Investigation on influences on the service life of running ropes under reverse bending

• Applicant: Professor Dr.-Ing. Robert Schulz, since 7/2019
• Subject Area: Engineering Design, Machine Elements, Product Development
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 406702566

The influences of reverse bending on the reduction of service life of running ropes compared to simple bending is today mostly uninvestigated. Nevertheless, in many applications of mechanical handling machinery like elevators, cranes, ropeways, or in stage machinery, it is not possible to avoid reverse bending completely and therefore it has to be included into the lifetime calculation of the rope drives. State of the art standards and lifetime calculation methods take account of the additional damaging of running ropes under reverse bending on basis of a general constant factor. On the other hand, in advance of this research proposal conducted literature research, as well as pilot tests on bending machines of IFT showed dependencies of the service life reduction due to reverse bending of many parameters, e.g number of strands, lay, rope force and sheave to rope diameter ratio. Especially the axis distance of the sheaves under reverse bending evidently have great influence on the amount of additional damaging to the running rope. The conducted pilot tests revealed remarkable discrepancies compared to the results of theoretical lifetime calculation what in many cases can lead to major safety risks. The proposed research project aims on conducting basic research to develop widely usable parameters for taking the service life reduction of ropes under reverse bending into account for lifetime calculation of rope drives. Especially the circumstances under which the rope can “escape” the additional damaging due to reverse bending, but also the circumstances under which the additional damaging of the rope is disproportionately higher are to be investigated. The results of the scientific investigation will increase the availability and safety of rope drives with reverse bending and eliminate today existing safety risks. Existing knowledge deficits will be closed and for example possibly wrong estimations of rope lifetime in rope drives with reverse bending, safety risks and wrong estimations with view to service and inspection intervals will be avoided in future. The acquired understanding of the mechanisms of damage of the rope under reverse bending can be of use in all fields of applications of materials handling.

• DFG Programme: Research Grants
• Ehemaliger Antragsteller: Professor Dr.-Ing. Karl-Heinz Wehking, until 7/2019