ENV 1007-6:2002
(Main)Advanced technical ceramics - Ceramic composites - Methods of test for reinforcements - Part 6: Determination of tensile properties of filament at high temperature
Advanced technical ceramics - Ceramic composites - Methods of test for reinforcements - Part 6: Determination of tensile properties of filament at high temperature
Migrated from Progress Sheet (TC Comment) (2000-07-10): Stage 41/51=ENV
Hochleistungskeramik - Keramische Verbundwerkstoffe - Verfahren zur Prüfung der Faserverstärkungen - Teil 6: Bestimmung der Zugeigenschaften von Fasern bei hoher Temperatur
Diese Europäische Vornorm legt die Bedingungen fest, die für die Bestimmung der Zugeigenschaften von Einzelfasern keramischer Fasern bei hoher Temperatur in Luft oder inerter Atmosphäre (in Vakuum oder einer geregelten Atmosphäre) einzuhalten sind. Das Verfahren gilt für keramische Endlosfasern mit einer Bruchdehnung gleich oder kleiner als 5 % und einem linear-elastischen Verhalten bis zum Bruch, die Faserbündeln, Einzelfasern, Stapelfasern, Geflechten und Gewirken entnommen werden.
Das Verfahren dient weder zur Überprüfung der Homogenität der Festigkeitseigenschaften der Fasern noch zur Beurteilung der Wirkungen, die von einem unter Spannung stehenden Volumen ausgehen. Statistische Aspekte des Faserbruchs werden nicht erfasst.
In Abhängigkeit von der Temperatur des Faserendes sind zwei Verfahren anwendbar:
¾ Verfahren mit erhitzten Probenenden.
ANMERKUNG Für dieses Verfahren liegen wegen der Anwendungstemperatur des Keramikklebstoffs bisher nur Erfahrungen bis zu einer Temperaturgrenze von 1 300 °C vor.
Mit diesem Verfahren sind die Zugfestigkeit, der Elastizitätsmodul und die Spannungs-Dehnungs-Kurve zu bestimmen.
¾ Verfahren mit kalten Probenenden.
ANMERKUNG Die Temperaturgrenzen für dieses Verfahren liegen bedingt durch die verfügbaren Öfen bei Temperaturen von 1 700 °C in Luft und 2 000 °C in inerter Atmosphäre.
Céramiques techniques avancées - Céramiques composites - Méthodes d'essai pour renforts - Partie 6: Détermination des propriétés en traction du filament à haute température
La présente Prénorme européenne spécifie les conditions pour la mesure des propriétés en traction d'un filament de fibres de céramique à haute température sous air ou sous atmosphère inerte (vide ou atmosphère contrôlée). La méthode s'applique aux filaments de céramiques continus issus de fils câblés, fils, fibres discontinues, tresses et tissus, dont la déformation à la rupture est inférieure ou égale à 5 % et qui présentent un comportement élastique linéaire à la rupture.
La méthode ne s'applique ni aux essais d'évaluation de l'homogénéité caractéristiques en résistance des fibres, ni à l'évaluation des effets de volume sous contrainte. Les aspects statistiques de la rupture des fibres ne sont pas inclus.
Deux méthodes sont proposées selon la température des extrémités du filament :
Méthode avec extrémités froides.
NOTE L'expérimentation actuelle avec cette méthode est limitée à 1 300 °C en raison de la température d'application des colles pour céramiques.
Cette méthode permet la détermination de la résistance en traction, du module de Young et de la courbe contrainte déformation.
Méthode avec extrémités chaudes
NOTE Cette méthode est limitée à 1 700 °C sous air et à 2 000 °C sous atmosphère inerte en raison des limitations des fours.
Sodobna tehnična keramika - Keramični kompoziti - Preskusne metode za ojačitve - 6. del: Določanje nateznih lastnosti vlaken pri visoki temperaturi
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST ENV 1007-6:2007
01-januar-2007
6RGREQDWHKQLþQDNHUDPLND.HUDPLþQLNRPSR]LWL3UHVNXVQHPHWRGH]DRMDþLWYH
GHO 'RORþDQMHQDWH]QLKODVWQRVWLYODNHQSULYLVRNLWHPSHUDWXUL
Advanced technical ceramics - Ceramic composites - Methods of test for reinforcements
- Part 6: Determination of tensile properties of filament at high temperature
Hochleistungskeramik - Keramische Verbundwerkstoffe - Verfahren zur Prüfung der
Faserverstärkungen - Teil 6: Bestimmung der Zugeigenschaften von Fasern bei hoher
Temperatur
Céramiques techniques avancées - Céramiques composites - Méthodes d'essai pour
renforts - Partie 6: Détermination des propriétés en traction du filament a haute
température
Ta slovenski standard je istoveten z: ENV 1007-6:2002
ICS:
81.060.30 Sodobna keramika Advanced ceramics
SIST ENV 1007-6:2007 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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EUROPEAN PRESTANDARD
ENV 1007-6
PRÉNORME EUROPÉENNE
EUROPÄISCHE VORNORM
August 2002
ICS 81.060.30
English version
Advanced technical ceramics - Ceramic composites - Methods
of test for reinforcements - Part 6: Determination of tensile
properties of filament at high temperature
This European Prestandard (ENV) was approved by CEN on 13 July 2001 as a prospective standard for provisional application.
The period of validity of this ENV is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the ENV can be converted into a European Standard.
CEN members are required to announce the existence of this ENV in the same way as for an EN and to make the ENV available promptly
at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the ENV) until the final
decision about the possible conversion of the ENV into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2002 CEN All rights of exploitation in any form and by any means reserved Ref. No. ENV 1007-6:2002 E
worldwide for CEN national Members.
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ENV 1007-6:2002 (E)
Contents
Foreword.4
1 Scope .4
2 Normative references .4
3 Principle.5
4 Definitions and symbols .5
5 Apparatus .7
5.1 Test machine .7
5.2 Load train.7
5.3 Adhesive .7
5.4 Test chamber.7
5.4.1 Gas atmosphere.7
5.4.2 Vacuum chamber .7
5.5 Set-up for heating .7
5.6 Temperature measurement.7
5.7 Data recording system .7
5.8 Travelling microscope, or other suitable measuring device.8
6 Hot end method.8
6.1 Test specimens .8
6.2 Test specimen preparation .8
6.3 Number of test specimens.8
6.4 Test Procedure.9
6.4.1 Test set-up : determination of the temperature profile.9
6.4.2 Test set-up : other considerations.9
6.4.3 Testing technique .9
6.5 Calculation of results .12
6.5.1 Calculation of the load train compliance, C .12
l
6.5.2 Tensile strength .13
6.5.3 Elastic modulus.13
6.5.4 Tensile strain at failure.13
6.5.5 Test report .14
7 Cold end method.14
7.1 Method A.14
7.1.1 Principle of the method.14
7.1.2 Test specimens .14
7.1.3 Test specimen preparation .14
7.1.4 Number of test specimens.15
7.1.5 Test Procedure.15
7.1.6 Testing technique .15
7.1.7 Calculation of results .16
7.1.8 Test report .17
7.2 Method B.18
7.2.1 Principle of the method.18
7.2.2 Test specimens .18
7.2.3 Test specimen preparation .18
7.2.4 Number of test specimens.18
7.2.5 Test Procedure.18
7.2.6 Testing technique .19
7.2.7 Calculation of results .20
7.2.8 Test report .22
2
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ENV 1007-6:2002 (E)
Annex A (Informative) Principle of method A (from R. Paar, P. Bonnel, M. Steen; Advanced Composite
Letters, 1998, Vol. 7, N° 3, pp. 69-73) .23
Annex B (Informative) Principle of method B.25
Bibliography .27
3
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ENV 1007-6:2002 (E)
Foreword
This European Prestandard (ENV 1007-6:2002) has been prepared by Technical Committee CEN/TC 184
"Advanced technical ceramics", the secretariat of which is held by BSI.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this European Prestandard: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain,
Sweden, Switzerland and the United Kingdom.
1 Scope
This European Prestandard specifies the conditions for measurement of tensile properties of single filament of
ceramic fibres at high temperature in air or inert atmosphere (vacuum or controlled atmosphere). The method
applies to continuous ceramic filaments taken from tows, yarns, staple fibre, braids and knitting, which have strain
to fracture less or equal to 5 % and show linear elastic behaviour to fracture.
The method does not apply to testing for homogeneity of strength properties of fibres, nor to assess the effects of
volume under stress. Statistical aspects of fibre failure are not included.
Two methods are proposed depending on the temperature of the filament end :
Hot end method.
NOTE Current experience with this technique is limited to 1300 °C, because of the application temperature of ceramic
glue.
This method allows determination of tensile strength, of Young's modulus and of the stress strain curve.
Cold end method.
NOTE This method is limited to 1700 °C in air and 2000 °C in inert atmosphere because of the limits of furnaces.
2 Normative references
This European Prestandard incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this European
Prestandard only when incorporated in it by amendment or revision. For undated references the latest edition of the
publication referred to applies.
ENV 843-5, Advanced technical ceramics – Monolithic ceramics – Mechanical tests at room temperature –
Part 5 : Statistical analysis.
ENV 1007-3, Advanced technical ceramics - Ceramic composites - Methods of test for reinforcements
Part 3 : Determination of filament diameter.
EN 1007-4, Advanced technical ceramics - Ceramic composites - Methods of test for reinforcements
Part 4 : Determination of tensile properties of filament at ambient temperature.
EN 10002-2, Metallic materials – Tensile testing – Part 2 : Verification of the force measuring system of the tensile
testing machine.
EN 60584-1, Thermocouples – Part 1 : Reference tables.
4
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ENV 1007-6:2002 (E)
EN 60584-2, Thermocouples - Part 2 : Tolerances.
3 Principle
A ceramic filament is heated to the test temperature and loaded in tension. The test is performed at constant
force/displacement rate up to failure. Force and cross-head displacement are measured and recorded
simultaneously. When required, the elongation is derived from the cross-head displacement using a compliance
correction. The test duration is limited to reduce time dependent effects.
Subjecting the whole length of a fibre to temperatures well above 1000 °C makes it difficult to fix the ends of the
specimen into appropriate temperature proof extensions. In high temperature cold-end tests this problem is
avoided by keeping the junction at the ends of the test specimen at room temperature, allowing organic resins to be
used like in the room temperature tests (EN 1007-4).
Two methods can thus be used :
one consists of heating the filament over its total length (hot end method) ;
the other one consists of heating only the central part of the filament (cold end method).
4 Definitions and symbols
For the purposes of this European Prestandard, the following definitions and symbols apply.
4.1
test temperature, T
temperature of the filament at the centre of the gauge length
4.2
Lengths
4.2.1
lauge length, L
o
initial distance between two reference points on the filament. The temperature variation in the gauge length shall be
within 20 °C at test temperature
4.2.2
test specimen length, L
f
initial distance between the gripped ends of the filament
4.2.3
uniformly heated length, L
h
length of the heated zone at the test temperature, where the temperature variation is within 20 °C (see Figure 2
Appendix A)
4.2.4
gradient zone length, L
d
length of each part of the test specimen where the temperature decreases from the temperature at the end of the
uniformly heated length to room temperature (see Figure 2 Appendix A)
4.2.5
room temperature zone length, Lc
length of each part of the test specimen where the temperature is equal to room temperature
4.3
initial cross section area A
o
initial cross section area of the filament within the gauge length determined at room temperature
5
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ENV 1007-6:2002 (E)
4.4
maximum tensile force, Fm
highest recorded tensile force on the test specimen when tested to failure
4.5
tensile stress, ss
the tensile force supported by the test specimen divided by the initial cross section area
4.6
tensile strength, ss
m
ratio of the maximum tensile force to the initial cross section area
4.7
longitudinal deformation, DDL
the increase of the gauge length during the tensile test
4.8
compliance
4.8.1
total compliance, C
t
the reciprocal of the slope in the linear part of the force/displacement curve
4.8.2
load train compliance, C
l
ratio of the force displacement excluding any test specimen contribution to the corresponding force during the
tensile test
4.8.3
gradient zone compliance, C
d
ratio of the test specimen elongation in the temperature gradient zone length L to the corresponding force during
d
the tensile test
4.8.4
cold zone compliance, C
c
ratio of the test specimen elongation at room temperature Lc to the corresponding force during the tensile test
4.8.5
hot zone compliance, C
h
ratio of the test specimen elongation in the uniformly heated length L to the corresponding force during the tensile
h
test
4.9
strain, ee
ratio of the longitudinal deformation to the gauge length
4.10
fracture strain, eem
the strain at failure of the test specimen
4.11
elastic modulus, E
the slope of the linear part of the tensile stress-strain curve
6
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ENV 1007-6:2002 (E)
5 Apparatus
5.1 Test machine
The machine shall be equipped with a system for measuring the force applied to the test specimen. The system
shall conform to grade 1 according to EN 10002-2.
The machine shall be equipped with a system for measuring the force displacement. The accuracy of the
measurement shall be better than 1 mm.
5.2 Load train
The grips shall align the specimen with the direction of the force. Slippage of the filament in the grips shall be
prevented. The load train performance including the alignment system and the force transmitting system shall not
change because of heating.
5.3 Adhesive
A suitable adhesive for affixing the filament to the ends of the grip, such as epoxy resin, cement or sealing wax.
5.4 Test chamber
When testing under inert conditions, a gastight chamber allows proper control of the test environment during the
test. The installation shall be such that the variation of the load due to the variation of pressure is less than 1 % of
the scale of the load cell being used.
5.4.1 Gas atmosphere
The gas atmosphere shall be chosen depending on the material to be tested and on the test temperature. The level
of pressure shall be chosen depending on the material to be tested, on the test temperature, and on the type of
gas.
5.4.2 Vacuum chamber
The level of vacuum shall not induce chemical and/or physical instabilities of the filament material.
5.5 Set-up for heating
The set-up for heating shall be constructed in such a way that the variation of temperature within the gauge length
is less than 20 °C at test temperature.
5.6 Temperature measurement
Thermocouples shall comply with EN 60584-1 and EN 60584-2.
Alternatively, pyrometers or thermocouples which are not covered by EN 60584-1 and EN 60584-2, but which are
appropriately calibrated can be used.
5.7 Data recording system
Calibrated recorders may be used to record force-displacement curves.
The use of a digital data recording system combined with an analogue recorder is recommended.
7
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ENV 1007-6:2002 (E)
5.8 Travelling microscope, or other suitable measuring device.
6 Hot end method
In high temperature hot-end tests the test specimen strain can be determined in simple analogy to the room
temperature method assuming that the test specimen sees isothermal conditions along its whole length. According
to this hypothesis, the gauge length L is equal to the test specimen length L .
0 f
6.1 Test specimens
Specimens with a gauge length of 25 mm shall be used to establish the force-displacement curves.
Specimens with a gauge length of 10 mm and 40 mm shall be used to determine the load train compliance C .
l
The tolerance on the gauge length is – 1 mm.
6.2 Test specimen preparation
Extreme care shall be taken during test specimen preparation to ensure that the procedure is repeatable from test
specimen to test specimen and to avoid handling damage.
NOTE As an example to prevent damage during test specimen manipulation and mounting, the assembly of test specimen
and alumina tubes is maintained straight by an extra alumina rod, as shown in Figure 1.
key
1 alumina tubes
2 temporary screw attachment
3 test specimen
4 high temperature joints between the test specimen and the alumina tubes
Figure 1
6.3 Number of test specimens
For each test condition, five valid test results at a gauge length of 25 mm, are required.
For the determination of strain related properties, three additional tests at each gauge length of 10 mm and 40 mm
are required in order to establish load-train compliance, C .
L
NOTE 1 If a statistical evaluation is required, the number of test specimens at a gauge length of 25 mm shall be in
accordance with ENV 843-5.
8
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ENV 1007-6:2002 (E)
NOTE 2 A compliance determination is not required if only strength needs to be determined.
6.4 Test Procedure
6.4.1 Test set-up : determination of the temperature profile
The following determinations shall be carried out under actual test conditions :
Prior to testing, the temperature profile inside the furnace shall be established over the temperature range of
interest. This shall be done by measuring the temperature at a minimum of three locations which correspond to the
ends and the centre of the maximum gauge length.
NOTE When the type of specimen assembly described in Figure 1 is used, the temperature profile may be determined
inside the furnace at the end and at mid-way between the tubes positioned at the distance corresponding to the maximum gage
length and without the filament mounted.
During a series of tests, the test temperature is determined indirectly from the temperature indicated by the
temperature control device.
The relation between the control temperature and the test temperature is established over the range of temperature
of interest.
NOTE Usually the determination of the temperature profile and the relation between control temperature and test
temperature are established simultaneously.
6.4.2 Test set-up : other considerations
The dimension of the filament varies with the temperature and the variation is very difficult to measure.
6.4.2.1 Determination of the gauge length, L
0
The gauge length is measured to an accuracy of – 0,1 mm at room temperature.
6.4.2.2 Determination of the initial cross section area, A
0
The filament diameter and thus the initial crass section area at test temperature, is measured at room temperature
in accordance with ENV 1007-3.
NOTE 1 In principle, the initial cross section area is to be determined on the filament to be tested. In practice, this may be
achieved by sampling the lengths to be tested from a single filament at intermittent locations and using the parts in between for
diameter measurement. This assumes that for the lengths of fibres to be tested, the diameter does not vary significantly with the
length.
NOTE 2 An alternative method consists of measuring the filament cross section after fracture from a transverse cross
section taken from the part of the grips still containing embedded fibre. In this case, care has to be taken not to damage the fibre
during preparation.
6.4.3 Testing technique
Follow the chronological steps :
6.4.3.1 Zero the load cell
6.4.3.2 Specimen mounting
Mount the specimen in the load train with its longitudinal axis coinciding with that of the test machine. Care shall be
taken not to induce torsional loads or surface damage to the filament. The position of the gauge length relative to
the furnace shall be identical to that previously use in 6.4.1.
9
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ENV 1007-6:2002 (E)
6.4.3.3 Setting of the controlled atmosphere
When testing in inert gas, air and water vapour shall be removed before setting the inert atmosphere. This can be
done by establishing vacuum (below 10 Pa) in the enclosure, or by circulating inert gas.
When testing under vacuum, the vacuum level shall be according to 5.4.2.
NOTE In view of the extreme oxidation sensitivity of some of the filament material, conventional flushing of the test
chamber may not be sufficient to reduce the oxygen level below acceptable limits.
6.4.3.4 Heating of test specimen
Raise the test specimen temperature to the required test temperature and maintain this test temperature for a short
period to allow for temperature stabilisation. The test specimen temperature is the furnace temperature. Ensure
that the test specimen stays in the initial state of stress during heating.
6.4.3.5 Measurements
Record temperature ;
record vacuum or gas pressure if applicable ;
set the cross-head speed ;
record the force versus force/cross-head displacement curve up to failure ;
cool down until the risk of degradation is removed before opening the test chamber.
6.4.3.6 Test validity
The following circumstances invalidate the test :
failure to specify and record test conditions ;
any slippage in the load train as evidenced by a drop in the force/displacement curve ;
before reaching the maximum tensile force ;
any deviation from linearity in the load/cross-head displacement curve after the initial slack has been taken up.
The following circumstance invalidates only the strength and stress to failure :
failure at the grip(s), - see Figure 2 –
10
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ENV 1007-6:2002 (E)
key
1 Alumina tubes
2 Temporary screw attachment
Rupture at the grips : rupture not valid
Valid rupture
3 Test specimen
4 High temperature joints between the test specimen and the alumina tubes
Figure 1
11
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ENV 1007-6:2002 (E)
6.5 Calculation of results
6.5.1 Calculation of the load train compliance, C
l
The load train compliance is determined at each test temperature.
NOTE This is because some of the contributions to the load train compliance (for example the cement used for fixing the
filament) may vary with temperature.
Calculate the total compliance C for the tests at each of the gauge lengths from the inverse slope in the linear part
t
of the force/cross-head displacement curve.
For each test, plot the total compliance C versus L /A . Perform a linear regression analysis of C versus L /A and
t 0 0 t 0 0
determine the load train compliance C from the intercept with the ordinate axis (Figure 3).
l
key
1 Total compliance, C (mm/N)
t
2. L = 10 mm
o
3. L = 25 mm
o
4. L = 40 mm
o
-1
5. L /A (mm )
o o
Figure 2
12
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ENV 1007-6:2002 (E)
6.5.2 Tensile strength
Calculate the tensile strength from the following equation :
s = F /A
m m 0
where
sis the filament strength, in megapascal, (MPa) ;
m
F is the maximum load, in Newton (N) ;
m
2
A is the initial cross sectional area, in square millimetres, (mm ).
0
6.5.3 Elastic modulus
The elastic modulus is calculated from the following equation :
L 1-3
0
E = 10
A (C-C )
0 t l
where
E is the elastic modulus, in gigapascal, (GPa) ;
2
A is the initial cross sectional area, in square millimetres, (mm ) ;
0
-1
C is the load train compliance, in millimetres per Newton, (mm.N ) ;
l
-1
C is the total compliance, in millimetres per Newton, (mm.N ) ;
t
L is the total gauge length, in millimetres, (mm).
0
6.5.4 Tensile strain at failure
The tensile strain at failure, eis calculated from the following equation :
m
e = s/ (10 . E)
m m
where
e is the tensile strain at failure, in % ;
m
sis the tensile strength, in megapascal, (MPa) ;
m
E is the elastic modulus in gigapascal, (GPa).
13
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ENV 1007-6:2002 (E)
6.5.5 Test report
The test report shall contain at least the following information :
a) name and address of the testing establishment ;
b) date of the test, unique identification of report and of each page, customer name and address, signatory to the
report ;
c) a reference to this standard, i.e. determined in accordance with ENV 1007-6;
d) a description of the equipment used ;
e) complete identification of the tested filament (manufacturer, type, batch, date of receipt, etc.) ;
f) agreed sampling scheme for selecting test specimen from the batch of material ;
g) method employed for determination of the filament diameter, and average filament diameter ;
h) number of tests carried out and the number of valid results obtained ;
i) for each test specimen, the gauge length expressed in millimetres ;
j) heating rate, temperature of test and displacement rate ;
k) individual values of tensile strength and strain to failure, the average tensile strength and strain to failure, and
the average elastic modulus ;
l) details of any aspect of experimental procedure which might influence the results ;
m) comments on the test or test results.
7 Cold end method
Two methods are presented, both using a change in specimen compliance in order to eliminate the parasitic
contributions to the measured total elongation.
7.1 Method A
7.1.1 Principle of the method
The principle of this method is summarised in Annex A.
7.1.2 Test specimens
Specimen with a total length L greater than that of the sum of the uniformly heated
...
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