Relation between Number and Distribution of Wire Breaks and the Residual Breaking Force

RoundTable – WIRE ROPE DISCARD CRITERIA - Zurich 1989

 Tensile tests on predamaged stranded ropes were performed. The aim of the tests was to determine the non-linearity of the relationship between the number and distribution of wire breaks on the one hand and the residual breaking force on the other. A reducing factor (k) was defined as a measure of the reduction of the breaking force. The tests show the following:
- if the damage to the rope is symmetrically distributed about its axis, the reduction of the breaking force varies little from the cross section loss (0 ≤ k < 0.15);
- the reducing factor is greater for an asymmetrical configuration of the damage,
the highest measured value being k < 0.5;
- crosslay ropes with an identical configuration of wire breakages have lower
reducing factors than Lang lay ropes.
The results show that the tests should be extended using further parameters.

Author(s): G. Oplatka & M. Roth