Float Length Research Articles

Interactions Between Internal Solitary Waves and Sea Ice

AbstractInternal Solitary Waves (ISWs) that form on internal density interfaces in the ocean are responsible for the horizontal transport and vertical mixing of heat, nutrients, and other water properties. The waves also induce fluid motion that can induce stresses and motion on floating structures, such as sea ice. This study investigates ISW‐sea ice interactions. Using laboratory experiments, ISWs generated via the lock gate technique are observed interacting with weighted floats of varying sizes. The motion of these floats can be modeled effectively, simply as the average velocity of the fluid under the float, and it is found that when floats are small relative to the wavelength, they behave in the same manner as a fluid particle, but as floats become bigger relative to the wavelength, the maximum velocity decreases, and interaction time increases. This phenomenon is explained simply by the wave‐induced flow as opposed to energy transfer arguments. By using this model with a large sample of theoretical waves, the float motion is parameterized based on the float length and wave parameters. Whilst small floats do not disrupt the flow patterns, the wave‐induced flow under larger floats forms a pair of counter‐rotating vortices at each end of the float. The formation and evolution of these flow features arise as a result of boundary layer separation with the horizontal wave‐induced flow relative to the float velocity. This reveals complex dynamics due to the non‐stationary behavior of both the float and flow.

Influence of tetrahedral architectures on fluid transmission and heat retention behaviors of auxetic weaves

Recently auxetic textiles have captured the attention of researchers. Yet no work is reported on the development and characterization of novel tetrahedral woven auxetic structures. In this study, six two-dimensional (2D) woven auxetic structures including diamond-based vertical pointed twill (S1), vertical inverse pointed twill (S2), vertical broken pointed twill (S3), vertical pointed twill (S4), open tetrahedral (S5), and closed tetrahedral (S6) were developed. For performance analysis, thermal comfort properties including fluid transmission characteristics (air permeability, water vapor permeability index, overall moisture management capability (OMMC)), and heat retention attributes were characterized. These fabrics were also characterized by their mechanical behavior including negative Poisson’s ratio (NPR), tensile and tear strength, pilling, abrasion resistance, and stretch and growth %. S5 has longer floats, hence it became more flexible and open which resulted in higher dry fluid transmission. All specimens showed more than 85% wet fluid transmission tendencies. S6 showed the highest and S5 showed the least OMMC values. Furthermore, S2 has a higher thermal resistance because of low air permeability. The developed fabric structures showed NPR up to −0.64. A significant effect of float length has been found on the auxeticity of fabrics along the warp direction. S5 showed a higher tensile strength and stretch % in warp and weft directions. All the developed woven auxetic fabrics remained unteared in both the warp and weft directions along with viable pilling (4–5 grade) and showed improved abrasion resistance.

Statistical insights on the effect of twill angle on denim fabrics Skewness

PurposeThis study aims to show that the manner of fabric deformation during relaxation depends upon the twill angle line and its direction (twill S or Z). The quantity of the skewness is related to the float length and the twill angle in reverse, with the warp tension when changed from cotton to lycra filling yarns.Design/methodology/approachThe experimental analytical method.FindingsThe most significant goals presented from this investigation are cost savings, time of production and metaphorically; new demands on denim fabric patterns presented.Originality/valueMoving away from just chasing cheap, more innovative and progressive for manufacturing and end users search for denim, this paper served to shift the market share map for denim manufacturers, which is looks on nearly the most common problem facing the denim industry; skewness.

Investigation on the effect of cotton-tencel (50:50) siro yarn twist multipliers on fabric stiffness

The properties of fabrics are mainly affected by constituent fiber properties and yarn structures. The yarn structures are primarily dependent on the spinning technique. The twist multiplier is a leading factor influencing yarn structure which directly correlates with fabric stiffness and mechanical properties due to structural behavior. In this study, siro spun yarn has been prepared using different twist multipliers (3.6, 4, 4.4, and 5.0) by blending cotton and tencel fiber at the spinning stage to investigate the effect of twist multipliers on fabric stiffness and the flexural rigidity of woven fabrics. The 1/1 plain, 2/2 twill, and 8-end satin fabrics have been woven using prepared yarns in warp and weft directions. The fabric stiffness has been measured using the ASTM D1388-2018 method. The results reveal that fabric stiffness increased with the increasing twist multiplier. Furthermore, a comparative study on different weave structures shows significant differences in stiffness. Overall, the experimental results present a close relationship between twist multiplier, spinning triangle, float length, fabric stiffness, and rigidity, and also show the optimum twist level for cotton-tencel siro yarn to attain maximum stiffness and strength.

Investigation of the Shrinkage and Air Permeability of Woolen Blankets and Blankets Made with Regenerated Wool

The aim of this article was to compare the shrinkage and air permeability properties of woolen fabrics and fabrics with regenerated wool woven with different weaves for establishing the suitability of regenerated wool for blankets. Two series of products with yarns of different raw materials were woven. One group of fabrics was woven with regenerated woolen yarn in the weft and woolen yarn in the warp. The other group of fabrics was woven only from 100% woolen yarns. The shrinkage in the directions of the warp and the weft and the air permeability of the fabrics with regenerated wool and 100% woolen fabrics with different weaves were investigated. The shrinkage in the directions of the warp and the weft in the fabrics with regenerated wool in the weft and 100% woolen fabrics depended on the float length in the weave. When the length of the weave increased, the shrinkage also increased. The air permeability value changed depending on the number of intersections and the float length. The fabrics with regenerated wool in the direction of the weft had higher air permeability. The Two-way analysis of variance (ANOVA) results showed that the weave influenced the shrinkage in the directions of the weft and warp, but the raw material had no influence on the shrinkage. The weave did not influence the air permeability, in contrast to the raw material. The shrinkage in the directions of the warp and weft and the air permeability did not depend on the interrelationships of the weave group and the raw material of the fabric.

Theoretical model to estimate the storage volume of rolled erosion control products/geomeshes

Storage effect created by cross laid weft yarns of runoff erosion control geomeshes has a significant influence on their performance. A theoretical model was proposed (prism model) in the recent past to evaluate the storage volume of the geomeshes (micro-barriers), but it has the limitation that is has not considered the warp and weft yarn interlacement. Therefore, a revised pyramid storage model is formulated in this paper by considering the yarn interlacement. To validate the proposed model, plain woven geomeshes are subjected to runoff erosion test at different slope angles (soil slope) in a bench-scale setup. Variation between experimental culmination and calculated culmination due to storage effect is compared by its percentage difference. It is observed that percentage difference between experimental culmination and calculated culmination is lower for proposed pyramid model at all slope angle and mass. It is also observed that at increased slope angle, percentage difference between calculated storage volume and experimental result increases for both pyramid and prism storage model, due to the reduced storage volume. In addition, pyramid storage model has been formulated for different open weave geomeshes by considering the weft yarn interlacement and float length. Theoretically, it is observed that initial increase in float length shows a significant increase in storage volume, but further increase in float length results in a limited increase in storage volume. The results correlate with the past studies on different woven geomeshes. Hence, the proposed storage model with consideration of yarn interlacement and weave can be used for optimising the performance of geomesh at different soil slope angles.

Study on the float-control weaves application algorithms of computer-aided jacquard graph designing for different figured fabrics

In the graph designing of jacquard figured fabrics, it is essential to edit the motif outline perfectly as per the required shape. It also needed that the weave mark applied should control the long floats and should be avoided where there is no longer floats to retain the perfection of the edited outline. In the manual graph designing, the designer decides the types of weave marks given for controlling the floats and applies them in the selected parts. While applying the marks, he retains the perfection of boundary by avoiding the marks wherever it is not required. In the ‘Computer-Aided Jacquard Graph Designing’, sequences of steps are followed to avoid the binding weave marks in the required boundary of the motif. In this study, the different types of controlling of binding weave mark required while preparing the jacquard graph design for different figured fabric varieties viz. double cloth, extra warp, extra weft, and single cloth are analyzed. The possibilities of using the ‘all directional color contour option’ and ‘selective directional color contour option’ for the float control application of binding weaves in the jacquard graph designing to get a perfect boundary of figure and ground are explored. The algorithms followed for preparing the jacquard graph for different fabric varieties using these two contour options are developed. A new procedure is also derived to identify the corner pixels for preparing the graph for single cloth figured fabric using the ‘Selective directional color contour option’, ‘Layer merging option’, and ‘Transparent color option’. It is observed that the systematic use of the appropriate color contour option applies the binding weave marks only in the essential places and avoids it in the non-required edges and corners of the figure and ground portions of the jacquard graph design. Because of this, after applying the binding weave marks, the edited design boundary is retained without any distortion in shape. The float length is also controlled throughout the figure and ground as required. The algorithms derived in the study are useful for the flawless application of binding weave for any intricate figured graph designs.

A Study of Woven Fabrics Made of Helical Auxetic Yarns

The paper presents a study on woven fabrics made of helical auxetic yarns (HAYs) and their key factors on Poisson’s ratio under tension. The work aims to create and evaluate auxetic woven fabrics with optimal parameters for achieving better auxeticity including weave structure, wrapping angle of the auxetic yarn, thickness of the auxetic yarn and properties of the warp yarn. The maximum negative Poisson’s ratio (NPR) of the woven fabric can be achieved as low as -2.92 for experiments. Then, a numerical study has been carried out as well to assist the development of auxetic woven fabrics. The findings of this paper showed longer float length, lower wrapping angle of the auxetic yarn, a thinner diameter of the auxetic yarn as well as lower tensile modulus of the warp yarn led to higher auxetic behaviour. This can also provide a reference for researchers to select the best parameters for producing the auxetic woven fabrics.

Color prediction model for hybrid multifilament fabric

In order to facilitate the design of a hybrid filament before spinning, a k-m (Kubelka-Munk) iteration model was proposed, which was based on the calculation method for reflectance of a translucent object and needed to be used in conjunction with a fabric model that can reflect the arrangement order of monofilaments. Therefore, the model can not only calculate the color of each point on the fabric surface, but also the mixed color of the fabric. Twenty fabrics with five different blending ratios of black monofilaments and white monofilaments, four multifilament fineness and three fabric weave types were woven. The relationship between the gray distribution of all points on the fabric surface captured by the camera in a DigiEye colorimeter and calculated by the k-m iteration model was analyzed, and the color difference between the mixed color of the fabric tested by the Datacolor spectrophotometer and that calculated by the k-m iteration model was calculated. The results show that the intersection distance and Pearson correlation coefficient between the gray histogram of the photographed fabric image and that of the calculated fabric image were 0.79 and 0.89, respectively. The average color difference obtained by the k-m iteration model was 0.92 Color Measurement Committee (2:1) units, which was best compared with the calculation results of other models. By discussing the fabric structure parameters causing the lightness difference, it was concluded that the calculated lightness was smaller than the measured lightness difference for fabric with a longer float length, smaller multifilament fineness and a larger black monofilament blending ratio.

Runoff erosion control performance of structurally modified coir geomeshes on different soil type and slope angle

ABSTRACT Geomeshes made up of coir fibers are a possible great alternative before vegetation establishes itself, and provides immediate soil erosion control on different types of slopes. In this study, coir geomeshes structure has been modified for better erosion over different soils. Different structurally modified coir geomeshes are tested for runoff erosion control, culmination discharge over loamy sand, silt loam, and silty clay loam soil at different slope angles. Lowest erosion control is observed over loamy sand due to higher amount of sand percentage. To know the overall effect of geomeshes, germination tests are also performed. It is observed that twill weave of coir geomeshes provides better erosion control due to the higher float length at the backside which reduces the water velocity. Twill weave geomeshes also provide better germination than plain and satin woven geomeshes. Overall, twill weave geomesh is preferred over loamy sand, silt loam, and silty clay loam at lower and medium slope angles.

Influence of binder float length on the out-of-plane and axial impact performance of 3D woven composites

This paper shows modifying binder float-length, an easily adjustable parameter, there is significant influence on impact energy absorption, impact resistance and damage tolerance in 3D-woven layer-to-layer carbon/epoxy composites. Binder float-length was changed by modifying textile design without changing loom set-up. Three float lengths (1/2, 2/2 and 3/2) in consistent architecture were woven using constant warp density. Out-of-plane drop-weight impact was performed at 32 J&42 J energy and showed increases in float-length decreased energy absorption by 49% and 32% respectively in warp direction with no significant changes in weft. Conversely, in axial impact tests, higher float length showed higher crush force efficiency and specific energy absorption. This study has also concluded, in both out-of-plane and axial impact scenarios, higher float lengths increase damage tolerance. This work has expanded how minor changes in preform parameters can significantly change both out-of-plane and in-plane impact performance of 3D-woven composites without increased manufacturing cost, time or complexity.

Numerical Analysis of Binding Yarn Float Length for 3D Auxetic Structures

Recently, the auxetic fabrics have gained much importance in the scientific and industrial community due to their excellent impact‐resistance property. Due to this property, they have several applications, including automotive, aerospace, and ballistic areas. The auxetic three‐dimensional (3D) woven fabrics are a less explored domain in the auxetic community. Herein, special attention is given to the numerical analysis of the 3D auxetic structure. The negative Poisson's ratio of 3D auxetic structures is studied using ANSYS workbench structural analysis module. The effect of binding yarn float length on negative Poisson's ratio is tested on ten different 3D orthogonal through the thickness structures with binding yarn float length of 1:1, 2:1, and 3:1. Furthermore, the effect of the number of binding yarns and the number of layers is also studied numerically. The results show that the auxeticity of the woven structure increases with increasing the number of binding yarns and their float length. Moreover, decreasing the number of layers from 3 to 1 increases the auxeticity.

Development of 3D auxetic structures using para-aramid and ultra-high molecular weight polyethylene yarns

In recent times, auxetic woven structures gained considerable attention from the researchers due to their excellent impact properties in high-performance areas. Researchers have done much work on the auxetic behavior of the natural and low-performance yarns in two-dimensional structures. Keeping in view the structural application of auxetic structures, in this work, three-dimensional (3D) woven auxetic fabrics were developed on conventional weaving machines with high-performance yarns. Effect of high-performance yarns (Para-aramid and UHMWPE) as the main structure and binding threads on the auxeticity of 3D fabric structures and the impact properties of their corresponding composites were discussed. For this purpose, eight different orthogonal 3D woven structures were produced with para-aramid filament yarn as warp and weft, whereas ultra-high molecular weight polyethylene (UHMWPE) filament yarn was used as a binder. The tensile load was applied to the 3D fabrics to check their auxeticity, and a change in thickness was recorded. The results showed that as the float length of binder yarn and warp yarn increases with the equal and same ratio, the auxeticity also increases. While auxeticity decreases as the difference between the float length of binder yarn and warp yarn increases. The Negative Poisson's Ratio (NPR) of 3D woven fabrics ranged from −0.9 to −2.98. In the second step, these 3D woven fabrics were fabricated into their composites using unsaturated polyester resin, and the hand-layup technique. Their impact strength was measured using the Charpy test method. Auxetic woven composites made of high-performance yarns structures showed impact strength ranging from 55.64 kJ/m2 to 158.46 kJ/m2. Highlights High-performance yarns (Para-aramid and Ultra-high molecular weight polyethylene) were used to create eight 3D woven and composite samples with enhanced auxetic behavior. The result shows that samples having maximum binding yarn float length and fewer intersection points show maximum auxeticity and increased energy absorption. The maximum auxeticity and impact energy absorption obtained was -2.98 and 158.46 kJ/m2, respectively. The current research has applications in protective textiles and bulletproof composite panels.

Design and X-Band electromagnetic response of single negative metacomposite containing periodic curved Co-based ferromagnetic microwires

Metamaterials possess attractive electromagnetically left-handed properties yet their nature as an artificial structure rather than a material restricts their further applications. In this article we propose to use Co-based ferromagnetic microwires as periodical metamaterial units interweaved into a fabric to realize a “metacomposite” for steering wave propagation. By introducing ferromagnetic microwires in quartz fabric at three curvatures and periodic lengths, the electromagnetic response and microwave behaviors on both horizontally- and vertically-arranged directions were presented and investigated. Tensile behaviors of metacomposites with different ferromagnetic microwire morphologies were monitored by non-contact full field strain measurement system. At X band (8.2–12.4 GHz), metacomposites containing vertically-arranged ferromagnetic microwires show negative permittivity due to the dielectric resonance of microwire arrays. The dielectric response of metacomposites conformed to Lorentz-oscillator mode, behaving similarly to diluted plasma. When ferromagnetic microwires reached the lowest periodic curved length 2.5 mm with the highest curvature was obtained, the metacomposites presented the maximum microwave absorption of 34% and tensile stress of 273 MPa. The incorporation of ferromagnetic microwires exerts trivial influence on the mechanical properties yet homogenizes the strain and reduces the stress concentration on metacomposites. The metacomposite with a periodic curved length of 7.5 mm has less interweaving points and the highest surface float length, therefore achieving the maximum tensile strength of 458 MPa. The single negative metacomposites containing ferromagnetic microwires are featured with excellent structural properties and amenable microwave left-handed properties in controlling wave-propagating behavior, which is of practical engineering significance in structural health monitoring, sensing and stealth applications.

Structure and breathability of silk/cashmere interwoven fabrics based on fractal theory

The fractal weave has a different appearance from the traditional weaves, and the fabric performances such as air and moisture comfort have not been studied. The relationship between the fabric structure and performance of the fractal weaves is not yet clear. In this paper, the corresponding fractal weaves were generated based on the fractal theory, and the corresponding fabrics were woven using raw silk as the warp yarn and cashmere/water-soluble vinylon as the weft yarn. The structural parameters, air permeability and moisture permeability were tested. The results show that fabric moisture permeability are not closely related with the three weave parameters of fractal dimension, average float length and weave coefficient. Its conduction mechanism is different from air permeability. The average floating length, fractal dimension, and its parameter combinations have a good fitting relationship with air permeability, and the polynomial fitting R2 can reach to 0.99938. The fitting formula 8 has guiding significance for the design of fabrics with certain air permeability requirements.

Shear Properties of Apparel Fabrics Using Different Spun Yarns

The shear properties of a fabric determine its performance properties as well as the appearances where it is subjected to a wide variety of complex deformations during usage as apparel. In This paper, woven fabrics have been made of cotton spun yarns with three different spinning techniques (ring spun, open-end spun and compact ring spun yarns) in weft direction. Some twill based weave structures were manufactured on the weaving machine with varying the weft density level. The Kawabata Evaluation System were used to measure the shear properties; shear rigidity, shear hysteresis at 0.5 deg. shear angle and shear hysteresis at 5 deg. shear angle. A statistical analysis was performed to get the effect of decided parameters on shear. A highly significant effect of the weave structures and weft density on the measured shear properties were found, while the type of weft yarns has insignificant effect. A multiple linear regression equations were derived to get a mathematical relationship between the influencing parameters; (the float length, yarn diameter, and weft density) and the shear properties. The derived regression equations had high correlation coefficients values.

Improved Energy Absorption in 3D Woven Composites by Weave Parameter Manipulation

3D woven composites show significantly improved out-of-plane properties over traditional 2D laminates. This high through-thickness reinforcement is desirable in crashworthiness applications where crushing energy can be increased by composites’ improved interlaminar toughness. However, their use in practical applications is stunted by the poor understanding of how small variations in weave parameters, whether intended or not, affect the performance of these materials. Here, we demonstrate that small changes in textile properties, in this case pick density and float length have a knock-on effect that can greatly improve or diminish the crush performance of a 3D woven layer-to-layer structural fabric. Quasi-static and dynamic energy absorption values up to approximately 95J/g and 92J/g respectively are achieved. Crush performance is investigated on omega-shaped coupons, under both quasi-static and dynamic loading conditions with crush rates between 2mm/min and 8.5m/s. The failure mechanisms present during progressive crush under quasi-static loading transitions between more expected brittle dominated failure and ductile dominated failure, which is more typical of metals under similar loading conditions. Whereas when dynamic loading is considered, the materials present a more typical splaying failure event. As a result, additional exploration of the three-point bending response of these varied architectures is presented as a means of further explaining the interplay between lamina bending and progressive folding/micro-buckling in these materials. The effect of the weave’s architectural alterations on physical composite properties such as weight, density and conformability to shape is also investigated.

EXPERIMENTAL INVESTIGATION OF THE TENSILE AND IMPACT PROPERTIES OF TWILL AND TWILL DERIVATIVE WOVEN FABRIC REINFORCED COMPOSITES

In recent years the use of woven composites in structural applications has increased rapidly due to the advantages it offers such as easy handling, dimensional stability, deep drawing shape-ability, enhanced toughness and increased impact resistance. Mechanical properties in textile composites are closely connected with the textile reinforcement’s internal structure. This paper reports and discusses a study of the tensile and impact properties of the twill and twill derivative woven fabric reinforced composites. Tensile strength, modulus of elasticity and elongation at break values of the composites were found by tensile tests. In addition impact tests are performed on specimens of woven fabric reinforced composite laminates in order to measure impact strength and characterize damage mechanisms at diverse impact energies. The experimental results reveal that the average float length and weave interlacing coefficient, which are determined by weave pattern, significantly affect the tensile and impact properties of the composites. It is observed that 3/1 twill woven fabric reinforced composite showed the best performance in tensile tests along warp and weft directions. It is also observed that 3/1 twill woven fabric reinforced composite has the lowest impact strengths at the highest deflections; whereas, 3/3 twill woven fabric reinforced composite has the highest impact strengths at the lowest deflections.

Development of composites, reinforced by novel 3D woven orthogonal fabrics with enhanced auxeticity

Auxetic materials are under great attention of researchers due to their excellent mechanical response under certain conditions. Previous works have been carried out in knitted or uni-stretch woven fabrics. In the present study, three-dimensional (3D) woven structures were produced and the effect of float length of ground weave and binding yarn on auxeticity of the fabric was investigated. Eight different 3D orthogonal woven structures/reinforcements were produced on rapier dobby loom by changing the float length in ground weave and binding yarns. Hand layup technique was used for composite fabrication, while green epoxy resin was used as a matrix. For investigating the auxeticity, 3D reinforcement samples were subjected to tensile loading and change in their thickness was measured. The results showed that 3D woven reinforcements with equal and maximum float length of ground weave and binding yarn showed greater auxetic behavior, because both weaves support each other and room for opening of structure increases. As the difference between the float length of ground weave and binding yarns increases, the auxeticity of reinforcement decreases because the ground weave and binding yarn cancel out the effect of each other. Moreover, the impact energy absorption of the developed composites was found to increase with the increase in float length, justifying that the structures are auxetic in nature.

Numerical Study on Optimization of the Float in a Shoreline Wave Energy Converter

Peng, W.; Fan, Y., and Zhang, J., 2018. Numerical study on optimization of the float in a shoreline wave energy converter.. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1296–1300. Coconut Creek (Florida), ISSN 0749-0208.In this paper, the hydrodynamic performance of the float in a shoreline wave energy converter is investigated under regular waves. A numerical model is built based on the Navier-Stokes solver coupled with immersed boundary method, volume of fluid method and the mechanics model of float. Making use of the laboratory measurements, the numerical model has been proved to be a reliable tool in reproducing wave deformations and the dynamics of the float. Then, the model is employed to test the sensibility of float performance to changes in some variables under various waves: spacing between breakwater and float, length of float. From numerical estimations, it can be concluded that the nondimensional motion amplitude of float will decrease with the increasing float length or spacing between breakwater and float. With different loads, the dynamic of float shows different variation trend against the length of float, which implies further investigations may be needed in the future on the effect of power take-off damping load. Last but not the least, the interactions between water waves and two types of floats (rectangle and convex) are simulated and discussed. With the help of snapshots of water particle velocity field and the water surface profile from numerical calculation, the flow pattern and external forces from the fluid field acting on the float can be estimated. Then, the motion amplitudes of floats are computed and compared, and the convex floats are proved to capture more power than the rectangular ones.