Standards Development

Scope

This document specifies test methods for determining the elastic moduli, specifically Young’s modulus, shear modulus and Poisson’s ratio, of advanced monolithic technical ceramics at room temperature. This document specifies four alternative methods for determining some or all of these three parameters:

a) Method A - the determination of Young’s modulus by static flexure of a thin beam in three- or four-point flexure;

b) Method 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) Method C - the determination of Young’s modulus, shear modulus and Poisson’s ratio from the time-of-flight of an ultrasonic pulse;

d) Method D - the determination of Young’s modulus from the fundamental natural frequency of a struck thin beam (impulse excitation method).

All the test methods assume the use of homogeneous test pieces of linear elastic materials.

NOTE 1 Not all ceramic materials are equally and linearly elastic in tension and compression, such as some porous materials and some piezoelectric materials.

With the exception of Method C, the test methods assume that the test piece has isotropic elastic properties. Method C can be used to determine the degree of anisotropy by testing in different orientations.

NOTE 2 An ultrasonic method and a resonant method for dealing with anisotropic materials (ceramic matrix composites) can be found respectively in EN ISO 18610 [1] and EN 15335 [2]. An alternative to Method D for isotropic materials using disc test pieces is given in Annex A.

NOTE 3 It is possible that at high porosity levels all of the methods except Method C become inappropriate. The methods are only suitable for a maximum grain size measured in accordance with EN ISO 13383‑1, excluding deliberately added whiskers, of less than 10 % of the minimum dimension of the test piece.

NOTE 4 The different methods given in this document can produce slightly different results on the same material owing to differences between quasi-isothermal quasi-static and quasi-adiabatic dynamic conditions. In addition, the calculation routines for different methods have different origins and different potential uncertainties which have not been rigorously evaluated in preparing this document. Some information is given in Annex C (see also [8]).