Wale Direction Research Articles

Sensitivity of the properties of the graduated compression stocking and soft tissues on the lower limb-stocking interfacial pressure using the orthogonal simulation test

Graduated compression stocking (GCS) plays an important role in the treatment of venous disease in the lower limb. However, the effect of the variation in the mechanical properties of the GCS and the soft tissues on the treatment of the venous disease in the lower limb remains unclear. The aim of the present study was to investigate the influence of the material properties of the GCS and soft tissues on the lower limb-stocking interfacial pressure using the orthogonal simulation test.A three-dimensional finite element (FE) model of the lower limb was established using the MRI dataset of a 40-year-old volunteer. The bones, the skin, the veins and the skeletal muscles were reconstructed in the FE model. The FE model of the GCS was generated using the information provided by the manufacturer. Then the parameter sensitivity analysis was performed using a two-step orthogonal simulation test. The first-step orthogonal test showed that the variation in the Young's modulus in the wale direction of the GCS induced a change of 0.37 mmHg in the lower limb-stocking interfacial pressure in the ankle section. The second-step orthogonal test showed that the variations in the Young's modulus in the wale direction of the GCS in the knee section induced the changes of 0.05 mmHg, 0.15 mmHg and 0.60 mmHg in the interfacial pressure in the ankle, the calf and the knee, respectively.In conclusion, the Young's modulus in the wale direction of the GCS and the Poisson's ratio of the GCS are the parameters significantly influencing the lower limb-stocking interfacial pressure. The interfacial pressure in the ankle is not sensitive to the Young's modulus in the wale direction of the GCS in the knee section. However, the interfacial pressures in the calf and knee are sensitive to the Young's modulus in the wale direction of the GCS in the knee section. These data provide important information for the design of GCS.

Role of Fabric Structure on the Second Tensile Elastic Modulus of Net Warp-Knitted Fabrics

This work aimed to study the second elastic modulus of net warp-knitted fabrics (NWKF) experimentally and theoretically. Net knitted fabrics were selected to study owing to their wide practical application and also lack of enough attention. Knitted fabrics have two regions of tensile elastic behavior which the initial one refers to the displacement of the elements of fabrics before jamming of the yarns. As soon as jamming takes place completely, the constituent yarns in the structure of fabrics go through tension. In other words, yarns in their spatial configuration resist the applied loads. This resistance is important in the ultimate strength of the fabrics and also in the composite materials reinforced with knitted fabrics. NWKFs were produced using a Raschel knitting machine. Uniaxial tensile tests were conducted in the course and wale directions. The second elastic modulus was measured using a statistical approach. In the theoretical part, a mechanical model based on the configuration of elements of fabrics after jamming status and using Energy method and Castigliano’s Theorem was proposed. The proposed model was used to calculate the second elastic modulus. To validate the model, the authors’ experimental data along with the collected data from the other researches were compared with the calculated values, and the results showed that the proposed model can predict the modulus reasonably. The results showed that the fabric structure including wale spacing, course spacing, and the number of lapping movements creating the holes affects the second elastic modulus despite the accepted concept, but the mechanical properties of yarns only influence the second elastic modulus of the fabrics.

Deformation Behaviors of Auxetic Warp Knitted Fabrics Based on Reentrant Geometry

A series of auxetic warp knitted fabrics based on reentrant geometry were developed in our previous study and their Poisson's ratio in the wale direction and course direction can be as low as −0.5 and −0.15, respectively. However, the quantitative relationships between structural parameters and auxetic effect, which can offer a guide to the design and manufacture process, are still unknown. Herein, the aim is to find such relationships. Based on the geometrical analysis, two semiempirical equations between Poisson's ratio and tensile strain are established when stretched in the wale direction and course direction, respectively. The study shows that the established semiempirical equations fit well with experimental results and can be used to predict auxetic effect of fabrics made with the same type of materials and similar structures. With the relationships proposed, warp knitted fabrics can be designed and manufactured directly without trials to obtain the desired auxetic effect, which can largely save the time and cost of production.

ОСОБЛИВОСТІ 3D МОДЕЛЮВАННЯ СТРУКТУРИ ТРИКОТАЖУ У МАКСИМАЛЬНО РОЗТЯГНУТОМУ СТАНІ

The study aims at the development mathematical basics for software for automated construction of three-dimensional geometric models of knitwear in the most stretched state due to uniaxial stretching along the wale or course direction. Methodology. The research methods of theoretical analysis, spline theory, methods of three-dimensional geometric modeling and parameterization, computer graphics tools, programming tools were used. Findings. During the research, it was assumed that in the maximally stretched state, the tangent to the centerline of the loop at the interlacing point is located at an angle of 45º to the vertical line oriented along the wale direction. Mathematical expressions are proposed for determining the co-ordinates of the characteristic points of the loop in three-dimensional space. An algorithm and its software implementation have been developed as a separate module of the Structure 3D program, designed to create models of knitwear in a stretched state. To verify the algorithm, samples of weft knitted fabrics were made with a 8th gauge flat-bed knitting machine of para-aramid and high-molecular polyethylene threads of linear density 58.8x2 tex and 44x3 tex, respectively. The parameters of the loop structure of the samples in dry-relaxed state and under maximum uniaxial stretching along the wale and the course directions. Tensile testing of specimens was performed on the machine KaoTieh KT-7010AZ. The maximum stress state of the samples was recorded using a Micro Capture Pro microscope to further determine the changes of the loop structure parameters under the action of tensile deformation. The obtained values of the the loop structure parameters of the samples were used as input data for the construction of three-dimensional models. The deviation of the value of the length of the spline representing the centerline of the thread in the loop model from the length of the thread in the loop obtained during the analysis of the samples does not exceed 5%. Scientific novelty. An algorithm for the automated construction of 3D models of knitted structures, undergoing maximum deformations coursed by uniaxial tension along the wales or course directions, has been developed. Practical value. A separate module of the 3D Structure program has been created for the automated construction of a knitted loop undergoing maximal stretching under has been developed.

Multifunctional, Wash Durable and Re‐usable Conductive Textiles for Wearable Electro/Physiological Monitoring

AbstractIntelligent functionalities coupled textiles have received massive attention in the wearable health monitoring devices owing to their lightweight, ease of wearability, intrinsic flexibility, and comfortable texture. This article describes multifunctional, highly conductive, wash durable, and re‐usable reduced graphene oxide (RGO) coated polyester knitted textiles by a simple, cost effective, and scalable dip‐dry‐reduce approach and a novel approach to integrate as fabricated RGO coated polyester knitted textile (RGT) with the wearable elastic band for electro/physiological signal monitoring. The RGT exhibits high conductivity of 0.23 KΩ sq−1 and excellent wash durability. The RGT textile as a strain sensor shows a high sensitivity of 4.1 and 8 at a strain of 5% along the course and wale direction, respectively, stability and durability for more than 1500 cycles and also shows its excellent performance in human motion detection. Obtained electrophysiological signals from the RGT electrodes integrated wearable elastic band are comparable to those of the conventional Ag/AgCl electrodes. Owing to its comfortable texture, ease of wearability, stability, and wash durability, the RGT has potential applications in the future wearable electronic devices.

Effects of Processing Variables on the Mechanical Behavior of Thermoplastic Polypropylene/Glass Composite Reinforced with Weft-knitted Fabric with Various Layups

In this study, the tensile and bending properties of thermoplastic composites reinforced with weft-knitted fabrics have been investigated in various production conditions. The hot-pressing method was performed to produce the composites samples from Co-mingled polypropylene/glass weft-knitted fabric, which manufactured using the side-by-side polypropylene and glass yarns. The effects of heating time, cooling rate, and processing temperature as the processing variables parameters and the composites variables such as weight fraction of fiber and layup on mechanical behaviors were investigated. One-way ANOVA test was performed to analyze some data statistically. The rate of cooling has a significant effect on the composites’ mechanical behaviors. With increasing the cooling rate, the maximum tensile load, stress at samples’ failure, and maximum bending load increased by about more than 30 %, 105 %, and 233 %, respectively. The maximum tensile load of samples in the wale direction was more than that in the course direction. The maximum tensile load of samples with a weight fraction of 44 % was about 93 % higher than that with the 22 wt.%. The optimum values of processing variables to achieve the best mechanical performance of samples were the temperature of 200 °C, 6 minutes of heating time, and the faster cooling rate.

Effect of yarn count and loop length on needle penetration force and needle cut index in single jersey fabrics

The present study embodies the sewability of single jersey knitted fabric based on needle penetration force and needle cut index. Four types of single jersey fabric, viz. 100% cotton, polyester/cotton, polyester/lycra, and cotton/lycra, are taken for investigation. The materials are prepared on circular knitting machine by varying the yarn count and loop length. The influence of various parameters, viz. type of fibre, yarn count and loop length, on needle penetration force and needle cut index have been analyzed. In addition, the influence of seam direction on the needle cut index is also studied. A 3 _ level factorial design is employed to analyse the influence of there parameters. The statistical analysis shows that yarn count and loop length has a significant effect on needle penetration force and needle cut index. It has been observed that in all single jersey knitted fabrics, cotton-lycra and polyester-lycra half plated fabrics have higher value of needle penetration force than cotton and polyester/cotton. The test results also show that for both coarser yarn and finer yarn count, longer loop length gives a lower value of needle penetration force. The needle cut index decreases with increase in the yarn count and loop length. Also it is observed that, the needle cut index is more in wale direction as compared to that in course direction. It is also concluded that cotton fabric samples are more susceptible to needle damages as compared to their counterparts.

Auxetic behavior of warp knitted fabric under repeating tension

In our previous study, a novel class of auxetic warp knitted fabrics were developed and their auxetic behaviors were studied under a single tensile test. However, during daily use, the fabrics are usually subjected to repeating tension rather than single tension. Therefore, the durability of the fabrics’ auxetic performance is of great importance. So far, the auxetic behavior of fabrics under repeating tension has not systematically been investigated. In this paper, we report a study on the auxetic behavior of warp knitted fabrics under repeating tension. All the fabric samples were subjected to a repeating tensile test within a tensile strain of 25% until 100 tensile cycles. The results show that the fabrics can keep their auxetic effect in both course and wale testing directions after 100 tensile cycles, and the auxetic effect in the wale direction is retained longer under higher tensile strains than that under lower tensile strains with the increase of tensile cycles. The results also indicate that auxetic stability in the course direction is much better than that in the wale direction. We hope that this study can offer useful information to improve the auxetic stability of auxetic fabrics for practical use.

Influence of inlaid material, yarn and knitted structure on the net buoyant force and mechanical properties of inlaid knitted fabric for buoyant swimwear

Buoyant swimwear is becoming more common in recreational swimming use, so the performance of buoyant fabric is important when designing functional swimwear. In this study, potential buoyant inlaid knitted fabrics for buoyant swimwear are investigated. Three types of knitted structures, half milano, full milano and 1 × 1 rib, are selected and various kinds of tubes and foam rods in different diameters are prepared for inlaying during the knitting process by using a 7 G hand-knitting machine. The mean differences among the levels of three independent variables, (1) inlaid material, (2) yarn and (3) knitted structure, on three dependent variables (net buoyant force, compression and tensile properties) are analyzed by using a multivariate analysis of variance. The result shows that the net buoyant force and mechanical properties of the fabric are significantly different due to the inlaid material and knitted structure, but not the yarn. The net buoyant force increases with fabric thickness and the outer diameter of the inlaid material. The inlaid fabrics are less compressible than the control fabric and show better recoverability with an increase in the diameter of the inlaid material. For the tensile properties, the inlaid material reinforces the fabric in both the wale and course directions, in which the stiffness in the course direction is significantly increased. The inlaid fabric is stronger and resistant to breakage in the course direction when the diameter of the inlaid material is increased. The findings of this study contribute to developments in the textile and sportswear industry.

A spacer fabric-based three-dimensional patterning method with two-colored jacquard systems

To generate three-dimensional (3D) patterned spacer structures with non-continuous jacquard appearance in two colors, such as the yarn-cutting style, this paper attempts to propose a novel 3D patterning method based on the single jacquard technique. Two sets of jacquard threads are spaced apart and threaded in split bars as two patterning systems with separate colors. Then, for independent patterns, each single loop should be able to be selectively observable on patterned layers and hidden in the spacer layer. Cases of continuous jacquard loops and zero-loop ones in both course and wale directions are to be solved based on the characteristic of one-wale left offset. Besides, by differing the moment when offset occurs, jacquard threads are transferred from stitching on both layers to a single or zero layer, thus enabling one to hide jacquard loops in non-patterning areas. This approach theoretically brings new patterning possibilities to 3D spacer structures with the single jacquard technique.

Three-dimensional stretchable knitted design with transformative properties

This paper proposes the use of digital knitting to fabricate three-dimensional stretchable fabric with transformative properties. The research focus is on the application of the curling effect and the resultant stitch structures. Rib, purl, and links structures, which have alternating face and back loops in the structural knit cell and produced the curling effect, are investigated. Thirty-six samples based on the three structures along with 12 different stitch combinations are produced through the digital knitting process. The properties of the samples, including the dimensional changes, surface texture, weight and thickness, and tensile properties, are subsequently evaluated and compared by using both quantitative and qualitative assessment methods. The results show that the developed knitted fabrics that use the curling effect through alternating face and back loops are significantly three-dimensional in surface texture and have considerable stretchability. These effects in general increase with the growth of stitch number in a structural knit cell. However, only the links structures show considerable extensibility along both course and wale directions, while the rib and purl structures have enhanced stretchability in only the course and wale directions, respectively. Therefore, this design-led textile study provides a simple but effective means for producing new materials that offer both function and aesthetics for fashion with transformable designs. The work here also provides a technical-based integrated approach for innovative textile and fashion developments.

Performance evaluation of conductive tracks in fabricating e-textiles by lock-stitch embroidery

Lock-stitch embroidery has been the centre of much interest as a versatile and precise method of producing conductive tracks in the fabrication of wearable electronic devices. However, improper fabrication parameter settings could result in the nonconformity of the conductive tracks and damage the conductive coating of the conductive yarns. In this study, we evaluate the appearance quality, dimensional stability and electrical resistance of conductive tracks by taking into account the embroidering speed (ES), stitch length (SL), needle thread pre-tension (NTP) and embroidering direction (ED). The conductive tracks are embroidered onto knitted fabric in different directions with silver-coated polyamide yarn as the needle thread. The results show that stitching the conductive tracks in the wale direction results in a more uniform stitch lines in comparison to the other directions. To resolve the problem of floated stitches, it is recommended that an SL of 4 mm and a higher NTP are used. The percentage of shrinkage in the wale direction is lower than in the course direction. The electrical resistance of the conductive tracks increases with a higher ES and shorter SL. It is also found that a thicker yarn is more sensitive to the NTP and some of the silver coating is rubbed off with an NTP of 50 gf. We also carry out an overlay plot analysis, through which we predict and validate the optimal embroidery parameters that balance appearance quality and electrical resistance. The technique parameters in this study can be used to embroider conductive tracks for smart clothing.

Experimental and numerical study on stiffness and damage of glass/epoxy biaxial weft-knitted reinforced composites

This paper deals with investigating the tensile characteristics of biaxial weft-knitted reinforced composites in terms of stiffness, strength and failure mechanism. The biaxial weft-knitted fabric was produced on an electronic flat knitting machine by E-glass yarns and then was impregnated with epoxy resin. Using an accurate geometrical model, the composite unit cell was designed in Abaqus software’s environment. Tensile tests were simulated in different directions on the created unit cell and the stiffness was calculated. By applying the proper failure theories, the composite strength was predicted and then critical regions of the unit cell were determined. In the next step, a micromechanical approach was also applied to estimate the same tensile features. Failure theories were also applied to predict the strength and most susceptible areas for failure phenomenon in the composite unit cell. The tensile properties of the produced composites were measured and compared with outputs of the finite element and micromechanical approaches. The results showed that the meso-scale finite element analysis approach can well predict the composite strength. In contrast, the meso-scale analytical equation model was not able to predict it acceptably because this model ignores the strain concentration. Both meso-scale finite element analysis and meso-scale analytical equation approaches predicted the similar locations for the composite failure in wale and course directions.

Stretchable Coplanar Self-Charging Power Textile with Resist-Dyeing Triboelectric Nanogenerators and Microsupercapacitors.

The integration between energy-harvesting and energy-storage devices into a self-charging power unit is an effective approach to address the energy bottleneck of wearable/portable/wireless smart devices. Herein, we demonstrate a stretchable coplanar self-charging power textile (SCPT) with triboelectric nanogenerators (TENGs) and microsupercapacitors (MSCs) both fabricated through a resist-dyeing-analogous method. The textile electrodes maintain excellent conductivity at 600% and 200% tensile strain along course and wale directions, respectively. The fabric in-plane MSC with reduced graphene oxides as active materials reaches a maximum areal capacitance of 50.6 mF cm-2 at 0.01 V s-1 and shows no significant degradation at 50% of tensile strain. The stretchable fabric-based TENG can output 49 V open-circuit voltage and 94.5 mW m-2 peak power density. Finally, a stretchable coplanar SCPT with one-batch resist-dyeing fabrication is demonstrated for powering small electronics intermittently without extra recharging. Our approach is also compatible with conventional textile processing and suggests great potential in electronic textiles and wearable electronics.

Investigation of the technical and physical properties of metal composite 1×1 rib knitted fabrics

In this study, it was aimed to determine electromagnetic shielding effectiveness, antibacterial activity, surface resistivityand bending rigidity properties of 1×1 rib knitted fabrics. For this purpose, copper (Cu), stainless steel (SS) and silver(Ag) wires were commingled with two nylon filaments to produce metal composite yarns. 1×1 rib fabrics were producedby these composite yarns. Electromagnetic shielding effectiveness (EMSE), antibacterial activity, surface resistivity andbending rigidity of the composite knits were measured. Electromagnetic shielding measurements of samples wereconducted between 1.0–5.0 GHz frequency. Antibacterial activity test was applied according to AATCC 100 standardagainst K. pneumoniae and S. aureus bacteria. Results showed that knitted fabrics generally have lower SE values than10 dB at wale direction. The double layer samples provide higher EMSE than single layer samples for all metal types.Maximum EMSE value was obtained as 57.12 dB. The use of metal wire significantly reduced surface resistivity ofknitted fabrics. Copper composite knitted fabrics showed 99 % antibacterial activity against both bacterial species. Whencompared to the control sample, the use of metal wire significantly increased the rigidity of the samples.

Comparative study on the thermal shrinkage behaviour of polyester yarn and its plain knitted fabrics

Heat-based processes on thermoplastic fibre materials cause the materials to shrink. Knitted fabrics may change their dimensions due to thermal shrinkage of the constituent yarns in the fabric and the change in loop shape. The extent to which the thermal shrinkage of polyester yarn affects the thermal shrinkage of the knitted fabric and the effect of heat on fabric parameters are the focus of this article. The thermal shrinkage behaviour of polyester yarn and the plain knitted fabric made of the same yarns were analysed after subjecting them to dyeing, heat-setting and subsequent heat curing processes. The thermal effects on yarns, the yarns in the fabrics and on the wale and course densities were investigated. Thermal shrinkage in the course direction is highly related to the width-wise extension applied during heat setting and the thermal shrinkage in the wale direction is highly correlated to the shrinkage behaviour of the yarns in hank form.

Resistive network model of the weft-knitted strain sensor with the plating stitch-Part 2: Resistive network model during the elongation along course direction

Based on the static resistive network investigated in Part 1 of this series, the resistive network model of the weft-knitted strain sensor with the plating stitch is explored under the elongation along course direction, and it changes with the conductive loops’ configuration and contact situation. Since the voltage is applied at both ends of the course, under a specific stretching state, the resistive network model can be reduced to a resistance network connected in series in the course direction and parallel in the wale direction, which determines that the sensor’s equivalent resistance increases with the growth of the conductive wale number, and decreases with the raise of the conductive course number. Through experiment and model calculation, it can be obtained that in the initial stage of stretching, the contact resistances’ changes are the main factors affecting the mechanical–electrical performance of the sensor. Then as the sensor is further stretched, the length-related resistances of the conductive yarn segments begin to affect the sensor’s properties due to yarns’ slippage and self-elongation. In addition, the weft jacquard plating technology makes the strain of the sensor reach about 32% before yarns’ slippage and self-elongation, which expands the sensor’s measurable strain range, and avoids irreversible deformation of the sensor after repeated use in this range. It can be verified that the sensor’s gauge factor can be improved by reducing the conductive course number and increasing the conductive wale number. It should be noted that the ground yarn will reduce the gauge factor of the sensor during stretching, so it is necessary to choose a ground yarn with a smaller fineness than the conductive face yarn and good elasticity in practical.

Comparing double jersey knitted fabrics made of Tencel and modal yarns, spun by different spinning methods

A double-bed circular knitting machine with a gauge of E17 and a needle bar diameter of 200 mm (8 in) was used to make three groups of plain weft knitted Tencel fabrics and three groups of modal knitted fabrics. The yarns were spun using three spinning methods: ring, rotor, and air-jet system. Their count was 20 tex. All the knitted fabric samples were manufactured under the same conditions. One-half of each knitted fabric sample remained unfinished, while the other half was finished. Structure parameters of all finished and unfinished knitted fabrics were analyzed, and the most significant parameters were compared. Tensile properties of the knitted fabrics in wale and course directions were measured. The difference in the elasticity of the knitted fabric was analyzed in particular, and the portions of knitted fabric stretch are given. The basic conclusion is that using equal yarn fineness, but different raw material composition and structure, the produced knitted fabrics had substantially different fabric masses per unit area. The raw material composition and construction of the yarn, that is, the yarn manufacturing process and the spinning process produce yarns of different structures and properties that are manifested in the structure and properties of the knitted fabric. Thus, the finishing process must be specific for each raw material composition and yarn structure.

Effect of profile and reinforcing the surface layers on bending behavior of 3D multi-cell spacer weft-knitted composites

3D multi-cell spacer-knitted reinforced composites are composed of knitted layers which are joined together by multiple fabric connecting layers. Despite numerous capabilities, they demonstrate inferior bending performance due to their highly looped construction as well as low fiber volume fraction. Bending characteristics could be enhanced by inserting the warp and weft yarns through the fabric’s surface layers in wale and course directions. This research aims to investigate the role of reinforcing warp and weft yarns and structure profile on bending behavior of the composites produced from 3D multi-cell spacer-knitted fabrics. 3D multi-cell spacer-knitted fabrics were produced with rectangular cross-sectional shape in single- and double-decker profiles on a computerized flat-knitting machine. The surface layers of both 3D multi-cell spacer-knitted fabrics were reinforced by glass straight yarns in course and wale directions. The produced fabrics were used to fabricate thermoset 3D composites using epoxy resin via vacuum-assisted resin-transfer method. Composite samples were subjected to three-point bending load. Statistical analysis revealed that the composite profile and presence of the reinforcing warp and weft yarns affect significantly the flexural properties of 3D-knitted composites. Accordingly, introduction of the reinforcing straight yarns causes an increase in maximum bending force by 75 and 62.5% for single and double-decker structures, respectively. In order to understand how the tensile and compressive stresses are distributed on the 3D-knitted composite structure as well as to predict their mechanical behavior, a macro-mechanical model was created in the ABAQUS software.

Investigation of the flexural behavior of self-consolidating mortars reinforced with net warp-knitted spacer fabrics

This work intended to study the flexural properties of self-consolidating mortars (SCM) reinforced with net warp-knitted spacer fabrics (WKSF). The effects of fabric structural parameters namely mesh size, the position of the meshes in the outer layers with respect to each other, and the fabric thickness on the properties of the composite materials were investigated. The uniaxial tensile tests were conducted to evaluate the influence of the fabric variables on the fabric elastic modulus. The cement-based specimens were made by casting in three forms: 1) plain SCM as the control specimen, 2) SCM reinforced with two 2D fabrics, and 3) SCM reinforced with the 3D spacer fabrics. Three-point bending tests were carried out. The mode of fracture was investigated through microscopic analysis using a Scanning Electron Microscope. Furthermore, the condition of the prepared SCM from porosity viewpoint was evaluated using the water absorption test with and without fabric inclusion. The tensile tests indicated that the modulus of fabrics in the wale direction is more than the modulus in the course direction. Fabrics with larger mesh and also thicker fabrics have lower modulus than the fabrics with smaller meshes and lower thickness. The fabric modulus was independent of the position of the meshes. The experimental results of the flexural tests showed the significantly better performance of the spacer fabrics owing to the presence of spacer yarns and their contribution towards the thickness reinforcement. Stiffness, strength, and strain capacity of the composite materials were improved using the spacer fabrics. Furthermore, SCM reinforced with 2D fabrics had better mechanical properties than the plain SCM. The flexural bending tests indicated that the composite materials which reinforced with larger mesh have better mechanical performance owing to the easier penetration of the matrix through the fabrics and making reasonable interfaces. There is an increase in the volume fraction of the reinforcement using thicker fabrics with longer spacer yarns which were resulted in higher modulus and strain capacity. The SEM images indicated that matrix cracking and then the breakage of the outer layers of the spacer fabrics are the major causes of the composite failure.