Method for determining lay length of outer-layer strand of steel wire rope through one-circle spread length of secondary spiral steel wire

The invention discloses a method for determining the outer strand lay length of a steel wire rope according to the one-circle spread length of a secondary spiral steel wire. The method comprises the steps of measuring the diameter D of the steel wire rope, the lay length T of the steel wire rope and the diameter delta of the secondary spiral steel wire; calculating a cosine value cos [alpha] of a steel wire rope twist angle [alpha]; the absolute gap eta < jdjx > of the outer-layer strand is obtained; calculating the strand diameter d of the steel wire rope; the unfolding length l2time of the secondary spiral steel wire rotating one circle around the central steel wire is obtained; and according to the geometrical relationship among the strand lay length, the strand lay angle, the strand diameter and the steel wire diameter, the outer strand lay length t of the steel wire rope is obtained by rotating the secondary spiral steel wire around the central steel wire of the strand by one circle and unfolding length