Flow-Induced Alignment in Composite Materials

All chapters end with a section of References. Preface Flow-induced alignment in composite materials: current applications and future prospects A brief survey of composites: Brief history of composite materials, An overview of aligned-fiber composites, Benefits of aligned short-fiber reinforcements, Flow-induced fiber alignment, Applications of aligned-fiber composite, Types of fiber reinforcement, Critical fiber length, Processing issues for producing aligned-fiber composites - Flow processes for producing aligned-fiber polymer matrix composites: Processing of thermoplastic polymer composites, Thermosets, Aligned fiber mats, Blends of liquid crystal polymers and thermoplastics - Flow processes for producing aligned-fiber metal-matrix composites - Flow processes for producing aligned-fiber ceramic matrix composites - Future prospects Fiber-fiber and fiber-wall interactions during the flow of non-dilute suspensions Introduction - Single fiber motion - Orientation characterization - Fiber-fiber interactions: Early work, Diffusion models, Slender body theory-based solution, Stokesian dynamics, Computer simulation/full numerical solutions - Concentrated suspensions - Fiber-wall interactions Summary and outlook Macroscopic modelling of the evolution of fibre orientation during flow Introduction - Theory: Evolution equations, Anisotropic fluid models - Numerical methods: The boundary element method, Solution of the evolution equations - Applications: Flow past a sphere, Injection moulding - Conclusions Flow-induced alignment in injection molding of fibre-reinforced polymer composites Introduction - The injection molding process: Overview, Modeling of mold filling, Velocity profiles in molding filling - Experimental observations of fiber orientation in injection molding: Filling patterns with fiber-reinforced melts, Skin-core structure, Other influences - Prediction of fiber orientation in injection molding: Modeling strategies: prediction of fiber orientation, Modeling strategies: effect of fibres on flow kinematics, Parametric sensitivity studies - Conclusion Control and manipulation of fibre orientation in large scale processing Introduction - Application of SCORIM for welding strength enhancement: Copolyester LCP-containing glass fibres, High temperature cure DMC - Application of SCORIM for physical property enhancement: Glass fibre-reinforced polypropylene, Glass fibre filled copolyester - Control of porosity in thick-section mouldings: Control of porosity and fibre orientation in a variable cross-section bar, Moulding and characterization of a thick-section moulding representing an actuation support structure - Control of fibre orientation in a selection of mould geometries: Injection moulded plaque, Injection moulded fin, Multicavity SCORIM for the production of moulded rings - Extensions of the shear controlled orientation concept Theory and simulation of shear flow-induced microstructure in liquid crystalline polymers Introduction - Shear flow-induced orientation phenomena in rod-like nematic polymers: Leslie-Ericksen continuum theory of nematics, Orientation modes and multistability, Pattern formation under forced convection, Non-equilibrium defect structures - Shear flow-induced molecular alignment phenomena in rod-like nematic polymers: Tensor continuum theory, Alignment-orientation coupling - Conclusions Mesostructural characterisation of aligned fibre composites Introduction: Definition of the measurement problem, Comparison of measurement techniques, Characterisation parameters of fibre orientation states - Optical reflection microscopy: Sample preparation, Overview of microscope and image analyser, An automated large area high spatial resolution design - Confocal laser scanning microscopy: Basic principles, Operational modes for three-dimensional reconstruction - Measurement errors in optical microscopy: Noise in pixellated images, Intrinsic fibre ellipticity, Minimising orientation errors by large angle sectioning, Confocal laser scanning microscope and the apparent depth problem, Stereological issues - Characterisation studies of fibre reinforced composites: Geometrical coefficients, Fibre length distributions, Nearest neighbor angular anisotropy, Fibre misalignments and fibre curvature, Power spectral density of fibre waviness - Future developments: Low level voidage determination, Pattern matching between successive two-dimensional sections, Automation of three-dimensional CLSM for large volume studies, Automated ultrasonic testing for elastic constants determination, Concluding remarks Materials property modelling and design of short fibre composites Introduction - Modelling the stiffness of fully aligned materials: Bounds on moduli, Self-consistent models, Mori-Tanaka model, Halpin-Tsai model, Comparison between models - Effect of fibre aspect ratio on stiffness - Effect of constituent properties on stiffness - Modelling the effect of fibre orientation: Introduction, Transversely isotropic subunit, Transformation of properties and the aggregatge model, Orientation averaging using tensors - Application in design and some results - Conclusions Micromechanical modelling in aligned-fibre composites: prediction of stiffness and permeability using the boundary element method Introduction - Boundary element method: Consideration of dispersed fibres, Massively parallel implementation - Representative results: Stiffness of an elastic rod reinforced with short fibres, Stokes flow across arrays of aligned fibres - Conclusion