ワイヤロープ心ロープの実働下での破損

抄録

The fracture of a wire rope used in a travelling jig crane caused a serious accident. In order to examine the mechanism of breakage, the reduction of diameter at the fracture portion of the wire rope was measured and the number of fractured wires around the wire rope was counted. Furthermore the sectional appearance near fracture portion and the fracture surface of the wires were observed. The main conclusions obtained in this paper were as follows;
(1) Friction among the wires of the wire rope core rope caused the wear of wires to reduce the sectional area of the wire rope. The wear extremely took place between outlayer of outer stand and the wire rope core (inner strand). The wear caused the reduction of sectional area and diameter of the wire rope.
(2) The increase of the applied stress in the wire due to the reduction of sectional area causes the growth and propagation of fatigue cracks.
(3) Usable limit for wire rope enacted by Japanese Labor Ministry for the structure of travelling crane is considered to be insufficient to use a wire rope core rope safely.