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Abstract The formula of tensile strengths from the cubic splitting test ignores the three-dimensional effect. In order to obtain a more accurate stress formula，the cubic splitting test was simulated using the 3D numerical method to analyze the 3D effects based on the Griffith strength theory. It was found that the influences of the cushion-side ratio(the ratio of the width of cushion to the length of cube) and Poisson's ratio on the stress of the cubic splitting test were significant. If the cushion-side ratio was constant，with the increase of the Poisson's ratio，the influence of the stress concentration on the stress in the cubic specimen became larger，and the crack initiation at the center were not guaranteed. However，the center crack initiation is the premise of a valid test. The smaller tensile strength was obtained in this case. If Poisson?s ratio was constant，the smaller the cushion-side ratio the larger the influence of the stress concentration on the stress in the cubic specimen，the easier for a stress convex point to occur near the loading location. So the validity of the test was difficult to be guaranteed. In order to guarantee the validity of the tests，a revised 3D formula of tensile strengths was established considering the effect of cushion-side ratio and Poisson?s ratio with corresponding recommended range of cushion-side ratios for different Poisson?s ratios.
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Received: 28 April 2014
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2014, Vol. 33 
