Design and Manufacture of Structural Composites

Description

Design and Manufacture of Structural Composites provides an overview of the main manufacturing challenges encountered when processing fibre-reinforced composite materials. Composites are unique in that the material is created at the same time as the structure, forming a very close link between the constituents, the manufacturing process and the resulting mechanical performance. This book takes an in-depth look at material choices and the intermediate steps required to convert different fibre and matrix combinations into finished products. It provides an insight into recent developments for each of the manufacturing processes covered, addressing design, cost, rate and mechanical performance. Topics covered include an introduction to composite materials, material preforming and conversion, moulding, digital design and sustainability, which addresses waste reduction, disassembly and fibre recovery. This book has been developed primarily as a teaching resource with contributions from leading experts in the field. The content has evolved from courses given by the authors to mechanical engineering and materials science students, at both undergraduate and postgraduate levels. It also draws upon experience gained during research projects and from leading industry experts. It therefore provides non-specialists with a valuable introduction to composite manufacturing techniques, helping to determine the most suitable manufacturing routes and to understand the challenges associated with the production of high-performance composite components. Design and Manufacture of Structural Composites Copyright Contributors Preface Introduction What is a composite? Composites manufacturing Where is the industry heading? Automation Sustainability Challenges Aerospace Renewable energy Energy storage Automotive Summary References Reinforcing fibres Introduction Types of fibre reinforcement Inorganic fibres Glass fibre Basalt fibre Ceramic fibres Organic fibres Carbon (graphitic) fibre Aramid fibre Natural (cellulosic) fibres Other polymer fibres Fibre coatings Fibre forms, nomenclature, properties, and testing Finished fibre forms Textile materials Discontinuous fabrics Properties and testing Sustainability, recycling, and reuse Summary References Resins for structural composites Introduction Thermosetting resins Epoxy Epoxy chemical structures Epoxy cure mechanism Epoxy curing agent selection Epoxy resin selection Bio-derived epoxies Recyclable epoxies Powder epoxy Unsaturated polyester Vinyl ester Benzoxazine Bismaleimide Toughened thermosets Thermoplastic resin systems PEEK and PEKK Chemical structure Crystallisation and morphology Anionic polyamide 6 (APA6) Liquid acrylic resins Resin characterisation Rheometry Differential scanning calorimetry Dynamic mechanical analysis Property comparison of resins Summary Acknowledgements References Intermediate composite materials Introduction Dry intermediate materials Dry fibre architectures Tow handling and spreading Continuous fibre architectures Woven textiles Non-crimp fabrics 3D fabrics Discontinuous fibres architectures Unifilo/chopped strand mat Thermoset matrix composite intermediates Preimpregnated reinforcements Thermoset prepreg manufacturing process Thermoset moulding compound manufacturing process Recent developments in thermoset prepregs Thermoplastic matrix composite intermediates Thermoplastic matrix classes and final applications Tape thermoplastic matrix intermediates Comingled fibre thermoplastic matrix intermediates Powder thermoplastic matrix intermediates Cores References Two-dimensional to three-dimensional dry fibre preforming Introduction Fabric materials for preforming Choice of commercial fabrics Formability mechanisms In-plane shear In-plane tension Out-of-plane bending Material sliding Fabric forming techniques Press tool forming Diaphragm forming Single vs double diaphragm forming Forming-induced defects Press tool forming defects Diaphragm forming defects Scenarios for defect mitigation Summary References Automated fibre placement Introduction History and development of the automated tape laying and automated fibre placement processes Current status of processes Basic principles of operation, gantry versus robot designs Thermoset matrix processing Thermoplastic matrix processing Current challenges Productivity issues Accuracy and control issues Temperature control and heating strategies Lay-up head design and operational issues Impacts on cured ply thickness and as-laid quality Monitoring and control Next-generation AFP/ATL Advantages and limitations of AFP and ATL Steering effects and tack Dry fibre AFP issues Tailored blanks and post-forming Development areas and future research References Braiding and filament winding Introduction Braiding 2D braiding 3D braiding Braid parameters Braid angle Cover factor Interlacement pattern Nesting factor Fibre tension Braid design tools Braid manufacturing challenges Filament winding Conventional filament winding Multifilament winding Multi-supply filament winding (MFW) 3D filament winding (3DFW) Multifilament winding with through-thickness reinforcement Toroidal winding Filament winding challenges Hybrid braid-winding Structural performance of braided and filament-wound composites Braiding Filament winding Braid-winding Summary References Three-dimensional woven composites Introduction Definition, classification, and motivation of 3D woven preforms Definition Classification of 3D woven preforms Motivation for 3D woven preforms Manufacturing of 3D woven preforms Influence of microstructural parameters on defects in 3D woven composites Performance and failure mechanisms of 3D woven composites Tensile performance Compressive performance Impact performance Machine developments for 3D woven composites Summary References Autoclave and out-of-autoclave processing of prepregs Introduction Prepreg processing Consumables Curing equipment and tooling Prepreg materials Prepreg fibre bed properties Fibre bed compaction Fibre bed permeability Air permeability Prepreg bulk factor Prepreg degree of impregnation Prepreg resin properties Prepreg cure kinetics Prepreg rheological behaviour Volumetric changes Resin elastic modulus Process design Air evacuation Cure cycle selection Challenges Sandwich panels Complex shaped parts Summary References Liquid composite moulding Introduction Theory Process cycle Resin flow Resin cure Heat transfer Inter-dependencies Solution for the resin flow problem Processing properties of reinforcement Reinforcement types Permeability Basics of permeability General comments on permeability Practical problems Compaction response Processing properties of matrix Thermoset matrix Thermoplastic matrix Implementation Practical considerations Process variants Resin transfer moulding High-pressure resin transfer moulding Vacuum infusion Light RTM Compression RTM Sandwich structures Summary References Compression moulding Introduction Overview of compression moulded composite materials and their associated processing routes Sheet moulding compounds (SMCs) Constituents Fabrication of SMCs SMC compression moulding process Glass mat thermoplastics (GMTs) Constituents Fabrication of GMTs GMT compression moulding process Long fibre thermoplastics (LFTs) Platelet and scrap materials Compression moulding challenges Consolidation and flow phenomena during compression moulding Flow-induced fibre microstructures Flow-induced pore evolution during compression moulding Current trends and outlook References Thermoplastic stamp forming Thermoplastic forming processes and process windows Materials and deformation mechanisms Material characterisation Process modelling and sensitivity analysis Forming-induced defects Design for manufacturing Current industrial practice Acknowledgments References Composite injection overmoulding Injection moulding process Composite injection overmoulding-Background Composite injection overmoulding process Single-stage injection overmoulding Two-stage composite injection overmoulding Material characteristics Material compatibility Interface formation in injection overmoulding Heat transfer and interface temperature Healing at the interface Common issues in composite injection overmoulding Weak bonding between the overmould and the composite insert Material-related issues Processing-related issues Warpage and residual stresses Fibre distortion Summary References Design for manufacture Introduction Design for manufacturability Manufacturing-informed performance Typical phenomena in composites manufacturing Continuous fibre composites Automated tape laying Polymer melting and kinetics Simulation methods Manufacturability Manufacturing-informed performance Laminate stamping Draping and forming Simulation methods Design for manufacturability Manufacturing-informed performance Liquid composite moulding Darcy flow through porous media Simulation methods Manufacturability Manufacturing-informed performance Discontinuous fibre composites Compression moulding Flow of fibre-filled suspensions Simulation methods Manufacturability Manufacturing-informed performance Future trends References Process simulation: Fabric forming Introduction Simulation frameworks Kinematic models vs finite element methods Implicit vs explicit algorithms FE modelling scale Fabric material modelling Continuous approach Hypoelastic continuous model Hyperelastic continuous model Discrete or mesoscale approach Semi-discrete approach Simulation for process design Defect prediction and visualisation Membrane-element-based simulation Shell-element-based simulation Process optimisation In-plane constraint optimisation Spring-loaded clamps Blank holder force Selective intra-ply stitch removal Simulation for large-scale preforms Multi-ply forming simulation Summary References Process simulation: Moulding processes Introduction Short-fibre reinforced polymers Discrete numerical simulation of the fibre orientation Fibre motion equations: Translation Fibre motion equations: Rotation Process modelling and simulation Flow model Case study Increasing fibre length: From SMC to RTM Micromechanical model Flow regimes Lubrication approximation Squeeze flow in narrow gaps Case studies Prepreg compression moulding 3D stokes flow problem in thin gaps Ericksen fluid flow model in a laminate Case study Summary References Digital factory Introduction to digital factories and digital twins Digital twin Digital factory State of the art Simulation of factories Simulation of manufacturing Simulation of parts Simulation of robot cells Instrumentation and measurement Sensor systems in manufacturing Interfaces for manufacturing equipment and sensors Communication between interfaces Data management Current application in structural composites Summary References Cost, rate, and robustness Introduction Different approaches to cost modelling Cost estimation and `should-cost Technical cost modelling Key considerations Types of cost models Cost model calculation Process flow Cycle time and utilisation Shifts and parallel activities Depreciation and amortisation Scrap and reject Other key concepts Cost analysis and examples Example production scenarios Cost analysis Sensitivity analysis Investment planning and business economics Business case analysis RandD investment and budgeting Supply chain planning Summary References Materials waste reduction Introduction Composite consumption and waste generation-By sector Sources of composite waste Storage 1% Lay-up: 0%-50% Cut-out waste Trimming waste Lay-up defects Curing mistakes: 1% Finishing: 2%-40% Impact of process selection on material yield Case study: Impact of process selection Strategies for improving material yield Digital manufacturing Real-time defect detection techniques Zone-based design Nesting optimisation Case study - Nesting optimisation Summary Acknowledgements References Disassembly Introduction Drivers for disassembly Circular economy strategies and standards Directives, legislation, and alternative approaches Automotive Aerospace Marine and renewable (wind) energy Summary Design for disassembly Holistic DfD approach DfD tools Industry 4.0 Component traceability Summary Disassembly technologies Disassembly-embedded design Active disassembly Shape memory effects Smart adhesives Tailored adhesive formulations Active substrates and tapes Chemical additives Physical additives Summary Concluding remarks References Fibre recovery and re-use Introduction Motivation Types of waste Waste pre-treatment options End use opportunities Requirements for end use applications Cost and added value The importance of fibre packing Recovery processes Mechanical fibre recovery Thermal processes for fibre recovery Combustion with energy recovery Thermal decomposition of thermoset composite materials Pyrolysis Fluidised bed Microwave pyrolysis Solvolysis processes for fibre recovery High-temperature and high-pressure solvolysis processes Low-temperature and low-pressure solvolysis processes Properties of recovered fibres Mechanical properties of glass fibre Mechanical properties of carbon fibre Surface properties Physical properties Conversion processes Direct re-use - Shredded laminate Direct re-use - Uncured prepreg Dry fibre - Trim scrap and bobbin ends End-of-life components Input formats and challenges Conversion options Re-use of thermoplastic composites Achievable mechanical properties Discussion and future prospects Environmental considerations References Index