When the outside temperature is high or the human body is engaged in strenuous activities, the clothing wrapped around the surface of the human body will be wetted by a large amount of sweat. In recent years, as the research on the development of functional textiles has intensified, the study on the comfort of fabric manikin under such conditions has attracted more and more attention from researchers. The balance of heat production and heat dissipation in the human body is a necessary condition for the continuation of life. Heat production depends on the physiological change process in the body, while heat dissipation is carried out through four ways: convection, conduction, radiation and evaporation. The heat dissipation is related to the surrounding environmental conditions and the performance and state of the clothing fabric, especially after the garment is wetted, the thermal resistance of the garment changes, and the balance of heat production and heat dissipation of the human body is broken.
Sweating Fabric Manikin principle analysis:
Human body sweating can be divided into hidden sweating and visible sweating. When the temperature is low, that is, below 20 ℃, people are in a static state, through breathing, skin pore diffusion, every hour from the body sweat, heat, this sweating people do not feel, so called no sense sweating, called recessive sweating. When the temperature rises above 25℃ to 30℃, the human body emits about 174-348 kcal of heat per hour through radiation and convection without showing sweat, but it is still lower than the heat produced and needed in the body, then the human body has to dissipate heat in the form of evaporation by discharging sweat through sweat glands all over the body. This sweat is in a liquid state, so that people are in a more comfortable state, thus maintaining the important function of energy and health. The unobtrusive sweating that occurs in a day and night is about 500-700 ml, while people who exercise vigorously or work in a hot environment, for example, sweat an average of 4.51±0.3 L when the temperature is 25-35°C for 4 hours of long-distance running training, and up to 6.4 L when the temperature is 37.7°C and the relative humidity is 80-100% for 70 minutes of soccer training. All of these conditions are manifest sweating.
Although it is said that the main reason for a lot of sweating is the external temperature, the intensity of thermal radiation, temperature, humidity and the amount of exercise per unit of time, but the human body's dressing situation should not be ignored. In fact, in the high heat and humidity of the apparent sweat state, with the increase in the level of human metabolism, the form of wet transfer has not only gaseous water but mainly in the form of liquid water transfer. At this time the body's discomfort will become particularly serious.
From the international Sweating Fabric Manikin laboratory research situation, although the research in the field of thermal and wet comfort of clothing has a certain scale, the test has also been refined to all aspects of thermal and wet comfort, but the theory of thermal and wet comfort research in wetted fabrics is not perfect, most of the indicators proposed to evaluate the thermal and wet comfort and the test instruments related to it are Established in the fabric is dry state, rarely see the wetted fabric thermal and wet comfort performance reports. When a person exercises vigorously, the body temperature will rise, and the body temperature will be restored to normal by the sweating function. Sweat in the form of liquid water all over the skin surface, and even flow, clothing is usually moistened, sometimes even soaked. It has been reported that after strenuous exercise, water vapor accumulation causes clothing weight to increase by up to 10%, and the moisture formed by perspiration must be absorbed through fabric penetration and then expelled to the body. If the body heat can not be discharged, moisture between the body and clothing back and forth, will cause uncomfortable feeling, the human body sweat function, is a normal behavioral response, so the comfort and fabric has a greater relationship, so in the design and development of sportswear or special clothing before, the wet state of the fabric heat and moisture comfort performance testing and evaluation is particularly important.