Research on Relationship between Pressure and Area on Lower Leg Cross-Section at Top Part of Men ’ s Socks

Socks are one of the most common wear covering the lower leg in daily life. In this experiment, 40 participants are scanned, all 20 to 22 years old college students, to research the distribution of the pressure of the cross section of the lower leg. First we obtain the figure of the cross section of lower leg at the top part of socks, 6cm above the ankle point, by using 3D body scanner (Tec Math). Next we can draw a standardized figure of the section. After that, 8 equations describing the curve of the section can be achieved by curve fitting. And then, we divide the section into 12 regions by angle (30°) and choose 12 testing points to measure the pressure. Finally, we have calculated the area of each region and have found the relationship between the pressure and the areas.


INTRODUCTION
With the improving lifestyles and changing notions of people, the clothing comfort has become one of the most important performances required by modern customers day by day (Meng and Zhang, 2006).In Li's research they found that the clothing comfort contains 3 independent factors: thermal comfort, tactual comfort and pressure comfort (Li, 1998).And the pressure comfort researching has become a hot spot in clothing comfort field in recent years.
Socks are one of the most common wear in people's daily life and the research about the comfort pressure value of the top part of socks is very important in designing and developing these products (Li, 2007).Currently, the researches about the pressure comfort of socks are still at early stage, but have covered many fields.Homata (Momota et al., 1993) and Toshiyuki (Tsujisaka et al., 2004) have found the comfort pressure value of the top part of socks.In 1998, Kenjishoh (Kenji, 1998) began to test the pressure of socks by using elastic optical fibers.Nakahashi learned the influence on the circulatory system caused by the pressure of stockings (Nakahashi et al., 2003).
Nowadays, the researches on clothing pressure were still focused on the measuring methods, testing machines and valuing peoples' feelings on the pressures.Current researches showed that there were still some shortcomings and limitations in these fields:  All the testing machines would change the status of the body when measuring clothing pressures. The participants' individual differences were very big, so valuing the comfort of the clothing pressure was very difficult.And the experimental procedure lacked repetition.
In this case, we must find a new method to predict the clothing pressure and value the comfort of pressure.So to build up a mathematic model based on ergonomics to predict clothing pressures became very important (Qiang et al., 2010).The cross section on lower leg at the top part of socks and the materials of the socks are both the important factors which could affect the pressure value directly.But now, researches on the figure of the cross section are still quite rare.Proceeding from the ergonomics and differential geometry, a mathematical model could be found to describe the distribution of curvature radius of the cross section, providing a good reference for the foundation of the mathematic model for predicting the pressure.
In this study, we have a research of the research on relationship between pressure and area on lower leg cross-section at top part of men's socks.Forty participants were scanned, all 20 to 22 years old college students, to research the distribution of the pressure of the cross section of the lower leg.First we obtain the figure of the cross section of lower leg at the top part of socks, 6 cm above the ankle point, by using 3D body scanner (Tec Math).Next we can draw a standardized figure of the section.After that, 8 equations describing the curve of the section can be achieved by curve fitting.And then, we divide the section into 12 regions by angle (30°) and choose 12 testing points to measure the pressure.Finally, we have calculated the area of each region and have found the relationship between the pressure and the areas.but the materials and the structures were different.We also selected one participant with a standard shape of the lower leg section to wear these socks and we could measure the pressure of each testing point by the AMI 3037-5S cells pressure tester.
First, we marked 12 spots on the surface at the lower leg of the participant.Next, the participant wore the socks.After that, put the cells of the pressure tester between the top part of socks and the surface of lower leg at the testing points.And then, we adjusted the socks to make the tension of the top part equal.Finally, we recorded the data.Figure 6 shows the AMI 3037-5S cells pressure tester.
Table 1 showed the pressure of each point and we also obtain the average pressure of each point from different socks.Figure 7 described the distributions of the pressure and Fig. 8 showed the average pressure distribution.From the figure we could also find that although the pressure of each sock was different, the regularities of the distributions were almost the same.The highest pressure of each socks occurred at the angle of 270° and the lowest at 0°.

RESULTS AND DISCUSSION
Correlation analysis between the pressures and the areas of the regions: According to the results of experiments, we found that the changing of pressure and the areas of the regions with the angle were similar.So we tried to get the relationship between the pressure and the area by SPSS Pearson's correlation analysis.-------------------- ---------------------  fitting.From Fig. 10, we found that most of the spots were on the curve and the rest were nearby.That meant we could predict the pressure by checking the area of each region and the materials of the socks.

CONCLUSION
In this research, we tried to find a method to predict the pressure when a man wears socks.The experiments have shown that there was a significant correlation between the pressure and the area and it might be possible to predict the pressure distribution by this way.And we also believe that the elastic potential energy must be linked with the pressure.

Fig. 4 :
Fig. 4: The regions and the testing points

Figure 5
Figure5showed the distribution of the areas changing with the angle.Pressure testing:We chose 6 socks (A1, A2, A3, B1, B2, B3) with same circle of 16 cm in the pressure tests,

Table 1 :
The p