Comsol Case Studies Improving Gas Pipeline Squeeze-Off Standards with Numerical Simulation

	Improving Gas Pipeline Squeeze-Off Standards with Numerical Simulation Comsol

Improving Gas Pipeline Squeeze-Off Standards with Numerical Simulation

Comsol

Technology Category	Analytics & Modeling - Predictive Analytics Analytics & Modeling - Real Time Analytics
Applicable Industries	Utilities Construction & Infrastructure
Applicable Functions	Maintenance Quality Assurance
Use Cases	Predictive Maintenance Process Control & Optimization Structural Health Monitoring
Services	Software Design & Engineering Services System Integration Testing & Certification
Challenge	Routine natural gas maintenance often requires digging into main roads, causing significant disruptions. GTI aimed to investigate the industry standards for squeeze-off length in gas pipelines to make the process more efficient and less invasive. The current ASTM standard requires a squeeze-off distance of either three pipe diameters or twelve inches from the next pipe fitting, whichever is greater. This large length requirement leads to more digging, rerouted roads, and increased time and costs. GTI researchers sought to determine if the twelve-inch distance is necessary for smaller pipes, aiming to reduce the minimum required distance without exceeding industry-accepted levels of strain and stress concentration. Read More
About Customer	Gas Technology Institute (GTI) is a research and development organization based in Illinois, committed to advancing new energy and natural gas technologies. GTI focuses on various sectors, including the investigation of squeeze-off distances for polyethylene (PE) gas pipelines. The organization aims to improve the efficiency and accessibility of gas pipeline maintenance procedures. GTI collaborates with various stakeholders, including Operations Technology Development (OTD), a partnership of natural gas distribution companies, to fund and support their research initiatives. GTI's expertise in natural gas research, development, and training positions them as a leader in the industry, driving innovations that enhance the safety, reliability, and efficiency of natural gas systems. Read More
Solution	GTI used the COMSOL Multiphysics software to set up a fully parametric time-dependent model for analyzing the stress and strain in polyethylene pipes during the squeeze-off procedure. The model included the mechanical and numerical properties of internal and external contacts, allowing for accurate analysis of large deformations. GTI collaborated with Veryst Engineering to implement a custom viscoelastic-plastic constitutive model for polyethylene. Veryst conducted material tests and used their MCalibration tool to fit the material parameters to the stress-strain response of PE. The calibrated material law was then implemented in COMSOL, enabling GTI to simulate the squeeze-off process accurately. The simulation results showed that for small-diameter pipes, the closer squeeze-off distance of three pipe diameters did not exceed industry-accepted strain limits. Additional accelerated lifetime testing validated these findings, confirming that the pipes would have an 80-year lifetime under normal operating conditions. Read More Log in to view content
Contents

Technology Category

Analytics & Modeling - Predictive Analytics

Analytics & Modeling - Real Time Analytics

Applicable Industries

Utilities

Construction & Infrastructure

Applicable Functions

Maintenance

Quality Assurance

Use Cases

Predictive Maintenance

Process Control & Optimization

Structural Health Monitoring

Services

Software Design & Engineering Services

System Integration

Testing & Certification

Challenge

Routine natural gas maintenance often requires digging into main roads, causing significant disruptions. GTI aimed to investigate the industry standards for squeeze-off length in gas pipelines to make the process more efficient and less invasive. The current ASTM standard requires a squeeze-off distance of either three pipe diameters or twelve inches from the next pipe fitting, whichever is greater. This large length requirement leads to more digging, rerouted roads, and increased time and costs. GTI researchers sought to determine if the twelve-inch distance is necessary for smaller pipes, aiming to reduce the minimum required distance without exceeding industry-accepted levels of strain and stress concentration.

About Customer

Gas Technology Institute (GTI) is a research and development organization based in Illinois, committed to advancing new energy and natural gas technologies. GTI focuses on various sectors, including the investigation of squeeze-off distances for polyethylene (PE) gas pipelines. The organization aims to improve the efficiency and accessibility of gas pipeline maintenance procedures. GTI collaborates with various stakeholders, including Operations Technology Development (OTD), a partnership of natural gas distribution companies, to fund and support their research initiatives. GTI's expertise in natural gas research, development, and training positions them as a leader in the industry, driving innovations that enhance the safety, reliability, and efficiency of natural gas systems.

Solution

GTI used the COMSOL Multiphysics software to set up a fully parametric time-dependent model for analyzing the stress and strain in polyethylene pipes during the squeeze-off procedure. The model included the mechanical and numerical properties of internal and external contacts, allowing for accurate analysis of large deformations. GTI collaborated with Veryst Engineering to implement a custom viscoelastic-plastic constitutive model for polyethylene. Veryst conducted material tests and used their MCalibration tool to fit the material parameters to the stress-strain response of PE. The calibrated material law was then implemented in COMSOL, enabling GTI to simulate the squeeze-off process accurately. The simulation results showed that for small-diameter pipes, the closer squeeze-off distance of three pipe diameters did not exceed industry-accepted strain limits. Additional accelerated lifetime testing validated these findings, confirming that the pipes would have an 80-year lifetime under normal operating conditions.

Impact #1	GTI's research confirmed that the current twelve-inch minimum distance requirement for squeeze-off can be reevaluated for smaller pipe diameters, making the process less invasive and more efficient.
Impact #2	The use of COMSOL Multiphysics allowed GTI to conduct accurate stress and strain analysis, leading to reliable results that support the revision of industry standards.
Impact #3	Collaboration with Veryst Engineering enabled the implementation of a custom material model, enhancing the accuracy of the simulations and ensuring the validity of the findings.

Impact #1

GTI's research confirmed that the current twelve-inch minimum distance requirement for squeeze-off can be reevaluated for smaller pipe diameters, making the process less invasive and more efficient.

Impact #2

The use of COMSOL Multiphysics allowed GTI to conduct accurate stress and strain analysis, leading to reliable results that support the revision of industry standards.

Impact #3

Collaboration with Veryst Engineering enabled the implementation of a custom material model, enhancing the accuracy of the simulations and ensuring the validity of the findings.

Benefit #1	The research confirmed that the pipes would have an 80-year lifetime when operating at an average temperature of 20ºC.
Benefit #2	The closer squeeze-off distance of three pipe diameters did not cause strains over current industry-accepted strain limits for small-diameter pipes.

Benefit #1

The research confirmed that the pipes would have an 80-year lifetime when operating at an average temperature of 20ºC.

Benefit #2

The closer squeeze-off distance of three pipe diameters did not cause strains over current industry-accepted strain limits for small-diameter pipes.

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Overview

Improving Gas Pipeline Squeeze-Off Standards with Numerical Simulation

Operational Impact

Quantitative Benefit