Abstract
In a wear experiment of cylindrical test-pieces rubbed against running yarn, contact pressure decreases with the growth, of wear of the groove, even if yarn tension is kept constant, Therefore, contact pressure should be taken into account when test results are to be analysed.
In the present report, a theoretical formula has been derived for the average contact pressure which dependeds on yarn tendon, the shape and size of the wear of the groove. It is assumed that the test-piece is not deformed by the action of contact pressure ; and that the contour of the ear of the groove is represented by a circular arc. The cross-sectional and lengthwise destributioris of contact pressure between the yarn and the groove on the test-piece are presumed to be expressed by the modified Hertzian formula and the exponential formula. The theoretical formula for the apparent coefficient of friction has also been derived to estimate the effects of compressibility of the yarn on the contact pressure.
Some results of the wear test have been analysed applying these formulas, and the wear behavior is interpreted in a more definite manner.
