Interfiber Friction Research Articles

Vibrational Property of Filament Woven Fabrics Based on Shear Deformation

In order to study basic phenomenon of dynamic drape of filament woven fabrics, dependency of vibrational property of woven fabrics based on shear deformation on fabric tension was investigated precisely in relation to shear property of the woven fabrics. The shear vibration of fabric dampled linearly with time in a small shear deformation range (<0.035rad) under all the fabric tensions examined here (0.1-3.5kg/m). This means the vibration damps by inter-fiber and/or inter-yarn friction in the woven fabrics. Optimum range of the fabric tension where the shear vibration continued the longest was recognized to exist experimentally and theoretically. The damping ratio correlated well with a combined characteristics of shear property measured by KES system; 2HG0/_??_G0, and this could be considered as a parameter of shear vibrational property of woven fabrics. Vibration of silk woven fabrics continued longer than that of the similar type of silk-like polyester woven fabrics.

Vibrational Property of Filament Woven Fabrics Based on Shear Deformation

In order to study basic phenomenon of dynamic drape of filament woven fabrics, dependency of vibrational property of woven fabrics based on shear deformation on fabric tension was investigated precisely in relation to shear property of the woven fabrics. The shear vibration of fabric dampled linearly with time in a small shear deformation range (<0.035rad) under all the fabric tensions examined here (0.1-3.5kg/m). This means the vibration damps by inter-fiber and/or inter-yarn friction in the woven fabrics. Optimum range of the fabric tension where the shear vibration continued the longest was recognized to exist experimentally and theoretically. The damping ratio correlated well with a combined characteristics of shear property measured by KES system; 2HG0/_??_G0, and this could be considered as a parameter of shear vibrational property of woven fabrics. Vibration of silk woven fabrics continued longer than that of the similar type of silk-like polyester woven fabrics.

Analysis of Mechanical Fatigue Phenomena in Wool and Wool Blend Suiting Fabrics

Fatigue phenomena in fabrics can be quantified by increases in mechanical hysteresis properties. Increase in the mechanical hysteresis properties of fabrics with wear are considered with respect to the structural modification of fiber assemblies, the increase in interfiber friction, and the changes in the mechanical properties and crimp of fibers. The crimp of both yams and fibers decreased due to considerable extension of the fabrics during wear; the yams became flattened, thus increasing the lateral pressure and contact region at yam crossover points in the fabrics. The shear torque parameter C1, which represents the effect of interfiber friction, increased with wear. Increased interyarn and interfiber friction is considered to govern the increase in the hysteresis properties of fabrics with wear. The yield stress and strain of fibers for tensile and torsional properties decreased with wear. The removal of fiber scales and the ragged fiber surfaces after wear were observed using scanning electron microscopy. Mechanical degradation and decreased crimp of kid mohair and polyester fibers with wear were greater than those of coopworth fibers.

フィラメント織物のせん断振動特性 （第２報） せん断角の大きな領域における振動減衰挙動

目的 フィラメント織物のせん断変形に基づく揺動振動特性について, せん断角の大きな (>0.035rad) 領域における減衰挙動をせん断特性との関連で検討し, 動的ドレープ挙動の基礎知見を得る.成果 振動の非直線性はせん断角が大きいほど顕著であり, これは主にヒステレシス変化によるものである.減衰率のせん断角依存性から, 絹フィラメント織物の減衰挙動は4種のパターンに分類でき, これらはKESシステムで得られる力学パラメータ, G, 2HGのせん断角による変化率の大小の組み合わせで区別される分類と対応する.衣服の動的ドレープ挙動には曲げ振動特性よりもせん断振動特性の方が効いていると思われる.

Vibrational Property of Filament Weaves Based on Shear Deformation

In order to study basic phenomenon of dynamic drape of filament weaves, dependency of fabric tension on vibrational property of the weaves based on shear deformation was investigated in detail in relation to shear property of the weaves. It was shown that the vibration damped linearly with time in the small shear deformation region (<0.035rad) at all the weight examined here (0.1-3.5kg/m). This means the vibration damps by inter-fiber and/or inter-yarn friction in the weaves. Optimum region of the weight at which the vibration continued the longest was recognized to exist experimentally and theoretically. The damping ratio correlated well with the combined parameter of shear property measured by KES system; 2HG0/√G0 and this could be considered as a arameter of vibrational property of weaves. Vibration of silk weaves lasted longer than the similar type of silk-like polyester weaves.

Studies of Wrinkling Properties of Wool Fabrics

Lowering or cycling of humidity during recovery from wrinkling increases the degree of recovery, despite the influence of a lower equilibrium recovery rate at the lower humidity. The effect is interpreted as a combination of increased stress relaxation and a swelling-deswelling phenomenon, resulting in changes in interyarn and interfiber friction.

The Importance of Interfiber Friction in Wrinkling

Some of the more important consequences of interfiber friction in fabric wrinkling are discussed. A simple approxi mate relation for a linear viscoelastic fabric is obtained which relates the residual set at which the fabric ceases recovering to the length of time it was held bent before release. It is also shown how the presence of friction can allow quite high residual deformations to build up following series of short wrinkle-and-recovery cycles. For a typical single wrinkle-and-recovery cycle the frictional moment interacts with the viscoelastic behavior of the single fibers to impose a limit on the final recovery that a fabric may eventually attain. This concept is interpreted in terms of previously defined parameters V and F obtained from a standard test procedure. The importance of evressing the wrinkling behavior of a fabric in terms of its viscoelastic and frictional components is emphasized.

Theoretical Analysis of the Large Deflection of the Elastic Yarn with Inter-Fiber Friction

In this paper, the large deflection of a thin elastic rod having internal friction is analysed.The analyses have been made for the two processes, the one is the increasing bending process and another is the recovering process where the forces are applied at the two free-ends of the rod.The obtained results shows following properties.At the increasing process, the effect of thct internal friction on the force-deflection property is small except in the very small deflection region, in which there is small rising of the force caused by internal friction.At the recovering process, the internal friction causes remarkable hysteresis phenomena, and it was found that the hysteresis behavior depends on a parameter a where, a=2HB/Bl0B Slope of the bending property (torque-curvature property) of the rod. 2HB;hysteresis-width in the bending property.l0;length of the rod.An experiment was carried out for the purpose to examine the calculated results using a ring shape specimen of spun yarn, and it was confirmed that the prediction by the theoretical calculation has good accuracy for both increasing and recovering processes of actual spun yarn.

Influence of Fiber Properties on Wrinkling Behavior of Fabrics Part I: Procedures and Apparatus

This is the first in a series of papers in which the mechanism of fabric wrinkling is analyzed. General geometric principles are outlined. Apparatus is described for the measurement of filament, yam, and fabric bending recovery, fabric wrinkling, filament bending modulus, interfiber friction, and planar shear properties of fabrics.

Bending Rigidity of the Yarn with Inter-Fiber Friction Induced by Lateral Compressive Force

The bending rigidity of the yarn with strong inter-friction is measured by elastic-ring method where the inter-fiber friction is given by the lateral compressive force applied on the yarn. That is, the yarn with tension is wound on the surface of a cylindrical tube which is made by a thin elastic plate, and the yarn tension induces the lateral compressive force on the yarn.The rigidity of the yarn on which the lateral compressive force is applied can be calculated by the deflection of the diameter of the ring compressed by the force along its radius direction It is found that there are two states of yarn bending process, one of them is “before slip region” in which the bending rigidity of the yarn takes a large value like as the value of a solid rod and another one is “slip region” in which the shear stress acting along fibers becomes larger than the inter-fiber-frictional force and the yield phenomena in the bending rigidity caused by the inter-fiber slip is observed. The value of the rigidity in this region becomes smaller than the value of “before slip region”.The bending rigidity in the both regions, however, are much higher than the rigidity of the yarn which has no latelal compressional force, and takes almost several handreds times of the value of it. Effect of yarn twisting on the rigidity is also observed and discussed.

The Effect of Certain Fiber Properties on Bulk Compressional Resilience of Some Man-Made Fibers

The compressional resilience of Acrilan, Terylene, and Tricel fibers at pressures ranging from 0.001 to 1.0 psi is reported, and the effects on the resilience of various fiber properties are determined experimentally. The behavior of a mass of fibers in compression can be adequately described by an equation of the form: T = aP-b, where T is thickness of the fibrous mass, P is the pressure, and a and b are constants which depend on fiber properties and also on the experimental conditions. Fiber properties investigated were staple length, fineness, crimp and interfiber friction. Crimp has the highest influence on resilience, whereas fiber friction and fineness indicate comparatively less effect. Fiber length shows no correlation with resilience. There is little difference between Acrilan, Terylene, and Tricel as suitable materials for fiberfill.

The Effects of Construction on the Wear Wrinkling of Dacron®/Wool Suitings

This paper describes a systematic investigation of the effects of fabric construction on the wear wrinkling of worsted spun "Dacron" polyester/wool blend fabrics. Variables studied were blend ratio, yarn count, yarn twist, yarn ply, fabric tightness, and fabric weave pattern. The effect of these variables on the wrinkle resistance of fabrics was compared in laboratory tests under controlled atmospheric conditions and in carefully monitored slack wear tests. These studies led to the conclusion that the three major construction factors which determine wear wrinkling are the proportion of polyester fibers, the yarn count, and the weave pattern. Best performance resulted from the use of high blend levels, coarse yams, and long-float weaves. While the absolute performance levels can be modified by changing test conditions (humidity, wearer severity, or recovery time), the over-all conclusions are unaltered. Within the limits of this investigation, interfiber friction, yarn twist, and tightness for a given weave and yarn size (weight) had little effect on wrinkle propensity. These findings are generally consistent with accepted mechanical concepts of fabric behavior.

Mechanism for Stretch and Recovery Properties of Certain Stretch Fabrics1

The crimp in all-cotton, nylon, and polyester/spandex core stretch fabrics was ex amined by physical tests and by photographic enlargements of yarns and fibers removed from the fabrics. Measurements of total crimp and crimp due to yarn crossover indicate that yarn crossover crimp, external yarn crimp, has a major influence on the stretch and recovery properties of the comfort stretch fabrics having less than 30% stretch. Hysteresis curves show that faisetwisted nylon is significantly changed by weaving and subsequent finishing treatments. Nylon yarns raveled from stretch fabrics and filaments removed from the yarn show no evidence of residual effects of fatsetwisting if the fabric has less than 30% easy strech. The limited data obtained in this study indicate that interfiber friction may play a significant part in the stretch and recovery properties of all-cotton stretch fabrics. These data also suggest that fabric design and processing procedures that promote crossover yarn crimp are the areas most likely to improve the stretch and recovery properties of a comfort stretch cotton fabric.

Effect of Hemicelluloses on the Difference of Papermaking Properties between Sulfite and Sulfate Pulps.

Bleached sulfite, bisulfite and sulfate pulps were made from fir and birch wood chips (Table 1), and their papermaking properties were compared, especially on the tearing strength.Sulfite pulps are easy to swell by beating operation (Fig. 1), and higher in water retention value and accordingly lower in specific scattering coefficient of dried sheet, namely higher in fiber bonded area, compared with sulfate pulp beaten to the equal freeness (Fig. 2). On the other hand, tensile or bursting strengths of sulfate pulp are generally higher than those of sulfite pulps at the equal freeness (Fig. 3 and 4). This is mainly due to that sulfate pulp is higher in strength of a fiber-to-fiber bond than sulfite pulps. The reason is that tensile and bursting strengths of sulfate pulp are considerably higher than those of sulfite pulps at the equal specific scattering coefficient (Fig. 8), in spite of a little difference between their fiber strengths (Fig. 9).Sulfate pulp is considerably higher in tearing strength than sulfite pulps at the equal freeness (Fig. 3 and 4), in spite of a slight difference in fiber strength and in average fiber length (Fig. 12) between these pulps. On the other hand, in comparison between sulfite and sulfate pulps at the equal specific scattering coefficient, tearing strength of sulfate pulp is higher than that of sulfite pulps in the early stage of beating, but these strengths approach together in the later stage of beating (Fig. 10).These facts are probably due to the following reasons ; (1) The higher tearing strength of sulfate pulp than that of sulfite pulp at the beginning of beating is mainly due to the higher strength of fiber bonds in sulfate pulp, because most part of tearing energy is consumed by the deformation of fiber, destruction of fiber-to-fiber bond and the following inter-fiber friction in this stage. (2) The fact that the tearing strengths of sulfite and sulfate pulps at equal specific scattering coefficient approach together at the later stage of beating, is due to the nearly equal fiber strength of the pulps, because tearing energy is mainly consumed by the cutting of fiber in this stage. (3) In comparison between sulfite and sulfate pulps at the equal freeness, the former is considerably lower than the latter in tearing strength even at the later stage of beating. This is explained by higher swellability and greater fiber bonded area of dried sheet of sulfite pulp, and accordingly the tearing work is performed mainly on the cutting of fiber, and the deformation and slip of fiber are lesser compared with sulfate pulp at the equal freeness.In short, it is considered that the difference of papermaking properties between sulfite and sulfate pulps are mainly due to the difference in swellability and strength of a fiber-to-fiber bond between them.Bisulfite pulp is higher in tearing strength than conventional acid sulfite pulp (Fig. 3. 4 and 10). It is probably due to that the former is poor in swellabilty (Fig. 1 and 2) and higher in strength of a bond than the latter.Further consideration was made on the difference in tearing strength between fir and birch pulps.

Relationship Between Fiber Properties and Fabric Wrinkle Recovery1

This research was undertaken to obtain a better understanding of the role of fiber properties in determining fabric wrinkle recovery. For a variety of fibers a one-to-one correspondence was found between fabric crease-angle recovery and a modified tensile recovery parameter, i.e., the average value of tensile recovery (over the range of strains imposed during creasing) measured against a restraining force related to the coefficient of intertiler friction. From this index of recovery, it was predicted that fabric bending recovery would tend toward zero with decreasing strain (increasing radius of crease curvature). Such behavior was observed in the fabrics of nylon and Dacron 2 polyester fiber subsequently studied. The tensile recoveries under load, effective frictional re straints, and qualitative fabric-recovery features are presented. The results reported here indicate that the predominant fiber properties controlling fabric recovery can be determined without recourse to a complete mathematical treatment. Consideration of a simple, idealized model showed interfiber friction to be a property which must be con sidered in order to obtain even a qualitative description of the mechanism of fabric recovery from deformations involving small strains.

The Mechanism of Pilling

Studies of the mechanism of pilling have demonstrated that pilling propensity is determined by the rates of fuzz formation, entanglement, and pill wearoff. Motion pictures of fabrics subjected to an abrading action showed that the abradant acted on exposed fiber sections to pull loops which then opened to form fuzz. A pill formed quickly when the fuzz density reached a critical level. The fibers were then twisted and entangled, gradually involving nearby fibers. As the abrading action continued, pills wore away. Techniques were developed which permitted independent quantitative study of each of these three phenomena. The physical properties of several textile fibers were correlated with their behavior in these tests. Interfiber friction and bending stiffness were important factors in fuzz formation. Entanglement tendency was correlated with denier, cross-sectional shape, and bending stiffness. Pill wearoff was determined by abrasion resistance and tenacity. The general applicability of this mechanism has been demonstrated with modified polyester fibers. The reduced pitting tendency of ribbon staple fibers was attributed to a directional bending which reduced their entanglement tendency. Heat-setting increased bending stiffness, which reduced pilling by lowering fuzzing tendency. The most pronounced effect on pilling tendency of polyester fibers was obtained by changes in abrasion resistance, which affected the rate of pill wearoff.

Time Dependence of Mechanical Breakdown in Bundles of Fibers. I. Constant Total Load

A previously published phenomenological theory of the statistics and time dependence of the creep failure of oriented polymeric filaments is here applied to bundles of filaments. The mathematical apparatus of the theory of stochastic processes is used to calculate relationships between the strength of filament bundles and the strength of their component filaments. The present paper is concerned with the case in which the total load on a given bundle is maintained contant in time. Two limiting idealized cases are discussed—bundles with no interfiber friction (called ``ideal bundles'') and bundles with very strong interfiber friction (called ``tight bundles''). Only the first case is discussed rigorously. It is assumed throughout that the bundles are composed of filaments which have been randomly selected from a first-order ensemble. The principle mathematical result is that, subject to certain rather general conditions, in the limit as the numbers of filaments, N, becomes infinite the distribution of lifetimes for an ideal bundle becomes normal with a coefficient of variation that is proportional to N−½. The present theory predicts an appreciable loss in strength upon the arrangement of filaments into bundles.

The Measurement of the Drag of Cotton Fibers

The drag of cotton fibers has been determined in card-sliver form, using the card- sliver stress-envelope method, and as a sliver made by hand carding using the hand- sliver IP method. In general, for the 12 cottons studied, there was a significant correlation between fiber drag data obtained using both methods and skein-strength data obtained from yarns made from these cottons. There were, however, a few notable exceptions. Fiber drag data was found to correlate poorly with interfiber friction data obtained using the Hood Tester, a dynamic method. The procedures used for evaluating the various cotton fiber drag methods are de scribed in detail.

ON THE APRON DRAFTING

Some slivers or rovings held between top and bottom aprons show a kind of wave motion by the schuffling action produced by irregular travelling speed of each apron band on the main draft field of the long draft spinning frame. The larger their maximum variation of travelling speed, and the smaller inter-fiber friction in slivers, the more frequently is such phenomenon. Such wave motion in slivers introduces a variation of the drafting curve on its back half.

Mechanical Hysteresis Properties of Single Fibers and Cords

An apparatus for stretching and relaxing single fibers for the purpose of determining mechanical hysteresis losses is described. Results obtained on cotton, viscose rayon, and nylon fibers are compared with similar data previously obtained on cords from which the fibers were taken. Such comparison indicates that interfiber friction is probably the major cause of hysteresis energy losses in cotton and rayon tire cords under cyclic loads at low frequencies.