Weave Style Research Articles

Effects of the addition of carbon nanofibers on mechanical properties of woven glass/epoxy composites with different weave patterns

The harness and the weave style are among the most important properties of woven fabrics. Most of the previous studies utilized woven fabrics with specific harnesses to explore the effects of nanoparticles on woven composites. Therefore, an experimental study was conducted to examine the impact of three weave patterns, namely plain, 5-harness satin, and 8-harness satin, on the mechanical properties of woven composites under tensile and shear loads. Subsequently, the effect of applying carbon nanofibers (CNFs) to epoxy resin reinforced with woven glass fibers with various harnesses was studied. The experimental results were evaluated statistically, indicating that using CNFs differently affects composite properties with various fabric harnesses. The addition of 0.5 wt.% CNFs to woven composites with varied harnesses enhanced the tensile strength by 19.2%–22.9% and the tensile fracture strain by 12.9%–13.8%, respectively. However, the elastic tensile modulus of woven composites was not increased. A further increase in the CNFs weight fraction from 0.5 wt.% did not improve the tensile properties. The addition of 0.5 wt.%, 1.0 wt.% and 1.5 wt.% CNFs increased the shear strength up to 30.6% and the shear modulus up to 18.7%, respectively. The results showed that the addition of CNFs more significantly affected the shear than the tensile properties. It was also revealed that employing a proper weight fraction of CNFs and a proper fabric harness significantly improves the mechanical properties of woven composites. Finally, an empirical model was developed to predict the strength and elastic modulus of woven composites with different harnesses and CNF weight fractions.

Evaluation of Variability in Gait Styles Used by Dogs Completing Weave Poles in Agility Competition and Its Effect on Completion of the Obstacle.

Objective: The aim of this study was to evaluate and define paw placement patterns for canines completing the weave pole obstacle during canine agility trials. The secondary objectives were to determine the most efficient running style and completion percentages and provide a basis for future studies to evaluate the long-term implications of variants in weave style and predisposition to injury. We hypothesized that dogs would display definitive gait patterns and that a single stepping pattern would yield faster run times compared to double stepping patterns.Animals: A total of 1,377 video recordings of dogs completing weaves poles at the American Kennel Club 2019 National Agility Championship were viewed.Procedures: Competition videos were reviewed as dogs attempted completion of the weave pole obstacle. Data collected included front limb and rear limb paw placement styles, time to complete the obstacle, and demographic data.Results: Attempts could be classified into one of five styles based on front and rear paw placement, with no one style dominant. Weave style differed by height and breed, with taller dogs and Border Collies preferring a single stepping style. Weave times were significantly faster for competitors using a single stepping style vs. other gaits.Conclusions and Clinical Relevance: This study found five identifiable gait styles used by dogs running weave pole obstacles, with front feet single stepping yielding significantly faster run times compared to other gaits. A clear classification of running styles will allow future studies to evaluate different stresses on joints, such as the shoulder, between varying gait styles, which could lead to recommendations for injury prevention.

Potency of natural and synthetic composites for ballistic resistance: A review

Mechanical characteristics of the laminated composite crafted from fabric type reinforcement perhaps inspired via the weaving method and reinforcement agent's usage due to each layer's constructional parameter. As a result, research on the arrangement configuration between bio composite and synthetic fibre for the material shape was proposed to enhance the composite structure's biodiversity and physical characteristics. Substitute for natural fibre in synthetic fibre composite works has shown the excessive capacity to be explored scientifically. The evaluation focused on the concept and essential of bio composite and the synthetic composite fabric positioned over the years from the previous studies of the preliminary researches. The sorts and features of matrix and fibre filler reinforcement materials in composites were also discussed. This assessment's main findings indicated that the composite centre relied on the weave styles and inter-ply and interplay lamination roles. Therefore, the state-of-the-art intraply for synthetic fibre and bio composite fibre in a composite shape was anticipated performing higher in mechanical energy, particularly within the application of ballistic resistance, besides decreased dependency on artificial fibre. It would ultimately suggest the excellent weave sample designs in the proper combination shape of natural and synthetic fibres embedded with polymers. The statistical results were compared with the experimental parameters available inside the literature review. The review explains approximately the studies and evolution within the enhancement of characteristic fibres reinforced polymer composites in ballistic resistance use. This paper goes over the body armour's profitable and present advancement materials, structure and development procedures, and related works on upgrading ballistic energy captivation and upgrading the mechanical tenacity for high impact resistance applications.

A complete comparison between JUTTON & COTTON-increase jute dependency instead of cotton

Jute producing sector is one in every of the oldest ancient manufacturing sectors of East Pakistan. As a lignocellulosic natural fibre jute possesses exhausting and harsh qualities that build it troublesome to provide attire and alternative fancy materials used in our daily life. Jute-Cotton mix is one in every of the doable choices to cut back the reliableness on the cotton. The aim of this work is to characterize the Jute-cotton alloyed material. During this work 100 gift cotton material is compared with a jute-cotton alloyed fabric. material samples like weave style, yarn count, material density, cowl issue, weight per unit space (g/m²), material strength, colouring performances like wash and rubbing fastness are evaluated. The reflection factor attempt to color strength K/S values of reactive colored material and basic dyed fabric samples were additionally studied. The experimental works are done at Dyeing laboratory and textile testing & quality control laboratory of Textile Engineering College, Noakhali.

The study of internal structure of woven glass and carbon fiber reinforced composite materials with embedded fiber-optic sensors

In this work, samples from composite materials with embedded optical fibers are investigated. It is known that for unidirectional layered composite materials, under certain conditions, a distortion of the internal structure and the formation of such technological defect as resin pocket in the region of the embedded optical fiber occur. So it is important to evaluate the change in the internal structure for other types of reinforcement, in particular, woven reinforcement. Analysis of the internal structure of the studied materials with 2´2 twill weave style was carried out using a digital microscope. In addition, the reflected optical signal from the Bragg gratings after being embedded into the composite material is analyzed.

Effect of Fiber Weave Structure in Printed Circuit Boards on Signal Transmission Characteristics

In this paper, we characterized and compared signal transmission performances of traces with different specifications of fiber weave. Measurements demonstrated that the dielectric constant, impedance fluctuation, and differential skew were all affected by fiber weave style. For flattened fiber weaves, the dielectric constant fluctuation reached 0.18, the impedance fluctuation amplitude was 1.0 Ω, and the differential skew was 2 ps/inch. For conventional fiber weaves, the three parameters were 0.44, 2.5 Ω, and 4 ps/inch respectively. Flattened fiber weave was more favorable for high-speed signal control. We also discussed the other methods to improve the fiber weave effect. It turned out that NE-glass (new electronic glass) fiber weave also had better performance in reducing impedance fluctuation and differential skew. Furthermore, made the signal traces and fiber weave bundles with an angle or designing the long signal line parallel to the weft direction both are simple and effective methods to solve this problem.

Cold Temperature Effects on Consistent and Architecturally Hybridized Woven Kevlar/Epoxy Laminates

The primary objectives of the present experimental research were to characterize and compare the interlaminar mode-I fracture toughness, crack growth and flexural stiffness behaviors of Kevlar KM2-Plus® fiber/epoxy matrix laminates constructed of various woven fabric architectures including plain, 2 × 2 twill and 4H satin weaves at cold [− 46 °C (− 50 °F)] and room [20 °C (68 °F)] temperatures. Secondary objectives were to evaluate and compare the fracture and flexure behaviors for two types of woven laminate constructions referred to as consistent and hybridized laminates. Consistent laminates were constructed with a single fabric weave style throughout all plies and were representative of laminate configurations used in traditional composites design. The hybridized laminates incorporated a mixture of different ply weave styles arranged in a strategic manner to achieve functionally-graded attributes and performance benefits such as enhanced damage tolerance, load carrying capacities, residual strengths and dynamic energy absorption/dissipation levels. The experimental results demonstrated that the interlaminar mode-I critical strain energy release rates, GIc and flexure moduli, Eflex were temperature dependent and that the hybridized laminate provided the optimal combination of highest fracture toughness and bending stiffness with the least sensitivity to temperature. The concept of hybridized laminate architectures can be used to mitigate temperature effects on fracture and flexural stiffness in addition to increasing damage tolerance, load carrying capacities, flexure stiffness, fracture toughness, residual strengths and dynamic energy absorption/dissipation.

Modeling the viscoelastic compaction response of 3D woven fabrics for liquid composite molding processes

In liquid composite molding processes, the compaction characterization of fibrous reinforcements plays a key role in determining the thickness, fiber volume content, and part shape. This study presents detailed experimental and modeling work to study the viscoelastic compaction response of three different types of 3D woven carbon fiber reinforcements, namely, orthogonal, angle interlock, and layer-to-layer, each having a different weave style and z-binder yarn pattern. For all reinforcements, single-step, multistep and cyclic compaction experiments were conducted. A nonlinear viscoelastic model is presented that accounts for large deformations and viscous effects, to capture the response of the material under various loading histories. Model verification is also presented to capture each response with separate sets of material parameters. Parametric studies are also performed to analyze the role of model parameters on the response of different types of loadings. X-ray computed tomography analysis showed significant permanent deformation of z-binder yarns through the thickness of the reinforcements. The comparison of modeling results with the experimental data show that the model is able to capture the stress decay after multiple compaction cycles, yet needs further investigations to predict complete cyclic hysteresis. However, model results agree reasonably well with the single and multistep compaction loading.

The morphological properties of PP coextruded tape fabrics

In the field of self‐reinforced composites many researchers have focused their attention on the coextruded tapes composed of polypropylene core and PP/PE copolymer skin. Two similar commercial fabrics (P and T) have been compared in respect of their peel resistance. For both materials, peel resistance has a periodic trend that regularly follows fabric weave style. T has demonstrated an average peel resistance and a well‐bonded area slightly greater than P. Skin/core interfacial properties have been investigated and a crosscheck between differential scanning calorimetry (DSC) and Raman spectroscopy has been adopted to understand the influence of skin structure on consolidated laminate. DSC curves exhibit three melting peaks during first heating for both fabrics, corresponding to copolymer, skin/core interface, and core melting. After consolidation at 140°C stretching‐induced superstructure and PP crystallinity degree are preserved. The presence of PP/PE copolymer + PE blend only in fabric P has been pointed out and PE content has been calculated. POLYM. ENG. SCI., 56:727–734, 2016. © 2016 Society of Plastics Engineers

Compression Failure Modes of Carbon Fiber Fabric Scraps/Epoxy Laminates

The composite prepreg waste is still an environmental challenge. In the last decade, several researchers have been studying the recycling and reuse processes of composite components, mainly to use in secondary (non-structural) components. In this paper, uncured aerospace grade prepreg scraps resulted from the production waste were used to manufacture laminates. The carbon reinforcement of the prepreg presented plain weave style fabric. To manufacture the laminates the hand-lay up process was used, randomly positioning the scraps and without respecting the preferred directions of the warp and weft. Therefore, the resulting laminate is multidirectional (in the plane) and orthotropic. The cure was performed in autoclave at the maximum temperature of (180 ± 1)°C and pressure of 100 psi. This laminate was tested in compression according to standard SACMA SRM 1R-94. The results show an average compression resistance equivalent to that of laminates produced with continuous layers, although with a higher dispersion. In order to understand this variation, the fracture surfaces of the laminates were analyzed by scanning electron microscopy (SEM) in order to identify the failure modes. The specimens present shear and interlaminar failure modes, in addition to a mixed mode of failure (a transition between the shear and interlaminar failures). For the same specimen, the analysis of the internal arrangement of the fibers shows that changes in failure modes occur in regions where the carbon fabric is not continuous, i.e. there are joinings of scraps. It was also observed that none of the compression tests resulted in catastrophic failure of the specimens, possibly due to a greater resistance to fracture growth in the presence of mixed failure mode.

Characterization of 3D woven reinforcements for liquid composite molding processes

Compaction and permeability characterization of fibrous reinforcements is fundamental to liquid composite molding (LCM) processes, given that these fabric properties determine the part thickness, fiber volume content and mold filling time and patterns. In this study, the permeability of three different 3D woven carbon fiber reinforcements (orthogonal, angle interlock and layer-to-layer) was studied, each having a different weave style and z-binder pattern. For all reinforcements, single-cycle and multiple cycle compaction experiments were conducted on dry and saturated samples. The orthogonal preforms were more difficult to compact to the target fiber volume fraction of 0.65, with peak stresses reaching up to 2.3 MPa. Cyclic compaction tests were conducted to highlight the importance of permanent deformation in the reinforcements, when higher fiber volume content is desired via manufacturing using an LCM process. Unsaturated in-plane radial and saturated through-thickness permeability data were obtained at several fiber volume fractions. The orthogonal and layer-to-layer fabrics exhibited greater levels of anisotropy in the plane of flow. The rate of change of in-plane permeability with increasing fiber volume content was lower compared to through-thickness values. The effect of cyclic compaction on permeability was greater in the orthogonal and angle interlock reinforcements. Micrographs of infused samples showed significant permanent deformation of the z-binder yarns, an effect that reduced permeability at high fiber volume contents.

Effects of Weave Styles and Crimp Gradients in Woven Kevlar/Epoxy Composites

This research investigates the effects of weave styles and crimp gradients (CGs) on the damage tolerance levels and energy absorption capacities of woven fabric reinforced polymer (WFRP) composites. A comparative study was conducted to determine the specific failure mechanisms including fiber/matrix cohesive failures, matrix cracking, fiber breakage and fiber buckling resulting from static and dynamic loading events. The tests included flexure, short beam shear, drop impact, flexure-after-impact, ballistic impact, and split Hopkinson compression bar (SHCB) and were performed on 20-ply Kevlar/epoxy WFRP laminates. Laminates of three different Kevlar fabric weave styles were fabricated using plain, 2 × 2 twill and 4H satin weaves. A fourth laminate was constructed having a mixture of weave styles forming a hybrid crimp gradient construction. The experimental results demonstrated (1) that weave style selections and CGs can positively influence the spatial and temporal distributions of stress resulting from severe loading events and (2) that the fiber/matrix cohesive zone stresses that often lead to delaminations can be reduced. Accordingly, the dependence of mechanical performance on weave styles, crimp contents, and CGs can be exploited to increase the damage tolerance levels and energy absorption capacities in WFRP composites.

Analysis of notched woven composites and fiber metal laminates with previous fatigue damage

Fiber metal laminates are hybrid materials consisting of alternating layers of thin metallic sheets and fiber reinforced epoxy prepregs. In this work, the fatigue damage effect on the residual strength, stiffness, and strain field in woven carbon-reinforced aluminum laminates with a circular open hole is studied. The strain fields were obtained by means of a noncontact optical deformation measuring system and then used to determine the normal stress distribution around the open hole. A squared pattern is observed in the strain mapping of the specimens with previous fatigue damage that disturbed the stress profile. The experimental stress profiles were compared with finite element modeling and an analytic solution; clear agreement is observed on this comparison for fatigue damage free specimens, except near the hole edge due to stress redistribution. Previous fatigue damage reduces residual strength and stiffness of notched woven composite samples and fiber metal laminates; it was also observed that notched fiber laminates are more fatigue tolerant than the base composite material. It is important to note that the fatigue loading caused not only damage such as matrix cracking and delamination, but also a weave style strain/stress redistribution along the warp direction.

Comparative Studies on the Mechanical Properties of Nonwoven- and Woven-Flax-Fiber-Reinforced Poly(Butylene Adipate-Co-Terephthalate)-Based Composite Laminates

Textile biocomposites made from woven- and nonwoven-flax-fiber-reinforced poly(butylene adipate-co-terephthalate) (PBAT) were prepared by compression molding using the film stacking method, and their tensile strength and stiffness, flexural strength and modulus, and impact strength were determined experimentally. The PBAT-based composites were subjected to water absorption tests. The mechanical properties of pure PBAT and the textile composites were compared, and the influence of flax weave styles on the properties were evaluated. The biocomposite reinforced with 4 × 4-plain weave fibers showed the highest strength and stiffness compared with those of the other textile biocomposites and pure PBAT.

Effect of woven flax structures on morphology and properties of reinforced modified polylactide composites

Composites composed of polylactide (PLA), modified PLA and woven flax fiber textiles (flax weave style of 2 × 2 twill and 4 × 4 hopsack) were produced by hot press technique. Two structurally different additives were used to modify PLA. The dispersion of the flax in the composites was studied by scanning electron microscopy and computed microtomography system (µCT). The PLA composites were subjected to water absorption and instrumented falling weight impact tests. The thermomechanical and creep properties of the composites were determined using thermogravimetric analysis, dynamic-mechanical thermal analysis and short-time creep tests. It was found that the modified PLA and its composite increased the impact resistance compared with the unmodified PLA. Incorporation of flax decreased resistance to thermal degradation and increased water uptake. The impact energy and stiffness value of PLA/flax composites were markedly higher than that of PLA but reflect the effects of composite structures and flax content. The storage modulus master curves were constructed by applying the time–temperature superposition principle. From the master curve data, the effect of modified PLA on the storage modulus was more pronounced in the low frequency range.

Structure and properties of flax/polylactide/alumina nanocomposites

Composites composed of polylactide (PLA), woven flax fiber textiles (weave style of 2 × 2 twill and 4 × 4 hopsack) and boehmite alumina were produced by hot press. The spraying technique served for the pre-dispersion of the alumina nanoparticles. The aqueous alumina slurry was produced by mixing the water with water dispersible alumina. The dispersion of the flax structures and alumina particles in the composites was studied by scanning electron microscopy. The polylactide composites were subjected to water absorption and instrumented falling weight impact tests. The creep and thermomechanical properties of the composites were determined in short-time creep tests (performed at various temperatures), thermogravimetric analysis and dynamic-mechanical thermal analysis, respectively. It was found that the incorporation of alumina particles reduced the water uptake compared to the polylactide/flax blends. The impact energy and stiffness value of polylactide/flax blends was markedly higher than that of PLA but reflected the effects of composite structures. Incorporation of alumina particles enhanced storage modulus and the creep resistance compared to the polylactide/flax blends but slightly incremented thermal resistance at high temperature. No clear trend in the flax weave style-effect was found in the thermal behavior. The creep master curves were constructed by applying the time–temperature superposition principle. The Findley power law could satisfactorily describe the creep compliance versus time traces for all systems studied.

Impact, thermal and mechanical properties of high density polyethylene/flax/SiO2 composites: Effect of flax reinforcing structures

Composites composed of high-density polyethylene, woven flax fiber textiles (flax weave style of 2 × 2 twill and 4 × 4 hopsack) and SiO2 were produced by hot press with nanospraying technique. The SiO2 slurries were sprayed on the woven flax fiber followed by drying. The related HDPE/woven flax fibers composites were prepared by hot press. The dispersion of SiO2 particles and flax in the composites was studied by scanning electron microscopy. The related high-density polyethylene based composites were subjected to instrumented falling weight impact test. The thermal resistance, stiffness and tensile strength properties of the composites were determined in thermogravimetric analysis, dynamic-mechanical thermal analysis and tensile tests, respectively. It was found that the impact energy and stiffness value of high-density polyethylene/flax composites was markedly higher than that of high-density polyethylene but reflect the effects of composite structures and flax content. Incorporation of SiO2 particles enhanced resistance to thermal degradation. It was established that the linear viscoelastic material principle are fairly applicable to convert from the modulus to the creep compliance results.

Conductive filament formation in printed circuit boards: effects of reflow conditions and flame retardants

Conductive filament formation, a major cause of failures in printed circuit boards, is an electrochemical process that involves the transport of a metal through or across a nonmetallic medium under the influence of an applied electric field. With an increasing potential to market “green” electronics, environmental and health legislations, and the advent of lead-free and halogen-free initiatives, newer types of printed circuit board materials are being exposed to ever higher temperatures during solder assembly. The higher temperatures can weaken the glass-fiber bonding, thus enhancing conductive filament formation. The effects of the inclusion of halogen-free flame retardants on conductive filament formation in printed circuit boards are not completely understood. Previous studies, along with analysis and examinations conducted on printed circuit boards with failure sites that were due to conductive filament formation, have shown that the conductive path is typically formed along the delaminated fiber glass and epoxy resin interfaces. This paper is a result of a year-long study on the effects of reflow temperatures, halogen-free flame retardants, glass reinforcement weave style, and conductor spacing on times to failure due to conductive filament formation.

Effect of fabric compaction and yarn waviness on 3D woven composite compressive properties

3D-woven fabrics incorporate through-thickness reinforcement and can exhibit remarkable inter-laminar properties that aid damage suppression and delay crack propagation. However, distortions in the internal architecture such as yarn waviness can reduce in-plane properties, especially in compression. The degree of yarn waviness present in a 3D woven fabric can be affected by a range of factors including weave parameters and manufacturing-induced distortions such as fabric compaction. This paper presents a thorough analysis of the effect of fabric compaction and yarn waviness on the mechanical properties and failure mechanisms of an angel-interlock fabric in compression. Tests were conducted on coupons moulded to different volume fractions and data compared to previous measurements of local yarn angle. Major findings show the importance of yarn straightness on compressive strength and how this can be affected by optimising moulding thickness. Failure initiation was also found to be heavily influenced by weave style and yarn interlacing.

The use of an interleaved film for optimising the properties of hot compacted polyethylene single polymer composites

It is shown that the incorporation of interleaved films has major advantages for the production of polyethylene single polymer composites by the process of selective melting (termed hot compaction). The key issue is to choose a compaction temperature which melts the minimum amount of the original oriented elements whilst achieving acceptable bonding within the compacted structure. Utilising an interleaved film, excellent interlayer peel strengths can be achieved at lower compaction temperatures giving greater retention of the oriented fraction of the original fibres or tapes and a wider processing window. For example, using a very high modulus, ultra-high molecular weight, polyethylene tape, together with an interleaved film, resulted in an in-plane modulus of 25 GPa, an in-plane strength of 500 MPa, and an interlayer strength of >10 N/10 mm. These are amongst the highest values reported for a single polymer composite. Other important factors have been investigated including fabric weave style and whether it is better to use fibres or tapes as the oriented reinforcement.