Quarterly Scientific-Research Goljaam

To study the way of folding handmade carpets, the selected sample has been put under pressure of 50g/cm2 weight at three different states. The pressure has increased uniformly and continuously at 100,200, 500, 1000 and 1500 g/cm2. The thickness of the carpet has been recorded continuously during the measurement of the thickness of the carpet sample. The pressing parameters of the carpet have been calculated in KES-F system with simulation and fitting of two components model of de-jong pressure. Also, the thickness of the part that is not able to be pressed is estimated. Based on the obtained results, it has been shown that pressing energy in the curved folded part of the carpet is very low, but the pressing energy in the part with two layers of the carpet on each other is very high. Nevertheless, the percentage of elasticity in two layers of the carpet placed on each other is remarkably low. It shows that the sensitivity and flexibility of this area is more in comparison with two layers of the carpet. On the other hand, the thickness of the part that is not able to be pressed in the area with two layers of the carpet on each other is more than that of the investigated areas. In this way, the pressing is carried out by piercing the upper naps on the lower ones. Without folding and flatting of the carpet, it is not pressed and just upper layer naps are pressed on the lower layers. In this study, the phenomenon of Domino folding is used to describe the folding behavior of the handmade carpet under static pressing

If a carpet is put under pressure during use or storage, its thickness decreases instantly and continues to decrease slowly as the pressure is not removed. Some part of this loss of thickness is not recoverable. This phenomenon is called creep and is influenced by parameters such as temperature and humidity, and it may cause breakage, burst, crease, bump, and folding line in the carpet. By studying creep of carpets, it is possible to predict their behavior under such loads to reduce the damages and effects of the creep. In this paper, a sample of folded–carpet is put under pressure of a 170 kg dead weight for 48 hours and its compression strain under various thermal and humidity condition is measured on-line. Then different statistical models were regressed on the collated data proving that creep-model of Voight-Kelvin is assumed as the best formula for determination of creep behavior of the folded carpet under different thermal and humidity conditions. Analysis of data variance detected a significant difference between various levels of thermal and humidity parameters in creep model implying their direct influence in the equation, although they are negligible compared to time effect. This research extended to calculate the Young modulus, creep constant and viscosity coefficient of the folded-carpet. 

One of the most common procedures for exporting and warehousing handmade carpets is keeping them folded over one another. Handmade carpets come out of their stable states by being folded,while increasing storage time can cause serious and sometimes irreversible changes to them. In this research, a pilot model carpet has kept folded under a load equal to 50 g/cm2 and then the applied load increased respectively to 100, 200, 500, 1000 g/cm2 continuously and uniformly, and at every stage the digital image of the form of folded carpet has been recorded. The received image was analyzed by software programs to identify and determine the morphology of folding curvature of handmade carpet under static pressure. It is possible to propose convenient predictions for storage and packing of carpets, considering the morphology of folding curvature of handmade carpet during successive loading and unloading phases. Accordingly,is this research it was determined that the empty space in folding curvature of handmade carpet after removing the pressure and returning to the first state isalmost 9 times less than the same for the first time the carpet was folded. This research also showed that if the setting height of stored carpets, which are folded over each other, does not change then the damage is much less comparing the time that carpets’ height decreases constantly and forcesapplied to carpets change. Moreover, possibility of carpets falling due to loss of instability of folding curvature length at loading time is much greater than during unloading time. Also in this research, folding curvature height, folding curvature length and empty space in folding curvature were studied and measured.