A texture that has a microstructure with arrangements of cyclic micrometric projections generates various effects on human skin owing to mutual contact. The mechanical effects, such as stimulus of the skin, owing to contact with such microstructures are complicated because of the skin structure itself. The evaluation of the effects is necessary for control and design of the microstructure. Since experimental measurements are relatively difficult, numerical analyses are effective for detailing and objectively evaluating the mechanical effects on human skin. For this reason, numerical analyses of the effects of surface textures on skin were performed in this study. In particular, differences caused by cyclic variations of the texture were ascertained for the evaluation. Pressure, von Mises stress, etc., of the skin sensory organs were ascertained by performing numerical modeling of the situations where the texture touches the skin. The results of the analyses showed several characteristic effects such as negative pressure at the boundary of the horny layer and epidermis. The negative pressure was increased according to the increase of texture cycle. The von Mises stress at shallow positions changed characteristically, whereas von Mises stress at deep positions decreased monotonously with an increase of texture cycle. The von Mises stress at a shallow position of the dermis had a local minimum value for a particular texture cycle without monotonous increasing or decreasing.

In this paper, we propose methods estimating untwisting torque of a twisted yarn that is the main cause of wale skew and predicting the skewness angle in a plain knitted fabric by using estimated untwisting torque. In general, as untwisting torque of a twisted yarn cannot be measured or estimated, snarl index obtained from untwisting test is used as one of its performance index. In this paper, untwisting test is modeled considering untwisting torque. Then, untwisting torque can be estimated by adjusting it so that simulated snarl index coincides with actual snarl index measured with untwisting test. Next, wale skew is also modeled considering untwisting torque. Then, the skewed knitted shape can be simulated with the estimated untwisting torque. In the above two models, the shape of a yarn, which is assumed to be a linear elastic object, and its potential energy are described by using the differential geometry. Minimizing the potential energy under geometric constraints, the stable shape of the yarn, which is physically valid, can be derived. Finally, the validity of our proposed method is verified comparing the simulated shape of a skewed fabric with the actual shape of the fabric.

In this study, we investigated how the yarn used in single tricot stitch affects the hand evaluation of knitted tapes for fasteners. For this purpose, experimental tapes that differed only in the yarn of the single tricot stitch were evaluated using the paired comparison method and their mechanical properties were measured. Furthermore, we compared the results with the effect of yarns of single satin stitch on hand evaluation reported in previous studies. The results are as follows. (1) Knitted tapes that differed only in the yarn of the single tricot stitch affected the hand evaluations of “dry” and “easy to slide”. (2) There was no significant correlation between the mean preference scores of “dry” and “easy to slide” and the friction property and roughness property. (3) Knitted tapes using a yarn with a high crimp recovery rate for single tricot stitch were evaluated as “dry”, and knitted tapes using a yarn with a low crimp recovery rate for single tricot stitch were evaluated as “not dry”. (4) Knitted tapes using a yarn with a high heating shrinkage tension for single tricot stitch were evaluated as “easy to slide”, and knitted tapes using a yarn with a low heating shrinkage tension for single tricot stitch were evaluated as “not easy to slide”.

In this study, each clothing pressure at 24 points of the subject’s shoulder was measured by the air-pack sensor system. And each pressure sensitivity threshold at same points was measured by the Semmes-Weinstein pressure aesthesiometer to investigate the burden of jacket weight on each region of the shoulder.
The results are as follows. (1)Both clothing pressures at the side neck and shoulder were higher than those of other parts when the subject wore the jacket. (2)The pressure sensitivity threshold at the side neck was lower than those of other parts. (3)From the relationship between the clothing pressure and the pressure sensitivity threshold, it is considered that the subject felt the jacket heavy when its weight gave pressure to the side neck with the low pressure sensitivity threshold.