Investigation of Repetitive Bending Durability of Synthetic Fiber Ropes

A synthetic fiber rope, which is lightweight and has a high tensile strength and flexibility, is receiving considerable attention as a replacement for a stainless steel wire rope. This letter describes its ability to endure repetitive bending. We performed experiments in conformity with the ISO 2020-2 standard using ten synthetic fiber ropes made of different materials and with different compositions, along with two stainless steel wire ropes. As a result, a 7 × 19 stainless steel wire rope and an ultrahigh molecular weight polyethylene rope (SK-71), which has a high resistance to frictional wear, did not experience significant loss of tensile strength. However, repeated bending caused the tensile strength deterioration of the other synthetic fiber ropes, which had low resistances to frictional wear. In the case of steep bending with a small pulley or bending with high tension, we experimentally revealed that some synthetic fiber ropes are superior to stainless steel wire ropes.