Research on appropriate topology for jacket-type platforms exposed to hydrodynamic forces

In this study, it is aimed to determine the design with the most stability and the least cost by creating structure models against the environmental forces as specially wave and wind that can cause destructive effects that jacket type platforms preferred in open seas are exposed to. Three different jacket type platform models were created, these platforms were dimensioned, and the material types to be used were determined. Steel pipe profiles with diameters between 300 and 600 were preferred for the elements that make up the platform. Wave parameters such as wave height (H), wave period (T) and water depth (d) were chosen as 5m, 11s and 55m, respectively. According to these values, the valid wave theory has been determined. Fluid particle velocity and acceleration values that change depending on time and depth are calculated in accordance with Stokes 2nd Order Wave Theory and transition depth conditions. The calculated velocity and acceleration values were used in the Morison Equation to determine the lateral hydrodynamic force FH values. The values of the hydrodynamic force increasing from the seabed to the free water surface at the jacket type platform nodes were calculated by load balancing. The forces obtained were assigned to the nodal points by analyzing in the Time Domain with the Sap2000 package program. The maximum displacement and stress values that may occur during the wave period in the strut, transverse and diagonal bars used in the platform model were recorded. The data set, in which the displacement and stress values used as determining parameters of stability are output, was created separately for the strut, latitude and diagonal elements the relationship between the diameter, wall thickness and hydrodynamic force accepted as input was examined. The results obtained by the regression analysis were presented and the performance of the established relationship was evaluated. It has been determined that the relationship between inputs and outputs also changes depending on the changing topology. Among the models used, it has been interpreted how to realize a design with a higher stability with less material. Keywords: Jacket Type Platform, Stokes 2. Order Wave Theory, Stability Analysis, Morison Equation, Regression Analysis