EN 13235:2006

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 creep behaviourDCéramiques techniques avancées - Propriétés mécaniques des céramiques composites a haute température sous atmosphere inerte - Détermination du comportement au fluageHochleistungskeramik - Mechanische Eigenschaften von keramischen Verbundwerkstoffen bei hoher Temperatur in inerter Atmosphäre - Bestimmung des KriechverhaltensTa slovenski standard je istoveten z:EN 13235:2006SIST EN 13235:2007en81.060.30Sodobna keramikaAdvanced ceramicsICS:SIST ENV 13235:20001DGRPHãþDSLOVENSKI
STANDARDSIST EN 13235:200701-januar-2007

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 13235October 2006ICS 81.060.30Supersedes ENV 13235:1998
English VersionAdvanced technical ceramics - Mechanical properties of ceramiccomposites at high temperature under inert atmosphere -Determination of creep behaviourCéramiques techniques avancées - Propriétés mécaniquesdes céramiques composites à haute température sousatmosphère inerte - Détermination du comportement aufluageHochleistungskeramik - Mechanische Eigenschaften vonkeramischen Verbundwerkstoffen bei hoher Temperatur ininerter Atmosphäre - Bestimmung des KriechverhaltensThis European Standard was approved by CEN on 10 September 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 13235:2006: E

Page Foreword.3 1 Scope.4 2 Normative references.4 3 Principle.4 4 Terms, definitions and symbols.5 5 Significance and use.6 6 Apparatus.7 6.1 Test installations.7 6.2 Load train.7 6.3 Test chamber.8 6.4 Set-up for heating.8 6.5 Extensometer.8 6.6 Temperature measurement.9 6.7 Data recording system.9 6.8 Micrometers.9 7 Test specimens.9 8 Test specimen preparation.10 8.1 Machining and preparation.10 8.2 Number of test specimens.10 9 Test procedures.10 9.1 Test set-up: temperature considerations.10 9.2 Test set-up: loading considerations.11 9.3 Test set-up: measurement of test specimen dimensions.11 9.4 Test technique.11 9.5 Test validity.13 10 Calculation of results.14 10.1 Test specimen origin.14 10.2 Results.14 10.3 Creep strain rate curve.15 11 Test report.15

longitudinal deformation, ∆∆∆∆L change in the gauge length caused by creep 4.10 tensile creep strain, εεεεcr relative change in the gauge length at time t, caused by creep NOTE The value corresponding to rupture is denoted εcr,m. 4.11 creep rupture time, t cr,m time elapsed from the moment when loading is completed until the moment of rupture 4.12 creep strain rate, ε&cr change in creep strain per unit time at time t

a)
b)
Key 1 creep strain εcr 6 creep strain rate εcr (creep strain with time) 2 time t 7 time t 3 primary creep 8 primary creep 4 secondary creep 9 secondary creep 5 tertiary creep 10 tertiary creep Figure 1 — Representations of a) creep strain versus time and b) creep strain rate versus time 5 Significance and use Several mechanisms may be responsible for time-dependent deformation of fibre-reinforced ceramic matrix composites at high temperature. These may be creep of the fibre and/or the matrix, or may be caused by the composite nature of the material (matrix micro-cracking, fibre-matrix interface sliding). Creep is characterised by the total time-dependent increase of the gauge length, starting from the time when the specified force level is reached, whatever the mechanism responsible. During the loading phase, the loading rate up to the specified force level can have a dramatic effect on the subsequent accumulation of creep strain. This is particularly the case when the fibres and the matrix have very different creep strengths. Upon fast application of the force, the load is distributed
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