Study On Wave Loads Calculating Methods And Simplified Methods Of Modeling In The Global Strength Analysis Of A Semi-submersible Platform

Wave loads calculating and FE modeling are two problems with global strength analysis of a semi-submersible platform. Firstly, the results of different methods are quite different, so it is needed to do a comprehensive and comparative study to help people selecting property method when calculating the wave loads. On the other hand, in the preliminary design period, the structure design and response analysis is interactive, and the immediate feedback of structure response is needed. It is valuable to use some simplified methods to improve efficiency significantly under certain accuracy for practice engineering. The problems above of a new semi-submersible platform are researched in this paper. The main research work is as follows:1) The basic principle of 3D potential flow in frequency domain and three different design wave methods of calculating wave loads are elaborated.2) With different influence factors including wave steepness, sea area, return period and wave spectrum forms taken into account, the design wave methods of a new semi-submersible platform are calculated comparatively and studied comprehensively.3) The principle of orthotropic plate as the equivalence of stiffened plate is studied and elaborated. The processes of equivalent parameters calculating and the coming back of concerned stress in plane stress condition and bending condition are derived and tested. 4) The simplified principle of stiffened plates is put into the FE software. Based on the secondary development modules using PCL, the derivation of equivalent parameters and the coming back processes of concerned stress are finished automatically...