Table of Contents
List of contributing authors v
Preface xi
Part I Multi-time-scale and multi-length-scale simulations of precipitation and strengthening effects
1 Linking nanoscale and macroscale P. Kizler D. Uhlmann S. Schmauder 3
1.1 Introduction 3
1.2 Nanoscale information from the material 4
1.3 Mesoscale theory 6
1.4 Micro:macroscale theory 8
1.5 Connection of length scales 10
1.6 Conclusions 11
2 Multiscale simulations on the coarsening of Cu-rich precipitates in α-Fe using kinetic Monte Carlo, Molecular Dynamics, and Phase-Field simulations D. Molnar R. Mukherjee A. Choudhury A. Mora P. Binkele M. Selzer B. Nestler S. Schmauder 15
2.1 Introduction 15
2.2 Multiscale Approach 16
2.3 Simulation Methods and Applied Models 17
2.3.1 Cu-precipitation - Kinetic Monte-Carlo Simulations 17
2.3.2 Structural Coherency - Molecular Dynamics Simulations 18
2.3.3 Particle Coarsening - Phase-Field Method 19
2.4 Simulation Results 22
2.4.1 Kinetic Monte Carlo simulations and Broken-Bond Model 22
2.4.2 Molecular Dynamics simulations 25
2.4.3 Phase-Field Method Simulations 25
2.4.4 Phase-field Results 27
2.5 Conclusions 32
3 Multiscale modeling predictions of age hardening curves in Al-Cu alloys C.V. Singh 37
3.1 Introduction 37
3.2 Atomistic modeling of precipitation hardening 39
3.2.1 Methodology 39
3.2.2 GP zone strengthening 41
3.2.3 θ" strengthening 46
3.3 Atomistic modeling of solute hardening 48
3.4 Dislocation dynamics model for macroscopic precipitate strength predictions 50
3.5 Modeling of precipitate kinetics 53
3.6 Age hardening predictions of Al-4 wt.% Cu aged at 110 °C 54
3.7 Effect of Cu concentration and aging temperature 58
3.8 Role of thermal activation and direct comparison to experiment 62
3.9 Summary and conclusion 65
4 Kinetic Monte Carlo modeling of shear-coupled motion of grain boundaries M. Prieto-Depedro I. Martin-Bragado J. Segurado 73
4.1 Introduction 73
4.2 Dynamics of shear-coupled motion of grain boundaries and coupling modes 75
4.3 Molecular Dynamics 77
4.3.1 Computational procedure 77
4.3.2 Shear-coupled motion at low temperatures 78
4.3.3 Shear coupled motion at medium temperatures 80
4.3.4 Nudged elastic band calculations 83
4.4 Kinetic Monte Carlo 83
4.4.1 Simulation methodology 84
4.4.2 Simulation results and discussion 85
4.5 Concluding remarks 88
4.A Effective shear modulus for planar GBs: Application to [001] STGB contained in bicrystal structures 89
5 Product Properties of a two-phase magneto-electric composite M. Labusch M. Etier D. Lupascu J. Schröder M.-A. Keip 93
5.1 Introduction 93
5.2 Theoretical framework 96
5.2.1 Magneto-electro-mechanical boundary value problem 96
5.2.2 Constitutive framework on the microscale 98
5.2.3 Constitutive framework of ME composites on the macroscale 99
5.3 Synthesis and manufacturing of ME composites 100
5.3.1 Synthesis schemes 100
5.3.2 Synthesis results for 0-3 composites 101
5.3.3 Experimental details 102
5.4 Computational determination of magneto-electro-mechanical properties of ME composites 103
5.4.1 Computational characterization of the magneto-electro-mechanical properties of an ideal microstructure 104
5.4.2 Computational characterization of the magneto-electro-mechanical properties of a real microstructure 106
5.5 Conclusion 110
6 Coupled atomistic-continuum study of the effects of C atoms at ct-Fe dislocation cores K. Chockalingam R. Janisch A. Hartmaier 115
6.1 Introduction 115
6.2 Coupling atomistic and continuum domains 117
6.2.1 Atomistic domain 117
6.2.2 Continuum domain 118
6.2.3 Coupling scheme 119
6.3 Verification by dislocation analysis 122
6.4 Carbon influence on critical stress 126
6.4.1 Screw dislocation 126
6.4.2 Edge dislocation 128
6.4.3 Discussion 129
6.5 Conclusion 129
Part II Multiscale simulations of plastic deformation and fracture
7 Niobium/alumina bicrystal interface fracture A. Siddiq S. Schmauder M. Rühle 135
7.1 Introduction 135
7.2 Concept of modeling 137
7.3 Results and discussion 141
7.4 Conclusions 148
8 Atomistically informed crystal plasticity model for body-centred cubic iron A. Koester A. Ma A. Hartmaier 151
8.1 Introduction 151
8.2 Crystal plasticity approach 152
8.3 Atomistic studies 154
8.3.1 Orientation dependence of the critical stress 156
8.3.2 Influence of shear stresses perpendicular to the glide direction 157
8.3.3 Influence of tension and compression perpendicular to the glide direction 158
8.4 FEM study of a bcc iron single crystal 161
8.5 Sensitivity analysis of the flow rule parameters 164
8.6 Summary 164
9 FE2AT- finite element informed atomistic simulations J.J. Möller A. Prakash E. Bitzek 167
9.1 Introduction 167
9.2 Methodology of FE2AT 170
9.2.1 Atom-localization in a finite element mesh 171
9.2.2 Interpolation of nodal displacements 172
9.2.3 The FE2AT approach 174
9.3 Application examples 176
9.3.1 Bending of a nano-beam 176
9.3.2 Fracture 181
9.4 Discussion 186
9.5 Summary 187
10 Multiscale fatigue crack growth modelling for welded stiffened panels Z. Bozic S. Schmauder M. Mlikota M. Hummel 191
10.1 Introduction 191
10.2 Molecular dynamics (MD) simulation of dislocation development in iron 194
10.2.1 Methods and model 194
10.2.2 Results and discussion 195
10.3 Microstructural crack nucleation and propagation 197
10.4 Modeling and simulation of crack propagation in welded stiffened panels 199
10.4.1 Specimen's geometry and loading conditions 200
10.4.2 Modeling of welding residual stresses in a stiffened panel by using FEM 201
10.4.3 Stress intensity factors and fatigue crack growth rate 203
10.5 Conclusions 208
11 Molecular dynamics study on low temperature brittleness in tungsten single crystals Y. Furuya H. Noguchi S. Schmauder 213
11.1 Introduction 213
11.2 A combined model of molecular dynamics with micromechanics 215
11.2.1 The principle of the combined model 215
11.2.2 Flexible boundary conditions using body forces 217
11.2.3 Transformation from an atomistic dislocation to an elastic dislocation 217
11.2.4 Movement of a molecular dynamics region with crack propagation 218
11.3 Simulation of a brittle fracture process in tungsten single crystals 219
11.3.1 Calculation conditions and additional procedures for the simulation of tungsten single crystals 219
11.3.2 Simulation results and size dependency of the molecular dynamics region on the results 223
11.4 Investigation of brittle fracture processes and temperature dependency of fracture toughness at low temperature 225
11.4.1 Simulation results at low temperature 225
11.4.2 A brittle fracture process 227
11.4.3 Temperature dependency of fracture toughness 229
11.5 Discussion 230
11.6 Conclusion 231
12 Multi scale cellular automata and finite element based model for cold deformation and annealing of a ferritic-pearlitic microstructure L. Madej M. Sitko K. Perzynski L. Sieradzki K. Radwanski R. Kuziak 235
12.1 Introduction 235
12.2 Experimental investigation of static recrystallization 237
12.3 Digital material representation of the ferritic-pearlitic microstructure 243
12.4 Multi scale model of rolling 245
12.5 Cellular automata model of static recrystallization 246
12.6 Conclusions 251
13 Multiscale simulation of the mechanical behavior of nanoparticte-modified polyamide composites J. Wiedmaier W. Verestek U. Weber S. Schmauder 255
13.1 Introduction 255
13.2 Used Materials 256
13.3 RVE model - tensile test 256
13.4 Molecular dynamics simulations: Derivation of the traction separation law 258
13.5 Results and discussion 260
13.6 Conclusion and outlook 261
Part III Multiscale simulations of biological and bio-inspired materials, bio-sensors and composites
14 Multiscale Modeling of Nano-Biosensors C.-S. Chen Y.-C. Shih C.-C. Chou S.-W. Chang C. Liou 265
14.1 Top-down Information Passage 267
14.2 Bottom-up Information Passage 269
14.3 Conclusion 269
15 Finite strain compressive behaviour of CNT/epoxy nanocomposites D. Weldt L. Figiel 273
15.1 Introduction 273
15.2 Framework of modeling 275
15.2.1 Representative volume elements (RVEs) 276
15.2.2 Computational homogenisation: RVE-to-macro transition 280
15.3 Results and discussion 281
15.3.1 Mesh convergence 282
15.3.2 RVE size and ensemble size 284
15.3.3 2D versus 3D RVE-based analyses of finite strain compressive behaviour of the nanocomposite 289
15.3.4 Computational time 298
15.3.5 Comparison with experiments 298
15.4 Conclusion 299
16 Peptide-zinc oxide interaction I. Schäfer G. Lasko T. A. Do J. Pleiss U. Weber S. Schmauder 303
16.1 Introduction 303
16.2 Material and Methods 305
16.2.1 Using MD simulations to estimate the adsorption affinity of the peptide 305
16.2.2 FEM simulations 306
16.3 Results and Discussion 310
16.3.1 MD-Simulations 310
16.3.2 Multiscale simulations 312
16.4 Conclusions 317
16.A Appendix 319
Index 323
