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Format: 1 online resource (468 pages) : , illustrations.

Series Statement: Schriftenreihe des Instituts für Angewandte Materialien, Karlsruher Institut für Technologie

Content: The main objective of this work is to significantly deepen the understanding of the material and the structural behaviour of continuous-discontinuous SMC composites, following a holistic approach to investigate microscopic aspects, macroscopic mechanical behaviour as well as failure evolution at the coupon, structure and component level. In addition, criteria to evaluate the effect of hybridisation are introduced and modelling approaches are presented and discussed.

Note: List of Figures xv -- List of Tables xxiii -- List of Abbreviations and Symbols xxv -- 1 Introduction. 1 -- 1.1 Motivation . 1 -- 1.2 Scope and objective. 5 -- 1.3 Contribution to the current state of research. 6 -- 1.4 Outline of this dissertation 8 -- 2 Current state of research 9 -- 2.1 Definition of hybrid materials 9 -- 2.2 Composite materials . 14 -- 2.2.1 Definition and fundamentals 14 -- 2.2.2 Basic mechanisms of fibrous reinforcement. 16 -- 2.3 Sheet moulding compound composites. 21 -- 2.3.1 Definition and terminology delimitation 21 -- 2.3.2 Discontinuous SMC composites 21 -- 2.3.3 Continuous SMC composites 57 -- 2.4 Hybrid composites . 61 -- 2.4.1 Definition, motivation and development -- of hybrid composites . 62 -- 2.4.2 Evaluation of hybridisation effects . 65 -- 2.4.3 Existing concepts of hybrid SMC . 68 -- 2.5 Research questions . 82 -- 3 Materials and specimen geometries 85 -- 3.1 Manufacturing of SMC composites 85 -- 3.1.1 Composition of resin systems . 85 -- 3.1.2 Manufacturing of semi-finished sheets 87 -- 3.1.3 Manufacturing of compression moulded sheets . 89 -- 3.1.4 Manufacturing of pure resin sheets 92 -- 3.1.5 Manufacturing of demonstrator part 93 -- 3.2 Specimen preparation and geometry 94 -- 3.2.1 Water-jet cutting and milling 94 -- 3.2.2 End tabs. 95 -- 3.2.3 Specimen geometries . 95 -- 4 Experimental setups, procedures and data evaluation 103 -- 4.1 Characterisation strategy 103 -- 4.2 Characterisation at the coupon level 105 -- 4.2.1 Microstructural characterisation 105 -- 4.2.2 Macrostructural characterisation . 106 -- 4.3 Characterisation at the structure level. 114 -- 4.3.1 Quasi-static puncture testing 114 -- 4.3.2 Dynamic puncture testing . 116 -- 4.4 Characterisation at the component level 118 -- 4.5 Data evaluation . 121 -- 5 Analytical modelling 123 -- 5.1 Description of modelling approach 123 -- 5.2 Micromechanics and homogenisation methods . 124 -- 5.2.1 Fundamentals of homogenisation 124 -- 5.2.2 Analytical modelling of fibre reinforced polymers 128 -- 5.3 Classical laminate theory 133 -- 5.3.1 Macromechanical characterisation of a lamina . 134 -- 5.3.2 Macromechanical characterisation of a laminate. 134 -- 5.4 Analytical modelling of hybrid composites 138 -- 5.4.1 Rule of hybrid mixtures 139 -- 5.4.2 Tensile and flexural modulus based on classical laminate theory . 140 -- 6 Results . 143 -- 6.1 Evaluation of testing methods and preliminary studies . 143 -- 6.1.1 Tensile properties of discontinuous SMC composites . 144 -- 6.1.2 Tensile properties of continuous SMC composites 150 -- 6.1.3 Flexural properties of SMC composites . 152 -- 6.2 Microstructural analysis . 158 -- 6.2.1 Fibre volume content . 158 -- 6.2.2 Fibre orientation distribution 164 -- 6.2.3 Interface of continuous-discontinuous SMC 173 -- 6.3 Mechanical properties and failure at the coupon level . 176 -- 6.3.1 Tensile and compressive properties of -- polyester-polyurethane hybrid resin . 176 -- 6.3.2 Process-induced material properties of -- discontinuous glass fibre SMC 179 -- 6.3.3 In-plane loading of SMC composites 190 -- 6.3.4 Out-of-plane loading of SMC composites . 229 -- 6.4 Mechanical properties and failure at the structure level . 237 -- 6.4.1 Puncture properties of discontinuous glass fibre SMC 238 -- 6.4.2 Puncture properties of continuous carbon fibre SMC . 248 -- 6.4.3 Puncture properties of continuous-discontinuous glass/carbon fibre SMC 256 -- 6.5 Mechanical properties and failure at the component level . 268 -- 6.6 Analytical stiffness prediction 271 -- 6.6.1 Analytical stiffness prediction of discontinuous glass fibre SMC 272 -- 6.6.2 Analytical stiffness prediction of continuous carbon fibre SMC . 277 -- 6.6.3 Analytical stiffness prediction of continuous-discontinuous glass/carbon fibre SMC 279 -- 7 Discussion. 283 -- 7.1 Testing methodology and preliminary studies 283 -- 7.2 Material behaviour of unsaturated polyester-polyurethane two-step curing hybrid resin system 285 -- 7.3 Discontinuous glass fibre SMC . 287 -- 7.3.1 Microstructural aspects of discontinuous glass fibre SMC 287 -- 7.3.2 Mechanical behaviour and damage evolution of discontinuous glass fibre SMC . 291 -- 7.4 Continuous carbon fibre SMC 301 -- 7.4.1 Microstructural aspects of continuous carbon fibre SMC . 301 -- 7.4.2 Mechanical behaviour and damage evolution of continuous carbon fibre SMC 302 -- 7.5 Continuous-discontinuous glass/carbon fibre SMC 308 -- 7.5.1 Microstructural aspects of continuous-discontinuous glass/carbon fibre SMC 308 -- 7.5.2 Mechanical properties, damage evolution and hybridisation effect 310 -- 8 Final remarks . 347 -- 8.1 Summary . 347 -- 8.2 Conclusion . 356 -- Bibliography 361 -- A Appendix 403 -- A.1 Influence of subset size and step size . 403 -- A.2 Influence of edge preparation 405 -- A.3 Tensile properties of discontinuous glass fibre SMC (2D) . 406 -- A.4 Tensile properties of discontinuous glass fibre SMC (1D) . 407 -- A.5 Compressive properties of discontinuous glass fibre SMC . 408 -- A.6 Tensile and compressive properties of continuous carbon fibre SMC . 409 -- A.7 Flexural properties of continuous carbon fibre SMC. 410 -- A.8 Flexural properties of continuous-discontinuous glass/carbon fibre SMC . 411 -- A.9 Classical laminate theory: calculations 412.

Additional Edition: ISBN 1000097160

Language: English

DOI: 10.5445/KSP/1000097160