Steel Convolution Wrap Augments Pipeline Toughness
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Solution Overview
Problem
Existing high-pressure pipelines face challenges in maintaining mechanical properties over time, particularly in toughness and fracture resistance, leading to potential seam failures and safety concerns, with existing repair methods focusing on pressure containment rather than toughness augmentation and often requiring destructive testing or high-temperature welding.
Innovation Solution
The method involves adhering thin, homogeneous isotropic steel convolutions to the external pipe wall, matched in modulus of elasticity to the existing steel, to enhance toughness and pressure-containing ability, eliminating welding discontinuities and promoting immediate stress sharing, thus ensuring ductile fracture arrest and mitigating fatigue cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional pipe replacement or welding methods are used to improve toughness and pressure containment, then mechanical properties are enhanced, but operational disruption, safety risks, and cost increase
Solution Approach 1:
An intermediary adhesive layer is introduced between the base pipe and the steel convolution wrap. This adhesive mediates the stress transfer, allowing the wrap to enhance toughness without requiring direct welding or mechanical fastening that would disrupt operations or create new discontinuities.
Solution Approach 2:
The mechanical properties of the pipe are enhanced by changing the structural parameters through the addition of the convolution wrap. The wrap modifies the stress distribution and energy absorption characteristics without altering the base pipe's operational parameters, enabling toughness enhancement while maintaining operational continuity.
2Reliability
If welding is used to repair pipe seams, then pressure containment is restored, but new welding discontinuities and crack initiation sites are created
Solution Approach 1:
The welding process is extracted and replaced with an alternative method. Instead of using welding to restore pressure containment, the invention uses an adhesive-bonded steel convolution wrap that achieves pressure containment without introducing welding discontinuities or heat-affected zones.
Solution Approach 2:
The mechanical welding system is replaced with a combination of adhesive bonding and mechanical wrapping. The steel convolutions provide structural reinforcement while the adhesive provides bonding, substituting the welding process with a method that avoids creating new discontinuities.
3Strength
If thick steel wraps are used to enhance toughness, then fracture resistance improves, but stress sharing delay and crack propagation risk increase
Solution Approach 1:
The steel wrap is segmented into thin convolutions rather than a single thick layer. This segmentation allows stress to be distributed across multiple interfaces with the base pipe, reducing stress sharing delay and preventing crack propagation through the wrap structure itself.
Solution Approach 2:
Thin steel convolutions are used instead of thick wraps. These thin layers conform to the pipe surface and allow rapid stress transfer to the base pipe while providing sufficient fracture resistance. The thin film structure minimizes the time for stress equilibration and reduces the risk of cracks developing within the wrap.
4Stress or pressure
If high-strength materials are used to restore pressure-carrying capacity, then MAOP is improved, but toughness and ductile fracture arrest capability are not enhanced
Solution Approach 1:
A composite structure is created combining the base pipe, adhesive layer, and steel convolution wrap. This composite system provides both the pressure-carrying capacity of high-strength materials and the toughness enhancement from the multi-layer construction, with the adhesive and convolution structure providing ductile fracture arrest capability.
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 solution effectively augments the pipeline's toughness and pressure-carrying capacity, allowing for safe operating pressure calculation without new discontinuities, reducing crack growth, and providing redundancy against external damage, while avoiding hot work issues and enhancing fire resistance.
Implementation Method 1
a. cleaning an external surface of the pipe; b. applying a structural adhesive to the cleaned external surface of the pipe; c. wrapping at least a portion of the pipe with the augmentation band
Implementation Method 2
The high modulus filler material is utilized to transfer a load created by an internal pressure of the section of pipe system or pipeline to an augmentation band
Implementation Method 3
The modulus of elasticity of the augmentation band reasonably matches that of the pipe and ensures no delay in dynamic stress/strain response
Data Source
AI summary
A method of augmenting the mechanical properties of a pipeline section comprises the steps of (1) identifying a pipeline section which requires verifiable data and analysis to calculate a safe operating pressure; (2) wrapping the external surface of the identified pipeline section with two or more convolutions of homogeneous isotropic thin steel augmentation bands; (3) adhering the convolutions together via a structural adhesive; and (4) determining the pressure-containing ability of the resultant augmented pipeline section, while simultaneously creating the inputs to determine at least one additional useful engineering design input parameter of the augmented pipeline section, required to calculate and validate a safe operating pressure.