Research On The Springing Response Of The Ultra Large Ore Carrier

In order to improve economic efficiency, the dimension of ore carriers becomes larger and larger. In the process of the construction of ultra large ore carrier, the increased use of high-strength steels make the hull stiffness relative lower. Sailing in waves, the global vibrations frequencies of ultra large ore carrier come closer to the some components of wave frequencies, may cause springing. Springing can cause vibration stress of high frequencies of the structure of the ultra large ore carrier, superposing with the wave frequency stress, causing serious fatigue strength problem of ultra large ore carrier. Currently, the societies released the assessment methodology guidance documents on the influence of springing on the fatigue strength, but it did not give the detailed process of computing of the stress. This essay study the computing of the spring response of the ultra large ore carrier, the main contents are as follows:(1)The transfer matrix method and 3-dimensional finite element method are applied to calculate the dry modes of the ultra large ore carrier. The computing of modes of the ultra large ore carrier is studied.(2)The springing load responses of the ultra large ore carrier are calculated. The characteristics of the springing load response are studied.(3) The beam theory, quasi-static 3-dimensional finite element method, stress modes superposition method, transient 3-dimensional finite element method are applied to calculate the springing stress response of the ultra large ore carrier. The methods to calculate the springing stress response of the ultra large ore carrier are studied.(4) The process of computing of the fatigue damage of the ultra large ore carrier due to springing is summarized, referring to the relative regulations. The fatigue strength of ultra large ore carrier is studied.