SOME MEASUREMENTS OF GARMENT COMPRESSION ON THE BODY

Abstract

Garment pressure on the body is an important index of garment restraint. A comparison is made between two direct methods (I and II) of measuring the compression provided by a knitting supporter, and an indirect method involving the measurement of supporter tension. Pressure exerted by the garment was measured at the knee sitting on the chair, using a model with two reduction sizes (5 and 20% reduction to the normal knee size). The 48 sites at the knee were measured for each testing.The results of the indirect method indicated that the pressure exerted on the knee by a garment was not only determined by supporter tension but was also dependent upon curvature of the knee surface. This is stated by the following modified Laplace relationship;where, P=pressure, T=tensile force, r=radius of curvature, w=wale direction and c=course direction. The level of biaxial strain on the supporter was measured by photographic methods. Stress-strain relationships on the supporter fabric by biaxial stretching, were determined using the values of tension of 48 points on the garment. The distribution of biaxial tensile force and pressure tended to decrease from the center to the circumference of the knee. It is considered that frictional force acts on between the body and the supporter. The ratio of frictional force F to pressure P is found to be given by F=kPn, where k and n are constants. This equation can be applied to some other non-metalic materials and textiles.In the direct method (I), semiconductor pressure sensor, which has high sensitivity and thin and small size not to disturb the wearing condition, was used. The pressure sensor was put into a small rubber bag with low viscous silicone oil to be suitable for measuring pressure on the human body surface. It was capable of dynamic measurement by this method. In the direct method (II), a small rubber bag, contained colored water, with a fine tube manometer, was used to measure the pressure in the static wearing condition. Some discrepancies found among the results obtained from three methods were compared and discussed.