Monopile Design Methodology

For details of the code implementation, please see Monopile Design API.

Overview

This module is based on initial pile dimension calculations from Arany (2017) [1]. Pile dimensions are chosen to withstand the bending moment from the 50-year Extreme Operation Gust (EOG). This corresponds to wind scenario U-3 in Section 2.2.1. This module is not intended to capture the complexities of a full engineering design study for monopiles, but rather broadly capture the scaling trends due to increased site depth, turbine size and material parameters.

The 50-year extreme wind speed can be calculated using the following cumulative density function.

$U_{10, 50 - y e a r} = K (- \ln (1 - {0.98}^{\frac{1}{52596}}))^{\frac{1}{S}}$

where $K$ and $S$ are the Weibull scale and shape factors respectively.

The mudline bending moment is calculated as:

$M_{w i n d, E O G} = γ_{L} F_{w i n d, E O G} (S + z_{h u b})$

where $γ_{L}$ is the load factor (defaults to 1.35), $F_{w i n d, E O G}$ is the total wind load on the turbine, $S$ is the water depth at site and $z_{h u b}$ is the hub height of the turbine. The derivation of $F_{w i n d, E O G}$ can be seen in detail in the ORBIT technical documentation.

Initial pile dimensions are then calculated using Arany (2017) [1], API (2005) [2], and Poulos and Davis (1980) [3].

Monopile Design Methodology

Overview

References