COMPARISON ON THE IMPACT OF REVERSE BENDING ON THE DETERIORATION BEHAVIOUR OF TWO TYPICAL RUNNING ROPES

Summary

At IFT, a public funded DFG-research project presently assesses the mechanisms and the quantity of additional deterioration of ropes running over sheaves in reverse bending, compared with simple bending. A first set of results are presented within this paper.

Comparative tests with two different constructions of steel wire ropes were conducted on standard bending fatigue testing machines and on a special reverse bending test apparatus. Ropes were tested until break to establish the target number of cycles for the subsequently conducted tests of partial deterioration of the ropes. All tests were done in both bending modes, simple and reverse bending.

While testing, special attention was given on the wire break appearance and rotation behaviour of the ropes in both modes.

With the 8x19S and the 35x7 rope, two very different rope constructions used in very different applications were chosen for the testing. Higher impact on the lifetime reduction, caused by reverse bending, was observed for the 35x7 than for the 8x19S.

Author(s): S. Hecht