Figure 3. Machine with mounted specimen that uses in Brazilian test

This method is very simple in terms of specimen preparation. The appropriate shape of sample for Brazilian test is form of drill core and after slicing core into the disk it can possible use this sample for testing. If the orientation of the disk is varied, the tensile strength can be measured across all cross-section of the core [1]. So, if disk is diametrically loaded by two platens that is mounted in direction perpendicular to the length of sample, it is derived the tensile strength perpendicular to the cross-section. Because of this all components with differential direction (x,y,z) of the tensile strength can be obtained with a minimum of sample preparation.

The stress distribution within a thin disc loaded by uniform pressure radially applied over an arc its circumference subtending an angle 2α at the center, has been analyzed by Hondros (1957) assuming that the material was homogeneous, isotropic and linearly elastic. At the center, the stress component normal to the loaded diameter was found to be [1]:

(2)

where

P – applied force, MN;

D – diameter of disk, m;

T – thickness of disk, m;

2α – angular distance over which P is assumed to be distributed

When α = о i.e. а line lоаd [1]:

(3)

The tensile strength is obtained by means of equation 3. It should be noted that using this equation it is assumed that stress value at the center is independent of the loading configuration [1].

The results and calculation of the Brazilian test is represented in figure 4 and table 2 respectively.

№ of samples	d, m	,	Maximum of N	, Mpa
R3	0.055	0.00475	3562.5	1.5
R4		1.895
W3	19312.5	8.133
W4	20812.5	8.765

Дата добавления: 2015-11-14