This paper attempts to obtain a geometrical condition for the strand arrangement in a 8-strand braided rope, where the strand axis goes on drawing an elliptical helix around the rope axis, The geometrical development is based on three conditions as follows:
Strands in a pair are in contact among themselves without overlapping.
Two pairs of the same twisted strands are in contact once every half round.
Two pairs of the different twisted strands are in contact twice every quarter round.
Under the above three conditions, using the coordinate transformation with parallel moved distance h and rotated angle Ò, the values of semimajor axis a, semiminor axis b, coefficient c(=dls/dt, ls is the length of a strand axis, t the essentric angle of the ellipse). Ò, and h are calculated numerically. The results of the calculated arrangements of strand agree well with the observed ones.