蛙又結節および本目結節の表面積

Abstract

This report clarifies the surface areas of knotted netting, especially on knot which plays an important role for carrying out fluid-dynamical studies on netting fabrics. In this study, the so-called “knot” is defined as a tied portion of the twine including short legs, provided that the legs are cut veritcally along a normal direction under a condition of stretched mesh. The nettings used are made of Weaver's knot and reef knot, with the three-ply z-twist polyethylene twine. The surface area of a knot is obtained by measuring the circumference of cross-section of a paraffin-knot-model, with curvimeter. Results obtained are as follows: 1) Netting surface area Ssw of Weaver's knot is represented as following experimental equation. Ssw=2ij{2Q(l-3.87d)+31.67d2}+31.67d2(i+j) 2) Netting surface area Ssr of the reef knot is represented as following experimental equation. Ssr=2ij{2Q(l-3.42d)+26.31d2}+26.31d2(i+j) Where each symbol is as follows, d: diameter of twine, i: mesh numbers along the twinewise direction, j: mesh numbers along the normal direction, l: length of a leg, Q: circumference of a twine, Ssr: surface area of the (i×j) meshes reef knot netting, Ssw: surface area of the (i×j) meshes Weaver's knot netting.