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8/12/2019 ECA Presentation Outline (Customer Copy)
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Dr. Basab Bhattacharya
Exova (Singapore) Pte Ltd.
Engineering Critical Analysis (ECA)& Fracture Toughness of Pipelines
Outline
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Outline
Factors controlling cost of Pipeline construction
Engineering Critical analyses of pipeline -introduction and importance
Acceptance criteria obtained from an Engineering
Critical Analysis
Evaluation of Fracture Toughness data
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Cost Reduction Options for pipeline installation
New pipeline design and construction plan
High productivity welding and advanced NDT
methods to increase production rate Reduction in welding repair rates
Recommendations
Use of proper welding process (Auto welding)
Replace Traditional workmanship criteria with ECA to
produce safe Acceptance Criteria for welding
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Engineering Critical Assessment
ECA enables the significance of flaws to be assessed in
terms of structural integrity during installation andoperational phases of the pipeline.
Used for calculating the defect acceptance criteria for fabrication.
Replaces arbitrary 'workmanship' standards normally used asacceptance criteria for NDT of welds.
Essential when replacing volumetric based NDT methods byAutomated Ultrasonic Testing (AUT) which require defect height as
part of an acceptance criteria.
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ECA for Pipeline
Analysis must consider defect tolerance under stresses (staticor dynamic) at different phases of the pipeline
Installation stage
Peak installation stress or strain
Installation fatigue
Hydro test pressure
Operation phase
fatigue loading due temperature or pressure variation,
VIV etc
Worst case loading during operation
Corrosion effect
Effect of Sour service conditions
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Computational analysis - key processes
Construction of the FADCalculation of Nominal Stresses (crack driving forces)Calculation of Kmat ValuesCalculation of reference stressLr cut of limit
Calculation of Kapplied
Determination of acceptable defect sizes
Unsafe
Critical
Safe
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Tolerable Defect Sizes for Installation and Operational conditions
Mainline welds42OD x 14.1 mm WT Pipe
Height (mm) Length (mm)
1.5 527
2.0 281
2.5 154
3.0 89
3.5 59
Tolerable Defect Sizes for Installation and Operational conditionsMainline welds including AUT uncertainty of measurementH=1 mm, length = 3mm
42OD x 14.1mm WT Pipe
Height (mm) Length (mm)
0.5 5241.0 278
1.5 151
2.0 86
2.5 56
Final Acceptance Criteria (example)
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Types of Weld Defects
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Advantages of using AUT with ECA
AUT inspection applied with ECA-based tolerabledefect acceptance criteria offers several advantagesover conventional radiographic inspection
Superior detection and sizing of planar flaws
Accurate assessment of the significance of weld flaws
Reduce Repair Rates as well as cost and installationtime of pipeline
Potential increased productivity
Avoidance of radiation hazards Increased confidence in engineering design limits
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Importance of Fracture Toughness testing and ECA
Fracture toughness test results on project material arevital input parameters of an ECA.
It is essential to measure the Fracture Toughness
properties of a structure properly in order to perform ECAof a pipeline.
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FRACTURE TOUGHNESS -Geometry and Terms
Fracture Toughness express in terms of -KIC, CTOD, JIC, CTOD-R Curves, J-R Curves
Specimen configurations include -Single-Edge Notched Bend (SENB)
Single-Edge Notched Tension (SENT)
Test conditions replicate serviceElevated and cryogenic temperaturesDynamic fracture toughness
Strain and agedSour service environment
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For more information contact
Basab Bhattacharya
Technical ManagerExova Singapore LaboratoryTel - +65 6372 5610E-mail [email protected]