Yarn Spacing Research Articles

Assessing compressive mechanical behavior of woven fabric green textile composite using finite element method

AbstractThe research aims to forecast the mechanical performance of a hybrid woven fabric natural composite subjected to compression, utilizing the three‐dimensional finite element method. A detailed finite element model of a plain woven fabric unit cell is created and analyzed for different materials like flax, basalt, and jute, and combinations of these materials (inter‐yarn hybrid basalt‐flax, jute‐flax and basalt‐jute fabrics). It is observed that fabric‘s response to compression is mainly influenced by the transverse longitudinal shear behaviour and the stiffness of the yarn cross‐section. Compression of single‐layer woven fabric involves yarn bending and compaction, resulting in varying fiber volume fractions in different areas due to compaction. The basalt‐jute hybrid plain woven fabric outperformed other plant‐based fiber fabrics with a polypropylene matrix in terms of mechanical performance under compression. Increase in yarn spacing and fabric thickness resulted in higher strain energy and displacement, attributed to changes in fiber volume fraction and crimp angle. Whereas, increasing yarn width led to a stiffer fabric due to increased contact area at the crossover region and higher bending rigidity, resulting in decreased strain energy and displacement. Importantly, this developed model can effectively simulate textile fabrics with diverse weaving patterns, material properties, and loading conditions.

Intra-yarn fibre hybridisation effect on homogenised elastic properties and micro and meso-stress analysis of 2D woven laminae: Two-scale FE model

In this paper, the effect of intra-yarn fibre hybridisation on the homogenised elastic properties and micro- and meso-scale matrix stress fields in 2D woven composite laminae (i.e. plain, 2/2 basket, 2/2 twill and 5-harness satin) is studied with a two-scale homogenisation scheme—employing a representative volume element model at micro-scale and a repeating unit cell model at meso-scale. The study is focused on S-glass/polypropylene/epoxy woven laminae with intra-yarn fibre hybridisation. A modified random sequential expansion algorithm generates microstructure for the micro-mechanical model, and a periodic meso-structure is used to generate the weave architecture for the meso-mechanical model. Both models are verified using analytical models. It is found that intra-yarn fibre hybridisation can significantly alter the homogenised properties as well as the micro- and meso-scale matrix stress fields—depending on the degree of hybridisation (i.e. the combination of S-glass and PP fibre volume fractions). Moreover, the homogenised lamina properties are found to be less sensitive to weave architecture and yarn thickness, but more so to the degree of intra-yarn fibre hybridisation, yarn width and yarn spacing. It is shown that the lamina properties can be tailored, and the micro- and meso-stress fields can be manipulated, by intra-yarn fibre hybridisation and weave architectures.

Bio-Inspired Textiles for Self-Driven Oil-Water Separation-A Simulative Analysis of Fluid Transport.

In addition to water repellency, superhydrophobic leaves of plants such as Salvinia molesta adsorb oil and separate it from water surfaces. This phenomenon has been the inspiration for a new method of oil-water separation, the bionic oil adsorber (BOA). In this paper, we show how the biological effect can be abstracted and transferred to technical textiles, in this case knitted spacer textiles hydrophobized with a layered silicate, oriented at the biology push approach. Subsequently, the transport of the oil within the bio-inspired textile is analyzed by a three-dimensional fluid simulation. This fluid simulation shows that the textile can be optimized by reducing the pile yarn length, increasing the pile yarn spacing, and increasing the pile yarn diameter. For the first time, it has been possible with this simulation to optimize the bio-inspired textile with regard to oil transport with little effort and thus enable the successful implementation of a self-driven and sustainable oil removal method.

The influence of yarn fiber volume fraction, shear angle, and yarn spacing on crack propagation resistance of plain‐woven fabric‐reinforced epoxy composites

AbstractThis study investigated the effect of fabric parameters on crack propagation in plain‐woven e‐glass reinforced epoxy composite plates. Through numerical analyses, the study contributes to understanding the effect of fabric structure on crack propagation and adopting a more precise approach in the design of composite materials. The yarn fiber volume fraction, shear angle, and yarn spacing parameters were selected as variables for the plain‐woven fabric, and material properties were determined for each parameter using the composite homogenization method. A finite element model was created using the Ansys software package, and stress intensity factors (SIFs) and tear stress values were obtained under mode I loading to investigate the effects of fabric structure on crack propagation. The results showed that as the yarn fiber volume fraction ratio increased, the SIF values decreased and the T‐stress values increased. When evaluated according to the shear angle of the yarn, the lowest SIF value was obtained for the 0‐degree shear angle. The same was observed for T‐stress values as well. Additionally, compared to the fabric structure aligned along the X‐axis, a significant decrease occurred in the SIF value due to the perpendicular fiber density increase to the crack propagation direction with symmetric orientation.

Influence of weaving parameters on thermal protection performance of gradient3Dwoven composite

AbstractA dual‐scale ablation model was developed to address the lack of research on the influence of weaving parameters of gradient 3D woven composites on the ablation performance. It consists of a mesoscale heat transfer model and a macroscale ablation model, and they are effectively connected by parametric conduction. By comparing with experimental results, the accuracy of the model was demonstrated. The effect of yarn spacing, recession resistant layer thickness on the thermal protection performance of gradient 3D woven composite was investigated. Furthermore, the effect of each weaving parameter on the integrated performance of ablation resistance, thermal insulation and light‐weight level is evaluated. The results show each weaving parameter has a substantial impact on thermal protection performance, with weft spacing and binder yarn spacing being the most significant influence. Reasonable design of these parameters can facilitate the comprehensive performance of composites. These results serve as a useful reference for refinement design of thermal protection materials.

Studies on the mechanical and durability performance of textile reinforced geopolymer concrete beams

The steel reinforcements used in structural elements are prone to corrosion due to adverse environmental effects. Hence, in recent years, the development of sustainable materials to replace steel reinforcement in concrete has been under research. In this paper, the mechanical and durability characteristics of Geopolymer Concrete (GC) and Epoxy-coated Carbon (EC) yarn against chemical attack were investigated. Tension tests were conducted on EC yarns immersed in acid, sulfate, marine water, and alkaline solution over an exposure period of 1 year. The test results reveal that better durability was achieved for GC specimens compared to cement concrete (CC) specimens in terms of water absorption, acid resistance, sulfate resistance, marine water attack, and chloride diffusion. Compressive strength and flexural strength obtained were 2.6–7.7 times and 1.65–2.36 times higher in GC compared to CC after immersion in various chemical solutions for 6 months. The chemical resistance of EC yarns over an exposure period of 1 year was measured with respect to loss in tensile strength and the reduction in strength was obtained as 29.6% for EC yarns immersed in acid solution, 14.71% in sulfate solution, 7.06% in alkali, and 3.82% in marine water. The study also investigated the flexural behavior of Textile Reinforced Geopolymer Concrete (TRGC) beams (100 × 100 × 500 mm) subjected to monotonic loading. The effectiveness of textile yarn spacing and the number of carbon textile layers to improve the load-bearing behavior of GC beams were evaluated. The reinforcing benefits of TRGC can be confirmed from the load-deflection graph in terms of ultimate load-carrying capacity, post-peak behavior, and failure mode. An energy absorption capacity of 80.06% was found for TRGC-4 L beams compared to TRGC-1 L beam specimens (43.76%), i.e., TRGC specimens with 4 layers showed improved strength and ductility compared to one layer of carbon textile. The failure surface of the TRGC sample was examined using Scanning Electron Microscope (SEM), and fiber-matrix interaction was identified. Hence, despite the high cost of carbon yarn, TRGC can be used for special applications where corrosion protection and durability are controlling parameters.

3D-printing textiles: multi-stage mechanical characterization of additively manufactured biaxial weaves

3D printing allows the fabrication of complex microstructures that would traditionally require specialized machinery. In the fabrication of textiles, 3D printing may enable unique yarn structures, greater manufacturing flexibility and facilitate the development of personalized and tunable devices. In literature, 3D printed textiles have not been subjected to a thorough mechanical characterization. In this paper, a generative model of 3D printed biaxial weaves is developed and a parametric study to effectively map the design parameters to the weaves’ mechanical properties is performed via a two-stage Design-of-Experiments methodology. The samples are printed with material jetting layer by layer in planar direction and destructively tested in tension to obtain the resulting stress–strain behavior. The stress–strain curves are approximated by a bilinear model characterized predominantly by a transition strain and the major modulus after transition. The transition strain is influenced by the load direction and the weave pattern, while the major modulus is impacted by the load direction, the yarn diameter, the weave pattern and the yarn spacing in descending order. Further evaluation of the fracture behavior shows a mitigation of layer-wise delamination. This result indicates that material jetting can enable the production of arbitrary, quasi-continuous textile structures. The characterization results presented here may pave the way towards the design of textiles with spatially varying mechanical properties.

A Thermo-Mechanical Properties Evaluation of Multi-Directional Carbon/Carbon Composite Materials in Aerospace Applications

Carbon/carbon (C/C) composite materials are widely used in aerospace structures operating in high temperature environments based on their high performance thermal and mechanical properties. The C/C composite material has a yarn architecture in which fiber bundles in different directions cross each other, and it is also divided into architecture types, such as 3-D orthogonal, 4-D in-plane, and 4-D diagonal, according to the arrangement of the fiber bundles. The thermo-mechanical performance of the carbon/carbon composite material may vary depending on the yarn architecture, and the material properties are also tailored according to constituent materials, such as fiber and matrix, and manufacturing parameters, such as yarn size, yarn spacing, and fiber volume fraction. In this paper, three types of geometric models are defined for repeating unit cells (RUCs), according to the yarn architecture of the C/C composite material, and the effective stiffness was predicted by applying the iso-strain assumption and stress averaging technique. In addition, the thermo-mechanical characteristics according to the yarn architecture and fiber volume fraction of RUC were compared and evaluated.

Finite element analysis of biaxial tensile mechanical properties and burst properties of woven fabric for layflat hose

AbstractThis paper explores the effects of woven fabric structures on the biaxial tensile mechanical properties and burst properties of woven fabric for layflat hose. A repeat unit cell finite element modeling for woven fabrics for layfalt hose is adopted. To investigate the effects of fabric structure, two parameters are studied: warp yarn spacing and weft yarn linear density. The mechanical response outcomes such as stress distribution, intensity, breaking elongation, and burst properties such as burst pressure, burst direction, are defined and the effects of structure parameters studied on these outcomes are studied. The effects of the warp yarn spacing and the weft yarn linear density on the biaxial tensile mechanical properties and the burst properties of woven fabric for layflat hose are determined. Moreover, the results suggest finite element method exhibits high accuracy in predicting the burst pressure of layflat hose.

Experimental study and finite element analysis of mechanical behavior of plain weave fabric during deformation through a cross-section observation

In this study, the mechanical behaviors of a plain weave polyester fabric were investigated, along with the consequent changes in the internal structure under uniaxial tensile loading. Optical microscopy was used to establish relationships between the changes in the internal structure of the woven fabric during loading at several strain levels (from initial to pre-breakage stages). Using computer-aided design tools, a 3D geometric model of a woven pattern was built based on a lenticular plain weave model, and a corresponding engineering analysis was performed using the finite element method. A comparison of the model and experimental data showed good results for predicting the shape of the stress-strain curve for both directions of tensile testing, as well as for determining the geometric parameters of the woven fabric, such as the yarn spacing, migrations of individual filaments within the yarn cross-section, and changes in the yarn shapes in the fabric structure.

Modelling of Auxetic Woven Structures for Composite Reinforcement

The current research is focused on the design and development of auxetic woven structures. Finite element analysis based on computational modeling and prediction of axial strain as well as Poisson’s ratio was carried out. Further, an analytical model was used to calculate the same parameters by a foldable zig-zag geometry. In the analytical model, Poisson’s ratio is based on the crimp percentage, bending modulus, yarn spacing, and coefficient of friction. In this yarn, properties and fabric parameters were also considered. Experimental samples were evaluated for the actual performance of the defined auxetic material. Auxetic fabric was developed with foldable strips created in a zig-zag way in the vertical (warp) direction. It is based on the principle that when the fabric is stretched, the unfolding of the folds takes place, leading to an increase in transverse dimensions. Both the analytical and computational models gave close predictions to the experimental results. The fabric with foldable strips created in a zig-zag way in the vertical (warp) direction produced negative Poisson’s ratio (NPR), up to 8.7% of axial strain, and a maximum Poisson’s ratio of −0.41 produced at an axial strain of around 1%. The error percentage in the analytical model was 37.14% for the experimental results. The computational results also predict the Poisson’s ratio with an error percentage of 22.26%. Such predictions are useful for estimating the performance of auxetic woven structures in composite reinforcement. The auxetic structure exhibits remarkable stress-strain behavior in the longitudinal as well as transverse directions. This performance is useful for energy absorption in composite reinforcement.

Prediction of Bending, Buckling and Free-Vibration Behaviors of 3D Textile Composite Plates by Using VAM-Based Equivalent Model.

To solve the microstructure-related complexity of a three-dimensional textile composite, a novel equivalent model was established based on the variational asymptotic method. The constitutive modeling of 3D unit cell within the plate was performed to obtain the equivalent stiffness, which can be inputted into the 2D equivalent model (2D-EPM) to perform the bending, free-vibration and buckling analysis. The correctness and effectiveness of the 2D-EPM was validated by comparing with the results from 3D FE model (3D-FEM) under various conditions. The influence of yarn width and spacing on the equivalent stiffness was also discussed. Finally, the effective performances of 3D textile composite plate and 2D plain-woven laminate with the same thickness and yarn content were compared. The results revealed that the bending, buckling and free-vibration behaviors predicted by 2D-EPM were in good agreement with 3D-FEM, and the local field distributions within the unit cell of 3D textile composite plate were well captured. Compared with the 2D plain-woven laminate, the displacement of 3D textile composite plate was relatively larger under the uniform load, which may due to the fact that the through-the-thickness constrains of the former are only dependent on the binder yarns, while the warp yarns and weft yarns of the latter are intertwined closely.

Digital holographic interferometry for the measurement of temperature distribution around textile conductive yarn embedded in heating garments

Due to the development of wearable smart/electronic integrated textiles, the heating compression bandages, conductive fabrics, and electrically heated garments have been extensively used in many fields. Heating garments could be widely applied in the field of body warming and physical therapy. To impart heating therapy through garments, we need to select conductive yarn to be incorporated into the fabric. In addition to this, voltage supply, resistance, temperature distribution, temperature gradient, heating area, and spacing between the two consecutive conductive yarns are some major factors that have to be optimized for heating garments. Therefore, identifying the proper conductive yarn and approximate spacing between them is important in the electrically heated garments. The measurement of temperature and temperature profile around heated textile conductive yarn is demonstrated using digital holographic interferometry (DHI). DHI has been widely used to measure temperature and temperature profile of gaseous flames and heat conduction studies, etc., as it is more accurate, precise, and provides better spatial resolution. DHI is chosen to measure temperature distribution around copper and stainless-steel yarns used in textiles. DHI is a noncontact, noninvasive, full-field, and almost real-time interferometric technique. We have chosen copper and stainless-steel yarn to study the temperature profile and uniform heating to approximate spacing between two yarns.

Finite element modeling and experimental testing of woven fabric based on a new instrument: simulative analysis of the compression property

A multi-scale finite element (FE) model including a macro-scale instrument and fabric composed of meso-scale yarns is established so as to deeply understand the compression mechanism of woven fabrics based on the Quick-Intelligent Handle Evaluation System. The compression stress and strain of the fabric and its internal warp and weft yarns are revealed in the FE analysis, and a parameter study involving the friction coefficient, Young’s modulus, yarn spacing and crimp height is addressed to understand the fabric deformation. The results show that fabric parameters have a significant impact on the compression behavior, indicating that the compression performance of the fabric is limited by the nonlinear mechanical and geometric properties of the yarn. Moreover, by comparing the FE modeling and experimental testing, the FE model proved to be sufficient to simulate the compression response of the fabric, so as to predict the compression property based on actual or preset material properties.

Static, buckling, and free-vibration analysis of plain-woven composite plate with finite thickness using VAM-based equivalent model

In this article, to remove the periodicity requirement in the thickness direction of plain-woven composite plates with finite thickness, a novel equivalent plate model (2D-EPM) based on the variational asymptotic method was established to study the static and dynamic behavior of plain-woven composite plates under different boundary and load conditions. The effective plate properties were obtained by the constitutive modeling of the unit cell, and inputted into the 2D-EPM to perform static and dynamic analysis. The accuracy and computational efficiency of the equivalent model were verified by comparing with the static and dynamic results of a three-dimensional finite element model (3D-FEM). The influence of the geometric parameters (yarn width, height, and spacing) and yarn laying angle on the equivalent stiffness and vibration characteristics of the plate were also examined. The results of the proposed model more closely with the experimental data than those of the 3D-FEM. This was possibly because the periodic boundary conditions in the thickness direction overestimated the stiffness of the plate. In addition, the local field distributions within the unit cell were well captured. The non-interlaced parts of the yarns were most likely to fail or become damaged. Overall, this research work has shown the ability of the 2D-EPM to predict the static displacement, global buckling and free vibration of plain-woven composite plates with finite thickness.

Parametric study on mechanical properties of basalt leno textile applied as concrete reinforcement

In this study, the mechanical properties of the basalt leno textile applied as concrete reinforcement were experimentally investigated considering different parameters including the impregnation materials, geometrical characteristics (the number of yarns, yarn structure, and yarn spacing), and loading rate. The tensile strength, elastic modulus, and failure mode were examined. Furthermore, the force mechanism of impregnated leno textile under tensile load was analyzed. The experimental results showed that the textile with a stiff impregnation material exhibited a higher strength and modulus than that with a flexible material. The leno textile with the straight yarn had a better performance than those with the twisted yarns. Besides, the constraint of the weft yarns is obvious to the textile in the warp direction, while the warp yarn makes no contributions to the bearing capacity of textile in the weft direction. The weft yarn spacing had a significant impact on mechanical properties of the textile in the warp direction. Furthermore, the loading rate of approximately 1.2 mm/min was suggested to determine the maximum force of the impregnated basalt leno textile. A tensile strength model was proposed considering the effects of the impregnation material, consistent deformation, torsion damage, and twisted angle.

Yarn Crimp Ratio in woven Fabrics Theory and Practice.(Dept.T)

Because of the importance of accuracy in measuring and estimating yarn crimp ratio in woven fabrics, non classical methods were searched for. In this paper mathematical formulate were derived to express yarn crimp ratio in terms of weave structure, yarn spacing, and yarn diameter. It is discriminated between floated weaves and extended weaves. In floated weaves yarn spacing is constant and equal to yarn spacing at the point of intersection. In extended weaves, yarns are separated only at points of intersection. To increase accuracy and safe effort and time consumed in measuring yarn crimp ratio is determined by weighing crimped yarns instead of decrimping them.

Influence of technical parameters on the structure of annular axis braided preforms

Abstract A modified vertical braiding machine and closed annular axis mandrels with a special-shaped cross section were used to braid annular axis preforms under four different technical parameters. After measuring the braiding angles and yarn spacing of the braided preform in different areas of the mandrels, it was found that the braiding angle increased by 20.9% and the yarn spacing decreased by 19.8% when the speed of the yarn carrier was doubled. The braiding angle decreased by 31.1% and the yarn spacing increased by 28.6% when the rotation speed of the mandrels was doubled. The results show that the rotation speed of the mandrel has a slightly greater influence on the braiding angle and the yarn spacing. By using the modified braiding machine to braid the annular axis preforms, multi-layer continuous braided preforms can be achieved on compact equipment. And the structure of the annular axis braided preforms can be changed by changing the technical parameters.

Modeling method of irregular cross section annular axis braided preform based on finite element simulation

The irregular cross section annular axis braided preform is modeled by using finite element simulation instead of geometric modeling. The braiding process is simulated by using a finite element software to obtain the yarn path. And the braided preform is modeled by using nine virtual fibers to form irregular cross section shape of yarn. Meanwhile, a modified vertical braiding machine is used to braid the actual preform, to compare with results from the simulation model. The results show that the simulation model is consistent with the actual braided preform, braiding angle is about 36°, and yarn spacing is about 6 mm. The finite element method can predict the yarn path more accurately without the need of complex analysis and derivation, especially when the irregular mandrel is used for braiding. In addition, the cross-section shape of yarn composed of virtual fibers can be used to achieve a more realistic simulation result. FEM is an efficient simulation method, and can also provide an effective basis in studies of the actual cross-sectional shape of yarn and the properties of its composite reinforcements.

A smartphone microscopic method for rapid screening of cloth facemask fabrics during pandemics.

BackgroundIn pandemics, because of increased demand and subsequent shortage of commercial facemasks, people need to use cloth facemasks, although such masks are reported to provide reduced protection. These masks can be prepared in local levels from different fabric materials. In developing countries, cloth masks are preferable because of low cost and added advantages of reusability. The filtering performance of a cloth facemask depends on the facial fit and on the material properties of fabrics such as porosity, yarn spacing or packing, and pore size. In resource limited settings, an affordable and easy to implement method that can assess the surface properties of cloth facemask fabrics would be important.MethodsIn this work, we developed a smartphone microscopic method for rapid screening of fabric quality. We measured the field of view of the microscope and as a proof of concept, we implemented the method to examine surfaces of sixteen locally available cloth mask fabrics.ResultsOut of the 16 masks examined, we found very diverse yarn packing and pore morphology (pore size and shape) in the fabrics. The pore size ranged from ~80 to 720 μm; much larger than respiratory droplet and bio-aerosol. This observation partly explains why such cloth facemasks provide reduced protection to the user during pandemics. The performance of a cloth facemask partly depends on the material properties of fabric such as yarn packing, pore size, porosity. Therefore, the surface properties of fabrics obtained from the smartphone method can be used to get preliminary idea on the facemask quality. We believe that the method can be an affordable and rapid method for selection of better fabrics for cloth facemask during pandemics.