Kooperativer Bibliotheksverbund

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Format: 1 online resource (277 pages)

ISBN: 0-12-811821-0 , 0-12-811820-2

Note: Front Cover -- Thermo-Mechanical Modeling of Additive Manufacturing -- Copyright -- Contents -- List of Contributors -- About the Editors -- Acknowledgments -- Chapter 1 -- Chapter 2 -- Chapter 3 -- Chapter 4 -- Chapter 6 -- Chapter 7 -- Chapter 8 -- Chapter 9 -- Chapter 10 -- Chapter 11 -- Chapter 12 -- Chapter 13 -- Chapter 14 -- Chapter 15 -- Part I The Fundamentals of Additive Manufacturing Modeling -- 1 An Introduction to Additive Manufacturing Processes and Their Modeling Challenges -- 1.1 Motivation -- 1.2 Additive Manufacturing Processes -- 1.2.1 Multipass Welding -- 1.2.2 Directed Energy Deposition -- 1.2.3 Laser Powder Bed Fusion systems -- 1.3 Challenges in the Finite Element Modeling of AM Processes -- 1.3.1 Material Addition -- 1.3.2 Heat Input -- 1.3.3 Thermal Losses -- 1.3.4 Distortion and Residual Stress -- 1.3.4.1 Coupled Versus Decoupled Models -- 1.3.5 Temperature Dependent Material Properties -- 1.3.6 Microstructural Changes -- 1.3.6.1 Material Property Changes -- 1.3.6.2 Anisotropy in Material Properties -- 1.3.6.3 Phase Transformation -- 1.3.7 Reducing Simulation Time -- 1.4 Conclusions -- References -- 2 The Finite Element Method for the Thermo-Mechanical Modeling of Additive Manufacturing Processes -- Introduction -- 2.1 A Non-Linear Finite Element Primer -- 2.2 The Decoupled Model -- 2.3 Model Types -- 2.4 The Thermal Model -- 2.4.1 Thermal Equilibrium -- 2.4.2 The Heat Input Model -- 2.4.2.1 Surface Flux Input Models -- 2.4.2.2 Volumetric Input Models -- 2.4.3 Boundary Losses -- 2.4.3.1 Convection -- 2.4.3.2 Radiation -- 2.4.3.3 Fixturing Losses -- 2.4.3.4 Powder Considerations -- 2.5 The Mechanical Model -- 2.5.1 Small Deformation Theory -- 2.5.1.1 Thermal Strain -- 2.5.1.2 Plastic Strain -- 2.5.2 Large Deformation Theory -- 2.5.3 The Quiet Activation Strategy -- 2.5.4 The Inactive Activation Strategy. , 2.5.5 The Hybrid Activation Strategy -- 2.6 Temperature Dependent Material Properties -- 2.7 Finite Element Meshing for Additive Processes -- 2.7.1 Mesh Convergence and Heuristics -- 2.7.2 Mesh Convergence and Heuristics -- 2.7.3 Adaptive Meshing -- 2.8 Model Veri cation -- 2.8.1 Analytical Solutions -- 2.8.1.1 1D Static Thermal Analysis -- Prescribed heat ux to an adiabatic system -- Prescribed temperature with a convection boundary condition -- 2.8.1.2 Time-Based Thermal Analysis by Lumped Capacitance -- 2.8.2 The Patch Test -- 2.8.3 The Method of Manufactured Solutions -- 2.9 Validation and Error Analysis -- 2.9.1 Thermal Error Analysis -- 2.9.2 Mechanical Error Analysis -- 2.10 Conclusions -- References -- Part II Thermomechanical Modeling of Direct Energy Deposition Processes -- 3 Convection Boundary Losses During Laser Cladding -- 3.1 Introduction -- 3.2 Modeling Approach -- 3.3 Experimental Procedures -- 3.4 Numeric Implementation -- 3.4.1 Temporal Discretization -- 3.4.2 Finite Element Mesh -- 3.4.3 The Evolving Free Surface -- 3.4.4 No Convection -- 3.4.5 Natural Convection -- 3.4.6 Forced Convection From Lumped Capacitance Experiments -- 3.4.7 Forced Convection Based on Published Research -- 3.4.8 Hot-Film Anemometry -- 3.4.9 Heightened Natural Convection -- 3.5 Analysis Cases -- 3.5.1 Case 1: No Convection -- 3.5.2 Case 2: Natural Convection Alone -- 3.5.3 Case 3: Forced Convection From Lumped Capacitance Experiments -- 3.5.4 Case 4: Forced Convection From Heat Transfer Literature -- 3.5.5 Case 5: Forced Convection Measured by Hot-Film Anemometry -- 3.5.6 Case 6: Forced Convection With a Non-Evolving Surface -- 3.5.7 Case 7: Heightened Natural Convection -- 3.6 Results and Discussion -- 3.6.1 The Effect of Convection Boundary Conditions -- 3.6.1.1 Case 1: No Convection -- 3.6.1.2 Case 2: Natural Convection. , 3.6.1.3 Case 3: Forced Convection From Lumped Capacitance Experiment -- 3.6.1.4 Case 4: Forced Convection From Heat Transfer Literature -- 3.6.1.5 Case 5: Forced Convection From Hot-Film Anemometry -- 3.6.1.6 Case 6: Forced Convection From Hot-Film Anemometry With a Non-Evolving Surface -- 3.6.1.7 Case 7: Heightened Natural Convection -- 3.7 Conclusions -- References -- 4 Conduction Losses due to Part Fixturing During Laser Cladding -- 4.1 Introduction -- 4.2 Modeling Approach -- 4.2.1 Conduction Losses, Surface Contact, and Gap Conductance -- 4.3 Experimental Procedures -- 4.4 Numerical Implementation -- 4.4.1 FE Solver -- 4.4.2 The Finite Element Mesh -- 4.4.3 Convection Model -- 4.4.4 The Gap Conductance Model -- 4.4.5 Modeling Assumptions and Approximations -- 4.5 Results and Discussion -- 4.5.1 Cantilevered Fixture -- 4.5.2 Bench Clamped Fixture -- 4.5.3 Thermal Loss Modes -- 4.6 Conclusions -- References -- 5 Microstructure and Mechanical Properties of AM Builds -- 5.1 Introduction -- 5.2 Experimental Characterization -- 5.2.1 Microstructure -- 5.2.2 Hardness -- 5.2.3 Yield and Ultimate Tensile Strengths, Elongation -- 5.2.4 Fatigue -- 5.3 Experimental Results -- 5.3.1 Microstructure -- 5.3.1.1 Inconel 625 -- 5.3.1.2 Ti-6Al-4V -- 5.3.1.3 Austenitic Stainless Steel -- 5.3.2 Hardness -- 5.3.2.1 Inconel 625 -- 5.3.2.2 Ti-6Al-4V -- 5.3.2.3 Austenitic Stainless Steel -- 5.3.3 Yield Strength, Ultimate Tensile Strength, and Elongation -- 5.3.3.1 Inconel 625 -- 5.3.3.2 Ti-6Al-4V -- 5.3.3.3 Austenitic Stainless Steel -- 5.3.4 Fatigue -- 5.3.4.1 Ti-6Al-4V -- 5.4 Discussion -- 5.5 Conclusions -- References -- 6 Understanding Microstructure Evolution During Additive Manufacturing of Metallic Alloys Using Phase-Field Modeling -- 6.1 Microstructures in Additively Manufactured Metallic Alloys -- 6.1.1 Experimental Observations. , 6.1.1.1 Grain Structures and Textures -- 6.1.1.2 Solid State Phase Transformation -- 6.1.1.3 Effect of Different AM Techniques -- 6.1.2 Computational Simulations -- 6.2 Multi-Scale Phase-Field Model for AM of Alloys -- 6.2.1 Linkage Between the Three Sub-Models -- 6.2.2 Finite-Element Thermal Model -- 6.2.3 Grain-Scale Phase-Field Model: Grain Growth & Solidi cation -- 6.2.3.1 Model Description -- 6.2.3.2 Simulation Results -- 6.2.3.3 Future Directions -- 6.2.4 Sub-Grain-Scale Phase-Field Model: Solid-State Phase Transformations -- 6.2.4.1 Model Description -- 6.2.4.2 Simulation Results -- 6.2.4.3 Future Directions -- 6.3 Summary and Outlook -- References -- 7 Modeling Microstructure of AM Processes Using the FE Method -- 7.1 Introduction -- 7.2 Microstructural Model -- 7.2.1 Phase Fractions and Morphology -- 7.2.1.1 Alpha Dissolution -- 7.2.1.2 Alpha Growth -- 7.2.2 Alpha Lath Width -- 7.2.3 Summary of Model -- 7.2.4 Model Optimization -- 7.3 Experimental Implementation -- 7.3.1 Deposition Process -- 7.3.2 Measurement of Alpha Lath Width -- 7.4 Results and Discussion -- 7.5 Conclusions -- References -- 8 Thermo-Mechanical Modeling of Thin Wall Builds using Powder Fed Directed Energy Deposition -- 8.1 Introduction -- 8.2 DED Simulation -- 8.3 DED Process Measurement Setup and Test Cases -- 8.3.1 Deposition Cases -- 8.3.2 Measurement Setup -- 8.4 Results from the In-Situ Measurements -- 8.5 Numerical Implementation -- 8.5.1 Finite Element Mesh -- 8.5.2 Determination of the Heat Source and Surface Loss Variables -- 8.6 Thermo-Mechanical Modeling Results -- 8.7 Conclusions -- References -- 9 Residual Stress and Distortion Modeling of Electron Beam Direct Manufacturing Ti-6Al-4V -- 9.1 Introduction -- 9.2 Electron Beam Deposition Simulation -- 9.2.1 Mechanical Analysis -- 9.3 Calibration and Validation -- 9.3.1 Deposition Process. , 9.3.2 In Situ Distortion and Temperature -- 9.3.3 Residual Stress -- 9.4 Numerical Implementation -- 9.5 Results and Discussion -- 9.5.1 Thermal History -- 9.5.2 Distortion History -- 9.5.3 Residual Stress -- 9.6 Conclusions -- References -- 10 Thermo-Mechanical Modeling of Large Electron Beam Builds -- 10.1 Introduction -- 10.2 Electron Beam Deposition Simulation -- 10.3 Mesh Coarsening Algorithm -- 10.3.1 Merging of Elements Layer by Layer -- 10.3.2 Interpolation of Gauss Point Values -- 10.3.3 Veri cation of Layer by Layer Coarsening Algorithm -- 10.3.4 Veri cation Results -- 10.4 Validation on a Large Part -- 10.5 Numerical Implementation -- 10.6 Results and Discussion -- 10.7 Conclusions -- References -- 11 Mitigation of Distortion in Large Additive Manufacturing Parts -- 11.1 Introduction -- 11.2 Evaluation of Distortion Mitigation Techniques -- 11.2.1 Electron Beam Deposition Simulation -- 11.2.2 Numerical Model -- 11.2.3 Deposition Strategies -- Case 1: Baseline With Topside Deposition Only -- Case 2: Topside Heating After Each Topside Layer -- Case 3: Backside Deposition After Topside Layers Deposited -- Case 4: Backside Deposition After Each Topside Layer -- 11.2.4 Small Model Results -- 11.3 Mitigation Techniques Applied on a Large Part -- 11.3.1 Experimental Procedure -- 11.3.2 Deposition Cases -- Case L1 -- Case L2 and Case L3 -- 11.4 Results and Discussion -- 11.5 Conclusions -- References -- Part III Thermomechanical Modeling of Powder Bed Processes -- 12 Development and Numerical Veri cation of a Dynamic Adaptive Mesh Coarsening Strategy for Simulating Laser Power Bed Fusion Processes -- 12.1 Introduction -- 12.2 Modeling Approach -- 12.3 Meshing Strategies -- 12.3.1 Dynamic Adaptive Mesh Implementation -- 12.3.1.1 Dependent Nodes -- 12.3.1.2 Mesh Coarsening Criterion -- 12.3.2 Static Nonconforming Mesh Analysis. , 12.3.3 Static Conforming Mesh Analysis.

Language: English