Spar Floating Structure Segmented Ballast Buoyancy Design

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Solution Overview

Problem

Spar-type floating structures face challenges in stability and oscillating motions due to deep draft, susceptibility to wave resonance, and limited installation in shallow marine areas, with existing designs experiencing high amplitude heave and pitch motions.

Innovation Solution

A spar-type floating structure design featuring a tall, thin floating body with horizontally-extending first and second extended portions and a hollow cylindrical column portion, where the first portion forms a ballast and the second portion provides buoyancy, with a third extended portion at the top to adjust the waterline and counteract wave pressures, reducing oscillating motions and draft.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the spar-type floating structure uses a deep draft design to ensure stability, then the stability is improved, but the difficulty of installation in shallow marine areas increases

Engineering Contradiction:
ImprovestabilityVSAvoidinstallability in shallow marine areas
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The floating body is segmented into multiple functional portions: a ballast portion (first extended portion) at the bottom, a buoyancy portion (second extended portion) in the middle, and a column portion extending upward. This segmentation allows the structure to achieve stability through strategic weight distribution while reducing the overall draft requirement compared to conventional deep-draft spar designs.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the spar-type floating structure uses a conventional design with small waterplane area, then the structure is simpler, but the resonance period becomes short causing resonance with waves

Engineering Contradiction:
Improvestructural simplicityVSAvoidresonance avoidance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention extends the floating body horizontally in multiple directions by adding first, second, and third extended portions. This dimensional expansion increases the waterplane area without significantly increasing structural complexity, thereby lengthening the resonance period and avoiding wave resonance while maintaining a relatively simple spar-type configuration.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Force

If the spar-type floating structure uses a large floating body near the waterline to ensure buoyancy, then the buoyancy is improved, but the susceptibility to wave influence increases

Engineering Contradiction:
ImprovebuoyancyVSAvoidwave influence
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The floating body employs local quality differentiation by concentrating buoyancy in the middle extended portion at a specific depth rather than distributing it uniformly near the waterline. The ballast portion is positioned at the bottom to provide stable weight distribution. This strategic local placement of buoyancy and ballast reduces wave influence while maintaining sufficient overall buoyancy.

Inventive Principle:
Principle #3Local quality

4Use of energy by moving object

If the spar-type floating structure uses high amplitude heave and pitch motions characteristics, then the structure responds more to wave energy, but the stability is worsened

Engineering Contradiction:
Improvewave energy responseVSAvoidstability
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The invention uses the ballast portion positioned at the bottom of the floating body to counterbalance the heave and pitch motions. The strategically placed ballast provides a stabilizing counterweight that reduces the amplitude of oscillating motions while maintaining the structure's ability to respond to wave energy through its extended portions.

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

The design achieves reduced vertically-oscillating motions, enhanced stability, and a reduced draft, allowing the structure to avoid wave resonance and maintain stability in varying wave conditions.

Implementation Method 1

a ballast portion provided to the floating body so that a weight of the ballast portion allows the floating body to float in upright position

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 2

a hollow, cylindrical second extended portion arranged in the middle and giving a buoyancy to the floating body

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 3

the first, second and third extended portions are configured such that pressures acting on respective upper and lower surfaces of the first and second extended portion and a pressure acting on a lower surface of the third extended portion counteract each other with a specific wave period

Methodology Applied
Scientific EffectPressure distribution: Pressure Gradient

Data Source

PatentEP2684792B1Spar type floating structure
Publication Date: 2017.10.04 JAPAN MARINE UNITED CORPORATION
  • EP2684792B1 patent drawingFigure 1
  • EP2684792B1 patent drawingFigure 2A
  • EP2684792B1 patent drawingFigure 2B

AI summary

In a spar-type floating structure comprising a tall, thin floating body 2 and a ballast portion 3 provided to the floating body 2 so that the weight of the ballast portion 3 allows the floating body 2 to float in upright position, the floating body 2 includes a horizontally-extending first extended portion 21 arrangeed at the bottom, a horizontally-extending second extended portion 22 arranged in the middle, and a column portion connecting the first and second extended portions 21, 22 and extending up to the waterline, the first extended portion 21 forms the ballast portion 3, and the second extended portion 22 constitutes a buoyancy portion giving buoyancy to the floating body 2.