Mari Inoue

Objective Evaluation of the Handle of Blankets

This study develops mathematical equations for an important quality of blankets, good handle, based on the compression and surface properties, thickness, weight, and thermal parameters. The handle of blankets is subjectively evaluated by thirty-nine judges. Two methods are investigated for evaluating the quality of blankets on the basis of these subjective evaluations. The first method uses Equations KN101-W and KN301-W, which were developed for evaluating the quality of mens winter suiting, to predict blanket quality. Equation KN101-W converts the fabric characteristic parameters into primary hand values (HV), then the overall quality value (total hand value or THV) is derived from these primary hand values using Equation KN301-W. The application of these equations to blankets is based on the idea that there may be similarities between the human sensation-based concept of good handle for mens winter suiting and that for blankets. The second method involves a new equation for directly evaluating the THV of blankets from the compression, surface, construction, and thermal properties of the blankets. This second method is based on the idea that the effects of thermal properties on THV must be investigated, although the interrelation of these thermal properties and primary hand is not explained by Equation KN101-W. Some characteristic parameters that are applied to Equation KN101-W may be omitted because they are less important to the THV of blankets. This makes the equation simpler, and applying the equation to blanket design becomes easier. The evaluation equations are investigated to ascertain their ability to predict the handle of blankets.

Theoretical analysis of the non-linear deformation properties of a triaxial weave under biaxial stress fields

A non-linear theory of the deformation properties of a triaxial weave is presented. The deformation is two-dimensional and composed of shear and biaxial extension deformations, and is derived by solving the equilibrium of contact forces acting on the yarn cross-over point. The experimental results and theoretical predictions prove to be in agreement. The linear theory is easily derived from the non-linear theory. Although the prediction ability of the linear theory is less satisfactory than that of the non-linear theory, the prediction equation is much simpler and more useful in some cases of practical application.

Non-linear Theory of the Biaxial Deformation of a Triaxial-weave Fabric

A new theory predicting the biaxial tensile properties of a triaxial-weave fabric is presented. This theory is based on the plain-weave theory developed by Kawabata, Niwa, and Kawai in 1973 and improved by Kawabata in 1984. The basic structures of the fabric are (i) the thread-spacing of two warp threads and one weft thread, (ii) the weave-crimp shrinkage of the three threads, and (iii) the crossing angles between these threads. The yarn properties applied in this theory are the tensile properties, the lateral-compressional properties, the bending property, and the yarn-crossing-torque property. The biaxial tensile properties of the triaxial-weave fabric are then derived by solving an equilibrium equation of the forces acting at a thread-crossover point. The prediction and the experimental result coincide well over the wide range of deformation from the small-strain region to the finite-deformation region near breaking strain. The theoretical analysis shows that the yarn lateral-compressional properties h...

The objective evaluation of blanket hand and durability

The purpose of this study is to investigate an objective method of evaluating the tactile comfort of blankets by a method of connecting the mechanical parameters of blankets to subjective evaluation. The two methods are preliminarily investigated as follows: (1) Transformation equations for the fabric hand of suiting, KN‐101‐W for primary hand values and KN‐301‐W for THV, are applied, with the mean and standard deviation applied to these equations replaced with new values for the blanket population. (2) A new prediction equation is constructed for deriving THV directly from the mechanical parameters and thermal properties. The prediction accuracy of method (2) is a little higher than that of (1). The durability of blankets during repeated use and repeated dry cleaning determined by the initial performance of blankets is also investigated.

Validity of the ‘Linearizing Method’ for Describing the Biaxial Stress–Strain Relationship of Textiles

The linearizing method is a modified linear theory of elasticity, and we can apply this method to almost any kind of textile fabric which possesses strong nonlinearity and anisotropy in the deformation property. A brief introduction of this method is first presented, then some examples of the applications of this analyzing method are reported. Inspection of the results obtained in these applications shows the validity of this method for a wide range of nonlinear textile materials, and for a large deformation region, with enough accuracy for practical application. This phenomenological analysis can be easily applied to any textile materials which possess a complex fiber assembly structure, making it difficult to solve the biaxial deformation properties by the method of structural mechanics. In this paper, it is concluded that the linearizing method has enough capacity to estimate the biaxial extension behavior of the fabric with considerably high accuracy and demonstrates its validity by showing examples of its application.

Tensile and Tensile Stress Relaxation Properties of Wool/Cotton Plied Yarns

The basic objective of this work is to understand the effects of humidity and the ratio of wool and cotton fiber on the initial tensile and tensile stress relaxation properties of plied yarns. These low strain properties relate directly to the fabric hand, appearance, and formability of clothing. We have found that wool/cotton plied yarns have high hygroscopicity, high water absorption properties, and a low stress relaxation rate at high relative humidity. Also, we have adapted the power law to provide a relation between wool fiber content and the values of tensile resilience and stress relaxation rate. Their values are then estimated from the values of tensile resilience and stress relaxation rate of the constituent fibers and the blend composition.

Theoretical analysis of compression properties of blankets

We predict the compression properties of blankets from the blanket structure and the fiber bending property. This study applies to the theory developed originally for the compressive deformation of carpets by Kimura, Kawabata and Kawai in 1970 to blankets. As a result, we found that the initial compression properties of Mayor and New Mayor blankets could be predicted by the compression theory.

Theoretical analysis of biaxial tensile properties of power net

Power net is a kind of warp knitted fabric and a distinctive feature of this fabric is its high extensibility in both wale and course directions. The main uses of this power net are supporters, ladies foundation garment, girdle etc. due to its high formability property. The theory of the biaxial extension of power net is introduced, in this study. And the theory is inspected by the biaxial extension experiments of a power net for various biaxial extension modes. The experimental results and theoretical predictions prove to be in agreement. The biaxial extension property of a power net was analyzed and compared with experimental results obtained by a biaxial tensile tester. Another sample was also inspected, and same results were given. The theory can predict well, especially in the forces along the tensile direction, and good agreement between experimental and calculated results was obtained. The theory by the simplified model might be useful for designing the power net, and with the various studies until now, this will be powerful tool for the design of the wearing comfort of ladies foundation garment and so on.

Surface Friction Properties of Fabrics and Human Skin

We will select and decide to buy our clothes not only by looking at the design and colour of the clothes, but also by handling the cloth. And for the people which their skin has any trouble, the surface friction property of fabrics is important. It is known that the fabric handle judged by hand is affected by the mechanical properties, surface property and the thermal and water transfer properties of the fabrics. The objective evaluation equations are developed by Kawabata and Niwa [1]. Figure1shows the factors concerning for the performance of clothing. The factors of the properties of clothing are the structure of clothing and the properties of fabrics. And the factors of the properties of fabrics are the structure of the fabrics and the properties of yarn, and the factors of the properties of yarn are the structure of the yarns and the properties of fiber. In the objective evaluation equations of hand value, especially, NUMERI and FUKURAMI, the effects of surface properties is so large. In this study, objectives are to be remarkable about three points. At first, the friction properties of fabrics which differ from the kinds of fiber, yarn counts, and yarn density, secondly, the friction properties of the human skin and next, the friction properties between human skin and the fabrics are experienced.

Effects of cultivating methods and area on the mechanical properties of cotton fiber and yarn

Two kinds of cotton fibers cultivated by different methods were measured and the mechanical properties of these fibers were compared with the mechanical properties of cotton yarns made of organic cotton fiber and non-organic cotton fiber. In this study, the mechanical properties of single cotton fibers and cotton yarns the authors measured and the moduli were calculated by assuming that the cross-section of the cotton fiber is elliptical. It was also found that the strains and stresses of breaking point of organic cotton fibers were larger than those of non-organic cotton fibers. Cotton fibers cultivated in different areas were then examined and it was found that the moduli of cotton fibers cultivated in the northern or southern hemisphere (USA and Australian cottons in this study) were very similar, and the yarn properties for yarns made from cotton fibers from both areas were also very similar. However, the yarn consisting of a mixture of cottons in the northern and southern hemispheres had larger strain, torsional stiffness and hysteresis. It was concluded that the deterioration of fibers consisting of a mixture of cotton contributes to the yarn properties, because the rules of surface orientation differ for cotton fibrils cultivated in the northern and the southern hemisphere as shown in Onogi’s study (Textile Res. J. 66, 406-410 (1996)).