Condition Monitoring Technologies for Steel Wire Ropes – A Review

In this research, we review condition-monitoring technologies for offshore steel wire ropes (SWR). Such ropes are used within several offshore applications including cranes for load handling such as subsea construction at depths up to 3-4000 meters, drilling lines, marine riser tensioner lines and anchor lines. For mooring, there is a clear tendency for using fiber ropes. Especially for heavy-lift cranes and subsea deployment, winches with strong ropes of up to 180 mm in diameter may be required, which has a considerable cost per rope, especially for large water depths. Today’s practice is to discard the rope after a predetermined number of uses due to fatigue from bending over sheaves with a large safety factor, especially for systems regulated by active heave compensation (AHC). Other sources of degradation are abrasion, fretting, corrosion and extreme forces, and are typically accelerated due to undersized or poorly maintained sheaves, groove type, lack of lubrication and excessive load. Non-destructive testing techniques for SWR have been developed over a period of 100 years. Most notably are the magnetic leakage techniques (electromagnetic methods), which are widely used within several industries such as mining and construction. The content reviewed in this research is primarily the developments the last five years within the topics of electromagnetic method, acoustic emissions (AE), ultrasound, X- and γ-rays, fiber optics, optical and thermal vision and current signature analysis. Each technique is thoroughly presented and discussed for the application of subsea construction. Assessments include ability to detect localized flaws (i.e. broken wire) both internally and externally, estimated loss of metallic cross sectional area, robustness with respect to the rough offshore environment, ability to evaluate both rope and end fittings, and ability to work during operation

Aplicação do ensaio de emissão acústica à inspecção de cabos de aço

Trabalho final de mestrado para obtenção do grau de Mestre em Engenharia Mecânica – Ramo ProduçãoNos recentes anos, a presença dos ensaios não destrutivos na indústria tem-se revelado como essencial para o envolvimento da qualidade na produção e na manutenção dos mais diversos equipamentos. Entre o vasto espectro de ensaios não destrutivos, este trabalho destaca a aplicação do ensaio de emissão acústica na inspeção de cabos de aço, um dos elementos de transmissão mecânica mais importantes atualmente. Este trabalho inicia-se por uma revisão teórica sobre cabos de aço, ensaios não destrutivos, o ensaio de emissão acústica e o estado da arte da aplicação desta técnica aos cabos de aço. Com base nesta revisão, são realizados dois ensaios experimentais, nomeadamente a análise do comportamento acústico de um cabo sob tração e a determinação da localização de fissuras através do software de processamento de sinal.In recent years, nondestructive testing presence in industry has been revealed as essential for quality involvement in production and maintenance of several equipment’s. Between the diverse spectrum of nondestructive testing, this work highlights the acoustic emission testing application in wire rope inspection, one of the most important transmission elements today. This work initiates with a theoretical review of wire ropes, nondestructive testing, acoustic emission testing and a state of the art of this technique applied in wire rope inspection. Based in this review, two experimental tests were conducted namely the acoustic behavior analysis of a wire rope subjected to tensile stress and the second test was the location of cracks via a signal processing software.N/