Refined assessment method for fatigue damage of wide, flat and fat large river-sea direct ships

Abstract

The invention relates to a method for finely evaluating the fatigue damage of a wide, flat, large-scale river-sea direct ship, which comprises the following steps: S1, simplifying the load into two-stage alternating loads with different load history ratios; S2, simplifying the load into different High and low frequency superimposed loads of frequency ratio and amplitude ratio; S3: Using the lognormal distribution model, according to the principle of maximum likelihood method and the fatigue test data of typical nodes of river-sea direct ships, determine the S-N curve of typical nodes of river-sea direct ships; S4: Evaluate the fatigue damage of typical nodes of river-sea direct ships under different routes; S5: Consider the high-frequency load components caused by wave shock vibration and slamming flutter in the load history of river-sea direct ships, and introduce nonlinear load coupling damage factors, Fatigue coupled damage considering high and low frequency superimposed loads. The invention can provide a strong support for the fatigue damage assessment method of the wide, flat and large river-sea direct ship hull for the anti-fatigue design and the lightweight design of the river-sea direct ship.

Description

technical field [0001] The invention relates to a refined assessment method for ship fatigue damage, in particular to a refined assessment method for fatigue damage of a wide, flat, large river-sea direct ship. Background technique [0002] The new type of river-sea direct container ship has the characteristics of an ultra-wide and flat ship shape, and its hull load, structure type, and stress concentration position will all change. The larger width-to-depth ratio results in a smaller vertical stiffness of the hull, which is easier to navigate in sea sections. Affected by the nonlinear high-frequency load components caused by wave shock vibration and slamming flutter, while the ship sails back and forth in the river and sea sections, it is always in the alternation of high-amplitude loads in the sea section and low-amplitude loads in the river section These will have a significant impact on the cumulative fatigue damage of river-sea direct ships. [0003] The structural des...

AI Technical Summary

Problems solved by technology

[0003] The structural design of traditional river-sea direct ships often refers to the specifications of sea-going ships, mainly for the route characteristics and load characteristics of sea-going ships. There is no specific specification for fatigue strength assessment, ignoring the coupling damage caused by the interaction of river-sea loads and the superposition of high and low frequency loads

Although this method can ensure the safety of the hull, due to its large safety margin, overblown structure, and low economic efficiency, it cannot meet the economic requirements of green ships in the new environment and the national development of the golden waterway of the Yangtze River.

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