ISO/TR 13086-4:2019
(Main)Gas cylinders — Guidance for design of composite cylinders — Part 4: Cyclic fatigue of fibres and liners
Gas cylinders — Guidance for design of composite cylinders — Part 4: Cyclic fatigue of fibres and liners
This document addresses the topic of cyclic fatigue of structural reinforcing fibres as used in composite cylinders, and cyclic fatigue of structural and non-structural liners in these cylinders. This document provides a basic level of understanding of these topics.
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TECHNICAL ISO/TR
REPORT 13086-4
First edition
2019-09
Gas cylinders — Guidance for design
of composite cylinders —
Part 4:
Cyclic fatigue of fibres and liners
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Background . 1
5 Cyclic fatigue evaluation . 2
6 Elements of cyclic fatigue . 2
6.1 Service conditions and requirements . 2
6.1.1 Temperature and moisture . 2
6.1.2 Pressure . 3
6.1.3 Pressure cycles . 3
6.2 Test conditions and specimens . 4
6.3 Fibre materials and their fatigue properties . 6
6.3.1 Materials . 6
6.3.2 Material properties and data . 6
6.3.3 Hybrid construction . 7
6.4 Liner materials and their fatigue properties . 8
6.4.1 Materials used . 8
6.4.2 Material properties and data . 8
6.4.3 Issues with localized strain differences . 8
6.5 Resin materials and their fatigue properties . 9
6.6 Composite/liner load sharing . 9
6.7 Autofrettage . 9
6.8 Analysis methods .10
6.9 Leak before burst (LBB) .11
6.10 Damage tolerance .11
6.11 Aging and environment .11
6.12 Counting cycles .11
6.13 Combining cycles.13
6.14 Qualification testing .14
7 Summary and conclusions .14
Annex A (informative) Equivalent pressure cycling .15
Bibliography .20
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 58, Gas cylinders, Subcommittee SC 3,
Cylinder design.
A list of all parts in the ISO 13086 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved
TECHNICAL REPORT ISO/TR 13086-4:2019(E)
Gas cylinders — Guidance for design of composite
cylinders —
Part 4:
Cyclic fatigue of fibres and liners
1 Scope
This document addresses the topic of cyclic fatigue of structural reinforcing fibres as used in composite
cylinders, and cyclic fatigue of structural and non-structural liners in these cylinders. This document
provides a basic level of understanding of these topics.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
NOTE Terms and definitions related to gas cylinders can be found in ISO 10286.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http: //www .electropedia .org/
— ISO Online browsing platform: available at https: //www .iso .org/obp
4 Background
Composite cylinders began service in the 1950s, initially as rocket motor cases with glass fibre
reinforcement. This soon led to glass fibre pressure vessels with rubber liners, and then to glass
fibre pressure vessels with metal liners. Metal liners were typically either aluminium alloy or steel.
Eventually, new structural fibres, such as aramid and carbon, came into use for reinforcing pressure
vessels. Today, typical reinforcements for composite gas cylinders are glass and carbon, either
individually or together as a hybrid. Typical liner materials are steel, aluminium alloy or polymers, for
example, high-density polyethylene (HDPE) or polyamide (PA); other materials may be acceptable.
Each of these materials is subject to cyclic fatigue based on the type of service and the construction of
the cylinder. Cylinders used in transport service generally see full range cycles, with a limited number
of cycles per year. Cylinders used as fuel containers would typically see up to three pressure cycles
per day for fleet vehicles, and less for private vehicles. Cylinders used in stationary applications such
as refuelling cascades could see a very large number of partial cycles in a year. Some cylinders could
see a combination of these conditions. Stationary cylinders used for fuel cells or emergency breathing
applications could see a very limited number of cycles. Design working pressures for high pressure
cylinders are typically in the range of 20 bar to 1 100 bar. Cylinders for liquified gases such as propane
may operate at pressures up to 20 bar, and normally see fewer pressure cycles.
The different reinforcing fibres have different fatigue lives for a given stress or strain range. Liner
materials will also have different fatigue lives for a given stress or strain range. The load-sharing
characteristics of a liner material with a given reinforcement will affect their fatigue lives. An
autofrettage cycle is used with metal lined cylinders to improve fatigue life. The low modulus of
elasticity of polymer liner materials often results in the liner being in compression when the cylinder is
pressurized, so their fatigue life could be very high. Welds in a liner, whether it is metal or polymer, can
affect the fatigue life due to the different mechanical properties in a weld and in heat affected zones.
Surface quality and conditions such as roughness will affect cyclic fatigue, particularly crack initiation.
Autofrettage generally blunts cracks, and adds surface compression, which will improve fatigue life.
Evaluation and understanding of cyclic fatigue will lead to improved designs and reduce the risk of
cyclic fatigue failures without the need to overdesign the cylinders or conduct extensive qualification
testing on each new design.
5 Cyclic fatigue evaluation
Cyclic fatigue of composite cylinders can be addressed with an understanding of:
— service conditions and requirements;
— test conditions and specimens;
— fibre materials and their fatigue properties;
— liner materials and their fatigue properties;
— resin materials and their fatigue properties;
— composite/liner load sharing;
— autofrettage;
— analysis methods;
— leak before burst (LBB);
— damage tolerance;
— aging and environment;
— counting and combining different cycles;
— qualification testing.
6 Elements of cyclic fatigue
6.1 Service conditions and requirements
6.1.1 Temperature and moisture
Service conditions depend largely on location and usage of the cylinder. If the cylinders are located
and used outdoors, they must be able to withstand ambient conditions. Common conditions include
temperature ranges from −40 °C to +85 °C (−40 °F to +185 °F), which include higher temperature
exposure due to solar input and storage in confined spaces. This may include use in a vehicle or shipment
in a rail car where direct sunlight will raise temperatures within the storage compartment. Surface
absorptivity and emissivity of the cylinder can affect solar input to the cylinder and its equilibrium
temperat
...
TECHNICAL ISO/TR
REPORT 13086-4
First edition
2019-09
Gas cylinders — Guidance for design
of composite cylinders —
Part 4:
Cyclic fatigue of fibres and liners
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Background . 1
5 Cyclic fatigue evaluation . 2
6 Elements of cyclic fatigue . 2
6.1 Service conditions and requirements . 2
6.1.1 Temperature and moisture . 2
6.1.2 Pressure . 3
6.1.3 Pressure cycles . 3
6.2 Test conditions and specimens . 4
6.3 Fibre materials and their fatigue properties . 6
6.3.1 Materials . 6
6.3.2 Material properties and data . 6
6.3.3 Hybrid construction . 7
6.4 Liner materials and their fatigue properties . 8
6.4.1 Materials used . 8
6.4.2 Material properties and data . 8
6.4.3 Issues with localized strain differences . 8
6.5 Resin materials and their fatigue properties . 9
6.6 Composite/liner load sharing . 9
6.7 Autofrettage . 9
6.8 Analysis methods .10
6.9 Leak before burst (LBB) .11
6.10 Damage tolerance .11
6.11 Aging and environment .11
6.12 Counting cycles .11
6.13 Combining cycles.13
6.14 Qualification testing .14
7 Summary and conclusions .14
Annex A (informative) Equivalent pressure cycling .15
Bibliography .20
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 58, Gas cylinders, Subcommittee SC 3,
Cylinder design.
A list of all parts in the ISO 13086 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved
TECHNICAL REPORT ISO/TR 13086-4:2019(E)
Gas cylinders — Guidance for design of composite
cylinders —
Part 4:
Cyclic fatigue of fibres and liners
1 Scope
This document addresses the topic of cyclic fatigue of structural reinforcing fibres as used in composite
cylinders, and cyclic fatigue of structural and non-structural liners in these cylinders. This document
provides a basic level of understanding of these topics.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
NOTE Terms and definitions related to gas cylinders can be found in ISO 10286.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http: //www .electropedia .org/
— ISO Online browsing platform: available at https: //www .iso .org/obp
4 Background
Composite cylinders began service in the 1950s, initially as rocket motor cases with glass fibre
reinforcement. This soon led to glass fibre pressure vessels with rubber liners, and then to glass
fibre pressure vessels with metal liners. Metal liners were typically either aluminium alloy or steel.
Eventually, new structural fibres, such as aramid and carbon, came into use for reinforcing pressure
vessels. Today, typical reinforcements for composite gas cylinders are glass and carbon, either
individually or together as a hybrid. Typical liner materials are steel, aluminium alloy or polymers, for
example, high-density polyethylene (HDPE) or polyamide (PA); other materials may be acceptable.
Each of these materials is subject to cyclic fatigue based on the type of service and the construction of
the cylinder. Cylinders used in transport service generally see full range cycles, with a limited number
of cycles per year. Cylinders used as fuel containers would typically see up to three pressure cycles
per day for fleet vehicles, and less for private vehicles. Cylinders used in stationary applications such
as refuelling cascades could see a very large number of partial cycles in a year. Some cylinders could
see a combination of these conditions. Stationary cylinders used for fuel cells or emergency breathing
applications could see a very limited number of cycles. Design working pressures for high pressure
cylinders are typically in the range of 20 bar to 1 100 bar. Cylinders for liquified gases such as propane
may operate at pressures up to 20 bar, and normally see fewer pressure cycles.
The different reinforcing fibres have different fatigue lives for a given stress or strain range. Liner
materials will also have different fatigue lives for a given stress or strain range. The load-sharing
characteristics of a liner material with a given reinforcement will affect their fatigue lives. An
autofrettage cycle is used with metal lined cylinders to improve fatigue life. The low modulus of
elasticity of polymer liner materials often results in the liner being in compression when the cylinder is
pressurized, so their fatigue life could be very high. Welds in a liner, whether it is metal or polymer, can
affect the fatigue life due to the different mechanical properties in a weld and in heat affected zones.
Surface quality and conditions such as roughness will affect cyclic fatigue, particularly crack initiation.
Autofrettage generally blunts cracks, and adds surface compression, which will improve fatigue life.
Evaluation and understanding of cyclic fatigue will lead to improved designs and reduce the risk of
cyclic fatigue failures without the need to overdesign the cylinders or conduct extensive qualification
testing on each new design.
5 Cyclic fatigue evaluation
Cyclic fatigue of composite cylinders can be addressed with an understanding of:
— service conditions and requirements;
— test conditions and specimens;
— fibre materials and their fatigue properties;
— liner materials and their fatigue properties;
— resin materials and their fatigue properties;
— composite/liner load sharing;
— autofrettage;
— analysis methods;
— leak before burst (LBB);
— damage tolerance;
— aging and environment;
— counting and combining different cycles;
— qualification testing.
6 Elements of cyclic fatigue
6.1 Service conditions and requirements
6.1.1 Temperature and moisture
Service conditions depend largely on location and usage of the cylinder. If the cylinders are located
and used outdoors, they must be able to withstand ambient conditions. Common conditions include
temperature ranges from −40 °C to +85 °C (−40 °F to +185 °F), which include higher temperature
exposure due to solar input and storage in confined spaces. This may include use in a vehicle or shipment
in a rail car where direct sunlight will raise temperatures within the storage compartment. Surface
absorptivity and emissivity of the cylinder can affect solar input to the cylinder and its equilibrium
temperat
...
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