ITAST (Iranian Textile Association of Science and Technology)Journal of Textiles and Polymers2322-520311320230101The flexural behavior of Stitched Polyurethane Foam Composite Sandwich Structures31018041210.48302/jtp.2023.388057.1261ENShekoufehRasouli RiziThe Department of Textile Engineering, Amirkabir University of Technology, Tehran, Iran0000-0002-1864-4846HooshangNosratyAmirkabirSayed AbolfazlMirdehghanعضو هیئت علمی گروه تکنولوژی نساجی دانشگاه صنعتی امیرکبیرJournal Article20230302Abstract<br /><br />One of the main advantages of sandwich composites is the high bending strength to their weight ratio. These structures have significant problems such as face sheet-core de-bonding, which could be prevented by a variety of techniques including z-pining and stitching through the thickness. In this study, the effect of stitching on the bending behavior of sandwich composites with E-glass composite face-sheets and polyurethane foam core has been investigated. Specimens are stitched at three stitch spaces 0.5, 1, and 2 cm with stitch pitch of 0.8 cm and stitch seam angles of 0, 90°, 0/90°, ±45°, 45°/90°, and ±60°. Face bending stress and core shear stress of stitched specimens has been studied by three-point bending test and compared to the results of unstitched specimen. Results indicate that with decreasing the stitch spacing and therefore increasing the stitch density, bending strength improves, and the best bending behavior observed in ±45° stitch angle.http://www.itast.ir/article_180412_e93bd16c19910594009b0d400915e189.pdfITAST (Iranian Textile Association of Science and Technology)Journal of Textiles and Polymers2322-520311320230101Experimental study on the effect of braiding angle on the fracture behavior of 2D braided composite cylinders111721051710.48302/jtp.2024.426763.1278ENMaryamZeynivand MojarradPhD student, Amirkabir University of Technology0009-0000-7872-5798HadiDabiryanTextile Engineering, Amirkabir University of Technology0000-0001-5161-2849Ali AkbarGharehaghajiAmirkabir University of Technology0000-0002-3819-5048Amir M.RezadoostIran Polymer and Petrochemical Institute0000-0003-0198-0795Journal Article20231124This research aims to study the fracture mechanism of two‐dimensional (2D) braided glass/epoxy composite cylinders under axial tensile load. For this purpose, three types of composite cylinders were fabricated using braids with three braiding angles, i.e., 30°, 45° and 60° to find out the role of braid angle on the fracture mechanisms of composites. Novel fixtures (jaws) were designed and produced for tensile testing of composite cylinders. Composite cylinders were subjected to the tensile test by applying SANTAM static tensile machine. Macroscopic damage morphologies of samples were provided after the tensile test by using an optical microscope. The results demonstrated that the different fracture modes occur in braided cylindrical composites. Fiber fracture, matrix fracture, and de-bonding were the dominant fracture modes observed in braided composite cylinders proportional to the angle of braids. Fiber fracture was the main mode of fracture in composite cylinders reinforced with braids with angle of 30, while the dominant fracture mode in the composite cylinder reinforced with braids having 60 was matrix fracture. In samples with 45° braiding angle, a combination of fracture modes was observed. In summary, the results indicated that the braiding angle has a significant influence on the fracture behavior of composite cylinders.http://www.itast.ir/article_210517_67e88b0237f41cfefbfd09428a25068c.pdfITAST (Iranian Textile Association of Science and Technology)Journal of Textiles and Polymers2322-520311320230101Optimization of Tensile and Shear Properties of Concrete Reinforced with Polypropylene and Glass Fibers Using Taguchi Method192721051910.48302/jtp.2024.435332.1282ENHamidehKazemiDepartment of Textile Engineering, Yazd University, Yazd, IranSaeedFattahiDepartment of Textile Engineering, Yazd University, Yazd, IranMohammad SalehAhmadiDepartment of Textile Engineering, Yazd University, Yazd, Iran0000-0002-0581-4033MiladSadeghi-SadeghabadDepartment of Textile Engineering, Yazd University, Yazd, Iran0000-0001-8846-1896Journal Article20240112This study explores the influence of fiber type (polypropylene and glass), length, and dosage on the mechanical properties of fiber-reinforced concrete, aiming to optimize these properties using the Taguchi method. Utilizing an L18 orthogonal array, 18 samples with varying conditions were produced. Findings indicate that tensile behavior is significantly affected by these factors, with fiber dosage being the most influential. Polypropylene-fiber-reinforced concrete exhibits superior tensile performance compared to glass fibers. Optimizing fiber length is crucial, as an increase from 6 mm to 12 mm enhances tensile strength, but extension to 18 mm results in a decline, highlighting an optimal fiber length. Regarding dosage, a moderate increase from 0.1% to 0.2% has negligible effects on tensile strength, while a sharp decrease is observed at 0.3%, indicating potential compromises in strength due to mixing and adhesion issues. Additionally, glass-fiber-reinforced concrete demonstrates inferior shear strength compared to polypropylene. Increasing fiber length and dosage contribute to reduced shear strength and higher fiber length correlates with a decreased shear modulus.http://www.itast.ir/article_210519_0492b307f6af6f4a6cb1f3a2fba5433c.pdfITAST (Iranian Textile Association of Science and Technology)Journal of Textiles and Polymers2322-520311320230101Experimental and analytical study on tensile strength of short-fiber-reinforced adobe (SFRA)293821052010.48302/jtp.2024.448732.1284ENMohammad RezaMirjaliliDepartment of Textile Engineering,Technical and Vocational University (TVU), Tehran, IranSaeedFattahiDepartment of Textile Engineering, Yazd University, Yazd, 89195-741, IranMohammad SalehAhmadiDepartment of Textile Engineering, Yazd University, Yazd, 89195-741, Iran0000-0002-0581-4033Journal Article20240315The exploration of reinforcing adobe with fibers is pivotal in revolutionizing sustainable construction methods and fortifying the resilience of traditional building materials. This study delves into the impact of incorporating three reinforcement fiber types—glass, polyester, and polypropylene, featuring lengths of 6, 12, and 18mm, and weight percentages of 0.5, 1, and 1.5—on the direct tensile strength of adobe. Additionally, an analytical model based on the modified rule of mixtures was utilized, both with and without porosity consideration, to predict the tensile strength of reinforced adobe. The results indicate that an increase in fiber length and percentage generally augments the tensile strength of samples across all three fiber types, except in cases where excessive elevation of these parameters disrupts proper fiber/mortar adhesion. Notably, samples reinforced with polypropylene fibers exhibited higher tensile strength, with a peak value of 0.69 MPa (using 6mm fibers at 1.5 wt.%), while the lowest value at 0.31 MPa was observed in the sample reinforced with 6mm glass fiber at 0.5 wt.%. The theoretical model yields acceptable predictions for polyester and polypropylene-reinforced samples, with average prediction percentage errors of 16.5% and 13%, respectively, when porosity is considered and samples with excessive fiber length and percentage values are excluded.http://www.itast.ir/article_210520_e53d1084080427cb9e1ecd9fdf657dd9.pdfITAST (Iranian Textile Association of Science and Technology)Journal of Textiles and Polymers2322-520311320230601Effect of Number and Position of Tuck Stitches in the Pattern Repeat on the Quality of Rib Weft-Knitted Fabrics from the Point of Comfort394821059310.48302/jtp.2024.474533.1296ENAzitaAsayeshDepartment of Textile Engineering, Amirkabir University of Technology (Tehran Polytechnic), Iran0000-0003-1757-7984MaedehNoori MoafradTextile Engineering Department, Amirkabir University of TechnologyJournal Article20240821Consumers are interested in knitted clothing that looks beautiful and feels comfortable. Incorporating tuck or float stitches in the basic weft-knitted fabrics produces many new structures that differ in appearance and characteristics. In this study, the effect of number of tuck stitches and their position in the structure of rib-weft knitted fabrics on some of the comfort properties of the fabrics has been investigated, and the quality of the fabrics has been measured by evaluating the ability of the fabrics to meet these properties. According to the calculated values of the complex criterion of fabric’s quality, all considered fabric structures exhibited good to excellent quality, however, the fabric containing one tuck stitch in the pattern repeat, demonstrated the best overall quality among the investigated fabrics (Qk=0.84). The Half Cardigan with tuck stitches on one side of the fabric showed similar quality as the Rib (Qk=0.8), in contrast, the Full Cardigan with tuck stitches on both sides of the fabric demonstrated inferior quality (Qk=0.76) than them. Eventually, it can be concluded that using tuck stitches in the fabric structure in a controlled manner leads to better fabric quality regarding comfort properties.http://www.itast.ir/article_210593_9230bca257b2d4d11da8650010dcad92.pdfITAST (Iranian Textile Association of Science and Technology)Journal of Textiles and Polymers2322-520311320230601Modeling Poisson’s Ratio and Tensile Behavior of Auxetic 4-Plied Yarn495721136910.48302/jtp.2024.481449.1299ENMiladRazbinDepartment of Textile Engineering, Amirkabir University of Technology, Tehran, Iran.0000-0002-5409-1476MortazaSalehianDepartment of Aerospace Engineering, Amirkabir University of Technology, Tehran, Iran.Journal Article20241002Auxetic yarns, renowned for their unique capability to expand laterally when subjected to tensile loading, are gaining recognition as innovative and adaptable structural materials. These yarns hold significant promise across a wide range of applications, including the development of auxetic fabrics with enhanced properties, the reinforcement of composite materials for improved strength and durability, and the creation of advanced smart wearable sensors with heightened sensitivity and functionality. In this study, a comprehensive theoretical framework is introduced, consisting of a geometrical model to predict the Poisson’s ratio and a mechanical model aimed at forecasting the stress-strain behavior of auxetic 4-plied yarns (A4PY). The proposed models integrate key parameters, such as the radius of the components, their respective Young’s modulus and Poisson’s ratio, and the twist per meter of the yarn structure. Rigorous validation against experimental data from previously published studies confirms the accuracy and reliability of these models in capturing both the Poisson’s ratio and the stress-strain responses, aligning with observed experimental trends.نخهای آگزتیک، که به دلیل توانایی منحصر به فرد خود در گسترش جانبی تحت بارگذاری کششی شناخته شدهاند، به عنوان مواد ساختاری نوآورانه و سازگار در حال شناخته شدن هستند. این نخها نویدبخش کاربردهای گستردهای هستند، از جمله توسعه پارچههای آگزتیک با خواص بهبود یافته، تقویت مواد کامپوزیتی برای افزایش استحکام و دوام، و ایجاد حسگرهای هوشمند پوشیدنی پیشرفته با حساسیت و عملکرد بیشتر. در این مطالعه، یک چارچوب نظری جامع معرفی شده است که شامل یک مدل هندسی برای پیشبینی ضریب پواسون و یک مدل مکانیکی برای پیشبینی رفتار تنش-کرنش نخ آگزتیک چهارلا است. مدلهای پیشنهادی پارامترهای کلیدی مانند شعاع اجزا، مدول یانگ و ضریب پواسون آنها، و میزان پیچش در هر متر ساختار نخ را در بر میگیرند. اعتبارسنجی دقیق این مدلها با دادههای تجربی منتشر شده قبلی نشان میدهد که این مدلها از دقت و اطمینان بالایی برخوردار هستند و میتوانند بهخوبی ضریب پواسون و پاسخهای تنش-کرنش را پیشبینی کنند و با روندهای تجربی مشاهدهشده هماهنگ باشند.http://www.itast.ir/article_211369_9e31ae99f2ecccbd129c63b141c802b4.pdf