Design Optimization of Jacket Substructure of Offshore Wind Turbine

The design optimization of the jacket substructure could reduce the cost of energy and the correlated carbon cost. The mass of jacket is optimized with respect to maximum stress and displacement responses. Wind and dead loads were applied at the top of the jacket referenced point. Wave load and foundation boundary were applied using Dload and UEL function in the Abaqus subroutine. Six different parameters were evaluated, including the pile height above mudline, the base width, brace thickness and diameter, and the main leg thickness and diameter. The parametrically optimized model has mass minimized by 16%. The maximum stress at the top of the optimal jacket reduced to 274.91 MPa from 288.70 MPa. The maximum displacement at the top increased to 87.37 mm from 83.88 mm, albeit, lower than the code limit of 175 mm. The absolute value of the maximum rotation at the top reduced from 0.309° to 0.304°, which is lower than the code limit of 0.382°. The pile rotation at the mudline increased by 14%, from 0.120° to 0.137°, nonetheless, lower than the DNV code limit of 0.250°. Initial numerical basis has been developed for the parametric design optimization of the jacket substructure. From the parameter studies conducted mathematical models could be developed for efficient numerical optimization.