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Textile composite i vps

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Textile composite i vps

  1. 1. Textile Preforms V.P.Senthilkumar 11MT71
  2. 2. Composite Material • Two inherently different materials that when combined together produce a material with properties that exceed the constituent materials.
  3. 3. Composites Offer High Strength Light Weight Design Flexibility Consolidation of Parts Net Shape Manufacturing
  4. 4. Fiber Reinforced Polymer Matrix Matrix • Transfer Load to Reinforcement • Temperature Resistance • Chemical Resistance Reinforcement • Tensile Properties • Stiffness • Impact Resistance
  5. 5. Textile Preform • In the recent years, the use of textile structures made from high performance fibres is finding increasing importance in composites applications. In textile process, there is direct control over fibre placements and ease of handling of fibres. • Besides economical advantages, textile preform technologies also provide homogenous distribution of matrix and reinforcing fibre. Thus, textile preforms are considered to be the structural backbone of composite structures. • This technology is of particular importance in the context of improving certain properties of composites like inter-laminar shear and damage tolerance apart from reducing the cost of manufacturing.
  6. 6. Materials Used for Preforms • High performance multifilament fibres, such as glass, aramid and carbon, which provide high tensile strength, modulus, and resistance to chemicals and heat to various types of preforms.
  7. 7. Techniques Used For Preforms Weaving Direction of yarn introduction : Two (0°/90°) (warp and weft) Fabric formation principle : Interlacing (By selective insertion of 90° yarns into 0° yarn system) Knitting Direction of yarn introduction : One (0° or 90°) (warp or weft) Fabric formation principle : Interlooping (By drawing loops of yarns over previous loops)
  8. 8. Techniques Used For Preforms • Braiding • Direction of yarn introduction : One (machine direction) • Fabric formation principle : Intertwining (Position displacement) • Nonwoven • Direction of yarn introduction : Three or more (orthogonal) • Fabric formation principle : Mutual fibre placement • Stitched fabrics (non-crimp fabrics)
  9. 9. Fabric description • warp fibres picks (shots) run full length of the fabric • weft fibres (shuttle direction in weaves) ends run across the fabric • fabrics are designated by areal weight normally grams/square metre (gsm) Weft in weave Course in knitWarp in weave Wale in knit
  10. 10. Balanced fabric a balanced fabric would have • equal numbers of equal weight tows/metre in both warp and weft Crimp crimp ratio = yarn length/cloth length
  11. 11. Woven fabrics 1: weave styles • Plain o high crimp, poor mechanical properties • Twill o intermediate properties • Satin o low crimp, good mechanical properties o but beware of orientation of each face • also matt, leno, flow-enhancement …
  12. 12. Woven fabrics 2 • plain weave • 2 orthogonal sets of fibres (ηo = 1/2) • high crimp, hence out of plane orientation (∴ηo < 1/2)
  13. 13. Woven fabrics 3: twill weave • Note the recurring diagonal pattern
  14. 14. Woven fabrics 4: satin weave • different fibre orientation on each face • interlace position is irregular
  15. 15. Woven fabrics 5: Flow- enhanced • constrained tow (blue) creates flow space • mechanical properties decrease
  16. 16. A comparative properties of some woven preforms Property Plain Twill Satin Basket Leno Mock-leno Higher stability 4 3 2 2 1 3 Good drape 2 4 5 3 5 2 Low porosity 3 4 5 2 1 3 Smoothness 2 3 5 2 1 2 Balance 4 4 2 4 2 4 Low crimp 2 3 5 2 5 2 Rating scale: (5) Excellent (4) Very good (3) Good (2) Poor (1) Very poor
  17. 17. Triaxial fabrics • Triaxial (three directions in a single layer) o usually -60°/0°/+60°
  18. 18. Three-dimensional fabrics • 3-D weaving o usually multi-layer  3D angle interlock (shown)  3D orthogonal (90° binder) o used for preforms Layer to layer interlock weave Angle interlock weave Orthogonal non-crimp interlock weave
  19. 19. Braid • interlacing three or more threads to produce a tubular reinforcement with fibres at ±45° to the principal axis of the tube
  20. 20. Knitted fabrics • knitting is intermeshing of loops of yarn • Marvin (1961-69) knitted rocket nose cones • can form complex shapes or create a matrix for aligned fibres: • WIWK = weft-insertion warp knit or = warp-insertion weft knit •
  21. 21. Stitched (non-crimp) fabrics detail of the stitch photo of real fabric cross-section of laminate •unidirectional layers stitched together • Beware! stitch fibre may be incompatible with the matrix •
  22. 22. Bonded/felted fabrics • Chopped strand mat • Unifilo continuous random swirl fibre mat • Bonding reinforcing scrims (e.g. Crenette)
  23. 23. Properties of some textile performs Textile Preform Advantage Limitation Low crimp, uniweave High in-plane properties; good taliorability; highly automated preform fabrication process Low transverse and out-of-plane properties; poor fabric stability; labor intensive ply lay-up 2-D Woven Good in-plane properties; good drapability; highly automated perform fabrication process; integrally woven shapes possible; suited for large area coverage and extensive data base Limited taliorability for off-axis properties ; low out-of-plane properties
  24. 24. Properties of some textile performs Textile Preform Advantage Limitation 3-D Woven Moderate in-plane and out-of- plane properties; automated preform fabrication process and limited woven shapes are possible Limited taliorability for off-axis properties and poor drapability 2-D Braid Good balance in off-axis properties; automated preform fabrication process; well suited for complex curved shapes; good drapability Size limitation due to machine availability and low out-of-plane properties
  25. 25. Properties of some textile performs Textile Preform Advantage Limitation 3-D Braid Good balance in in-plane and out-of-plane properties; well suited for complex shapes Slow preform fabrication process; size limitation due to machine availability Multi-axial warp knit Good taliorability for balanced in-plane properties; highly automated preform fabrication process; multi-layer high throughput; material suited for large area coverage Low out-of-plane properties Stitched fabrics Good in-plane properties; highly automated process; provides excellent damage tolerance and out-of-plane strength and excellent assembly aid Small reduction in in-plane properties; poor accessibility to complex curved shapes
  26. 26. Conclusions • Optimization of traditional textile technologies and development of new textile production techniques will help to reduce manufacturing cost of advanced composites. • With the advancement in geometrical modeling and predictive calculations of the physical and structural properties of textile preforms, desired textile preforms can be tailored with essential modifications in preform specifications as well as in structure and properties of fibres and yarns. • Although simple 2D textile preforms are finding extensive usage in the commercial applications, the advanced 3D textile preforms are being used mostly in defense and aerospace applications only. • As composites with 3D textile preforms can effectively replace conventional materials, it is necessary to develop cost effective ways of producing complicated 3D textile preforms and evaluating the properties relevant to commercial applications.

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