ABSTRACT

Nowadays, the probabilistic-based design method is gradually getting attention as an alternative method in the design and analysis field of offshore wind turbines (OWTs) to substitute the traditional deterministic design methods, which account for the uncertainties existing in structural geometrical parameters, loadings, materials, etc. by employing partial safety factors (PSFs). However, the partial safety factors method is a simplified and indistinct approach because it condenses several uncertain parameters that affect the OWTs' performance into a factor, and it ignores the discrepancy in the structural responses caused by these different uncertainties. In this paper, the sensitivity analysis of the typical load characteristics and structural responses concerning structural geometrical parameters, met–ocean parameters, and material behaviors are investigated for a 5 MW OWT installed on a monopile foundation. The standardized regression coefficients (SRC) method and elementary effects (EE) method are utilized for two different load cases. Results show that the same parameters have different significance rankings according to which load case is considered. In general, the highest influence on deformation and stress output are both governed by these met–ocean parameters. This work points out the parameters that affect the OWT structural response and should be emphasized by the designers.

INTRODUCTION

Over the past decades, offshore wind energy has shown significant potential in the energy market. "The Global Wind Report 2022" released by the Global Wind Energy Council states that the accumulative total installed wind-power capacity by 2021 reached 94 GW. However, the Levelized cost of energy concerning offshore wind energy is still too high to be truly competitive compared to the traditional energy resource. It should be noted that the manufacturing cost of the supporting structures of the offshore wind turbines (OWTs) and the cost of operation and maintenance after the wind farm have been put onto nets represent a significant part of these costs. Hence, an obvious cost-reduction method is optimizing the supporting structures as far as possible, on the premise of ensuring the safe operation of the OWT during the whole lifespan. Generally speaking, the optimization design process of OWT needs to take into account numerous randomness factors, such as structural geometrical parameters, loadings, materials so on, and these factors are represented by a couple of partial safety factors (PSFs) in the prevailing designs (Yang et al., 2015).

This content is only available via PDF.
You can access this article if you purchase or spend a download.