The Study On The Interface Pressure Distributions And The Temperature Between The Testee And The Seat

Seats are the necessary furniture for people inside. Its degree of comfort affects the working efficiency and the rest quality. The west countries have put a lot to study the degree of seat comfort, and there has been the research on it in China in recent years. The interface pressure distribution and the temperature between the testee and the seat has been studied by changing the dimensions of the seat and the material of the seat surface. We get the conclusions as following.1 The study on the temperature between the testee and the seat⑴In the interface between the testee and the seat, the temperature of the points rises rapidly in the early five minutes and rise slowly after five minutes. It does not change after forty or sixty minutes usually.⑵The centre of the interface between the testee and the seat is of the highest temperature. And the temperature of the centers under the two hucklebone is a little bitter higher than that of the thighs. Maybe it is because the pressure of the hucklebones is much higher than that of the thighs.⑶Under a low room temperature, all these materials is comfortable for the testee. Among these the wood is not as warm as we want when the teastee sits down, but the testee does not feel cold any longer after five minutes.⑷When the room temperature is much higher, the temperature between the seat and the testee rises to more than 28℃in a short time and the temperature reach 34℃after 60 minutes. Though the temperature of the wood and the drapery are nearly the same, but the testee does not feel so fuggy on wood as on the drapery. Maybe it is because the wood can transfer humidity faster than the drapery.⑸The heat and humidity transfer capability of the seat surface materials in the standard are limited to a definite value, and they are not connected with the sense of the users. A new method is put forward here to study the heat performance of the seat surface material. For the heat and humidity transfer capability is relative to the nether sponge material though the users contact with the surface material only when they sitting on their seats.Generally speaking,the materials we use in the seat surface can meet the needs in a low room temperature. But in a higher room temperature the draperies make the testee feels fuggy. So in a high room temperature where air condition is not needed or available, we need the seat surface have a good temperature and humidity property.2 The study on the interface pressure distributions between the testee and the seat Conclusions from the experiments of single factor: ⑴According to the result of the subjective evaluation, when the height of the seat surface equals to the height of the back of the knees, the angle of the seat surface is zero degree and the angle of the seat back is ten degrees, the testees feel best.⑵The interface pressure distribution between the testee and the seat is different when changing the height of the seat surface. When raising the height of the seat surface, some indexes of pressure distribution reduce such as the peak contact pressure, average contact pressure, peak pressure grads and average pressure grads while the contact area between the testee and the seat becomes larger.⑶As the angle of the seat surface, the peak pressure, the average pressure, the peak pressure grads and the average pressure grads are all the lowest when the seat angle is negative five degrees(the seat is turned five degrees toward the front). But the testee feel not as well as the seat which is not turned an angle.⑷As far as the seat back is concerned, the peak pressure and the average pressure are the lowest when the angle between the seat back and the vertical surface is ten degrees.Conclusions from the experiments of multiple factors:⑴Most indexes of pressure distributions are of high association when changing the seating postures of the testee.⑵It is concluded from the range analysis that the angle of the seat back affects the peak pressure and the average pressure of the seat surface and the average pressure and the contact area of the seat back most, the height of the seat surface affects the average pressure , the peak pressure grads and the contact area of the seat surface most, and the angle of the seat surface affects the peak pressure of the seat back most.⑶From the results of the variance analysis, we can get that the height of the seat surface affects the indexes of the pressure distribution of the seat surface distinctly while the angle of the seat surface and the seat back influences the indexes of the pressure distribution of the seat back notably.⑷A part of the reasonable parameters of the seats is given: the height of the seat surface equals to the height of the back of the knees, the angle of the seat is 0°and the angle of the seat back is 20°。Generally speaking the dimension of the seat affects the pressure distributions. When changing the rigidity, the material distribution and the shape of the seat is impossible, we can change the pressure distributions through changing the dimension of the seat. Different pressure distribution index has a different physical meaning, it should be chosen to use according to the function of the seat.