Investigation of the damage caused by wire contact points and its influence on the safety of running high-strength ropes

• Applicant: Professor Dr.-Ing. Robert Schulz
• Subject Area: Engineering Design, Machine Elements, Product Development
• Term: from 2020 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 454015252

• Final Report Year: 2023

Final Report Abstract

The two methods established today for calculating rope service life result in incorrect estimates with overestimated service life predictions for ropes with wire strengths greater than 1960 MPa at the same absolute load. In reality, the service life may be reduced with increasing wire strength. The reason for the incorrect estimation is seen in the previous neglect of the different deformation capacity of wires and ropes made from them. The methods used to date in rope technology are stress-based and consider the acting rope stress in comparison with the nominal strength as decisive for the fatigue behavior. The aim is to clarify the service life differences of ropes. To this end, rope fatigue was evaluated on the basis of deformation behavior in systematic investigations. The relationship between fatigue behavior and deformation capacity was first systematically investigated and demonstrated by individual rope wires of different strength. The results confirm the decisive influence of the deformation behavior of the various rope wires on their fatigue behavior. Based on this, this relationship was equally confirmed in systematic investigations on ropes, which explains the differences in service life. For the evaluation of the service life of ropes, the comparison of the deformation behavior by means of a comparison of the stress-strain curves in normalized representation serves to classify the fatigue behavior at a given load. The research project carried out has for the first time provided a comprehensive and fundamental understanding of the influence of deformation capacity on the fatigue life of wire and rope. A methodical approach as the basis of a new method for evaluating and predicting the service life of ropes of different quality was demonstrated.

Publications

• „Einfluss von Pressellipsen auf das Versagensverhalten hochfester Seildrähte. In: Ilmenauer Drahttag, 2019, pp. Einfluss von Pressellipsen auf das Versagensverhalten hochfester Seildrähte. In: Ilmenauer Drahttag, 2019, pp. 83-99“, 2019. ISBN-10: 3-938843-96-9
  W. Frick
  
• „Loss of breaking load of high-strength wires during transverse pressure. In: OIPEEC Conference – The Hague, 2019, pp. 247-264“, 2019. ISBN-13: 978-1- 7336004-0-8
  W. Frick,
  
• „On the assessment of the residual service life of fibre ropes in use. In: OIPEEC Conference – The Hague, 2019, pp. 35-50“, 2019.
  A. Frick; W. Frick & G. Novak
  
• „Den Fasertyp bei Faserseilen identifizieren - Teil 1“, f+h Fördern und Heben, Nr. 07-08, Juli 2021.
  A. Frick; W. Frick & R. Schulz
  
• „Den Fasertyp bei Faserseilen identifizieren - Teil 2“, f+h Fördern und Heben, Nr. 09, Sep. 2021
  A. Frick; W. Frick & R. Schulz
  
• „Seildehnung als Ermüdungsursache?!“, Technische Logistik Hebezeuge Fördermittel, Huss-Medien GmbH, Nr. 07–08, Juli 2021.
  A. Frick; W. Frick & R. Schulz
  
• „A new method for evaluating the service life of steel wire ropes of different wire strength“, in Proceedings of OIPEEC Conference 2022 and 7th International Stuttgart Ropedays, Stuttgart, Sep. 2022, S. 1–21. ISBN-13: 978-1-7336004-1-5
  W. Frick
  
• „Rope deformation as the cause of fatigue in running ropes“, in Proceedings of OIPEEC Conference 2022 and 7th International Stuttgart Ropedays, 2022, S. 55–73. ISBN-13: 978-1-7336004-1-5
  A. Frick; W. Frick & R. Schulz