Warp direction

Fabric, Cloth or Mat Woven strands of filament. The weave pattern used depends on the flexibility and balance of strength properties required in the warp and fill directions. Fig. 4.65 shows a plain weave in which the strength is uniform in both directions. The warp direction refers to the direction parallel to... 

Tensile Testing. Tensile tests were run on an Instron 1000 using a 5.08 cm (2 Inch) guage length and a speed of 12.7 cm (5 lnches)/mln. The procedures In Burlington Test Procedure FP-015 (ASTM-D-579) were followed. At least 5 specimens of each sample were tested. Fabric tests results are quoted for the warp direction only. The percent retention of tensile strength was calculated from the equation % retention where F and F(j are the... 

Initial Characterization. Modern silk was subjected to tensile testing to evaluate the test procedure to be used, the number of samples required and the expected precision. Five fabric samples tested in the warp direction were found to give a coefficient of variation of less than 5% for breaking-load and less than 10% for strain-to-break. 

In cellulose triacetate virtually all the hydroxyl groups in the cellulose have been acetylated and this makes the fibre more hydrophobic and, therefore, less receptive to dye molecules. Triacetate differs from secondary cellulose acetate in that it can be heat set, making it in this respect competitive with the true synthetic fibres. Steam setting is made difficult because tried extends slightly during the process, unlike the synthetic fibres which contract. This adds to the difficulty of fixing dimensions and may cause a ripple effect in the warp direction. For this reason dry-heat setting is preferred because it is not accompanied by extension. 

Three fabric types are available, i.e., woven, nonwoven and knit. Woven fabrics are primarily what is used industrially. Yams are laid into the length and width at a predetermined alignment. The width is called the fill direction and the length, the v/arp direction. They are at 90° angles and usually the yam coimt in the warp direction is the higher figure. 

With all the simplicity of the OA method it produces reasonable predictions for the fibre-dominated properties and low crimp, when deviations from the iso-strain assumption play a minor role. For off-axis properties, or for cases when transverse parts of the reinforcement (e.g. weft yams for warp-direction loading) play an important role, or in the presence of high-crimp yams (e.g. 3D reinforcements with significant fraction of binder), the iso-strain assumption is not valid any more, and quality of the OA predictions is decreased. There are approaches that combine iso-strain and iso-stress formulations [3], but these approaches leave open the choice of the combination mles open, which makes their predictive abilities limited. 

The evolution of modulus in the warp direction is shown in Figure 2.6(a). We notice first a strong increase of the modulus. This can be explained by both the increase of warp ratio in the unit cell and by the decreasing interlock angle. The orientation of warp yarns becomes closer to the x-axis, increasing mechanical properties in this direction. Figure 2.6(b) shows the evolution of the modulus in w ... 

Figure 2.6 Dependencies of mechanical properties of angle interlock reinforced composite on parameters of the reinforcement (normalised values) (a) Young s modulus in the warp direction, Ff = 58% (b) Young s modulus in the weft direction, Ff = 58% (c) shear modulus, Ff=58% (d) Young s moduli versus fibre volume fraction, PSl and PS2 refer to two values of the weft spacing.

During fatigue in stage I, the fabric composite transverse cracks initiate and propagate along the transverse threads in the warp direction. The... 

At least three samples for each load in the warp direction and three in the weft direction... 

Coating firm, fabric manufacturer At least five in each direction, warp and weft Twenty samples in warp direction, 20 samples in weft direction for both the coating firm and the fabric manufacturer... 

Five samples in warp direction, five samples in weft direction per 1000 nf of fabric Ten samples in warp direction, 10 samples in weft direction... 

Test quantity Ten strips in the warp direction, 10 strips in the... 

FIGURE 5 Cross sections of fabrics along warp direction. 

As it can be concluded Equation (13) leads to a better approximation of E under such situation. The modiffed lateral forces T can be calculated from Equation (10) by employing the modiffed yam modulus. Table 2 represents the mean values of the weave angle in a relaxed situation, the fabric modulus along warp direction, and the modiffed warp yams modulus. 

By measuring 6, in warp direction, yam linear density, and fabric deformation angle in pullout test, /tg, and of oscillation model can be computed using Equa-... 

Corrstrained yams in the fabric or other textile stractures reveal mechanical responses, which are different in compare with the free yams. Therefore, their intrinsic behavior would not be displayed perfectly. This is actually the reason of representation of Equations (13) and (15). Table 3 reveals fabric modulus along the warp direction the modiCbd warp yams modulns the spring stiffness constarrt, and the equivalent spring stiffness constant for the weft yam of each fabric. 

Fabric, Woven—A generic material construction consisting of interlaced yarns or fibres, usually a planar structure, in a fabric lamina, the warp direction is considered to be the longitudinal direction, analogous to the filament direction in a filamentary lamina. 

In 1972, Hitco produced HG1900, which was made from a Bayer PAN precursor, processed in a unidirectional woven fabric form because it could only be stretched in the warp direction (UTS 1.72 GPa and YM 552 GPa). 

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