THE ANALYSIS OF PRACTICAL USAGE EXPERIENCE OF THE SHIP STRUCTURES FATIGUE STRENGTH CRITERION

摘要

It is shown in the report, that the trial-and-error requirements of the Rules of classification societies to the minimum section modulus of transport ships, including the FPSO-type ships, are based, mainly, on the maintenance of their strength, the lack of which in riveted ships exhibits in the form of weakening of rivet joints, and in welded ships in the form, of cracks. The analysis of proposals for analytical formulation of the fatigue strength criterion (F.S.C.) during 150 years of development of steel shipbuilding confirms this thesis. It is shown, that modern recommendations of IACS (1999) do not provide stable reserves of fatigue resistance for ships of different standard-sizes, especially those constructed from high-tensile steels. In the report the ways of perfecting of the requirements to fatigue strength are offered.