فهرست مطالب

Journal of Textiles and Polymers
Volume:3 Issue: 1, Winter 2015

  • تاریخ انتشار: 1394/03/03
  • تعداد عناوین: 6
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  • Rasoul Mahdi, Mohammad Sheikhzadeh, Dariush Semnani, Sayyed Mahdi Hejazi* Page 1
    In random cone winding system، the patterning concept results in many problems in further processes، e. g. yarn breakage and/or early take off of the package. In current winding machines، there is no system to detect the patterning and consequently the anti-patterning system is working continuously. In this research، an online-computer-vision system is used to detect the concept of patterning through the linear mean and variance technique. In fact، photographs of bobbin surface are continuously taken with specified time interval. In this way، the mean or variance is calculated from columns within the image matrix، and a vector is obtained. Then again، the variance or the mean of the vector is calculated، thus a number is obtained for each matrix. Therefore، there are four methods including mean of mean (MOM)، mean of variance (MOV)، variance of mean (VOM) and variance of variance (VOV) to give the index number. Accordingly، a diagram of image number versus index value is plotted for each method، and a peak is perceived in place of patterning defect. By finding this peak، the moment of occurrence of defect is diagnosed، and the “patterning” can be recognized. The results show that among the four methods، the MOV is more accurate. Finally، this outcome is mathematically analyzed.
    Keywords: Random winding, patterning, image processing, linear mean, variance technique
  • Ali Safavi, Masoud Latifi *, Mohammad Amani, Tehran, Abbas Rezaee, Shirin, Abadi Page 7
    This study has been carried out in order to investigate the effects of type of phase change materials on the thermo-regulating performance of clothing. Three systems of clothing with the same construction are chosen and their effects on the temperature response of the body (skin temperature changes) during the activity under a defined scenario are investigated. One of the clothing systems is normal (without PCM, i.e. phase change material), the other one is incorporated with PCM with a melting point of 18°C and the third one is incorporated with PCM with a melting point of 28°C. The skin temperature which is mainly affected by the physiological response of the human body is recorded by an on-line measuring system in the field room. Experimental results showed that PCM can affect the thermo-regulating performance of clothing. Furthermore, PCM with a melting point of 28°C shows a more significant effect than PCM with a melting point of 18°C. On the other hand, under cold environmental conditions (-5°C) and during activity of body, PCM with a melting point of 28°C decreases the fluctuations of temperature more than PCM with a melting point of 18°C. Finally, results of this research show that the type of PCM affects the skin temperature of the body. By this method, it is possible to design smart protective clothes with desired level of comfort.
    Keywords: PCM (phase change material), temperature change rate, activity level, temperature response
  • Pedram Payvandy*, Saeed Ebrahimi Page 12
    Lockstitch sewing machine is one of the most common apparel industrial machines. The thread take-up lever mechanism of a sewing machine has an important role for proper stitch forming and smooth working of the machine. Acquiring a mechanism with optimized geometry is of great importance to reach this goal. Therefore, in this study the optimization of the thread take-up lever mechanism with respect to some important features such as the optimal path of the coupler point and variation of coupler point acceleration (jerk) is presented. Modification of the objective function with respect to the jerk is applied to assure smooth movement of the thread take-up lever during sewing process. For this purpose, the imperialistic competitive algorithm is used to find the optimal link lengths of the take-up lever mechanism. The analysis results present further verify that the coupler point jerk in the optimized mechanism in the horizontal direction has been decreased about 52 percent without any conflict in the consistent operation of different parts of the sewing machine.
    Keywords: Optimization, imperialistic competitive algorithm, thread take, up lever mechanism, coupler point, jerk
  • Afsaneh Valipouri, Seyed Abdolkarim Hosseini Ravandi*, Ahmadreza Pishevar, Emilian I. Parau Page 20
    Centrifuge spinning is a method that makes possible of fabrication nanofibers rapidly and at high yields. In the centrifugal spinning process, a polymer solution is delivered by the centrifugal force through small nozzle of a rapidly rotating cylindrical drum. Thereby, thin fibers are formed and collected on a collector in the form of a web. In this study, a mathematical model of the dynamics of a viscous liquid jet, which emerges from rotating drum through centrifuge spinning, was derived. The Navier-Stokes equations were solved in this system with the usual viscous free surface boundary conditions. One-dimensional equations were derived using asymptotic methods based upon a slender jet assumption and solved numerically. The effect of angular velocity upon the trajectory, radius, and tangential velocity of the jet was simulated and presented. Increasing angular velocity resulted in a decrease in the size of the liquid jet. Also, increasing angular velocity tended to increase the jet velocity which translated to increase the production rate. The jet centerline became more tightly coiled when the angular velocity increased. In addition, simulated jet diameter was compared with some results reported in our previous work.
    Keywords: Centrifuge spinning, Navier, Stokes equations, curved jet, angular velocity
  • Behnam Namiranian, Saeed Shaikhzadeh Najar*, Ali Salehzadeh Nobary Page 26
    The aim of this paper is investigation of some important parameters in shell buckling of fused interlining worsted fabric with different weight and considering five different relative orientation angles (0°, 22.5°, 45°, 67.5°, 90°) according to the machine direction of non-woven fusible interlining and a face fabric. The formability of the prepared fused fabric composite based on shell buckling curves and Lindberg''s hypothesis is also reported. The shell buckling compression behavior of fused fabric composite is investigated using a special corrugated clamp based to Dahlberg''s test method.The result show that with increasing the interlining relative orientation angle, buckling loads and buckling energy parameters decrease, whereas, hysteresis and compression remaining increase. The fused fabric composites exhibit the highest formability at 67.5° relative orientation angle. The results show that at 0° relative orientation angle, the lowest buckling hysteresis, compressibility and compression remaining are obtained.
    Keywords: Shell buckling, relative orientation angle, mechanical properties, interlining, fused fabric composite
  • Majid Tehrani, Dehkordi*, Hooshang Nosraty Page 34
    The properties and structure of the yarns within the fabric generate a complex mechanism of deformation. Although many literatures are available on mechanical properties of woven fabrics, little micro-mechanical information have become public on tensile behavior of such materials. In this study, the tensile behavior of woven fabrics with different weave patterns is simulated by using finite element method. Yarn geometry parameters are measured with the help of microscopy and image processing techniques. Three-dimensional geometrical models are simulated by use of fabric geometry data. To evaluate the proposed model, the numerical results are compared to the experimental measurements. The results show that by using the three dimensional modeling of fabric and precisely imparting the yarn properties in the finite element program, the tensile properties of fabric with different weave patterns can be reasonably predicted.
    Keywords: Simulation, finite element method, tensile behavior, woven fabric, weave pattern