Composite Pipe-Laying Stinger Structure for Rough-Sea Operation

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Solution Overview

Problem

Conventional stingers used in maritime pipe laying operations are prone to corrosion, damage, and high maintenance costs due to their steel composition and weight, limiting their use in rough seas and increasing operational costs and time.

Innovation Solution

A stinger formed from non-metallic materials, such as composite materials made from fibers and polymers, with a unique geometry and buoyancy system that reduces hydrodynamic loads and allows for operation in higher sea states without suspension, featuring a first and second body member with varying widths and inner chambers for buoyancy control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional steel stingers are used, then structural strength is sufficient, but corrosion and damage occur in saltwater environments increasing maintenance costs

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidmaintenance costs

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The stinger is constructed from composite materials consisting of a foam core surrounded by a fiberglass reinforcement layer. This composite structure provides both the necessary structural strength and inherent corrosion resistance, eliminating the need for protective coatings and reducing maintenance requirements in saltwater environments.

Inventive Principle:

Principle #40Composite materials

2Strength

If conventional steel stingers are used, then structural strength is adequate, but weight is high causing damage near attachment points

Engineering Contradiction:

Improvestructural strengthVSAvoidstinger weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The composite construction with foam core and fiberglass reinforcement achieves high strength-to-weight ratio. The fiberglass provides tensile strength while the foam core reduces density, creating a structure that is both strong and lightweight enough to minimize stress at vessel attachment points during heaving operations.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The foam core provides buoyancy that counteracts the weight of the stinger, reducing the net downward force and stress on attachment points. This buoyant effect helps offset the hydrodynamic loads and reduces the risk of damage near the vessel connection during wave action.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Strength

If conventional steel stingers are used, then structural integrity is maintained, but hydrodynamic loads are high in rough seas

Engineering Contradiction:

Improvestructural integrityVSAvoidhydrodynamic load

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

The fiberglass reinforcement layer acts as a flexible yet strong shell that can flex with wave action while maintaining structural integrity. This flexibility allows the stinger to accommodate hydrodynamic loads in rough seas without exceeding strength limits, unlike rigid steel structures that are more susceptible to stress concentration and damage.

Inventive Principle:

Principle #30Flexible shells and thin films

4Strength

If conventional steel stingers are used, then strength is sufficient, but transportation and handling costs increase due to weight

Engineering Contradiction:

Improvestructural strengthVSAvoidtransportation efficiency

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The composite material construction reduces the stinger's weight compared to equivalent steel structures, making it easier and more cost-effective to transport to job sites and handle during installation and maintenance operations, while maintaining the required structural strength for pipe laying operations.

Inventive Principle:

Principle #40Composite materials

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 non-metallic stinger is lighter, more buoyant, and corrosion-resistant, enabling pipe laying operations in higher sea states with reduced maintenance and transportation costs, while maintaining strength and buoyancy, thus completing operations more quickly and efficiently.

Implementation Method 1

Conventional stingers fabricated from steel. Thus, conventional stingers corrode in the presence of saltwater.

Methodology Applied

Scientific EffectCorrosion resistance:

Implementation Method 2

the buoyancy force exerted by the sea against the stinger

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 3

the drag force exerted by the sea against the stinger

Methodology Applied

Scientific EffectDrag force: Drag

Data Source

PatentUS12152702B2Stinger for a pipe laying operation

Publication Date: 2024.11.26 J RAY MCDERMOTT SA

AI summary

A stinger including a first member formed from a first non-metallic material, a second body member formed from a second non-metallic material, and a plurality of cross-support members disposed between the first body member and the second body member. The first body member includes a first lower portion, a first upper portion, and a first intermediate portion disposed between the first lower portion and the first upper portion. A width of the first lower portion is greater than a width of the first intermediate portion and a width of the first upper portion, and wherein the width of the first upper portion is greater than the width of the first intermediate portion. The second body member includes a second lower portion, a second upper portion, and a second intermediate portion disposed between the second lower portion and the second upper portion.