Creep in Structures VI

ISBN-13: 9783031390692 / Angielski / Twarda / 2023

Opis

This book offers a current state of the art in analysis and modeling of creep phenomena with applications to the structural mechanics. It presents the some presentations from the IUTAM-Symposium series "Creep in Structures", which held in Magdeburg (Germany) in September 2023, and it discusses many advances and new results in the field. These are for example: interlinks of mechanics with materials science in multi-scale analysis of deformation and damage mechanisms over a wide range of stresses and temperature;  development and analysis of new alloys for (ultra)high-temperature applications; formulation and calibration of advanced constitutive models of inelastic behavior under transient loading and temperature conditions; development of efficient procedures and machine learning techniques for identification of material parameters in advanced constitutive laws; introduction of gradient-enhanced and non-local theories to account for damage and fracture processes; and application of new experimental methods, such as digital image correlation, for the analysis of inelastic deformation under multi-axial stress state.

Spis treści

Chapter 1: Phase-Field Damage Modeling in Generalized Mechanics by using a Mixed Finite Element Method (FEM)

1.1 Introduction to Standard Phase-Field Formulation 

1.2 Extension to Generalized Mechanics 

1.3 Strain Gradient Parameters

1.4 Numerical Implementation and Results 

1.5 Conclusion 

References 

Chapter 2: Creep-Damage Processes in Cyclic Loaded Double Walled Structures

2.1 Introduction 

2.2 Constitutive Equations 

2.2.1 Static Loading 

2.2.2 Cyclic Loading. Stresses Lower the Yield Limit 

2.2.3 Cyclic Load. Overloading with Transition to Plastic Deformation 

2.3 Problem Statement 

2.4 Comparison Between Data of Direct Approach and Use of Averaged Function ���� 

2.5 Numerical Simulation of the Cyclic Creep-damage in DWTC System Model 

2.5.1 Description of the Calculation Model 

2.5.2 Determination of the Temperature and Stress Field in the Blade 

2.5.3 Creep Calculations for a Two-dimensional Model of a Blade Made of Nickel Based Alloy 

2.5.4 Creep Calculations for a Two-dimensional Model of a Blade Made of an Inconel X Alloy 

2.6 Conclusions 

References 

Chapter 3: Creep Mechanics – Some Historical Remarks and New Trends 

3.1 Starting Point - the Early Period of Creep Mechanics 

3.2 IUTAM Symposia and Other Events Devoted to Problems in Creep Mechanics 

3.3 Research Directions and Magdeburg’s Contributions 

3.3.1 Kachanov-Rabotnov Approach and Mechanism-Based Models 

3.3.2 Non-Classical Creep 

3.3.3 Benchmark Tests for Creep Problems 

3.3.4 Rheological Models 

3.3.5 Thesis 

3.4 Outlook 

References 

Chapter 4: Various State-of-the-Art Methods for Creep Evaluation of Power Plant Components in a Wide Load and Temperature Range 

4.1 Introduction 

4.2 Applied Creep Models 

4.2.1 Norton-Bailey Equation

4.2.2 Modified Garofalo Eequation

4.2.3 Constitutive Model

4.3 Structural Analysis 

4.3.1 Verification of the Creep Models Based on Creep Tests 

4.3.2 Relaxation Test with Cube-one-Element Model

4.3.3 Pipe Benchmark FE Model 

4.3.4 Performance Evaluation of User-Creep Routines

4.3.5 Temperature Interpolation for Norton-Bailey Creep Equation 

4.3.6 Isothermal Steam Turbine Valve FE Model with a Constant Loading 

4.4 Conclusions 

References 

Chapter 5: Creep and Irradiation Effects in Reactor Vessel Internals 

5.1 Introduction 

5.2 Problem Statement and Description of Solution Approaches

5.3 Constitutive Equations 

5.3.1 Materials with Isotropy of Properties 

5.3.2 Materials with Transversal Isotropy of Properties

5.4 Deformation, Damage Accumulation and Fracture in RVI 

5.4.1 Creep of T-joint of Tubes

5.4.2 Damage Accumulation and Fracture of Reactor Fuel Element 

5.4.3 Transversal-Isotropic Creep-Damage Behaviour of Aluminium Notched Plate 

5.5 Conclusions 

References

Chapter 6: Analysis of Damage and Fracture in Anisotropic Sheet Metals Based on Biaxial Experiments 

6.1 Introduction 

6.2 Constitutive Framework

6.3 Numerical Simulations and Results 

6.4 Conclusions 

References 

Chapter 7: Effect of Physical Aging on the Flexural Creep in 3D Printed Thermoplastic 

7.1 Introduction 

7.2 Theoretical Background 

7.2.1 Viscoelasticity of Thermoplastics

7.2.2 Physical Aging 

7.3 Material and Methods 

7.3.1 Test Specimens 

7.3.2 Sequential Creep Tests 

7.3.3 Long Term Creep Test 

7.4 Experimental Results 

7.4.1 Sequential Creep Tests 

7.4.2 Long Term Creep Test

7.5 Discussion

References 

Chapter 8: Development of a Microstructure-Based Finite Element Model of Thermomechanical Response of a Fully Metallic Composite Phase Change Material 

8.1 Introduction 

8.2 Microstructure-Based FE model of a Al-Sn C-PCM with Free Expansion 

8.3 Results and Discussion 

8.4 Final Remarks 

References 

Chapter 9: The Effect of Dynamic Loads on the Creep of Geomaterials 

9.1 Introduction

9.2 Materials and Methods 

9.2.1 Materials 

9.2.2 Methods 

9.3 Results and Discussion 

9.4 Conclusion 

References 

Chapter 10: A Novel Simulation Method for Phase Transition of Single Crystal Ni based Superalloys in Elevated Temperature Creep Regions via Discrete Cosine Transform and Maximum Entropy Method 

10.1 Introduction

10.2 Materials and Experiments 

10.2.1 A Single Crystal Ni Based Superalloy, CMSX-4 

10.2.2 Creep Tests 

10.2.3 Two Dimensional Discrete Cosine Transform 

10.2.4 Maximum Entropy Method 

10.3 Estimation of Phase Transition and Results 

10.4 Discussion 

10.5 Conclusion 

References 

Chapter 11: Anisotropic Creep Analysis of Fiber Reinforced Load Point Support Structures for Thermoplastic Sandwich Panels

11.1 Introduction 

11.2 Material Model 

11.2.1 Basic One-Dimensional Formulation

11.2.2 Generalization to Three Dimensions 

11.2.3 Unidirectionally Fiber Reinforced Thermoplastics

11.2.4 Discontinuously Fiber Reinforced Thermoplastics 

11.3 Experimental Investigation 

11.3.1 Coupon Experiments 

11.3.2 Structural Experiments

11.4 Multiscale Simulation 

11.5 Results 

11.5.1 Parameter Identification on Coupon Experiments 

11.5.2 Validation on Structural Level 

11.6 Summary and Conclusion 

References

Chapter 12: Time-Swelling Superposition Principle for the Linear Viscoelastic Properties of Polyacrylamide Hydrogels

12.1 Introduction 

12.2 Experiment 

12.2.1 Materials 

12.2.2 Mixed Solvents for Transient Equilibrium Swelling 

12.2.3 Measurement of Swelling 

12.2.4 Measurement of Dynamic Moduli 

12.3 Experimenta Results 

12.3.1 Transient Equilibrium Swelling 

12.3.2 Linear Viscoelastic Behavior 

12.4 Swelling–Dependent Linear Viscoelasticity 

12.4.1 Model Formulation 

12.4.2 Time-Swelling Superpostion Principle 

12.5 Discussion 

12.5.1 Master Curves of Dynamic Moduli 

12.5.2 Swelling Dependence of Linear Viscoelastic Properties 

12.5.3 Frequency Dependence of Complex Shear Moduli 

12.6 Conclusion 

Appendix A: Validity for Transient Equilibrium Swelling Using Ethanol 

Appendix B: Experimental Data 

References 

Chapter 13: Application of Nonlinear Viscoelastic Material Models for the Shrinkage and Warpage Analysis of Blow Molded Parts 

13.1 Introduction 

13.2 Material Models 

13.2.1 Linear Viscoelastic Material Model

13.2.2 Abaqus Parallel Rheological Framework Model 

13.3 Shrinkage and Warpage Analysis 

13.4 Calibration Strategy 

13.4.1 Experimental Data 

13.4.2 Implementation of a One-Dimensional Model to Reduce Computation Time 

13.4.3 Reduction of Material Parameters 

13.4.4 Calibration Workflow 

13.5 Results 

13.6 Discussion and Outlook 

References 

Chapter 14: Modeling Solid Materials in DEM Using the Micropolar Theory 

14.1 Introduction 

14.2 Formulation of the Thermo-Elasto-Viscoplastic Contact Model 

14.2.1 Short introduction to DEM basics 

14.2.2 DEM Interaction Force Model Based on Micropolar Theory

14.2.3 Visco-Plasticity 

14.3 Model Verification

14.3.1 Simulation Set-up 

14.3.2 Results and Discussion 

14.4 Concluding Remarks 

References 

Chapter 15: The Development of a Cavitation-Based Model for Creep Lifetime Prediction Using Cu-40Zn-2Pb Material 

15.1 Introduction 

15.2 Stress Breakdown and Creep Lifetime 

15.3 Creep Cavitation and Cavitation Data Concerns 

15.3.1 How to Use Cavitation Data 

15.3.2 Current Approach to Cavitation Modelling and Creep Life Prediction 

15.4 Aims 

15.5 Experimental Data and Method 

15.5.1 Experimental Data 

15.5.2 Method 

15.5.3 Determination of Cavitation Constants 

15.5.4 Cavity Size Distribution Modelling 

15.6 Conclusions and Future Work 

References 

Chapter 16: Self-heating Analysis with Respect to Holding Times of an Additive Manufactured Aluminium Alloy 

16.1 Introduction 

16.2 Thermomechanical Experiment 

16.2.1 Experimental Set-Up 

16.2.2 Temperature and Deformationfield Measurement by Digital Image Correlation 

16.2.3 Experimental Results with Respect to Holding Time 

16.3 Theoretical Framework 

16.3.1 Energy Balance and Heat Conduction 

16.3.2 Material Model 

16.4 Modelling Methods 

16.4.1 Parameter Identification 

16.4.2 Concept for Thermomechanic FE Analysis

16.5 Results 

16.6 Discussion 

16.7 Conclusion and Outlook 

References 

Chapter 17: Creep Under High Temperature Thermal Cycling and Low Mechanical Loadings 

17.1 Introduction 

17.2 Experimental Methods 

17.2.1 Materials 

17.2.2 Creep Test Equipment 

17.3 Observation of Accelerated Creep Under Anisothermal Testing Conditions 

17.3.1 Anisothermal Creep Tests 

17.3.2 Influencing Factors 

17.3.3 Observations on the Creep Behavior Within a Cycle 

17.4 Discussion 

17.4.1 Possible causes of accelerated creep under thermal cycling

17.4.2 Microstructural Processes Under Anisothermal Creep Testing 

17.5 Summary 

References 

Chapter 18: The Development and Application of Optimisation Technique for the Calibrating of Creep Cavitation Model Based on Cavity Histogram 

18.1 Introduction 

18.2 Background Theories and Knowledge

18.2.1 Cavitation Model Theory 

18.2.2 Current Calibration Methods 

18.3 Optimisation with Excel Solver 

18.4 Cavitation Data 

18.5 Results 

18.6 Discussion and Conclusion 

References 

Chapter 19: A Temperature-Dependent Viscoelastic Approach to the Constitutive Behavior of Semi-Crystalline Thermoplastics at Finite Deformations 

19.1 Introduction 

19.2 Preliminaries of the Finite Thermo-Viscoelasticity 

19.3 Constitutive Formulation of Finite Thermo-Viscoelasticity 

19.3.1 Helmholtz Energy 

19.3.2 Creep Law 

19.3.3 Governing Equations 

19.4 Numerical Study 

19.4.1 Stress-Controlled loading 

19.4.2 Strain-Controlled loading 

19.5 Summary 

References