ISO/TR 13086-4:2024
(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.
Bouteilles à gaz — Recommandations pour la conception des bouteilles en matière composite — Partie 4: Fatigue cyclique des fibres et liners
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Standards Content (Sample)
Technical
Report
ISO/TR 13086-4
Second edition
Gas cylinders — Guidance for
2024-11
design of composite cylinders —
Part 4:
Cyclic fatigue of fibres and liners
Bouteilles à gaz — Recommandations pour la conception des
bouteilles en matière composite —
Partie 4: Fatigue cyclique des fibres et liners
Reference number
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ii
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) .10
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 . 13
7 Summary and conclusions .13
Annex A (informative) Equivalent pressure cycling . 14
Bibliography .20
iii
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
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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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
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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.
This second edition of ISO/TR 13086-4 cancels and replaces the first edition (ISO/TR 13086-4:2019) which
was technicall revised.
The main changes are as follows:
— editorial and technical changes throughout the document.
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
Technical Report ISO/TR 13086-4:2024(en)
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 https:// 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 could 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 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 can 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
can 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 in
Type 2 or Type 3 cylinders. 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 materia
...
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