Fabric deformation characterized by large displacements and rotations but small strains is analyzed using a geometric nonlinear finite element method. The fabrics are modeled by shell/plate elements. Special considerations for applying the finite element method to fabric analysis are discussed and several examples of fabric deformation presented. The results from the finite element model are compared with experimental data and are in good agreement.
Recently developed by CSIRO for quality control and assurance of fabrics, FAST, or fabric assurance by simple testing, consists of a series of instruments that are in expensive, robust, and simple to use, and their related test methods. FAST is specifically designed for use by tailors and worsted finishers; it measures fabric properties that are closely related to the ease of garment making-up and the durability of worsted finishing. FAST- I gives a direct reading of fabric thickness over a range of loads with micrometer resolution. FAST-2 measures the fabric bending length and its bending rigidity. FAST- 3 measures fabric extensibility at low loads. Fabric shear rigidity is calculated from the 45° bias extensibility. FAST-4 is a quick test for measuring fabric dimensional stability, including both relaxation shrinkage and hygral expansion.
A plausible model is used to derive formulas for the expected number of fibers with zero, one, or two ends in a given length segment of a random assembly of aligned fibers. These results are then combined to form the expectation of the number of ends and various related quantities. By making a stronger assumption, an expression for the variance of the number of ends is found. A numerical illustration is used to show how the variance depends on the length of the segment involved. Various definitions for the proportion of ends are given and discussed. A brief discussion of the relevance of these results to the study of the mechanics of staple fiber yarns is included.In studying the irregularity of slivers and yams [7] or the mechanical properties of staple fiber yarns such as strength [3] and bending rigidity [6], a statistical expression for the number, or proportion, of fibers that end (i.e., one or two fiber endpoints) in a segment of the fiber assembly is desirable.The expected number of ends per unit length is given in reference 11 as 2n/L where n is the expected number of fibers in the assembly that intersect a normal cross section and L is the expected (mean) length of fibers. A simple derivation of this result follows from a proportionality argument: consider a long length G of assembly with approximately nG/L complete fibers and, therefore, close to twice as many endpoints. For a segment of length A the expected number of ends is thenThe implied proportion of fiber ends from this result, as given in reference 11, is when expressed as a ratio of the number of fiber ends to the number of fibers intersecting a cross section.A more suitable definition may be to express the ratio in terms of the expected number of fibers that intersect the segment of assembly lVo rather than n.In what follows, a more detailed derivation of the simple result for Ñ E is given that sheds light on related matters and, in particular, leads to the variance of the number of ends. Various formulae for the proportion of ends are given and briefly discussed.. Methods A random assembly of aligned fibers is defined as a linear assembly of straight parallel fibers arranged at random along the axis. Any fiber in such an assembly may be represented by a pair (X, L) where X is the location of a point, say the left-hand end, on the fiber and L is the length of the fiber. Assume that the points X form, when projected onto the assembly axis, a stationary point process (see Chapter 4, reference 2) independent of fiber lengths. Later, to obtain variances, we shall make the stronger assumption that the stationary point process is a Poisson process (Chapter 2, reference 2), and we may note that this implies a uniform distribution for the positioning of points with respect to a segment that contains a given number of points (left-hand end points of fibers in our case), a well known conditional property (see Chapter 2, reference 2) of the Poisson process and one that has been used in the past (e.g., Suh [9]) as a starting point to model the bundle of a...
Contact angles of various liquids on wool fibers are measured using the liquid droplet method. A computational technique greatly simplifies contact angle calculations. Sur face energy components of differently treated wool fibers are determined from the contact angle data using current theories of surface energy. Values for the surface energy of wool fibers calculated using the equation of state and the geometric-mean equations show a dependence on the kind of liquid used. Calculations based on the acid-base approach give more consistent results, but for wool fibers with high polar components, reliable results are obtained only with particular liquids. Untreated wool fibers are weak γ- monopoles. Wool fibers set in steam have a higher γ LW and γ+, with the γ - remaining unchanged. Chlorination changes wool fibers to bipolar solids with substantial increases in γ LW,γ+, and γ-.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.