This study attempts to investigate the pressure behavior of tubular knitted fabrics after a long period of time. For this purpose, two kinds of knitted fabric (plain and interlock) with various stitch lengths were chosen and the interfacial pressure and pressure reduction of fabrics after 48 hours were analyzed at different strain percents. The same tests were performed on the same specimens after repeated washing and repeated usage. Finally, the experimental pressure values were compared with the theoretical results obtained from Laplace's law. The results reveal that the stitch length and strain percent are important factors affecting the interfacial pressure and pressure reduction of both plain and interlock fabrics. As the results of statistical analysis, the repeated washing and repeated usage have significant effect on interfacial pressure and pressure reduction of both fabrics. The comparison between experimental pressure values and theoretical values calculated from Laplace's law shows a considerable difference in both plain and interlock fabrics.

To suitably treat and cure special skin damage, the exertion of pressure on the injured limb is advised by therapists. This type of therapy is called pressure therapy. Currently, pressure therapy is performed with pressure garments on the tissue. In all pressure-garment applications, the amount of exerted pressure on the limb is very essential, and the success of treatment is extremely dependent on this pressure. Accordingly, the accurate prediction of exerted pressure is very important. Until now, in most related articles and researches, Laplace law has been used as the pressure predictor equation. In this study, the accuracy of Laplace law for two types of structures, elastic fabric and rubber, were investigated. The obtained results indicate that the measured pressure in all specimens was considerably more than that predicted by Laplace law. Therefore, the accuracy of Laplace law was proven to be inefficient for the prediction of pressure, and as such, more investigation is recommended.

In this study, a system was designed and constructed in order to measure the drag force acting on the swimmer simulator. This system must be able to obtain the drag force for a range of swimsuit fabrics to characterize the hydrodynamic properties of swimsuit fabric. In this system, a DC motor was used as the propelling unit; also a voltmeter and an ammeter were applied to measure the input power of motor. To find the relationship between input powers and drag force, calibration was done. The simulator was made from wood in two different sizes. The samples of fabrics were prepared from three kinds of weft knitted fabrics, which are common in production of swimsuits, and were knitted from polyamide6 (nylon), polyamide6-elastan (nylon-lycra) and polyester. The statistical analysis of results show the importance of fabric surface properties and swimsuit design on swimmer's performance, so clothing engineering and technical clothing design can play a key role in sport engineering.

Many kinds of pressure garments are currently used for various applications, such as treating of hypertrophic scars, reversing the effect of shock on the body's blood distribution, improving energy saving for athletes and enhancing the aesthetic appearance of the wearer. In order to design the desired pressure garments, predicting the amount of pressure is mandatory. Although many researchers have used the Laplace law as the prediction equation, there has been some discrepancy between predicted and experimental measured pressures. In this study, we focused on one of the parameters which influence this discrepancy. To predict the pressure by this law, the induced tension in the material is measured by a tensile strength device, and then is inserted into the equation while the real tension is induced by extending on curvature shape. We measured the tension induced in the rubber band, which was extended on a cylindrical surface by using a new tensile test assembly. Subsequently, this tension was compared with the tension induced in the flat geometry which is commonly used. The results show that there is a significant difference between the tension in the curvature and flat geometry.

Weft density has been considered as one of the most effective factors on woven fabric construction and it is influenced physical and mechanical fabric properties. Therefore, we developed a closed loop control system in a weaving machine. The manipulator element was take-up roller rotation speed. The weft density was measured by means of a special computational image processing routine. The PID control algorithm used to calculate the desired modification of take-up speed. However, the existing variable delay on the sensing weft density variation by the measuring system causes the conventional PID control system to have been disabled in providing robust action, so the control system was utilized by the Smith predictor to modify control behavior. To adjust control parameters, the function of the weaving machine has been investigated and a simulated model of the weaving process was constructed. The result of set point tracing and regulatory control in various tests indicated satisfactory performance of our new system.A. Almasi Zefrehyee was with the Textile Engineering Department,