Study on Damage Tests Based on Structure and Operating Parameters of Wire Ropes Used by Conveyors in Orchards

Abstract The regularity of wire rope breakage of new-type rail conveyors used in orchards is not clear yet. The breakage may be mainly associated with the diameter and material of pulleys, wire rope tension, and linear speed, as well as exposure to acid rain and sandy soil. This paper took wire rope structure and operating parameters as the research object, designed and built a simulation conveyor wire rope winding test platform based on programmable logic controller (PLC), and verified the feasibility of the system to automatically control wire rope tension, and then conducted the wire rope winding test. According to the tests, a wire rope will have earlier wire breakage and faster wear if it works at a higher speed or in greater tension—a wire rope reached the scrapping criterion after 2,000 cycles of working at the speed of 29.35 m/s or at the tension of 6,500 N. Sandy soil and acid rain are also great contributors to wire breakage, and finer sandy soil or greater acidity of acid will cause more severe wire breakage—a wire rope reached the scrapping criterion after 3,300 cycles of work if exposed to acid rain with pH value of 2.0. Pulley diameter also counts: the smaller the pulley diameter is, the less wear the pulley will cause; and pulley material also plays a part—Q235 steel pulley may cause greater wear than a nylon pulley. Wear and plastic deformation of outer wires lead to surface material loss of a wire rope, thereby resulting in crack or even fracture of single wires, greater tension of other unbroken wires, and accelerated wear of the whole wire rope to the scrap criterion. The study aims to provide a reference for optimizing the safety performance of conveyors in orchards, as well as for maintenance and care of wire ropes in other applications.