tailieunhanh - Ebook Fabric analysis: Part 2

Following the contents part 1, part 2 the book "Fabric analysis" presented the contents: The geometry of cloth structure, fugurative analysis of fabric structure, a general system of woven fabric geometry, geometry of weaves other than plain, fabric tightness as a measurable quality. | CHAPTER 3 THE GEOMETRY OF CLOTH STRUCTURE Crimp Theory Peirce s theory of crimp is based on the following assumptions . 1 Flexible rigidity of yam is zero . yams in the structure are pliable . 2 Yam is inextensible. 3 Yam is incompressible. 4 Circular in cross-section with uniform diameter through out the length. Notations Parameters Warp Modular length AD 11 Yam diameter- di Weft b d2 Maximum displacement height 2 hl Thread spacing Pl 1 2h2 p2 Weave Angle 01 02 Crimp Cl c2 Relation between parameters By definition Warp crimp Cl 1ị - p2 11 - 1 . P2 P2 Weft crimp c2 l2-pi 12 - 1 pl pl or 11 P2 Cl 1 . h p 1 c2 1 hl h2 2 _hi J12 2 di d2 d d2 D. 2 2 2 75 HW Zk----------------- Figure . Racetrack Geometry - Weft Section Referring to Figure it will be seen that the sum of warp and weft diameters normal to the plane of the cloth B is always equal to the sum of the warp and weft crimp-wave heights H . B bl b2 hl h2 H. In the general case therefore in order to determine fabric thickness t uniquely three out of the four quantities bl b2 hl and h2 must be known or alternatively bl hl and t ti or b2 h2 and t t2. However where ti t2 hl bl h2 b2 whence h b2 and h2 bl. Here fabric thickness t is equal to the sum of minor yarn diameter B which is in turn equal to the sum of crimp-wave heights H . Warp and weft crests are co-planar which is an important factor in several fabric properties . abrasive wear. 76 Cover Factor K Fabric cover is defined geometrically as the proportion of fabric area covered by actual yam. In practice cover factors are normally calculated for warp and weft independently being given respectively by the proportion of fabric area covered by the yam in that particular sheet. For example a fabric having 50 warp threads per inch each inch in major diameter would have a warp cover factor of or 50 . Fractional warp cover factor for plain weave is thus given by Ki njai . and weft cover factor by K2 n2a2

• Thời trang - Làm đẹp
• Fabric analysis
• The geometry of cloth structure
• Fugurative analysis of fabric structure
• A general system of woven fabric geometry
• Geometry of weaves other than plain
• Fabric tightness as a measurable quality
• Theory of fabric construction
• The construction of cloth
• Fundamental theories of weave construction
• Analysis of weave design
• Classification of plain cloths
• Holonomic non linear modelling
• Heterogeneously resisting structures
• Drastic simplifications of the fabric
• Non linear analyses
• Full mathematical modeling
• Drape coefficient
• Crease recovery
• Image pixel
• Quantitative analysis
• Graphic software