Study on the Contact Pressure between the Lower Leg and the Top Part of Socks Using Finite Element Method
|Keywords||Socks Pressure Anthropometric Displacement Finite Element Curve fitting Principal Component Analysis|
With the continuous improvement of the living standards and health dress concept is deeply rooted in the hearts of the people, the growing trend of high clothing comfort. In recent years, pressure the comfort has gradually become one of the important indicators in addition to the the hot wet comfort and tactile comfort measure clothing wearing comfort. Wearing parts in the human body, from the current situation, rare reports of male socks socks pressure, pressure socks literature, mostly starting from a medical point of view, explore varicose socks on the human body the pressure, but not from clothing ergonomic point of view of a reasonable explanation, not more pressure to quantify. Subject to male socks socks, socks depth pressure on the neck of the human foot, and the relationship between pressure and compression of a use of human body surface displacement pressure study new methods provides a theoretical basis for the optimal design of socks to fill the gaps in the field. In this study, by age in 50 healthy male college students between the ages of 20-25 standard size three-dimensional body scanning, for the first time to determine the socks at section morphology of the human foot neck, the cross-section curve equation and curve perimeter for socks The mathematical model of the pressure at the data base. In the course of the study, the human body as the contact between the elastic body, feet, neck and welt as resilient contact, combined with the welt at the structure of the human foot neck, the position of the bone, the shape as well as the skin, soft tissue thickness, elastic modulus the amount and Poisson's ratio, for the first time established the socks at the foot neck bit finite element simulation model, the model assumes that the leg skin, soft tissues, bones are a homogeneous isotropic linear elastic material, and by the ANSYS finite element software socks at the pressure and displacement distribution for simulation analysis, the functional relationship between pressure and surface displacement of any point of view in the leg-section for the the pressure comfortable quantitative research provides the basic data. The study shows that, for two socks, in the same point where the leg cross section, different socks between pressure and displacement of multiple relationships are basically the same, i.e. the pressure between the multiples ratio is approximately equal to the displacement between the multiples than. The studies have also socks at the neck of the human foot section is divided into four zones according to the angle, respectively [0o, 90o] (region Ι) [90o, 180o] (region ΙΙ) [180o, 270 °] (region ΙΙΙ) and 270 °, 360o] (region ΙV). Based on the finite element simulation results, when participants dress in static, regional ΙΙΙ leg-sectional area shrinkage largest sites, regional ΙΙ minimum site area of ??shrinkage area Ι shrinkage, and regional ΙV area almost equal region ΙΙΙ area shrinkage of about three times the area ΙΙ, approximately the regional Ι, and regional ΙV the 2 times, the conclusion provides a theoretical basis for the optimal design of the socks. This study also discusses the dynamic pressure, when the human body wearing socks and the dynamic pressure is divided into two portions of the pressure change over time, and the pressure of the body during walking. Which change over time, the pressure is divided into six time periods, respectively, for the instantaneous pressure, 1h, 2h, 4h, 8h, longest time duration defined as 12h. Walking into an upright position, the leg elevation 10 ° and 30 ° leg elevation and leg kick after four stages. The study shows that the socks at the foot neck and the pressure gradually decreases with the socks wearing time prolonged. Within 1h after dress, the pressure decline, approximately one-third of the overall decline after 2 hours, the pressure drop is basic to half of the overall decline, then, the pressure to reduce the speed over time extend gradually slow after about 8h the socks at pressure equilibrium, and the pressure of the gap between the maximum and the minimum value is shrinking with time, to the last leg cross-section point pressure values ??are becoming more and more The basic approximate state. Socks the same mouth fabrics socks, socks and socks at the original larger the initial pressure, the greater the pressure point, the greater the decrease in pressure with time. For cotton and nylon fabric used in the present experiment, with the dress time prolonged Mianwa inlet pressure decrease greater than nylon socks. Leg-sectional area of ??shrinkage with time and showed an increasing trend, in this process, the Regional ΙΙΙ area shrinkage most obvious change, the change of the regional the ΙΙ area shrinkage minimum. Dress 12h later, the area of ??the region ΙΙΙ shrinkage is about five times the growth ΙΙ area. During walking, less pressure on the leg-section point pressure values ??changed little. When the welt fabric with the same, the greater the pressure of the sock in the walking process, the greater the magnitude of pressure variation in the pressure value of the larger position,. For cotton and nylon fabrics, cotton socks mouth pressure variations greater than nylon socks. Socks pressure during walking for most of the leg-section area, the upright position by the leg after kicking stage pressures minimal. The legs cross-sectional area of ??the region of shrinkage is little change in the walking process, while the area of ??the upright state shrinkage is slightly larger than the other three phases. The study also analyzed the relationship between the various factors affect the pressure level, and ultimately determine the pressure level is closely related to the four indicators were socks material stiffness coefficient, Poisson's ratio, socks elastic elongation, original socks width. Establish the functional relationship between the pressure with four indicators through principal component analysis and as a basis for the establishment of a mathematical model to predict by the pressure of socks at graphics tests and chi-square test, the goodness of fit of this model with actual measurements can provide a theoretical basis for prediction of clothing pressure.