CEN/TS 820-5:2004
(Main)Advanced technical ceramics - Methods of testing monolithic ceramics. Thermomechanical properties - Part 5: Determination of elastic moduli at elevated temperatures
Advanced technical ceramics - Methods of testing monolithic ceramics. Thermomechanical properties - Part 5: Determination of elastic moduli at elevated temperatures
This part of ENV 820 describes methods for determining the elastic moduli, specifically Young's modulus, shear modulus and Poisson's ratio, of advanced monolithic technical ceramics at temperatures above room temperature. The Technical Specification prescribes three alternative methods for determining some or all of these three parameters:
A The determination of Young's modulus by static flexure of a thin beam in three- or four-point bending.
B The determination of Young's modulus by forced longitudinal resonance, or Young's modulus, shear modulus and Poisson's ratio by forced flexural and torsional resonance, of a thin beam.
C The determination of Young's modulus from the fundamental natural frequency of a struck bar (impulse excitation method).
This Technical Specification extends the above-defined room-temperature methods described in ENV 843-2 to elevated temperatures. All the test methods assume the use of homogeneous test pieces of linear elastic materials. The test assumes that the test piece has isotropic elastic properties. At high porosity levels all of the methods can become inappropriate. The maximum grain size (see EN 623-3), excluding deliberately added whiskers, should be less than 10% of the minimum dimension of the test piece.
Hochleistungskeramik - Monolithische Keramik - Thermomechanische Eigenschaften - Teil 5: Bestimmung der elastischen Moduln bei erhöhten Temperaturen
Céramiques techniques avancées - Méthodes d'essai des céramiques monolithiques - Propriétés thermomécaniques - Partie 5: Détermination des modules élastiques à températures élevées
La présente partie de EN 820 décrit des méthodes de détermination des modules élastiques, en particulier du module de Young, du module de cisaillement et du coefficient de Poisson des céramiques techniques avancées à des températures supérieures à la température ambiante Cette Spécification Technique décrit trois méthodes possibles permettant de déterminer un ou plusieurs de ces trois paramètres.
A - Détermination du Module de Young par flexion statique d'une poutre mince en trois ou quatre points.
B - Détermination du Module de Young par résonance longitudinale forcée ou détermination du module de Young, du module de cisaillement et du coefficient de Poisson par résonance forcée en flexion et en torsion d'une poutre mince.
C - Détermination du module de Young à partir de la fréquence naturelle fondamentale d'une barre que l'on frappe( méthode d'excitation par impulsion);
La présente Spécification Technique étend les méthodes à température ambiante définies ci-dessus et décrites dans ENV 843-2 aux températures élevées. Toutes les méthodes d'essai supposent l'utilisation d'éprouvettes homogènes faites en matériaux élastiques linéaires. L'essai est fait en considérant que l'éprouvette a des propriétés élastiques isotropes. Toutes ces méthodes peuvent se révéler inappropriées pour des niveaux de porosité élevés. Il convient que la granulométrie maximale (voir EN 623-3),qui ne tient pas compte de l'ajout de « whiskers », représente moins de 10% de la plus petite dimension de l'éprouvette.
Sodobna tehnična keramika – Metode za preskušanje monolitske keramike – Termomehanske lastnosti – 5. del: Ugotavljanje elastičnih modulov pri povišanih temperaturah
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Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2005
6RGREQDWHKQLþQDNHUDPLND±0HWRGH]DSUHVNXãDQMHPRQROLWVNHNHUDPLNH±
7HUPRPHKDQVNHODVWQRVWL±GHO 8JRWDYOMDQMHHODVWLþQLKPRGXORYSULSRYLãDQLK
WHPSHUDWXUDK
Advanced technical ceramics - Methods of testing monolithic ceramics.
Thermomechanical properties - Part 5: Determination of elastic moduli at elevated
temperatures
Hochleistungskeramik - Monolithische Keramik - Thermomechanische Eigenschaften -
Teil 5: Bestimmung der elastischen Moduln bei erhöhten Temperaturen
Céramiques techniques avancées - Méthodes d'essai des céramiques monolithiques -
Propriétés thermomécaniques - Partie 5: Détermination des modules élastiques a
températures élevées
Ta slovenski standard je istoveten z: CEN/TS 820-5:2004
ICS:
81.060.30 Sodobna keramika Advanced ceramics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL SPECIFICATION
CEN/TS 820-5
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
February 2004
ICS 81.060.30
English version
Advanced technical ceramics - Methods of testing monolithic
ceramics. Thermomechanical properties - Part 5: Determination
of elastic moduli at elevated temperatures
Céramiques techniques avancées - Céramiques Hochleistungskeramik - Monolithische Keramik -
monolithiques - Propriétés thermomécaniques - Partie 5: Thermomechanische Eigenschaften - Teil 5: Bestimmung
Détermination du module élastique à température élevée der elastischen Moduln bei erhöhten Temperaturen
This Technical Specification (CEN/TS) was approved by CEN on 19 October 2003 for provisional application.
The period of validity of this CEN/TS 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 CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, 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
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 820-5:2004: E
worldwide for CEN national Members.
Page
Contents
Foreword .3
1 Scope.4
2 Normative references.4
3 Terms and definitions.5
4 Method A: Static bending method.5
4.1 Principle .5
4.2 Apparatus.5
4.3 Test pieces.7
4.4 Procedure.7
4.5 Calculation of results.8
4.6 Accuracy and interferences.9
5 Method B: Resonance method .10
5.1 Principle .10
5.2 Apparatus.10
5.3 Test pieces.12
5.4 Procedure.12
5.5 Calculation of results.13
5.6 Accuracy and interferences.15
6 Method C: Impulse excitation method .15
6.1 Principle .15
6.2 Apparatus.15
6.3 Test pieces.16
6.4 Procedure.16
6.5 Calculation .17
6.6 Accuracy and interferences.18
7 Test report.18
Bibliography .24
Foreword
This document (CEN/TS 820-5:2004) has been prepared by Technical Committee CEN/TC 184
“Advanced technical ceramics”, the secretariat of which is held by BSI.
This document has been prepared under a mandate given to CEN by the European Commission and
the European Free Trade Association.
EN 820 Advanced technical ceramics — Methods of testing monolithic ceramics —
Thermomechanical properties comprises five parts:
Part 1: Determination of flexural strength at elevated temperatures
Part 2: Determination of self-loaded deformation
Part 3: Determination of resistance to thermal shock by water quenching
Part 4: Determination of flexural creep deformation at elevated temperatures
Part 5: Determination of elastic moduli at elevated temperatures
Part 4 is a European Prestandard (ENV) and Part 5 is a Technical Specification (CEN TS).
This document includes a bibliography.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to announce this Technical Specification: Austria, Belgium, Cyprus,
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
1 Scope
This part of EN 820 describes methods for determining the elastic moduli, specifically Young's modulus,
shear modulus and Poisson's ratio, of advanced monolithic technical ceramics at temperatures above
room temperature. The Technical Specification prescribes three alternative methods for determining
some or all of these three parameters:
A - the determination of Young's modulus by static flexure of a thin beam in three- or four-point
bending.
B - the determination of Young's modulus by forced longitudinal resonance, or Young's modulus,
shear modulus and Poisson's ratio by forced flexural and torsional resonance, of a thin beam.
C - the determination of Young's modulus from the fundamental natural frequency of a struck bar
(impulse excitation method).
This Technical Specification extends the above-defined room-temperature methods described in
ENV 843-2 to elevated temperatures. All the test methods assume the use of homogeneous test pieces
of linear elastic materials. The test assumes that the test piece has isotropic elastic properties. At high
porosity levels all of the methods can become inappropriate. The maximum grain size (see EN 623-3),
excluding deliberately added whiskers, should be less than 10 % of the minimum dimension of the test
piece.
NOTE 1 Method C in ENV 843-2 based on ultrasonic time of flight measurement has not been incorporated
into this Technical Specification. Although the method is feasible to apply, it is specialised, and outside the
capabilities of most laboratories. There are also severe restrictions on test piece geometries and methods of
achieving pulse transmission. For these reasons this method has not been included in CEN/TS 820-5.
NOTE 2 The upper temperature limit for this test depends on the properties of the test pieces, and can be
limited by softening within the timescale of the test. In addition, for method A there can be limits defined by the
choice of test jig construction materials.
NOTE 3 Methods B and C may not be appropriate for materials with significant levels of porosity (i.e. >15%)
which cause damping and an inability to detect resonances or natural frequencies, respectively.
NOTE 4 This method does not provide for the effects of thermal expansion, i.e. the measurements are based
on room temperature dimensions. Depending upon the use to which the data are put, it can be necessary to
make a further correction by multiplying each dimensional factor in the relevant equations by a factor (1 + aT)
where a
T from room temperature.
2 Normative references
This Technical Specification 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 Technical Specification only when incorporated in it by amendment
or revision. For undated references the latest edition of the publication referred to applies (including
amendments).
EN 820-1, Advanced technical ceramics — Method of testing monolithic ceramics — Thermo-
mechanical properties — Part 1: Determination of flexural strength at elevated temperatures
EN 843-1:1995, Advanced technical ceramics — Monolithic ceramics — Mechanical properties at
room temperature — Part 1: Determination of flexural strength
EN 60584-2, Thermocouples — Part 2: Tolerances (IEC 60584-2:1982 + A1:1989)
EN ISO 7500-1, Metallic materials — Verification of static uniaxial testing machines —
Part 1: Tension/compression testing machines — Verification and calibration of th eforce-measuring
system (ISO 7500-1:1999)
EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
(ISO/IEC 17025:1999)
ISO/R 463, Dial gauges reading in 0,01 mm, 0,001 in and 0,0001 in
ISO 3611, Micrometer callipers for external measurement
ISO 6906, Vernier callipers reading to 0,02 mm
3 Terms and definitions
For the purposes of this Technical Specification, the following terms and definitions apply.
3.1
Young's modulus
stress required in a material to produce unit strain in uniaxial extension or compression
3.2
shear modulus
shear stress required in a material to produce unit angular distortion
3.3
Poisson's ratio
negative value of the ratio of lateral strain to longitudinal strain in an elastic body stressed longitudinally
3.4
static elastic moduli
elastic moduli determined in an isothermal condition by stressing statically or quasistatically
3.5
dynamic elastic moduli
elastic moduli determined non-quasistatically, i.e. under adiabatic conditions, such as in the resonant,
ultrasonic pulse or impulse excitation methods
4 Method A: Static bending method
4.1 Principle
Using three- or four-point bending of a thin beam test piece, the elastic distortion is measured, from which
Young's modulus may be calculated according to thin beam equations.
4.2 Apparatus
Test jig, in accordance with that described in EN 820-1 for flexural strength testing at elevated
4.2.1
temperatures in terms of its function, i.e. the support and loading rollers shall be free to roll, and to
articulate to ensure axial and even loading as described in EN 843-1. The test jig shall be made of
materials which do not interact with the test piece and which remain essentially elastic at the
maximum test temperature. A typical arrangement is shown in Figure 1.
NOTE 1 Articulation is not essential for carefully machined flat and parallel-faced test pieces.
The outer span of the test jig shall be 40 mm or greater.
NOTE 2 If the displacement is to be measured by method 1 (see 4.2.5), a span of up to 100 mm, or a span to
thickness ratio in excess of 20, is recommended to obtain large displacements and to ensure that the compliance
of the machine is a small correction if displacement is recorded as a machine cross-head movement.
The test jig may be either for three-point or four-point flexure. The latter method is required if
displacement is determined by differential transducer.
4.2.2 Mechanical testing machine, capable of applying a force to the test jig at a constant
displaceme
...
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