Wire ropes under fluctuating tension and bending

Over the last years a method has been developed to calculate the endurance of wire ropes in rope drives Feyrer (1988,1989). This method is based on a statistical evaluation of results of wire rope bending tests. ln this method an initial estimate is given of the influence of combined fluctuating tension and bending on the wire rope endurance. Two types of combined bending and fluctuating tension exist. ln the first type the bending and fluctuating tensile loads do not increase the amplitude of the wire stress simultaneously. This type is called independent loading by bending and fluctuating tension. The longitudinal wire stress in a wire rope under independent bending and tension is illustrated in Figure 1 (a). After being bent over a sheave for a time the wire rope is subsequently stressed by a higher tensile load.