Flexural strength tests of ceramics

Flexural strength tests of ceramics
To avoid the high expense and difficulties of performing tensile tests on
ceramics, tensile strength is often determined by the bend test. The main
advantage of the bend test, other than its lower cost, is that we use simple
sample geometries. The specimens have either a rectangular or cylindrical
geometry.
Brittle Materials, including ceramics, are tested by Flexure Test
(Transverse Beam Test, Bending Test). There are two standard Flexure
Test methods:
3-point Flexure Test
4-point Flexure Test
flexural strength—a measure of the ultimate strength of a specified beam
in bending.
Flexural strength calculation
3-point Flexure Test
In this test a specimen with round, rectangular or flat cross-section is placed
on two parallel supporting pins. The loading force is applied in the middle
by means loading pin. The supporting and loading pins are mounted in a
way, allowing their free rotation about:
? axis parallel to the pin axis;
? axis parallel to the specimen axis.
This configuration provides uniform loading of the specimen and prevents
friction between the specimen and the supporting pins.
4-point Flexure Test
In this test the loading force is applied by means of two loading pins with
a distance between them equal to a half of the distance between the
supporting pins. The four-point bend test is preferred because an extended
region with constant bending moment exists between the inner rollers