Russian Maritime Register of Shipping (RS) says it has issued the new Guidelines on Fatigue Assessment of Ships (the Guidelines).
The document is to underpin the new distinguishing marks FTL(years) and FTL(years) Spectral North Atlantic, that confirm fatigue life of a ship, with check calculations requirements.
Fatigue life assessment at the design stage is necessary to ensure the required service life of hull structures through the prevention of failures originated by fatigue cracks at welded joints that affect plate structures and fatigue cracks at detail edges. The new Guidelines include the procedure for calculation of fatigue life by using S-N curves, cumulative damage approach as well as a range of stress assessment methods. The document is developed with close consideration of the relevant IACS requirements, inter alia, IACS Recommendation No. 56.
Distinguishing marks FTL(years) and FTL(years) Spectral North Atlantic were introduced in 2019 with an added objective to contribute to the construction of innovative assets, such as state-of-the-art gas carriers.
The distinguishing mark FTL(years) may be granted to the character of classification if design remaining life of a ship (fatigue life) exceeds 25 years. The design remaining life of a ship within the range of 25 – 40 years (in 5-year increments) is indicated in parentheses. The distinguishing mark FTL(years) Spectral North Atlantic is granted upon the verification of the fatigue life by direct calculation with the application of spectral method.