ISO/TS 17920:2015

TECHNICAL ISO/TS
SPECIFICATION 17920
First edition
2015-08-01
Fibre ropes for offshore
stationkeeping — Aramid
Cordages en fibres pour le maintien en position des structures
marines — Aramide
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
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ii © ISO 2015 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Materials . 2
4.1 Rope core material . 2
4.2 Rope cover material . 2
4.3 Other materials . 2
5 Requirements — Rope properties . 2
5.1 Minimum breaking strength . 2
5.2 Minimum core tenacity . 3
5.3 Axial compression fatigue properties . 3
5.4 Particle ingress protection . 3
5.5 Cyclic loading performance . 3
6 Requirements — Rope layout and construction . 3
6.1 General . 3
6.2 Type of construction . 3
6.3 Rope core . 3
6.4 Protective cover . 4
6.5 Terminations . 4
6.6 Length of rope . 4
7 Rope testing . 5
7.1 Type testing . 5
7.1.1 General. 5
7.1.2 Sampling. 5
7.1.3 Breaking strength, core tenacity and stiffness tests. 5
7.1.4 Axial compression fatigue properties test . 6
7.1.5 Torque properties tests . 6
7.1.6 Linear density test . 6
7.1.7 Cyclic loading (endurance) test . 6
7.1.8 Protective cover thickness . 6
7.1.9 Particle ingress protection . 6
7.2 Testing of current production . 6
7.2.1 Sampling and testing . 6
7.2.2 Length measurement . 7
8 Report . 7
8.1 Prototype rope . 7
8.2 Current production . 7
9 Certification . 7
10 Marking, labelling, and packaging . 8
10.1 Marking . 8
10.2 Labelling . 8
10.3 Packaging . 8
Annex A (normative) Fibre qualification and testing . 9
Annex B (normative) Rope testing .12
Annex C (normative) Axial compression fatigue properties test .21
Annex D (informative) Guidance for rope handling care .23
Annex E (informative) Certificate of conformity — Aramid ropes for offshore stationkeeping .34
Annex F (informative) Commentary.35
Bibliography .41
iv © ISO 2015 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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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
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assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 38, Textiles.
TECHNICAL SPECIFICATION ISO/TS 17920:2015(E)
Fibre ropes for offshore stationkeeping — Aramid
1 Scope
This Technical Specification specifies the main characteristics and test methods of new aramid fibre
ropes used for offshore stationkeeping.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 139, Textiles — Standard atmospheres for conditioning and testing
ISO 1968, Fibre ropes and cordage — Vocabulary
ISO 2060, Textiles — Yarn from packages — Determination of linear density (mass per unit length) by
the skein method
ISO 7500-1, Metallic materials — Verification of static uniaxial testing machines — Part 1: Tension/compression
testing machines – Verification and calibration of the force-measuring system
ISO 18692, Fibre ropes for offshore stationkeeping — Polyester
ASTM D1907, Test Method for Linear Density of Yarn (Yarn Number) by the Skein Method
ASTM D1776, Practice for Conditioning and Testing Textiles
ASTM D6611, Standard Test Method for wet and dry Yarn-on-Yarn Abrasion resistance
ASTM D7269, Test Methods for Tensile Testing of Aramid Yarns
CI 1503, Test method for yarn-on-yarn abrasion
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1968, ISO 18692, and the
following apply.
3.1
aramid
long-chain synthetic polyamide in which at least 85% of the amide linkages are attached directly to two
aromatic rings
[SOURCE: ISO 1968, 3.3.1, modified]
3.2
axial compression fatigue
failure mode for fibre rope such as aramid (3.1) under low tension or compression
4 Materials
4.1 Rope core material
The aramid fibre used in the core of the rope shall have an average tenacity of not less than 1,8 N/tex and
in accordance with Annex A. Qualification and testing requirements are given in Annex A.
4.2 Rope cover material
Where polyester yarn is used in the protective cover, its minimum tenacity shall be 0,73 N/tex.
4.3 Other materials
Other materials employed in rope assembly shall be identified in the rope design/manufacturing
specification.
For each material, the following shall be specified, as applicable:
a) base material;
b) size (linear density, mass per unit area, …);
c) relevant mechanical properties (tenacity, stiffness, …).
5 Requirements — Rope properties
5.1 Minimum breaking strength
The minimum breaking strength (MBS) of the rope (spliced) when tested according to Annex B shall
conform to Table 1.
Table 1 — Minimum breaking strength (MBS)
a
Reference number Minimum breaking strength
kN
80 2 500
90 3 100
100 3 900
106 4 400
112 5 000
118 5 600
125 6 300
132 7 000
140 7 800
150 8 700
160 10 000
170 11 200
180 12 500
a
The reference number corresponds to the approximate outer diameter of the rope, in
millimetres (mm). Actual diameters may vary for a given reference number.
2 © ISO 2015 – All rights reserved

Table 1 (continued)
a
Reference number Minimum breaking strength
kN
190 14 000
200 15 500
212 17 500
224 19 500
a
The reference number corresponds to the approximate outer diameter of the rope, in
millimetres (mm). Actual diameters may vary for a given reference number.
5.2 Minimum core tenacity
The minimum tenacity of the aramid rope core shall be 0,90 N/tex measured according to Annex B. All
samples tested shall comply with the minimum value specified herein.
5.3 Axial compression fatigue properties
The rope shall have demonstrated 95 % retention of MBS following the axial compression fatigue test
method in Annex C.
5.4 Particle ingress protection
If specified, the rope shall be constructed with a protection of the core against the ingress of particles
having a size greater than 20 μm (microns) or as agreed between involved parties. Testing of the
protection shall be performed in accordance with Annex B.
5.5 Cyclic loading performance
The rope shall have demonstrated performance under cycling loading following the requirements of
7.1.7 and B.5.
6 Requirements — Rope layout and construction
6.1 General
The typical section of a rope shall comprise a rope core providing intended strength and stiffness and a cover.
6.2 Type of construction
The rope shall be of one of the following types of construction:
— torque-neutral construction (type TF);
— torque-matched construction (type TM).
The type of rope shall be specified by the purchaser.
NOTE Torque-neutral ropes are intended for use in mooring systems together with chain or torque-neutral
spiral strand wire ropes. Torque-matched ropes are intended for use in mooring systems together with six-strand
wire ropes or other non torque-neutral wire ropes. Typical constructions are illustrated in Figure F.3 and Figure F.4.
6.3 Rope core
6.3.1 The total number of yarns in the rope shall be at least the number specified in the rope design
specification.
6.3.2 Splices are not allowed in the rope core nor in sub-ropes except for those at the end terminations.
Strands shall be uninterrupted over the length of the rope with no splice or strand interchange.
NOTE Yarns may be joined if necessary.
6.4 Protective cover
6.4.1 A protective cover shall be provided around the rope core to protect the rope core from mechanical
damages during handling and in service.
The protection shall be water-permeable.
6.4.2 A polyester braided protective cover shall have a minimum thickness, t, with
— t = 7,0 mm, for a reference number RN above 100, and
— t = 0,07 × RN, but not less than 4 mm, for a reference number RN less than 100.
Strand interchanges, i.e. the overlapping continuation of an interrupted strand with another identical
strand following the same path, are permitted if they are properly staggered.
6.4.3 If an alternative protective cover is used, it shall demonstrate a level of protection equal to that of
a polyester braided cover.
6.4.4 A braided cover shall include coloured strands forming a pattern so that rope twist during
installation or in service can be identified. There shall be a minimum of one “S” coloured strand and one
“Z” coloured strand to form a cross on the rope.
An alternative protective cover shall be fitted with an axial stripe of contrasting colour or other means
to identify rope twist during installation or in service.
6.5 Terminations
The terminations shall be made of an eye splice plus abrasion protection materials.
NOTE There can be other terminations provided that they do not jeopardize the rope performance.
The dimensions and arrangement of the eye shall match the diameter and groove shape of the thimble (or
other interface piece) to be used for end connections and shall be the same as for the rope prototype testing.
In the splice area, the integrity and the continuity of rope cover and particle-ingress protection, if fitted,
shall be preserved or restored.
The eye and the splice area shall be further covered by an abrasion protection coating such as
polyurethane. Each termination shall be made according to the manufacturing practice as described in
the termination specification.
6.6 Length of rope
The bedded-in lengths of the rope sections shall be calculated in accordance with 7.2.2 under 20 % of
MBS unless otherwise agreed on the purchase order or contract.
The calculated length of supplied rope shall be within ±1 % of the specified length.
For each supplied rope, the actual length at the reeling tension or during manufacture shall be reported
as an indicative value.
Adequate extra length shall be manufactured in order to prepare the samples for testing which are
considered to be part of the delivery.
4 © ISO 2015 – All rights reserved

7 Rope testing
7.1 Type testing
7.1.1 General
Prototype tests shall demonstrate that ropes certified by the manufacturer as complying with the
requirements laid down in this Technical Specification possess the properties specified in this Technical
Specification. The purpose of these tests is to verify the design, material, and method of manufacture of
each size of finished rope including protective cover and terminations.
All ropes to be prototype tested shall comply with all the other requirements laid down in this Technical
Specification. The tests specified below shall be carried out on a prototype rope for each size of rope,
unless otherwise noted in this Clause.
Any change in the design, material, method of manufacture, including protective cover and terminations
which may lead to a modification of the properties as defined in Clause 5, shall require that the prototype
tests specified in this Technical Specification be carried out on the modified rope.
7.1.2 Sampling
The number of rope samples to be tested is given in Table 2.
Table 2 — Number of samples for testing
Test Number of samples
Breaking strength, core tenacity, and stiffness 3
a
Axial compression fatigue 1
b
Torque properties 1
Linear density 1
c
Cyclic loading endurance 1
a
See 7.1.4.
b
See 7.1.5.
c
See 7.1.7.
7.1.3 Breaking strength, core tenacity and stiffness tests
7.1.3.1 Three samples shall be tested according to the procedure specified in Annex B and each shall be
capable of meeting the requirements of 5.1 (minimum breaking strength) and of 5.2 (minimum core tenacity).
7.1.3.2 The rope core tenacity and stiffness at the end of bedding-in shall be calculated according to the
methods defined in Annex B.
7.1.3.3 Measurement of the stiffness at other load levels shall be performed within the same tests.
These measurements are, however, not required when results are available for another qualified rope of
the same design, material and method of manufacture with a reference number of not less than 90, and
when the stiffness at end of bedding-in does not differ by more than 10 %.
NOTE 1 These measurements are performed for design purposes only. There are no acceptance criteria on
these parameters.
NOTE 2 These measurements can also be performed on a separate rope sample (see Annex B).
7.1.4 Axial compression fatigue properties test
One sample shall be tested for axial compression fatigue properties.
This test need not be performed when data is available from the previous qualification test of another
rope with the same design, material and method of manufacture of rope core, and a size not less than
reference number 90.
7.1.5 Torque properties tests
Where applicable, torque properties tests shall be performed according to the procedure specified in
ISO 18692. These tests are, however, not required when results are available for another qualified rope
of the same design, material, method of manufacture, and termination with a reference number of not
less than 90.
7.1.6 Linear density test
The linear density shall be calculated from the measured weight and elongation according to the method
defined in Annex B.
7.1.7 Cyclic loading (endurance) test
7.1.7.1 One sample shall be tested for cyclic loading. However, cyclic loading (endurance) tests
performed with one size of qualified rope having the same design, material, and method of manufacture
including protective cover and terminations is enough to qualify all sizes with an MBS between 50 % and
200 % of the size tested. The test for cyclic loading (endurance) is not required if such data is available.
7.1.7.2 The cyclic loading (endurance) test shall be performed according to the procedure specified in
B.5. A load range shall be selected by the manufacturer and the rope shall withstand, without breaking, at
least the number of cycles for that load range as given in Figure B.2.
The residual strength of the rope shall be at least 80 % of its MBF.
7.1.8 Protective cover thickness
The thickness of the protective cover shall be verified.
The thickness of a braided cover shall be measured as twice the thickness of cover strands under the
maximum braiding tension.
7.1.9 Particle ingress protection
See 5.4 and Annex B.
7.2 Testing of current production
7.2.1 Sampling and testing
When the ropes are already certified by the manufacturer as complying with the requirements laid down
in this Technical Specification, the rope tests including breaking strength and core tenacity, as well as
protective cover thickness verification, shall be performed on one sample taken from the manufacturing
process for each type and size of rope.
6 © ISO 2015 – All rights reserved

7.2.2 Length measurement
The bedded-in length of each supplied rope section (other than short sections) shall be calculated from
the linear density, ρ , by Formula (1):
l
mm− ⋅1000
()
TS
L= (1)
ρ
l,20
where
L is the length of the rope in metres (m);
m is the mass of the total rope length in kilograms (kg);
T
m is the mass of the materials used to form the eyes and the splices in kilograms (kg);
S
is the linear density of the rope, in ktex, obtained from the prototype test in accordance
ρ
l,20
with 7.1.6.
The length of short rope sections (i.e. sections of less than 20 m) shall be measured at a load of 2 % of
MBS as the length between the centres of termination fittings (i.e. same as L on Figure B.1).
u
8 Report
8.1 Prototype rope
A complete and detailed report of the prototype rope manufacturing shall be supplied including the fibre
manufacturer, the fibre type and finish, and all rope characteristics that can influence the mechanical
properties like design, material specifications, and method of manufacture, including protective cover
and terminations, with sketches or pictures.
A complete and detailed report of type tests with sketches or pictures of the test set-up shall also be provided.
8.2 Current production
The manufacturing report of supplied ropes shall be provided. A complete and detailed report of rope
tests with sketches and pictures of the test set-up shall also be provided.
9 Certification
The certificate of approval and control issued by an RCS (recognized classification society) shall be
presented together with the ropes in order to ensure that testing and fabrication are in accordance with
the approved specifications.
The rope manufacturer shall issue or obtain a rope certificate including at least the following information:
a) reference number;
b) type of construction;
c) linear density;
d) MBS;
e) individual identification number;
f) length at a specified load;
g) length at the reeling handling tension.
NOTE A suggestion for a certificate of conformity can be found in Annex E.
10 Marking, labelling, and packaging
10.1 Marking
A tape of at least 3 mm wide printed with a reference identifying the manufacturer shall be incorporated
into the rope. The maximum distance between two consecutive markings shall be 0,5 m.
10.2 Labelling
An identification plaque or alternative means shall be installed close to the splice with the following
information as a minimum:
a) purchase identification;
b) individual identification number;
c) reference to this Technical Specification;
d) type of construction (TF or TM) in accordance with 6.2;
e) rope MBS;
f) rope length at a specified load according to 7.2.2.
10.3 Packaging
If the assembly is packed on a spool or a reel, these shall be suitable for the applicable transportation
means and of appropriate construction in terms of strength.
The packaging shall be marked with the manufacturer’s trademark and with the lot identification number.
NOTE The ropes may be delivered in steel reels or in containers. Alternative packaging designs may be
provided with the prior approval of the purchaser.
8 © ISO 2015 – All rights reserved

Annex A
(normative)
Fibre qualification and testing
A.1 General
This Annex specifies the requirements for fibre qualification and testing.
A.2 Fibre specification
A.2.1 General information
A fibre specification shall include at least the information defined below:
a) identification and general properties of fibre;
b) detailed specification of physical and mechanical properties.
NOTE General properties of material can be found in the material safety data sheet.
A.2.2 Identification and general properties
The following information shall be provided in the fibre specification:
a) producer of fibres;
b) fibre designation;
c) fibre material;
d) number of filaments;
e) nominal size (linear density);
f) average tenacity;
g) finish designation;
h) finish content.
A.2.3 Physical and mechanical properties
The following information shall be provided in the fibre specification including tolerances on
specified properties:
a) linear density;
b) dry breaking strength;
c) dry elongation to break;
d) dry elongation at a specified load level;
e) effect of hydrolysis in seawater (reduction of strength with time).
These properties shall be documented by results of tests in accordance with A.4.
A.3 Fibre test certificate
For each delivery, the fibre manufacturer shall issue a raw material certificate including at least the
following information:
a) fibre designation;
b) merge number/batch identification;
c) size (linear density);
d) dry breaking strength;
e) dry elongation to break;
f) test result of finish level on fibre (see A.4.2 below).
For acceptance testing, the above properties shall be obtained from testing on a representative number
of samples taken from the delivery, not less than once every 5,000 kg.
For each property, the number of tests, the mean value, and the standard deviation or range shall be reported.
A.4 Fibre testing
A.4.1 Fibre linear density and strength
The fibre linear density shall be determined and recorded according to ASTM D1907 or ISO 2060.
The fibre strength and elongation shall be determined based on five specimen of basic yarn samples.
The following samples shall be preconditioned according to ASTM D1776:
— 45 °C ± 5 °C and relative humidity of 15 % ± 5 % during 4 h.
Subsequently, conditioned according to ISO 139 or ASTM D1776:
— standard atmosphere 20 °C ± 2 °C and relative humidity 65 % ± 5 %;
— optional atmosphere 24 °C ± 2 °C and relative humidity 55 % ± 5 %.
The conditioning time shall be 14 h at least.
After conditioning, the specimen shall be loaded to break according to ASTM D7269. The average yarn
breaking strength and elongation shall be calculated and recorded. The used test methods shall be
documented with the results.
A.4.2 Yarn-on-yarn abrasion performance
A.4.2.1 Qualification testing (efficiency)
A.4.2.1.1 Qualification testing for efficiency of finish shall be performed on wet yarns. Tests shall be
done in accordance with CI 1503 or ASTM D6611. The results shall be kept for reference.
NOTE The number or wraps used in the tests may be one.
A.4.2.1.2 Tests shall be performed at least at three load levels including one in each of the
following ranges:
a) 20 mN/tex to 30 mN/tex;
b) 35 mN/tex to 45 mN/tex;
10 © ISO 2015 – All rights reserved

c) 55 mN/tex to 60 mN/tex.
A minimum of eight yarns shall be tested for each level.
A.4.2.1.3 The results at each load level shall be derived and reported in accordance with the
procedure in CI 1503 or in ASTM D6611.
Based on these results, acceptance levels for further production tests shall be chosen by the fibre
manufacturer.
A.4.2.2 Qualification testing (persistence)
The persistence of the marine finish in a marine environment shall be demonstrated.
The assessment method shall be duly documented by the fibre producer.
NOTE Yarn-on-yarn abrasion tests after artificial ageing may be used.
A.4.2.3 Testing of current production
The effectiveness of the application of the marine finish during fibre production shall be verified by
yarn-on-yarn abrasion tests or another documented testing method.
When a yarn-on-yarn abrasion test is used, the testing shall be performed at least at one load level on a
minimum of four yarns at each test with an acceptance level according to A.4.2.1.3.
Any other testing method shall be duly documented by the fibre producer.
A.4.3 Hydrolysis properties of aramid fibres
The material shall have a residual strength of at least 90 % of its nominal value (new fibre) after
immersion for three weeks in 80 °C seawater.
NOTE 1 Water can be either natural or artificial seawater (e.g. ASTM D1141) and can be used for testing.
NOTE 2 Accelerated test based on a factor 1 000 in time over a -60 °C increased temperature [e.g. see ISO 9080
to simulate the conditions of a mooring line (20 years in seawater at 4 °C to 20 °C)].
Annex B
(normative)
Rope testing
B.1 General
This Annex specifies the requirements for full-size testing of rope samples and it addresses the
following tests:
a) strength and stiffness;
b) linear density;
c) cyclic loading endurance;
d) particle ingress resistance.
NOTE 1 For the requirements for axial compression fatigue testing, see Annex C.
NOTE 2 Requirements for testing of the torque properties whenever applicable can be found in
ISO 18692:2007, B.6.
B.2 Testing conditions
B.2.1 Rope samples
The rope tests including strength, cyclic loading endurance, and torque measurement shall be performed
on samples with terminations that are identical to the supplied ropes. The strength and cyclic loading
tests shall be performed with fixed end conditions (without a swivel).
Termination fittings shall be provided with the same type of material and the same profile and
dimensions (radius, groove shape) as the thimbles for the supplied rope.
B.2.2 Ambient conditions
In all tests, the ambient temperature and humidity shall be recorded.
The water used for soaking, wetting, and immersing shall be fresh water with no additives.
During the cyclic loading endurance test (see B.5), the rope shall be wetted by a water spray or immersed
and the temperature shall be controlled in order to avoid over-heating.
The temperature of the out-flowing water should not exceed 30 °C.
B.2.3 Testing machine
The testing machine shall be of at least class 2 according to ISO 7500-1 and it shall be of such a type that
load (or cross-head displacement) can be controlled at all time during both extension and retraction.
For the breaking test (step 10 in B.3.1), the use of a test machine with a fixed cross-head speed is
acceptable provided that time to failure is at least 2 min.
12 © ISO 2015 – All rights reserved

B.2.4 Load and elongation measurements
Load shall be measured by a strain gauge system and continuously recorded during each test.
NOTE In the loading sequences specified below, loads are given as a percentage of the specified MBS of the rope.
The measurements of the gauge length elongation of the rope core shall be performed with a system
of adequate sensitivity for the intended sequences taking into account the very small elongation of an
aramid rope under such conditions. Extensometer or video image processing may be used.
The cover and the filter shall be cut for fastening of extensometer ends or for marking of core (in case of
measurement by video image processing).
B.3 Strength and stiffness test
B.3.1 Test procedure
The following rope test procedure applies to verify the rope MBS, the minimum core specific strength,
and the stiffness. The test shall be performed according to the steps below.
— Step 1: The sample shall be soaked for at least 4 h in fresh water.
— Step 2: The sample shall be installed in the test machine.
— Step 3: A load of 2 % of MBS shall be applied.
— Step 4: The rope shall be marked at each end at a distance of three times the rope diameter from the
last tuck of splices (see Figure B.1).
— Step 5: The extensometer shall be installed in a section of the rope undisturbed by the termination
between these marks.
— Step 6: A tension of 50 % of the rope MBS shall be applied at a rate of 10 % MBS per minute and
held for 30 min.
— Step 7: The tension shall be reduced to 10 % of the rope MBS at a rate of 10 % MBS per minute.
— Step 8: A cycling tension between 10 % and 30 % of the rope MBS shall be applied 100 times, without
interruption at a frequency between 0,03 Hz and 0,1 Hz (bedding-in and measurement of dynamic
stiffness after bedding-in).
— Step 9: When applicable, a cycling tension between specified limits shall be applied for a specified
number of cycles (dynamic or static stiffness measurements, see B.3.5) and without interruption,
otherwise this step is omitted;
— Step 10: The sample shall be unloaded, the extensometer removed, and the rope pulled to failure at
a loading rate of approximately 20 % MBS per minute.
r
Figure B.1 — Marks “r” on the rope sample
B.3.2 Breaking strength
The tension at break of the rope sample shall be recorded.
All samples tested shall meet the MBS.
If the breaking load of one sample is lower than the MBS, two other samples shall be prepared and tested.
The rope is considered to comply with the breaking strength requirement in this Technical Specification
only if the results of both the subsequent two tests meet the MBS.
B.3.3 Load-elongation measurements
The rope test shall include the measurement of the following:
a) load versus total elongation (stroke), four plots as below:
1) steps 5 to 7;
2) step 8;
3) step 9 (when performed);
4) step 10;
b) gauge length (extensometer) elongation (for the prototype rope), three plots as below:
1) load versus elongation encompassing steps 5 to 7;
2) load versus elongation for the last three full cycles at least in step 8;
3) load versus elongation for the last three full cycles at least, in step 9 (when performed);
c) continuous record of load and elongation versus time during the three cycles of the quasi-static
stiffness measurement (when performed).
NOTE Step numbers refer to B.3.1.
B.3.4 Dynamic stiffness at end of bedding-in
The dynamic stiffness at end of bedding-in (step 8 of B.3.1) shall be obtained from the load and gauge
length elongation measurements and shall be calculated according to B.3.6.2.
B.3.5 Quasi-static stiffness and dynamic stiffness
B.3.5.1 The quasi-static stiffness and the dynamic stiffness at other load levels shall be obtained from load
and gauge length elongation measurements in step 9 in B.3.1, and calculated according to B.3.6.3 and B.3.6.4.
NOTE Additional measurements of dynamic stiffness may be performed when agreed between the purchaser
and the manufacturer (see Annex F).
B.3.5.2 For the measurement of the quasi-static stiffness, the following cycling shall be applied in three
full cycles without interruption:
a) slowly load the rope from 10 % of the rope MBS to 30 % of the rope MBS in a period of time between
2 min and 6 min;
b) hold the load at 30 % of the rope MBS for 30 min from the start time of a) above;
c) slowly unload the rope from 30 % of the rope MBS to 10 % of the rope MBS in a period of time
between 2 min and 6 min;
d) hold the load at 10 % of the rope MBS for 30 min from the start time of c) above.
14 © ISO 2015 – All rights reserved

This cycling shall be performed during step 9 of B.3.1 above on one sample before the cycling for the
dynamic stiffness.
NOTE Other load levels may be considered when agreed between involved parties (see Annex F).
B.3.5.3 For the measurement of the dynamic stiffness, the following cycling shall be applied during
step 9 of B.3.1 at a frequency between 0,03 Hz and 0,1 Hz:
— step 9a: On one sample: 100 cycles between 20 % and 30 % of the rope MBS;
— step 9b: On a second sample: 200 cycles between 30 % and 40 % of the rope MBS;
— step 9c: On a third sample: 300 cycles between 40 % and 50 % of the rope MBS.
In the case of an interruption within a set of cycling, this set of cycling shall be repeated.
If the interruption leads to unloading of the rope, the step 8 shall be performed again before re-running
the interrupted set of cycling.
B.3.5.4 Alternatively to the above, measurements may be performed as follows.
a) All measurements are performed on the same sample, quasi-static stiffness, then dynamic stiffness
as steps 9a, 9b, and 9c (see B.3.5.3) in ascending order of load. Then, the cycling may be limited to
100 cycles at each level.
b) These measurements are performed on a separate rope sample in either wet or dry condition
according to the steps below:
1) the sample shall be installed in test machine;
2) steps 3 to 8 of B.3.1 including measurement of the dynamic stiffness at the end of bedding-in;
3) step 9 of B.3.1 with cycling as per B.3.5.2 for the measurement of the quasi-static stiffness;
4) steps 9a, 9b, and 9c of B.3.5.3 with cycling for the measurement of the dynamic stiffness.
B.3.6 Calculation of mechanical properties
B.3.6.1 Core tenacity
The rope core tenacity shall be calculated according to Formula (B.1):
F
BS
t= (B.1)
ρ
lc,0
where
t is the rope core tenacity, expressed in newtons per tex (N/tex);
is the actual breaking strength of the rope, expressed in newtons (N), obtained in
F
BS
step 10 of B.3.1;
is the linear density of the rope core, expressed in tex at 2 % of MBS, as measured
ρ
lc,0
during the linear density test (see B.4).
B.3.6.2 Dynamic stiffness at end of bedding-in
The dynamic stiffness at end of bedding-in is calculated from the load-elongation measurement at the
end of step 8 of B.3.1.
The dynamic stiffness is calculated according to Formula (B.2):
FF−
30 10
F
MBS
K = (B.2)
rb
LL−
30 10
L
where
is the dynamic stiffness after bedding-in;
K
rb
is the recorded variation of load over the 100th cycle;
FF−
30 10
is the specified minimum breaking strength of the rope;
F
MBS
LL−
is the elongation (strain variation) between F and F over the 100th cycle.
30 10
10 30
L
NOTE Alternatively, the stiffness can be obtained from the average slope of the load-elongation plot over the
last three full cycles.
B.3.6.3 Dynamic stiffness
When required, the dynamic stiffness is calculated according to Formula (B.3) from load-elongation
measurements of step 9a, 9b, or 9c of B.3.5.3:
FF−
YX
F
MBS
K = (B.3)
rd,XY−>
LL−
YX
L
X
where
is the dynamic stiffness under cycling between load X and Y;
K
rd,XY−>
is the recorded variation of load over the last cycle;
FF−
YX
is the elongation between F and F over the last cycle.
X Y
LL−
YX
L
X
NOTE Alternatively, the stiffness can be obtained from the average slope of the load-elongation plot over the
last three full cycles.
16 © ISO 2015 – All rights reserved

B.3.6.4 Quasi-static stiffness
When required, the quasi-static stiffness is calculated according to Formula (B.4) from load-elongation
measurem
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