The Study Of Cushion Pressure Distribution Based On Ergonomics

Sitting Posture is the daily behavior of most of the crowd. Its comfort is important because the poor sitting posture may lead to fatigue, scoliosis, and spur. Cushion, which is from the direct contact with the hard seat, is the well known tool that can alleviate the discomfort. And it can help to improve the efficiency of human’s work or study.The research of cushion pressure comfort involves an objective experiments and subjective evaluation. The BIOFORCEN Pressure Distribution System was used to accomplish the objective pressure tests in this thesis. It can obtain4pressure values per square centimeter. The pressure distribution and the basic parameters, such as: total pressure, the contact area, the average pressure and the pressure center position, the geometric center location, etc can be put out. Pressure test of cushions are closely related to sitting posture with taking the seat. Two sitting postures with single support point and double support points sitting posture were studied in this thesis. The Martin Measuring Instrument was used to get the basic physiological data of the subjects in two sitting postures, such as sitting deep, sitting wide, etc. The subjective evaluation was carried out simultaneously during the pressure tests. The items include the comfort in waist, hips, legs and the psychological feelings.(1)Taking seat is a short dynamic process. There is small variation of the pressure centre and geometric centre in the width while the displacement of them is significant in the depth. Both centers are stable in in one position.(2)Large deformation cushion reduce the average pressure through increasing the contact area of the buttocks and cushions. The contact area is related to hip width. It is bigger in the large deformation cushions more than in the small deformation cushion.(3)It is irrelevant whether the area of cushion surface have been increased. For example, the average pressure of the cushion with wave-surface does not decrease.(4) During the experiments with30min, the average pressure of small deformation cushions increase greater than that of large deformation cushions.(5) During the experiments with30min, the buttocks feeling are more comfortable in the sitting posture with double support points; the sitting posture with single support point is better able to reduce the pressure of lumbar; and the comfort of legs are no relationship with sitting posture.