NONLINEAR FINITE ELEMENT ANALYSIS

A short course taught by

Thomas J.R. HUGHES & Ted BELYTSCHKO


Next venues: Austin Texas, Oct. 2007
Paris, France, Dec. 2008,

Pictures of course in Berlin 2002
Pictures of course in Paris 2003
Pictures of course in Berlin 2007

last update 6.2007

COURSE OBJECTIVES

The purpose of this course is to provide engineers, scientists, and researchers with a critical survey of the state-of-the-art of finite element methods in solids, structures, and fluids, with an emphasis on methodologies and applications for nonlinear problems. The fundamental theoretical background, the computer implementations of various techniques and modeling strategies will be treated. Advantages and shortcomings of alternative methods and the practical implications of recent research developments will be stressed. Recent mathematical and algorithmic developments will be explained in terms comprehensible to engineers.

 

WHO ATTENDS

This seminar is designed for engineers in industry, government, and academia who wish to obtain an overview and understanding of nonlinear finite element methods. A background in engineering or applied sciences and some previous exposure to finite element methods are necessary for understanding the material covered in this course. The course has been offered annually in the U.S. and Europe since 1985. The attendees are engineers and scientists from: corporations, such as Dassault, Boeing, General Motors, Ford, Daimler Benz, BMW, Fiat, PSA, Renault, Philips, Fujitsu, IBM, EDF, Siemens; software companies; government laboratories, such as Livermore, Argonne, Sandia; government offices, such as NSF and the Defense Nuclear Agency; U.S. Navy, NASA, ESA, Air Force Laboratories, and universities.

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COURSE OUTLINE

 

NONLINEAR FORMULATIONS AND SOLUTION STRATEGIES

 

Nonlinear FEM in Engineering                                                (TB)

     Historical Perspective

     Linear Benchmark Problems; Patch Tests

     Nonlinear Benchmark Problems, Test Problems

Nonlinear FEM Analysis                                                          (TB)

     Geometric and Material Nonlinearities

     Stress and Strain Measures: Piola-Kirchhoff stresses,

       Green Strain, Rate-of-deformation                     

     Examples of Material Models: Hypoelastic, Hyperelastic,

       Elastic-plastic, Damage Models

 Conservation  Equations

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SEMIDISCRETIZATION AND SOLUTION METHODS

 

FE Methods of Nonlinear Mechanics                                     (TB)

     Semidiscretization of Continuum Equations

     Static and Dynamic Discrete Equations

     Lagrangian, Eulerian, and Arbitrary Lagrangian Eulerian (ALE) 

      meshes

     Frame Invariant Stress Rates

     Total and Updated Lagrangian Formulations

     Material and Geometric Stiffness

Solution Algorithms for Nonlinear Problems                                  (TH)

     Newton and Modified Newton Methods

     Consistent Linearization

     Line Search

     Quasi-Newton Updates ("BFGS", etc.)

     Arc-Length Strategies

Time Integration Procedures                                                  (TH)

     Stability, Consistency, and Convergence

     Survey of Algorithms

     Formulation of Algorithms for Nonlinear Problems

     Implicit-Explicit Element Partitions

     Space-Time Finite Elements

Explicit Dynamic Integration                                                  (TB)

     Implicit and Explicit Methods

     Element Eigenvalue Inequalities; Time Step Selection

     Accuracy and Stability; Mass Lumping

     Time Step Partitions; Subcycling

     Symplectic and Energy Conserving Integrators

Direct and Iterative Equation Solvers                                    (TH)

     Direct Solvers : Band, Profile and Sparse

     Anatomy of an Iterative Equation Solver:

      Driver Algorithms, Preconditioners, 

      Residual Calculations

CAD and Finite Elements                                                     (TH)

     Computational Geometry

     Geometrical Errors

     NURBS

     Comparison of p- and k-refinement Methods

      Isogeometric Structural Analysis
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ELEMENT TECHNOLOGY

 

Element Technology - I : Incompressible and Slightly Compressible Media                                                                (TH)

     Mixed and Displacement Methods

     Volumetric Locking

     Babuska-Brezzi (BB) Condition

     Survey of Effective Elements

     Reduced and Selective Integration Techniques

     Pressure Oscillations

     Strain Projection Methods: B-bar; Linear and Nonlinear Cases

Element Technology - II : Underintegrated Elements          (TB)

   Element selection

     Stiffness Matrix Rank and Rank Deficiency

     Spurious Singular Modes (Hourglassing)

     Mixed Variational Principles : Hu-Washizu

     Stabilization by Perturbation, Assumed Strain, and Variational     

        Methods; Physical Hourglass Control

     Convergence Rates of  Elements

Element Technology - III : Plates and Shells                         (TB)

     C0 and C1 Flexural Theories; Discrete Kirchhoff Theory

     Continuum Based (Degenerated )Elements

     Shear Locking and Elimination of Locking by Assumed Strain

     Membrane Locking and Inextensional Modes

     Hourglass Modes and Control

     Shear Instabilities; Physical Hourglass Control

     Survey and Comparison of Elements

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CONSTITUTIVE MODELS                                                      (TH)

Rate-Independent Deviatoric Plasticity                                 

     Small and Finite Deformation Formulations

     Radial Return Methods

     Algorithms for the Finite Deformation Case

Unstable Materials, Fracture and Failure                               (TB)

     Material Instabilities : Strain-Softening, Nonassociated Plasticity

     Loss of Ellipticity (Hyperbolicity); Localization

     Regularization: Viscous, Gradient, Nonlocal

     Explicit and Smeared Crack Models

     Failure Modeling : Static and Dynamic Crack Propagation

     Discontinuous Elemennts (XFEM, others)

     Level Sets for Evovling Discontinuities

     Quantum/Molecular/Continuum Multiscale Methods

Return Mapping Algorithms for General Classes of Inelastic Materials                                                                                   (TH)

     Cutting Plane Algorithm

     Closest Point Projection Algorithm

     Elastic Damage and Viscoplastic Models

     Operator Splitting

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OTHER TOPICS

 

Contact-Impact                                                                         (TB)

     Variational Inequalities

     Penalty and Lagrange Multiplier Methods

     Augmented Lagrangian Methods

     Regularization of Impact and Friction; Pinball Algorithm

     Crashworthiness Analysis

Adaptivity and Meshfree Methods                                          (TB)

     p-, h-, and r-Adaptivity

     Error Indicators : Residual, Global and Local Projection

     Strategies for Adaptative Analysis

     Smooth Particle Hydrodynamics

     Element-free Galerkin Method

RKPM, Petrov-Galerkin meshfree methods

Moving least square and radial basis functions

Visibility method for discontinuities, smoothing

Integration methods: background mesh; stress-points

     Extended and Generalized Finite Element Methods (XFEM)

     Partitions of Unity

     Fluid-Structure Interaction: Level Set Methods, Immersed FEM         Methods

 

Fluids - I and II                                                                          (TH)

     Scalar Advection-Diffusion Equation

     SUPG and Galerkin/Least-Squares Method

     Space-Time Generalizations

     Discontinuous Galerkin Method

     Advective-Diffusive Systems

     Incompressible Euler and Navier-Stokes Equations

     Stokes Equations; Methods which Circumvent the BB-Condition

     Compressible Euler and Navier-Stokes Equations

     Entropy Variables

     Conservation and Physical Variables

     Shock-Capturing Operators

     Domain Decomposition

     Iterative Procedures; GMRES

     Matrix Free Algorithms

     Turbulence, LES

     Variational Multiscale Methods

     Isogeometric Fluid Analysis

     Acoustic Wave Propagation

 


 

ZACE SERVICES Ltd, P.O.Box 2-CH-1015 Lausanne 15, Switzerland, Phone +41/21/802 46 05, fax +41/21/802 46 06

http://www.zace.com,                              e-mail: info@zace.com

 

 

LECTURERS

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THOMAS J.R. HUGHES

Computational and Applied Mathematics Chair III

The University of Texas at Austin

 

Previously taught at the University of California, Berkeley, the California Institute of Technology and Stanford University. He is the author of over 300 works on numerical analysis and continuum mechanics, with emphasis on finite element methods. Author or editor of eighteen books, including  The Finite Element Method: Linear Static and Dynamic Finite Element Analysis and Computational Inelasticity . He has received the Bernard Friedman Memorial Prize in Applied Mathematics from the University of California, Berkeley, the Walter L. Huber Research Prize from the ASCE, the Melville Medal from the ASME, the Computational Mechanics Award of the Japan Society of Mechanical Engineers, the von Neumann Medal of USACM, the Gauss-Newton Medal of IACM, the Worcester Reed Warner Medal of ASME and an Honorary Doctorate from Université Catholique de Louvain, Belgium He has held the Cattedra Galileiana (Galileo Galilei Chair), Scuola Normale, Pisa, and Eshbach Professorship, Northwestern University. He is editor of the International Journal Computer Methods in Applied Mechanics and Engineering, past Chairman of the Applied Mechanics Division of ASME, past President of USACM and of IACM, and a member of the National Academy of Engineering.

 

 

TED BELYTSCHKO

Walter P. Murphy Professor of Computational Mechanics, Northwestern University

 

He is the author of over 300 works on a wide variety of applied mechanics problems, with emphasis on explicit finite element methods. Editor of seven books, including: Computational Methods for Transient Analysis (with T.J.R. Hughes). He is author of the recent book Nonlinear Finite Elements for Continua and Structures. He is editor of the International Journal for Numerical Methods in Engineering. He has received the Timoshenko and Pi Tau Sigma Medals from ASME, the USACM von Neumann Medal and Computational Structural Mechanics Award, the Gauss-Newton Medal from IACM, the von Karman Medal, the Aerospace Structures and Materials Award and the Walter L. Huber Research Prize from ASCE, the Thomas Jaeger Prize from IASMIRT, the Computational Mechanics Award of the Japan Society of Mechanical Engineers, the IACM Computational Mechanics Award, the Baron Medal and Honorary Doctorates from the University of Liège, University of Lyon 1, and Ecole Centrale, Paris.  He is past Chairman of the Engineering Mechanics Division of ASCE, the Applied Mechanics Division of ASME, past and the U.S. National Committee on Theoretical and Appplied Mechanics, past President of USACM and the American Academy of Mechanics, and a member of  the American Academy of Arts and Sciences and the National Academy of Engineering.