[AutoUni – Schriftenreihe] Temperature-dependent Deformation and Fracture Behavior of a Talcum-filled Co-polymer Volume 147 ||

"David Degenhardt develops an elasto-viscoplastic material model in order to predict the temperature and strain rate-dependent deformation and fracture behavior of thermoplastic polymers. The model bases on three supporting ambient temperatures, where a thermoplastic polymer has been characterized profoundly at the stress states 1) uni-axial tension and compression, 2) bi-axial tension and 3) shear. The core of the material model builds a pressure-dependent yield function with a non-associated flow rule. Further, it contains an analytical hardening law and a strain rate-dependent fracture criterion. The model is validated with components subjected to impact loading at different ambient temperatures. The comparison of the simulation and the experiments shows that stiffness, hardening, fractures strain as well as thicknesses can be well captured. Contents Material Modeling; Yield Functions and Flow Rules Static and Dynamic Material Testing Temperature-dependent Material Model Model Validation with Component Tests Target Groups Scientists and students in the field of material sciences and simulation Practitioners in industry in the field of material characterization About the Author David Degenhardt is a calculation engineer in the chassis development department of a German automobile manufacturer and earned his doctorate while working at the Technische Universität Carolo-Wilhelmina zu Braunschweig, Germany."--Prové de l'editor. Acknowledgements Contents List of Figures List of Tables Nomenclature Abstract Kurzzusammenfassung 1 Motivation 2 Objectives, Scope and Outline of Work 2.1 Scope 2.2 Outline 3 State-of-the-Art 3.1 Experiments 3.1.1 Overview 3.1.2 Dynamic Mechanical Analysis 3.1.3 Measurement Systems 3.2 Thermoplastic Polymers 3.2.1 General 3.2.2 Material Behavior 3.2.3 Specific Characteristics 3.2.4 Morphology 3.2.5 Anisotropy 3.2.6 Manufacturing 3.3 Modeling 3.3.1 Material Modeling 3.3.2 Yield Functions and Flow Rules 3.3.3 Fracture 3.3.4 Optimization Method 3.4 Summary and Conclusions 4 Experimental Work 4.1 Overview 4.2 Design of a Volkswagen Spline UT Test Specimen 4.3 Material Testing 4.3.1 Material Preparation 4.3.2 Test Procedure 4.3.3 Experimental challenges 4.3.4 Dynamic Mechanical Analysis 4.3.5 Temperature Softening at UT 4.4 Mechanical Test Calibration 4.4.1 Characterization Tests at Major Supporting Ambient Temperatures 4.4.2 Characterization Tests at Additional Supporting Ambient Temperatures 4.4.3 Comparison of DMA and Proposed UT Calibration 4.5 Summary and Conclusions 5 Temperature-dependent Material Model 5.1 Overview 5.2 Theory of Material Model 5.2.1 Elasticity 5.2.2 Yielding 5.2.3 Hardening 5.2.4 Plastic Strain Softening 5.2.5 Fracture 5.2.6 Evaluation of the Material Model 5.3 Parameter Identification Procedure for Polymers (Polymer PIP) 5.4 Non-linear Interpolation Concept 5.4.1 Elasticity 5.4.2 Plastic Poisson’s Ratio 5.4.3 Hardening 5.4.4 Interpolation of Remaining Model Parameters 5.4.5 Fracture 5.5 Calibration of Temperature-dependent Material Model 5.6 Summary and Conclusions 6 Model Validation 6.1 Bi-axial Tensile Tests 6.2 Component Tests 6.2.1 Overview 6.2.2 Results of Preliminary UT Tests 6.2.3 Design of Glove Box Flap Testing Apparatus 6.2.4 Validation Results 6.2.5 Shell vs. Volume Discretization 6.3 Summary and Conclusions 7 Critical Assessment of the Material Model 8 Conclusions and Recommendations 8.1 Summary 8.2 Outlook Bibliography Geometry of the UT Test Specimen A.1 Spline Functions for Gauge Section A.2 Mathematical Background of Parameter κ Stress Invariants Experimental Set-up of Material Characterization Tests Strain Field Data Material Model Parameters