Semi-Submersible Floater Pontoon Ballast for Wind Turbine Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Semi-submersible floaters for floating wind turbines face instability due to unbalanced forces and mechanical stresses from environmental conditions, which are exacerbated by the dynamic motion of the turbine, necessitating a solution to enhance stability during operation.

Innovation Solution

The semi-submersible floater design incorporates pontoon-shaped branches with a first portion and a second portion, where the second portion is filled with ballast material in the operating state, while the first portion remains empty, allowing for adjustable ballast distribution to balance forces and reduce stress on the structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the pontoon-shaped branches have significant buoyancy to support the floating wind turbine, then the floater can maintain its position on the sea surface, but significant shear stresses are generated at the junction of each pontoon-shaped branch with the central column

Engineering Contradiction:

ImprovebuoyancyVSAvoidshear stresses

Core Design Contradiction:

ForceVSStress or pressure

Solution Approach 1:

The pontoon-shaped branch is divided into a first portion and a second portion along the branch axis. The second portion is at least partially filled with ballast material while the first portion remains empty, segmenting the buoyancy distribution to reduce shear stresses at the junction with the central column

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the pontoon-shaped branch have different properties: the second portion contains ballast material to provide localized weight and reduce uplift forces, while the first portion remains empty to maintain buoyancy. This local differentiation optimizes the balance between buoyancy and stress reduction

Inventive Principle:

Principle #3Local quality

2Force

If the outer columns have significant submerged volume to provide buoyancy, then the floater can remain stable on the sea surface, but tensile stresses are generated in the bottom slab of the central column and the pontoon-shaped branch

Engineering Contradiction:

ImprovebuoyancyVSAvoidtensile stresses

Core Design Contradiction:

ForceVSStress or pressure

Solution Approach 1:

Ballast material is introduced into the second portion of the pontoon-shaped branch to act as a counterweight that offsets the uplift forces generated by the buoyancy of the outer columns. This balances the forces and reduces tensile stresses in the bottom slab

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Force

If the central column has significant submerged volume to provide buoyancy, then the floater can maintain its position, but the central column is subjected to downward force toward the seabed

Engineering Contradiction:

ImprovebuoyancyVSAvoiddownward force

Core Design Contradiction:

ForceVSStress or pressure

Solution Approach 1:

The ballast material is selectively placed in the second portion of the pontoon-shaped branch rather than uniformly distributed. This localized placement creates a counterbalancing force that offsets the downward force on the central column while maintaining overall buoyancy

Inventive Principle:

Principle #3Local quality

4Power

If the turbine generates thrust during operation, then the floating wind turbine can produce electricity, but the thrust creates additional forces that must be counterbalanced to stabilize the floater

Engineering Contradiction:

Improvepower generationVSAvoidthrust

Core Design Contradiction:

PowerVSForce

Solution Approach 1:

The ballast material in the second portion of the pontoon-shaped branch acts as a counterweight that helps balance the thrust forces generated by the turbine. This stabilization allows the turbine to operate effectively without compromising the floater's stability

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design significantly increases the stability of the floater by adjusting hydrostatic stiffness and balancing forces, reducing shear and flexural stresses, and compensating for buoyancy, thereby enhancing the structure's ability to withstand environmental pressures and turbine thrust.

Implementation Method 1

each pontoon-shaped branch is formed by a first portion and a second portion that extend successively along the corresponding branch axis... in the operating state of the semi-submersible floater, the second portion of each branch is at least partially filled with a ballast material

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentUS11492078B2Semi-submersible floater, particularly for a floating wind turbine

Publication Date: 2022.11.08 SAIPEM SA

AI summary

Disclosed is a semi-submersible floater defining an operating state and a non-operating state, and including at least two outer columns, a central column for receiving a payload, and, for each outer column, a branch in the form of pontoon connecting the outer column to the central column and defining a branch axis oriented from the central column towards the outer column. Each branch is formed from a first portion and a second portion which extend successively along the corresponding branch axis, each one over at least 10% of the total extent of the branch, along the branch axis. In the operating state of the floater, the second portion of each branch is at least partially filled with a ballast material, and the first portion does not contain any ballast material.