Fabric deformation

Mimran Y. (1975) Fabric deformation induced in Cretaceous chalks by tectonic stresses. Tectonophysics 26, 309-316. 

By wrinkling is understood any fabric deformation resulting from the formation of folds that is not immediately and completely reversible. 

FIGURE 1 Schematic of fabric deformation in yam pullout test. 

In the two last steps, fabric displacements and its deformation angle named and respectively declaring their dynamic nature. Dynamic lateral forces T, dynamic friction coefUfcient and dynamic normal load F may be calculated using parameters such as and 0 related to the fabric deformation, through Equations (9)-(l 1). 

In this study the yam pullout test is applied to investigate internal mechanical properties of the plain woven fabrics. In the first step an analytical model was developed, inputs of which employs simple mechanical properties such as the fabric modtrlus, the weave angle, and the fabric deformation angles during the pullout test. This model predicts important mechanical parameters such as the weave angle variations, the yam-to-yam friction coefficient, the normal load in crossovers, the lateral forces, and the opposed yam strain within the fabric. This approach may be extended to other types of the woven fabrics. 

As a physical study, yam pullout test would be an appropriate approach to realize an estimation of the internal friction forces between the yams within the fabric. Under the circumstances of this test, a pulled yam sUdes along the intersecting perpendicular yams during fabric deformation. 

Force balance model is capable of predicting the irttemal mechanical parameters of the plain woven fabrics in a similar yam prrllout test based on the force distribution concepts. These parameters are yam-to-yam friction coef ftierrt, normal load at crossovers, lateral forces, lateral strairr, weave angle variatiorrs, arrd pullout force. Crimp angle of yams within the fabric 9 in (Figure 3)), its elastic modulus and linear density and fabric deformation data (a in (Figure 1(a))) are the required empirical factors of force balance model. The main equations of this model are presented in (Table 1) [10] ... 

Variation of crimp angle for the opposed yam due to fabric deformation by angle a during pullout test (Figure la) 0 = arctan(tan0 cos a) (7)... 

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-... 

Motamedi, E., Baily, A. I., Briscoe, B. J., and tabor, D. Theory and practice of localized fabric deformation. Textile Research Journal, 59, 160172 (1989). 

V = Sample volume during pulling (mm3) a = Fabric deformation angle... 

The subject divides itself into (a) micromechanics, which predicts the constitutive equations for the material in terms of the arrangement of fibers with the yarns and fabrics (b) macromechanics, which determines the total deformation of the material under particular forces. A hierarchical approach is often needed in dealing with fiber, yarn, and fabric deformation. 

El Said, B., Green, S., Hallett, S., 2014. Kinematic modelling of 3D woven fabric deformation for structural scale features. Compos. Part A 57, 95-107. 

Mohiar, P., Ogale, A., Lahr, R., Mitschang, P., 2(X)7. Influence of drapability by using stitching technology to reduce fabric deformation and shear during thermoforming. Compos. Sci. Technol. 67 (15), 3386 3393. 

Knowing the mechanical behaviour allows to know the pocket , that is, to say the lowest point of the awning. The simplest model is to represent the fabric as a sum of the linear elements. The blind can thus be modelled at each point of its width as a set of hanging yams. Recovery areas are stiffer than the simple thicknesses. These zones also serve to support all the weft yarns constimting the fabric. The elongation of the fabric deforms its edges as a fabric sample piece subjected to a tensile force on a tensile testing machine. 

The basic fabric material characterization consists of quantifying the evolution of the shear stiffness as a function of yarn rotation and the tensile behavior. Such characterization should be done over the range of temperatures that can occur during fabric deformation when using prepreg fabrics. For dry fabrics, that is, no prepreg, the characterization can be done at room temperature. 

To reduce manufacturing cost and time and to achieve an acceptable composite design without expensive prototype testing, it is desirable to simulate the thermostamping process. There is currently no widely accepted modeling approach that can accurately capture all the important aspects of fabric deformation and effectively predict both the macroscopic mechanical response of the fabric as well as the response of the yarns at the meso-structural level. Specialized models employing various approaches have been proposed. 

N. Mao, Towards objective discrimination evaluation of fabric tactile properties quantification of biaxial fabric deformations by using energy methods, in Proceedings of 14th AUTEX world textile conference, Bursa, Turkey, May 26—28, 2014. 

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