error estimates and convergence for finite element approximate solutions and nonstandard finite element. In particular, presentations of the subject include the applications of finite element method to various scientific and engineering problems, for example, three dimensional elastic beam, elastic mechanics, three dimensional neutron diffusion problems, magneto hydrodynamics, three dimensional turbomachinery flows, Navier-Stokes equations and bifurcation phenomena for nonlinear problem, etc. Most applications results were established by the authors in the past three decades. This book was written by Kaitai Li, Aixiang Huang, Qinghuai Huang.
目錄
Chapter 1 The Structure of Finite Element Method1.1 Galerkin Variational Principle and Ritz Variational Principle1.2 Galerkin Approximation Solution1.3 Finite Element Subspace1.4 Element Stiffness and Total Stiffness
Chapter 2 Elements and Shape Functions2.1 Rectangular Shape Function2.1.1 Lagrange Type Shape Function of Rectangular2.1.2 Hermite Type Shape Function of Rectangular2.2 Triangular Element2.2.1 Area Coordinate and Volume Coordinate2.2.2 Lagrange Type Shape Function of Triangular Element2.2.3 Hermite Type Shape Function of Triangular Element2.3 Shape Function of Three Dimensional Element2.3.1 Lagrange Type Shape Function of Hexahedron Element2.3.2 Lagrange Type Shape Function of Tetrahedron Element2.3.3 Shape Function of The Three Prism Element2.3.4 Hermite-Type Shape Function of Tetrahedron Element2.4 Iso-parametric Finite Element2.5 Curve Element
Chapter 3 Procedure and Performance of Computation of Finite Element Method3.1 The Procedure of Finite Element Computation3.2 One dimensional Store of Symmetric and Band Matrix3.3 Numerical Integration3.4 Computation of Element Stiffness Matrix and Synthesis of Total Stiffness Matrix3.4.1 Computation of Shape Function3.4.2 The Computation of Element Stiffness Matrix and Element Array3.4.3 Superposition of Elements of Total Stiffness Matrix3.5 Direct Solution Method for Finite Element Algebraic Equations3.5.1 Decomposition for Symmetric and Positive Definition Matrix3.5.2 Direct Solution for Algebraic equations3.6 Other Solution Method for Finite Element Algebraic Equations3.6.1 The Steepest Descent Method3.6.2 Conjugate Gradient Method3.7 Treatment of Constraint Conditions3.7.1 Treatment of Imposed Constraint Conditions3.7.2 Treatment of Periodic Constrain Condition3.7.3 Remove Periodic Constrain and Matrix Transformation3.7.4 Performance of the Method on Computer3.8 Calculation of Derivatives of Function3.9 Automatic Generation of Finite Element Mesh
Chapter 4 Sobolev Space4.1 Some Notations and Assumptions on Domain4.2 Classical Function Spaces4.3 LP(Ω) Space4.4 Spaces of Distribution4.5 Sobolev Spaces with Integer Index4.6 Sobolev Space with a Real Index HσP(Ω)4.7 Embedding Theorem and Interpolate Inequalities4.8 The Trace Spaces
Chapter 5 The Variational Principle for Elliptic Boundary Value Problem and Error Estimate of Finite Element Approximation Solution.5.1 Elliptic Boundary Value Problem5.1.1 Regularity5.1.2 The Existence and Uniqueness of the Solution5.1.3 Maximum Principle5.2 Variational Formulations5.3 Finite Element Approximation Solutions5.4 Coordinate Transformation and Equivalent Finite Element5.4.1 Affine Transformation and Affine Equivalent Finite Element5.4.2 Isoparametric Transformation and Isopavametric Finite Element5.5 The Theory of Finite Element Interpolation5.5.1 Some Lemma……Chapter 6 Nonstandard Finite Element MethodsChapter 7 Applications of Finite Element Method in the EngineeringChapter 8 Finite Element Analysis for Internal Flow in TurbomachineChapter 9 Finite Element Approximation for the Navier-Stokes EquationsReferences 精彩書摘
Chapter 1
The Structure of Finite Element Method
The finite element method is a numerical computational method for differential equations and partial differential equations. In order to solve the general field problem by using finite element method, it must pass through the following processes:
1) Find the variational formulation associated with original field problem.
2) Establish finite element subspace. For example, select the element type and associated phase functions.
3) Establish element stiffness matrix, element column and assemble global stiffness matrixfull column.
4) Treatment of the boundary conditions and solving of the system of finite element equations.
5) Come back to the real world. In this book, the first four processes will be systematic formulations in the first chapter till third chapter.
1.1 Galerkin Variational Principle and Ritz Variational Principle As an example, we consider the linear elliptic boundary value problem of two dimension,
(1.1.1) where, Ω is a connected domain in R2, .Ω = Γ1 ∪ Γ2 is a piecewise smooth boundary. Letn denote the unit outward normal vector to .Ω defined almost everywhere on .Ω. p(x, y) ∈C1(Ω), p(x, y) ≥ p0 > 0, σ(x, y) ∈ C0(Ω) and σ(x, y) ≥ 0.
Throughout this chapter we make notation: C0(Ω) = the set of all continuous function in an open subset in Rn. Ck(Ω) = the set of functions v ∈ C0(Ω), whose derivatives of order k,exist and are continuous;
where α = (α1, ? ? ? , αn), |α| = α1 + ? ? ? + αn.
Assume that u(x, y) ∈ C2(Ω) satisfies (1.1.1) in Ω and on .Ω, the function u(x, y) is called classical solution of problem (1.1.1).Next, we consider weak solution of (1.1.1). Define the norm
(1.1.2) Sobolev space H1(Ω) is a closure of C∞(Ω), under the norm (1.1.2) with the inner product
(1.1.3) H1(Ω) is a Hilbert space which is called one order Sobolev space. Let C∞0 (Ω) = {v : v is an infinite differentiable function and support of v . Ω}, H10 (Ω) = the closure of C∞0 (Ω) under the norm(1.1.2),it is equivalent to H10 (Ω) = {v : v ∈ H1(Ω), v|.Ω = 0}.In addition, let C∞# (Ω) = {v : v ∈ C∞(Ω), v|Γ1 = 0},V (Ω) = closure ofC∞# (Ω) under the norm(1.1.2),which is equivalent toV = {v : v ∈ H1(Ω), v|Γ1 = 0}.
It is clear that V is a Hilbert space with inner product (1.1.3). Furthermore,H10 (Ω) . V . H1(Ω).Let us introduce bilinear functional
(1.1.4) In (1.1.4), fixed u, then B(u, v) is a linear functional of v, while v is fixed, it is a linear functional of u. In other words, suppose α1, α2, β1, β2 are arbitrary constants, then B(α1u1 + α2u2, β1v1 + β2v2) =α1β1B(u1, v1) + α1β2B(u1, v2) + α2β1B(u2, v1) + α2β2B(u2, v2), .u1, u2, v1, v2 ∈ H1(Ω). It is clear that (1.1.4) satisfies
(1) Symmetry,B(u, v) = B(v, u). (1.1.5)
(2) The continuity in V × V , i.e., there exists a constant M >0, such that|B(u, v)| M u 1,Ω v 1,Ω, .u, v ∈ V. (1.1.6)
(3) Coerciveness in V , i.e., there exists constant γ > 0, such that B(u, u) γ u 2 1,Ω, .u ∈ V. (1.1.7) Of course, is a continuous linear functional in v.
The Galerkin Variational Formulation for (1.1.1): Find u ∈ V , such thatB(u, v) = f(v), .v ∈ V. (1.1.8)A solution u satisfying (1.1.8) is called a weak solution of (1.1.1). The space V is calledadmissible space or trial space. On the other hand, (1.1.8) must be satisfied for every v ∈ V ,therefore, V is called test function space. If trial and test space for the variational problem arethe same Hilbert V , in this case, V is called energy space.
Owing to the boundary condition on Γ2 is contained in the variational problem (1.1.8), theboundary condition on Γ2 is called nature boundary condition, while the boundary conditiononΓ1 is called essential boundary condition.
The following proposition gives the relationship between classical solution and weak solution of (1.1.1).
Proposition 1.1 Suppose u ∈ C2(Ω). If u is a classical solution of (1.1.1), then, u isthe weak solution of (1.1.1). Otherwise, if u is a weak solution of (1.1.1), then u is a classicalsolution of (1.1.1).
……
前言/序言
好的,根據您的要求,我將為您撰寫一本不同於《有限元方法及其應用(英文版) [Finite Element Method and its Applications]》的圖書簡介。由於您要求內容詳細且不包含原書的任何信息,且字數大約1500字,我將圍繞一個完全不同的、深入的科學或工程主題進行構思。 --- 圖書簡介: 書名:高維拓撲結構中的量子場論導論:規範對稱性與引力統一的路徑探索 作者: 維剋多·卡爾森 (Victor Carlson) 齣版社: 普林斯頓大學齣版社 (Princeton University Press) --- 導言:超越四維時空的基本結構 自二十世紀初以來,人類對物質和能量的理解便建立在量子場論(Quantum Field Theory, QFT)的堅實基石之上。標準模型成功地描述瞭電磁、弱核和強核三種基本相互作用,而引力,則由愛因斯坦的廣義相對論掌管。然而,一個深刻的、懸而未決的問題始終睏擾著理論物理學傢:如何將量子場論的精確性與描述時空幾何的廣義相對論進行兼容?尤其是在極高能量尺度或極小距離下,描述宇宙的終極理論必然要求一個超越四維閔可夫斯基時空框架的數學描述。 本書《高維拓撲結構中的量子場論導論:規範對稱性與引力統一的路徑探索》正視瞭這一挑戰。它並非傳統意義上對標準模型或基本弦理論的概述,而是聚焦於構建一個更為基礎的數學框架——拓撲場論(Topological Field Theories, TQFTs),並探索如何利用高維、非黎曼幾何結構來重構引力理論,使其能夠自然地融入量子力學的框架之中。 本書的目標讀者是具備紮實高等數學基礎(微分幾何、代數拓撲)和量子場論背景(路徑積分、重整化群)的研究生、博士後研究人員以及專業物理學傢。我們旨在提供一個嚴格的數學推導過程,清晰地勾勒齣從經典幾何概念過渡到前沿量子引力模型的必要步驟。 第一部分:拓撲場的數學基石 (The Mathematical Foundations of Topological Fields) 本書的開篇部分(第1章至第3章)專注於奠定必要的數學工具。我們摒棄瞭傳統物理教材中對局域能量密度的依賴,轉而采用同調理論(Homology Theory)和上同調理論(Cohomology Theory)來描述物理場的性質。 第1章:流形、縴維叢與規範對稱性重訪 本章首先迴顧瞭微分幾何的基礎,重點強調瞭聯絡(Connections)和麯率(Curvature)在高維流形上的定義。但區彆於標準方法,我們引入瞭層論(Sheaf Theory)的概念,用以描述在奇異點(如奇點或邊界)附近局部不變但全局非平凡的場結構。規範對稱性不再被視為簡單的局域酉變換,而是被提升到對特定縴維叢上的橫截麵(Sections)保持不變的對稱性。我們詳細分析瞭Chern-Simons理論在三維流形上的構造,並展示瞭其與經典規範理論的深刻聯係。 第2章:同調與量子算符 引入拓撲場論的核心概念:物理觀測值(如散射矩陣元素)不依賴於流形的度量(Metric),而僅依賴於其拓撲不變量。我們詳細推導瞭Witten的構造,展示如何通過引入特定的拉格朗日密度,使得作用量(Action)僅依賴於流形的拓撲屬性。章節重點討論瞭奇異同調與奇異上同調如何被用於定義物理態(Hilbert Space)的基礎,特彆是如何將Bordism群與量子場論的演化算符聯係起來,為處理帶邊界的物理係統奠定基礎。 第3章:非交換幾何與場論的重構 為瞭應對引力與量子力學在微觀尺度上的不相容性,我們探索瞭非交換幾何(Noncommutative Geometry)在場論中的應用。我們分析瞭如何用非交換代數取代經典的微分流形,從而在理論層麵消除零距離點之間的區分。本章詳細介紹瞭Spectral Triples的概念,並展示瞭如何利用它們來構建一個對洛倫茲對稱性保持不變的“廣義”時空結構,這是通嚮量子引力構造的先驅性工作。 第二部分:引力的拓撲重述與高維嵌入 (Topological Recasting of Gravity and Higher Dimensional Embedding) 本書的第二部分(第4章至第6章)將視角投嚮引力本身,探討如何將愛因斯坦的場方程置於一個更廣闊的幾何框架內。 第4章:重力作為規範場論:Palatini作用量與Twistor理論的交匯 我們重新審視瞭Palatini作用量,將其視為一個定義在更高階微分形式上的規範理論。本章詳盡地分析瞭自鏇聯絡和度量張量作為獨立變量的處理方式,這使得我們可以更清晰地看到引力與楊-米爾斯理論的結構相似性。隨後,我們深入探討瞭Penrose的Twistor理論,特彆是在零慣性係(Null Coordinates)下的錶示。通過構建四維時空上的超對稱Twistor理論,我們展示瞭如何通過對自由度進行精細選擇,使得引力場方程自然地從規範對稱性中湧現齣來。 第5章:Kaluza-Klein理論的現代修正與邊界條件 經典Kaluza-Klein理論受睏於其對宏觀尺度的不切實際預測。本章則聚焦於緊緻化(Compactification)的現代處理方式。我們分析瞭Calabi-Yau流形上的場論,特彆是如何利用流形上的霍奇對偶性(Hodge Duality)來確定額外維度中場的穩定性和質量譜。我們詳細推導瞭非緊緻維度的動力學行為,並討論瞭由Flux(通量)引起的真空能問題,這是理解有效場論的關鍵。 第6章:膜世界場景與AdS/CFT對偶性:拓撲視角 本章探討瞭將場論嵌入高維背景的最新進展。我們以AdS/CFT對偶性(反德西特空間/共形場論對偶)為核心,但著重於其拓撲含義。我們闡述瞭如何將AdS空間上的引力理論(包含量子修正)映射到其邊界上的一個CFT(共形場論),後者本質上是一個受拓撲約束的理論。特彆是,我們分析瞭在AdS/CFT框架下,Entanglement Entropy(糾纏熵)如何通過Ryu-Takayanagi公式與幾何(測地綫長度)聯係起來,從而揭示引力幾何本身可能是信息論和拓撲結構湧現的産物。 第三部分:量子引力的非微擾探究 (Non-Perturbative Investigations into Quantum Gravity) 本書的收官部分(第7章和第8章)聚焦於構建完整的、非微擾的量子引力框架。 第7章:循環量子引力與自鏇網絡 我們對圈量子引力(Loop Quantum Gravity, LQG)的數學形式進行瞭嚴格的審查。不同於微擾方法,LQG將時空本身視為由自鏇網絡(Spin Networks)構成的離散結構。本章詳細介紹瞭Ashtekar變量的重新參數化,以及如何使用Holonomy(路徑積分)來定義約束方程。我們推導瞭圈量子宇宙學(Loop Quantum Cosmology)的基本方程,並討論瞭“大反彈”(Big Bounce)的物理意義,這提供瞭對傳統奇點概念的替代方案。 第8章:信息、熵與統一理論的終極展望 最後,本章將信息論、熱力學與拓撲結構聯係起來,探討統一理論的哲學和數學前沿。我們討論瞭Black Hole Entropy(黑洞熵)的微觀起源,並展示瞭拓撲量子場論如何提供一個無依賴於度量(Metric-independent)的計數方法。我們探討瞭全息原理(Holography)的更深層含義——物理定律可能並非植根於時空結構,而是植根於對高維信息集閤的特定操作和投影。本書以一個開放性的討論結束,展望未來理論如何能夠利用張量網絡(Tensor Networks)等新興工具,在不依賴傳統背景幾何的情況下,完全描述量子場與引力動力學。 --- 總結: 本書提供瞭一條嚴謹的、從純數學結構通往統一物理理論的路綫圖。它避開瞭對標準弦論的傳統描述,而是深入探討瞭拓撲、規範對稱性以及高維幾何在量子引力構造中的核心作用。通過對自鏇網絡、非交換幾何和AdS/CFT對偶性的深入剖析,讀者將獲得一個全新的視角,理解我們所處的四維時空可能僅僅是更深層、更抽象的拓撲結構在特定邊界條件下的投影。本書是物理學前沿研究不可或缺的參考資料。