| Contents |
|
| 1 | Introduction | 1 |
|
| 2 | Models in elasto-plasticity | 13 |
| 2.1 | Governing equations | 14 |
| 2.2 | Examples | 20 |
|
| 3 | The dual-weighted-residual method | 23 |
| 3.1 | A model Situation in plasticity | 24 |
| 3.2 | A posteriori error estimate | 25 |
| 3.3 | Evaluation of a posteriori error bounds | 26 |
| 3.4 | Strategies for mesh adaptation | 28 |
| 3.5 | Example | 30 |
|
| 4 | Extensions to stabilised schemes | 33 |
| 4.1 | Discretisation for the membrane-problem | 35 |
| 4.2 | A posteriori error analysis | 37 |
| 4.3 | Numerical tests | 42 |
|
| 5 | Obstacle problem | 47 |
| 5.1 | Energy norm | 48 |
| 5.2 | Duality argument | 49 |
| 5.3 | A posteriori estimates | 51 |
| 5.4 | Numerical results | 54 |
|
| 6 | Signorini's problem | 57 |
| 6.1 | A posteriori error bounds | 58 |
| 6.2 | Numerical results | 62 |
| 6.3 | A posteriori controlled boundary approximation | 66 |
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| 7 | Strang's problem | 69 |
| 7.1 | A posteriori error bounds | 70 |
| 7.2 | Numerical results | 73 |
|
| 8 | General concept | 75 |
| 8.1 | Orthogonality relation | 75 |
| 8.2 | Duality argument | 76 |
| 8.3 | Modifikation | 77 |
| | | 8.3.1 | Example | 79 |
|
| 9 | Lagrangian formalism | 81 |
| 9.1 | Torsion problem | 81 |
| 9.2 | A suboptimal error estimate | 83 |
| 9.3 | Saddle point problem | 84 |
| | | 9.3.1 | Discretisation error of the Lagrange multiplier | 86 |
| | | 9.3.2 | Discretisation error of the primal variable | 87 |
|
| 10 | Obstacle problem revisited | 91 |
| 10.1 | Weak formulation | 91 |
| 10.2 | A posteriori error estimates | 92 |
| 10.3 | Numerical results | 94 |
|
| 11 | Variational inequalities of second kind | 95 |
| 11.1 | A flow problem | 95 |
| | | 11.1.1 | Saddle point problem | 96 |
| 11.2 | A friction problem | 97 |
| | | 11.2.1 | Saddle point problem | 98 |
| 11.3 | A posteriori error estimate | 99 |
| 11.4 | Numerical results | 101 |
| | | 11.4.1 | Bingham fluid | 101 |
| | | 11.4.2 | Friction problem | 102 |
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| 12 | Time-dependent problems | 105 |
| 12.1 | Discretisation | 105 |
| 12.2 | Error estimation | 107 |
|
| 13 | Applications | 109 |
| 13.1 | Grinding | 109 |
| | | 13.1.1 | Discretisation | 110 |
| | | 13.1.2 | Solution Process | 111 |
| | | 13.1.3 | Simulation | 112 |
| 13.2 | Milling | 116 |
| 13.3 | Elasto-plastic benchmark problem | 117 |
| | | 13.3.1 | Solution of the benchmark: Hencky model | 120 |
| | | 13.3.2 | Solution of the benchmark: Prandtl-Reuss model | 126 |
|
| 14 | Iterative Algorithms | 129 |
| 14.1 | Introduction | 129 |
| 14.2 | A Smoothing Procedure | 131 |
| 14.3 | The Multilevel Procedure | 132 |
| 14.4 | A Conjugate Gradient Algorithm | 134 |
| 14.5 | Numerical Results | 135 |
| | | 14.5.1 | Example 1 | 135 |
| | | 14.5.2 | Example 2 | 138 |
|
| 15 | Conclusion | 141 |
| A Algorithmic Aspects | 143 |
| Bibliography | 155 |