Quarterly Scientific-Research Goljaam

In this research, an apparatus was designed and constructed in order to simulate the storage behavior of hand-woven carpet under different environmental conditions. Silk hand-woven carpet (“Gom”) with 115×75 cm dimensions and 102×97 knot per 10 cm was selected and then inserted into the packing simulator with two different laying configurations including flat and folded. The environmental conditions was adjusted at 3 different conditions including 25 ± 5% r.h and 30 ± 2°c (July-Tehran-Dry), 65 ± 5% r.h and 6 ± 2°c (February-Tehran-humid), 40 ± 5% r.h and 19 ± 2°c (October -Tehran-mild). The carpet sample was compressed under constant loads of 135 and 150 kg. The variation of carpet thickness with time in different parts of carpet was continuously measured using data acquisition system. The result of experiment shows that the carpet thickness is suddenly decreased at a short period of time and then reached to a stable condition. The variation trend of carpet thickness with time is accordance with a logarithm equation(y=a×Ln(t)-b) which is highly in agreement with Eyring model proposed in creep theory . But at the dry conditions, the variation of carpet thickness at the folded point follow a non-linear power equation (y=a×(t)^b) with a low correlation coefficient. However, the variation of carpet thickness at the non-folded point and flat configuration is very low.
Generally, at the humidity condition, maximum carpet thickness variation occurred at folded point with folded configuration. On the other hand, carpet thickness variations at dry condition are less those of at humidity and mild conditions. In addition, carpet thickness at dry condition more quickly reached to stable condition than those of at humidity and mild conditions.

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.