1 / 128

Textile Structural Composites

Textile Structural Composites. Yiping Qiu College of Textiles Donghua University Spring, 2006. Reading Assignment. Textbook chapter 1 General Information. High-Performance Composites: An Overview, High-Performance Composites , 7-19, 2003 Sourcebook.

ila-riley
Download Presentation

Textile Structural Composites

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Textile Structural Composites Yiping Qiu College of Textiles Donghua University Spring, 2006

  2. Reading Assignment • Textbook chapter 1 General Information. • High-Performance Composites: An Overview, High-PerformanceComposites, 7-19, 2003 Sourcebook. • FRP Materials, Manufacturing Methods and Markets, Composites Technology, Vol. 6(3) 6-20, 2000.

  3. Expectations • At the conclusion of this section, you should be able to: • Describe the advantages and disadvantages of fiber reinforced composite materials vs. other materials • Describe the major applications of fiber reinforced composites • Classification of composites

  4. Introduction • What is a composite material? • Two or more phases with different properties • Why composite materials? • Synergy • History • Current Status

  5. Introduction • Applications • Automotive • Marine • Civil engineering • Space, aircraft and military • Sports

  6. Applications in plane

  7. Fiber reinforced composite materials • Classifications according to: • Matrices • Polymer • Thermoplastic • Thermoset • Metal • Ceramic • Others

  8. Fiber reinforced composite materials • Classifications • Fibers • Length • short fiber reinforced • continuous fiber reinforced • Composition • Single fiber type • Hybrid • Mechanical properties • Conventional • Flexible

  9. Fiber reinforced composite materials • Advantages • High strength to weight ratio • High stiffness to weight ratio • High fatigue resistance • No catastrophic failure • Low thermal expansion in fiber oriented directions • Resistance to chemicals and environmental factors

  10. Comparison of specific gravities 8 6 Specific gravity (g/cc) 4 2 0 Steel Al alloy Ti alloy Kevlar/epoxy Carbon/epoxy materials

  11. Fiber reinforced composite materials • Disadvantages • Good properties in one direction and poor properties in other directions. • High cost due to expensive material and complicated fabrication processes. • Some are brittle, such as carbon fiber reinforced composites. • Not enough data for safety criteria.

  12. Design of Composite Materials • Property Maps • Merit index

  13. Design of Composite Materials • Merit index • Example for tensile stiffness of a beam • However, for a given tensile sample, tensile stiffness has nothing to do with length or L = 1 may be assumed

  14. Design of Composite Materials • How about for torsion beams and bending plates? Lets make the derivation of these our first homework.

  15. Major components for fiber-reinforced composites • Reading assignment: • Textbook Chapter 2 Fibers and matrices • Fibers • Share major portion of the load • Matrix • To transfer stress between the fibers • To provide a barrier against an adverse environment • To protect the surface of the fibers from mechanical abrasion

  16. Major components for fiber reinforced composites • Coupling agents and coatings • to improve the adhesion between the fiber and the matrix • to protect fiber from being reacted with the matrix or other environmental conditions such as water moisture and reactive fluids. • Fillers and other additives: • to reduce the cost, • to increase stiffness, • to reduce shrinkage, • to control viscosity, • to produce smoother surface.

  17. Materials for fiber reinforced composites Mainly two components: • Fibers • Matrices

  18. Materials for fiber reinforced composites • Fibers • Influences: • Specific gravity, • Tensile and compressive strength and modulus, • Fatigue properties, • Electrical and thermal properties, • Cost.

  19. Materials for fiber reinforced composites • Fibers • Fibers used in composites • Polymeric fibers such as • PE (Spectra 900, 1000) • PPTA: Poly(para-phenylene terephthalamide) (Kevlar 29, 49, 149, 981, Twaron) • Polyester (Vectran or Vectra) • PBZT: Poly(p-phenylene benzobisthiozol)

  20. Materials for fiber reinforced composites • Fibers • Inorganic fibers: • Glass fibers: S-glass and E-glass • Carbon or graphite fibers: from PAN and Pitch • Ceramic fibers: Boron, SiC, Al2O3 • Metal fibers: steel, alloys of W, Ti, Ni, Mo etc. (high melting temperature metal fibers)

  21. Materials for fiber reinforced composites • Most frequently used fibers • Glass • Carbon/graphite • PPTA (Kevlar, etc.) • Polyethylene (Spectra) • Polyester (Vectra)

  22. Materials for fiber reinforced composites • Carbon fibers • Manufacturing processes • Structure and properties

  23. Materials for fiber reinforced composites • Carbon fibers • Manufacturing processes • Thermal decomposition of fibrous organic precursors: • PAN and Rayon • Extrusion of pitch fibers

  24. Materials for fiber reinforced composites • Carbon fiber manufacturing processes • Thermal decomposition of fibrous organic precursors • Rayon fibers • Rayon based carbon fibers • Stabilization at 400°C in O2, depolymerization & aromatization • Carbonization at 400-700°C in an inert atmosphere • Stretch and graphitization at 700-2800°C (improve orientation and increase crystallinity by 30-50%)

  25. Materials for fiber reinforced composites • Carbon fiber manufacturing processes • Thermal decomposition of fibrous organic precursors • PAN (polyarylonitrile) based carbon fibers • PAN fibers (CH2-CH(CN)) • Stabilization at 200-300°C in O2, depolymerization & aromatization, converting thermoplastic PAN to a nonplastic cyclic or ladder compound (CN groups combined and CH2 groups oxidized) • Carbonization at 1000-1500°C in an inert atmosphere to get rid of noncarbon elements (O and N) but the molecular orientation is still poor. • Stretch and graphitization at >1800°C, formation of turbostratic structure

  26. Materials for fiber reinforced composites • Pitch based carbon fibers • pitch - high molecular weight byproduct of distillation of petroleum • heated >350°C, condensation reaction, formation of mesophase (LC) • melt spinning into pitch fibers • conversion into graphite fibers at ~2000°C

  27. Materials for fiber reinforced composites • Carbon fibers • Advantages • High strength • Higher modulus • Nonreactive • Resistance to corrosion • High heat resistance • high tensile strength at elevated temperature • Low density

  28. Materials for fiber reinforced composites • Carbon fibers • Disadvantages • High cost • Brittle

  29. Materials for fiber reinforced composites • Carbon fibers • Other interesting properties • Lubricating properties • Electrical conductivity • Thermal conductivity • Low to negative thermal expansion coefficient

  30. Materials for fiber reinforced composites • Carbon fibers • heat treatment below 1700°C • less crystalline • and lower modulus (<365 GPa) • Graphite fibers • heat treatment above 1700°C • More crystalline (~80%) and • higher modulus (>365GPa)

  31. Materials for fiber reinforced composites • Glass fibers • Compositions and properties • Advantages and disadvantages

  32. Materials for fiber reinforced composites • Glass fibers • Compositions and Structures • Mainly SiO2 +oxides of Ca, B, Na, Fe, Al • Highly cross-linked polymer • Noncrystaline • No orientation • Si and O form tetrahedra with Si centered and O at the corners forming a rigid network • Addition of Ca, Na, & K with low valency breaks up the network by forming ionic bonds with O   strength and modulus

  33. Microscopic view of glass fiber Cross polar First order red plate

  34. Materials for fiber reinforced composites • Glass fibers • Types and Properties • E-glass (for electric) • draws well • good strength & stiffness • good electrical and weathering properties

  35. Materials for fiber reinforced composites • Glass fibers • Types and Properties • C-glass (for corrosion) • good resistance to corrosion • low strength

  36. Materials for fiber reinforced composites • Glass fibers • Types and Properties • S-glass (for strength) • high strength & modulus • high temperature resistance • more expensive than E

  37. Materials for fiber reinforced composites • Properties of Glass fibers

  38. Materials for fiber reinforced composites • Glass fibers • Production • Melt spinning

  39. Materials for fiber reinforced composites • Glass fibers • sizing: • purposes • protest surface • bond fibers together • anti-static • improve interfacial bonding • Necessary constituents • a film-forming polymer to provide protecting • e.g. polyvinyl acetate • a lubricant • a coupling agent: e.g. organosilane

  40. Materials for fiber reinforced composites • Glass fibers • Advantages • high strength • same strength and modulus in transverse direction as in longitudinal direction • low cost

  41. Materials for fiber reinforced composites • Glass fibers • disadvantages • relatively low modulus • high specific density (2.62 g/cc) • moisture sensitive

  42. Materials for fiber reinforced composites • Kevlar fibers • Structure • Polyamide with benzene rings between amide groups • Liquid crystalline • Planar array and pleated system

  43. Materials for fiber reinforced composites • Kevlar fibers • Types • Kevlar 29, E = 50 GPa • Kevlar 49, E = 125 GPa • Kevlar 149, E = 185 GPa

  44. Materials for fiber reinforced composites • Kevlar fibers • Advantages • high strength & modulus • low specific density (1.47g/cc) • relatively high temperature resistance

  45. Materials for fiber reinforced composites • Kevlar fibers • Disadvantages • Easy to fibrillate • poor transverse properties • susceptible to abrasion

  46. Materials for fiber reinforced composites • Spectra fibers • Structure: (CH2CH2)n • Linear polymer - easy to pack • No reactive groups • Advantages • high strength and modulus • low specific gravity • excellent resistance to chemicals • nontoxic for biomedical applications

  47. Materials for fiber reinforced composites • Spectra fibers • Disadvantages • poor adhesion to matrix • high creep • low melting temperature

  48. Materials for fiber reinforced composites • Other fibers • SiC and Boron • Production • Chemical Vapor Deposition (CVD) • Monofilament • Carbon or Tungsten core heated by passing an electrical current • Gaseous carbon containing silane

More Related