Database method for supporting the condition assessment of modern wire ropes
It is obvious that various wire ropes used in different applications behave (work) differently. The endurance depends on so many factors: construction, different mechanisms of degradation, environmental conditions and human factors as well. According to ISO and European Standards concerning wire ropes the most popular discard criterion is loss of metallic area. It is measured by NDT means (Magnetic Rope Testing - MRT) or visually (Visual Testing - VT) by number of broken wires or loss of metallic area. New (modern) constructions of ropes have been used in specific applications for more than ten years. Compacted ropes and ropes with modern sophisticated cores are very popular. After more than ten years of observations in ropeways it is clear that such ropes behave differently compared to typical stranded ropes with fibre core. Almost no broken wires, corrosion and elongation are observed. This means that discard criteria based on loss of metallic area are insufficient to assess the state of such wire ropes. The authors suggest that during periodic inspections more parameters should to be taken into account. For example: local lay length and diameter changes, not typical “odd” MRT traces, visual inspection of the rope surface, local geometrical changes, X-ray inspection, etc. The problem is that hauling and carrying ropes in ropeways work for a very long time, sometimes more than 30 years. During such a long time it is difficult to collect many different data without knowledge, of which factor in the future will determine that the wire rope should be discarded. The solution could be a database system designed for different data formats, which are collected during the periodic wire rope inspections. The authors present such a dynamic database system. It allows not only collecting of data but their analysis and presentation as well. The system can help store data from modern visual inspections of ropes as well as different information about the rope installation, MRT equipment, environmental conditions, visual and additional tests results etc. The system will help also in managing all inspections, generating reports and scheduling the next date of the wire rope inspection.
Author(s): J. Kowalski, J. Nowacki and A. Tytko