Support Structure Optimization for Offshore Wind Turbines With a Genetic Algorithm

Abstract

This study considers the use of a genetic algorithm for the structural design optimization of support structures for offshore wind turbines. Member diameters, thicknesses and locations of nodes are jointly optimized. Analysis of each design is performed with a complete wind turbine simulation, for a load case in the time domain. Structural assessment is in terms of fatigue damage, evaluated for each joint using the hot-spot stress approach. This defines performance constraints. Designs are optimized with respect to their weight. The approach has been tested with the modified 4-legged UpWind jacket from the OC4 project. The weight is quickly reduced, convergence slows after about 100 iterations, and few changes occur after 250 iterations. Interestingly, the fatigue constraint is not active for any member, and it is the validity of stress concentration factors that determines the best design, which utilizes less than 90 percent of the available fatigue lifetime. These results of the preliminary study using the genetic algorithm demonstrate that automatic optimization of wind turbine support structures is feasible under consideration of the simplified load approach. Even for complex, multi-member structures such as the considered jacket a weight reduction was achieved.

On gradient‐based optimization of jacket structures for offshore wind turbines

“…Since then, much work has been done on optimizing both onshore and offshore monopile structures using gradient‐free methods . As jackets gained in popularity, different gradient‐free methods have also been applied in the design thereof . A different approach to efficient optimization is shown in Schafhirt et al By using a two‐stage approach where the optimization of tube geometry and stress concentration factors (SCFs) are assumed independent of the structural analysis, the computational effort needed in the jacket optimization is greatly reduced.…”

Review of Recent Offshore Wind Turbine Research and Optimization Methodologies in Their Design

“…Recently, metaheuristic optimization approaches based on genetic algorithms were presented by AlHamaydeh et al [84,85] and Kaveh and Sabeti [86], although these approaches incorporated limited load assumptions without appropriate structural code checks. Pasamontes et al [87] conducted an optimization study on the jacket of the OC4 project. A genetic algorithm was used to minimize the weight of the offshore wind turbine.…”

“…The evaluation and comparison were conducted by a multi-objective genetic algorithm optimization method. The study by Pasamontes et al [87] used a genetic algorithm for the structural design optimization of the support UpWind jacket structures from the OC4 project. Each design was analyzed with a complete wind turbine simulation for a load case in the time domain.…”

Improving the Computational Efficiency for Optimization of Offshore Wind Turbine Jacket Substructure by Hybrid Algorithms

“…Because of the randomness of the algorithms, the stochastic algorithms can be more likely to find the optimum of the real-world problem. The most common stochastic algorithm, standard genetic algorithm (SGA), was introduced to achieve a global optimum [5][6][7][8]. SGA includes crossover and mutation as evolutionary operators, originating from the concept of competition and survival of biological evolution.…”