"If you tell the truth you don't
have to remember anything." Mark Twain
"Once you get rid of integrity the rest is a piece of cake." Larry
Hagman
Maintaining the integrity of pipelines is an ongoing challenge. This recent
article by Colton Sheets, of Stress Enginnering Services, provides a useful
review of the role that composites can play in that endeavor.
///////
Pipeline & Gas Journal (https://pgjonline.com/)
June 20, 2020, Vol. 247, No. 6
Operating,
Installation Considerations For Pipeline Composite Repairs
By Colton Sheets, Senior Associate, Stress Engineering Services,
Inc.
[ EXCERPTS ]
Composite repairs are no longer new to the pipeline integrity world. A
significant body of work has been developed over the last several decades
characterizing their performance and developing guidelines for end-users.
Unlike steel sleeves, the nonmetallic materials used in most pipeline composite
repair applications cannot easily be inspected and qualified according to
industry standards. Therefore, special consideration must be given before,
during and after the installation to ensure the chosen composite repair has the
best chance to perform as intended for the requisite life.
Since it is always important to be reminded of the first principles that guide
success and failure, this article will highlight some easily overlooked design
considerations at three key points in the life of a composite repair:
Surface preparation prior to
installation
Operating conditions during
installation
Operating conditions following
installation
In many cases, the industry-recognized standards for pipeline composite repairs
(ASME PCC-2 and ISO 24817) provide subtle, and not so subtle, guidance for each
of these stages in a composite repair’s life. In other instances, the
ever-popular “engineering judgment” must be relied upon to ensure the success
of the composite repair solution.
Overview
A composite, by definition, is a material that consists of multiple, distinct
parts that are combined on a macroscopic scale to produce a new material that
has properties different from each of the individual components.
Typically, the objective is to have the new material exhibit the desirable
properties from each of its constituents. In the case of composites for
pipeline repair applications, the most common systems are fiber-matrix,
wet-layup composites.
In a wet-layup system, a fabric material, typically composed of woven carbon or
glass fibers, is saturated with a matrix material – often a thermoset resin
(polyester, vinyl ester, water-activated polyurethane, etc.) – that cures or
hardens via chemical reaction. The fibers making up the fabric material are
what provide strength and stiffness to the composite repair in its final form.
The matrix material is used to support, transport load between and protect the
fibers.
Once the matrix material has fully cured, the cloth material that previously
had little to no stiffness becomes a hard, rigid layer. Because the cloth
remains formable during initial saturation (prior to cure), the composite
system can be shaped into complex geometries that readily conform to molds or
forms.
This characteristic of wet-layup systems is particularly attractive as an
alternative to steel sleeves as they can be formed to closely fit pipeline
geometries that may be ovalized or have some degree of curvature.
Since many of the defects being reinforced by composites change the profile of
the pipe surface (e.g., external corrosion, dents, wrinkles), another
hardenable nonmetallic material is used between the reinforcing fibers of the
composite and the pipe profile.
This material is commonly referred to as the load transfer, or filler, material
and serves as a rigid transition between the deformed pipe profile and the
reinforcing fibers of the composite. The filler material has a high compressive
strength and is critical in transferring load from the pipe to the
reinforcement provided by the composite.
A pipeline composite repair typically will be comprised of many layers of the
fiber-matrix material. For most applications, these layers are saturated and
then wrapped circumferentially around the pipe. Each wrap, or ply, increases
the thickness of the composite repair, which, in turn, increases the overall
strength capacity of the repair once it has cured and, for the most part, can
function as a single unit.
This is similar to increasing the wall thickness of the substrate pipe
material. During installation, the number of wraps is increased until the
design thickness is achieved. This design thickness is equal to the product of
the thickness of each ply and the number of plies (wraps) installed.
Because the components of the composite repair are typically nonmetallic, they
are influenced differently by variations in temperature, moisture or other
contaminates. Unlike steel sleeve repairs, this can result in significant
variability from system to system.
The structure of a composite repair also makes it heavily dependent upon the
integrity of the load-transfer material – again, a fundamental concept that can
be influenced by operating or installation variables. One of the easiest
variables to overlook is surface preparation of the substrate; however, it is
clear that the governing standards leave little room for interpretation of its
importance.
Author: Colton Sheets is a professional engineer and senior associate at Stress
Engineering Services, Inc. He holds a master of science degree from LeTourneau
University and a bachelor of science degree from the University of Tulsa, both
in mechanical engineering.
Free full text source: https://pgjonline.com/magazine/2020/june-2020-vol-247-no-6/features/operating-installation-considerations-for-pipeline-composite-repairs
///////
TIP:
For more of the same, Google® Stress Engineering Services composite
Here are some of the results of that search …
///////
Repair of Dents
Subjected To Cyclic Pressure Service Using ...
www.stress.com › publication ›
repair-of-dents-subjecte...
ABSTRACT. For the better part of the past 15 years composite materials have been used to repair corrosion in high
pressure gas and liquid transmission ...
Composite Repair -
Stress Engineering Services
www.stress.com › capabilities ›
pipelines › composite-r...
Stress Engineering Services is
the world leader in assessing the use of composite
materials to reinforce pipelines, risers, and piping systems for the oil and
gas ...
composite repair
Archives - Stress Engineering Services
www.stress.com › tag ›
composite-repair
Composite Materials for
Pipeline Repair Numerous public and private studies completed over the last 20
years have investigated the potential benefits of using ...
Composite Repair
Performance at Elevated Temperatures ...
www.stress.com › publication ›
composite-repair-perfo...
For the better part of the past 20 years composite
materials have been used to repair damaged piping and pressurized components in
plants, refineries, and ...
Polymers | Elastomers
| Composites - Stress Engineering ...
www.stress.com › capabilities ›
materials-engineering
Stress Engineering Services
offers customized solutions to meet your unique demands. We are an experienced
firm that will help you, contact us today!
pipeline repair
Archives - Stress Engineering Services
www.stress.com › tag ›
pipeline-repair
Composite Materials for
Pipeline Repair Numerous public and private studies completed over the last 20
years have investigated the potential benefits of using ...
Literature - Stress
Engineering Services
www.stress.com › news-media ›
literature
Home »News & Media »Literature. Literature. Stress Talk. Stress
Talk 2017. Download Brochure. Stress
Talk 2016. Download Brochure. Stress
Talk 2015.
ww.stress.com › capabilities ›
pipelines › engineering...
The backbone of this initiative is the API 579/ASME FFS-1 Fitness for Service ... has led industry's charge
to evaluate composite repair
technology for pipelines.
Field Inspection and
Testing | Stress Engineering Services, Inc
www.stress.com › capabilities ›
materials-engineering
Our multi-disciplinary team of skilled engineers
and technicians regularly perform in-situ assessments and ... Polymers |
Elastomers | Composites ·
Accelerated ...
Untitled - Stress
Engineering Services
www.stress.com › literature ›
stress-talk
PDF
Updated Perspectives on the Use of Composite
Materials to. Reinforce Damaged Pipelines, Risers, and Piping. 23 Monitoring
Real-Time Stresses on Mining ..
///////
Google® Better!
Jean Steinhardt served as Librarian,
Aramco Services, Engineering Division, for 13 years. He now heads Jean
Steinhardt Consulting LLC, producing the same high quality research that he
performed for Aramco.
Follow Jean’s blog at: http://desulf.blogspot.com/ for continuing tips on effective online
research
Email Jean at research@jeansteinhardtconsulting.com with questions on research, training, or
anything else
Visit Jean’s Web site at http://www.jeansteinhardtconsulting.com/ to see examples of the services we can
provide
No comments:
Post a Comment