Advanced technical ceramics - Mechanical properties of ceramic composites at high temperature under inert atmosphere - Determination of fatigue properties at constant amplitude

This European Standard specifies the conditions for the determination of constant-amplitude of load or strain in uniaxial tension/tension or in uniaxial tension/compression cyclic fatigue properties of ceramic matrix composite materials (CMCs) with fibre reinforcement for temperature up to 2 000 °C under vacuum or a gas atmosphere which is inert to the material under test.
NOTE   Test environments are specified which are intended to prevent the material under test from chemically reacting with them.
This European Standard applies to all ceramic matrix composites with fibre reinforcement, unidirectional (1D), bi-directional (2D), and tri-directional (xD, where 2 < x ? 3).

Hochleistungskeramik - Mechanische Eigenschaften von keramischen Verbundwerkstoffen bei hoher Temperatur in inerter Atmosphäre - Bestimmung der Dauerschwingeigenschaften bei Belastung mit konstanter Amplitude

Diese Europäische Vornorm legt für faserverstärkte Verbundwerkstoffe mit keramischer Matrix (CMC) die Bedingungen zur Bestimmung der Dauerschwingeigenschaften bei Temperaturen bis zu 2 000 °C im Vakuum oder in einer gegenüber dem zu prüfenden Werkstoff inerten Gasatmosphäre fest, wenn eine einachsige Beanspruchung innerhalb des Zugschwell  (Zug/Zug) oder des Wechselbereichs (Zug/Druck) so aufgebracht wird, dass eine Last oder Dehnung mit konstanter Amplitude erreicht wird.
ANMERKUNG   Die Anwendung dieser Atmosphären hat den Zweck, Veränderungen des zu prüfenden Werkstoffs aufgrund einer chemischen Reaktion mit der umgebenden Atmosphäre während der Prüfung zu vermeiden.
Diese Norm ist auf alle faserverstärkten Verbundwerkstoffe mit keramischer Matrix mit unidirektionaler (1D), bidirektionaler (2D) und mehrdirektionaler (xD, mit 2 < x L 3) Verstärkung anwendbar.
Der Zweck dieser Vornorm besteht darin, das Verhalten der CMC zu bestimmen, wenn sie gleichzeitig einer mechanischen Dauerschwingbeanspruchung und einer Oxidation ausgesetzt werden. Im Gegensatz zu den Prüfungen zur Bestimmung der Dauerschwingeigenschaften bei hoher Temperatur in inerter Atmosphäre treten bei den Prüfungen, die bei hoher Temperatur und in oxidierender Umgebung durchgeführt werden, Werkstoffschädigungen verstärkt dadurch auf, dass neben der rein mechanischen Ermüdung auch chemische Einflüsse durch die Oxidation des Werkstoffs wirksam werden.

Céramiques techniques avancées - Propriétés mécaniques des céramiques composites a haute température sous atmosphere inerte - Détermination des propriétés de fatigue a amplitude constante

La présente Norme européenne spécifie les conditions de détermination des propriétés de fatigue cyclique a amplitude constante de contrainte ou de déformation en traction uniaxiale/traction ou en traction uniaxiale/compression des matériaux composites a matrice céramique (CMC) avec renfort des fibres pour une température allant jusqu'a 2 000 °C sous vide ou sous une atmosphere gazeuse qui soit neutre vis-a-vis du matériau soumis a essai.
NOTE   L'utilisation de ces environnements permet d'éviter que le matériau ne subisse de changements dus a une réaction chimique avec l'environnement pendant l'essai.
La présente Norme européenne s'applique a tous les composites a matrice céramique avec renfort des fibres, unidirectionnel (1D), bidirectionnel (2D) ou tridirectionnel (xD, ou 2< x < or = 3).

Sodobna tehnična keramika - Mehanske lastnosti keramičnih kompozitov pri visoki temperaturi v pogojih inertne atmosfere - Določanje lastnosti utrujanja pri konstantni amplitudi

General Information

Status
Published
Publication Date
31-Dec-2006
Withdrawal Date
31-Dec-2006
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Jan-2007
Due Date
01-Jan-2007
Completion Date
01-Jan-2007

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Advanced technical ceramics - Mechanical properties of ceramic composites at high temperature under inert atmosphere - Determination of fatigue properties at constant amplitudeCéramiques techniques avancées - Propriétés mécaniques des céramiques composites a haute température sous atmosphere inerte - Détermination des propriétés de fatigue a amplitude constanteHochleistungskeramik - Mechanische Eigenschaften von keramischen Verbundwerkstoffen bei hoher Temperatur in inerter Atmosphäre - Bestimmung der Dauerschwingeigenschaften bei Belastung mit konstanter AmplitudeTa slovenski standard je istoveten z:EN 15158:2006SIST EN 15158:2007en,fr,de81.060.30Sodobna keramikaAdvanced ceramicsICS:SLOVENSKI
STANDARDSIST EN 15158:200701-januar-2007







EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 15158August 2006ICS 81.060.30 English VersionAdvanced technical ceramics - Mechanical properties of ceramiccomposites at high temperature under inert atmosphere -Determination of fatigue properties at constant amplitudeCéramiques techniques avancées - Propriétés mécaniquesdes céramiques composites à haute température sousatmosphère inerte - Détermination des propriétés defatigue à amplitude constanteHochleistungskeramik - Mechanische Eigenschaften vonkeramischen Verbundwerkstoffen bei hoher Temperatur ininerter Atmosphäre - Bestimmung derDauerschwingeigenschaften bei Belastung mit konstanterAmplitudeThis European Standard was approved by CEN on 14 July 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.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, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2006 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15158:2006: E



EN 15158:2006 (E) 2 Contents Page Foreword.3 1 Scope.4 2 Normative references.4 3 Terms, definitions and symbols.5 4 Principle.8 5 Significance and use.8 6 Apparatus.9 6.1 Fatigue test machine.9 6.2 Load train.9 6.3 Test chamber.10 6.4 Set-up for heating.10 6.5 Extensometer.10 6.6 Temperature measurement.11 6.7 Data recording system.11 6.8 Micrometers.11 7 Test specimens.11 8 Test specimen preparation.12 8.1 Machining and preparation.12 8.2 Number of test specimens.12 9 Test procedure.12 9.1 Test set-up: temperature considerations.12 9.2 Measurement of test specimen dimensions.13 9.3 Testing technique.13 9.4 Test validity.14 10 Calculation of results.15 10.1 Time to failure, tf.15 10.2 Damage parameters.15 10.3 Residual properties.17 11 Test report.17 Annex A (informative)
Schematic evolution of E.18



EN 15158:2006 (E) 3 Foreword This document (EN 15158:2006) has been prepared by Technical Committee CEN/TC 184 “Advanced technical ceramics”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February 2007, and conflicting national standards shall be withdrawn at the latest by February 2007. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.



EN 15158:2006 (E) 4 1 Scope This European Standard specifies the conditions for the determination of constant-amplitude of load or strain in uniaxial tension/tension or in uniaxial tension/compression cyclic fatigue properties of ceramic matrix composite materials (CMCs) with fibre reinforcement for temperature up to 2 000 °C under vacuum or a gas atmosphere which is inert to the material under test. NOTE Test environments are specified which are intended to prevent the material under test from chemically reacting with them. This European Standard applies to all ceramic matrix composites with fibre reinforcement, unidirectional (1D), bi-directional (2D), and tri-directional (xD, where 2 < x ≤ 3). 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 658-1, Advanced technical ceramics — Mechanical properties of ceramic composites at room temperature — Part 1: Determination of tensile properties EN 1892, Advanced technical ceramics — Mechanical properties of ceramic composites at high temperature under inert atmosphere — Determination of tensile properties EN 1893, Advanced technical ceramics — Mechanical properties of ceramic composites at high temperature in air at atmospheric pressure — Determination of tensile properties EN 12291, Advanced technical ceramics — Mechanical properties of ceramic composites at high temperature in air at atmospheric pressure — Determination of compression properties prCEN/TR 13233:20071, Advanced technical ceramics — Notations and symbols EN 60584-1, Thermocouples — Part 1: Reference tables (IEC 60584-1:1995) EN 60584-2, Thermocouples — Part 2: Tolerances (IEC 60584-2:1982) EN 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 7500-1:2004) EN ISO 9513, Metallic materials — Calibration of extensometers used in uniaxial testing (ISO 9513:1999) ISO 3611, Micrometer callipers for external measurement
1 To be published in 2007



EN 15158:2006 (E) 5 3 Terms, definitions and symbols For the purposes of this document, the terms and definitions given in prCEN/TR 13233:2007 and the following apply. 3.1 test temperature, T temperature of the test specimen at the centre of the gauge length 3.2 calibrated length, l part of the test specimen which has uniform and minimum cross-section area 3.3 gauge length, Lo initial distance between reference points on the test specimen in the calibrated length 3.4 controlled temperature zone part of the calibrated length including the gauge length where the temperature is within 50 °C of the test temperature 3.5 initial cross-section area, So initial cross-section area of the test specimen within the calibrated length, at the test temperature NOTE Two initial cross-section areas of the test specimen can be defined: - apparent cross-section area: this is the total area of the cross-section So app; - effective cross-section area: this is the total area corrected by a factor, to account for the presence of a coating, So eff. 3.6 longitudinal deformation, A change in the gauge length between reference points under a uniaxial force 3.7 strain, εεεε relative change in the gauge length defined as the ratio A/Lo 3.8 stress, σσσσ force supported by the test specimen at any time in the test, divided by the initial cross-section area NOTE Two stresses can be distinguished: - apparent stress, σapp, when the apparent cross-section area (or total cross-section area) is used; - effective stress, σeff, when the effective cross-section area is used. Stress can be either in tension or in compression. 3.9 constant amplitude loading in cyclic fatigue loading, constant wave form loading in which the peak loads and the valley loads are kept constant during the test (see Figure 1 for nomenclature relevant to cyclic fatigue testing)



EN 15158:2006 (E) 6
Key 1 time 6 mean 2 control parameter (test mode) 7 peak (maximum) 3 triangular form 8 valley (minimum) 4 trapezoidal form 9 amplitude 5 sinusoidal form 10 range Figure 1 — Cyclic fatigue nomenclature and wave forms 3.10 Cyclic fatigue phenomena 3.10.1 load ratio, R in cyclic fatigue loading, algebraic ratio of the two loading parameters of a cycle NOTE The most widely used ratios are: R = (minimum load/maximum load) or R = (valley load/peak load). 3.10.2 Stress cyclic fatigue 3.10.2.1 maximum stress, σσσσmax maximum applied stress during cyclic fatigue 3.10.2.2 minimum stress, σσσσmin minimum applied stress during cyclic fatigue



EN 15158:2006 (E) 7 3.10.2.3 mean stress, σσσσm average applied stress during cyclic fatigue such that: σm = (σmax + σmin)/2 3.10.2.4 stress amplitude, σσσσa difference between the maximum stress and the minimum stress, such that: σa = (σmax - σmin)/2 = σmax - σm = σm - σmin 3.10.3 Strain cyclic fatigue 3.10.3.1 maximum strain, εεεεmax maximum applied strain during cyclic fatigue 3.10.3.2 minimum strain, εεεεmin minimum applied strain during cyclic fatigue 3.10.3.3 mean strain, εεεεm average applied strain during cyclic fatigue such that: εm = (εmax + εmin)/2 3.10.3.4 strain amplitude, εεεεa difference between the maximum stress and the minimum stress, such that: εa = (εmax - εmin)/2 = εmax - εm = εm - εy 3.10.4 Fatigue parameters 3.10.4.1 number of cycles, N total number of loading cycles which is applied to the test specimen during the test 3.10.4.2 cyclic fatigue life, Nf total number of loading cycles which is applied to the test specimen up to failure 3.10.4.3 time to failure, tf time duration required to obtain the number of cycles Nf 3.10.5 Stress-strain curve parameters stress-strain curve parameters are defined as given in Figure 2.



EN 15158:2006 (E) 8 4 Principle A test specimen of specified dimensions is heated to the testing temperature and tested in cyclic fatigue as follows:  method A: The test specimen is cycled between two constant stress levels at a specified frequency;  method B: The test specimen is cycled between two constant strain levels at a specified frequency. The total number of cycles is recorded. If strain is not determined, only the life-time duration or the residual mechanical properties can be determined. If strain is determined, a number of stress-strain cycles are recorded at specified intervals to determine damage parameters, in addition to the life-time duration and residual mechanical properties. NOTE Residual properties can be determined on the test specimens which have not failed during the test, using the methods described in the appropriate European Standards. 5 Significance and use This test method enables characterization of the cyclic fatigue behaviour at constant amplitude of CMCs subjected to long duration loading. The simplest way to determine the fatigue properties of a material is to establish life-time diagrams. In these diagrams, the time to failure (or the cyclic fatigue life) is plotted versus stress (or strain) amplitude. The complete life-time diagram requires the use of a great number of test specimens,
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