Table 1 Summary of the loading geometries studied and the equations used to calculate the Indirect tensile strength.

C

U

R

\( \sigma_{\text{ITS}} = \frac{{2P_{\hbox{max} } }}{\pi Dt}C_{f}^{\text{CUR}} \)

\( C_{f}^{\text{CUR}} = \frac{{\sin \alpha \cos^{2} \alpha }}{\alpha } \)

(Satoh 1986)

\( C_{f}^{\text{CUR}} = \frac{{\sin \alpha \cos^{2} \alpha }}{\alpha };\alpha \ge 20^{ \circ } \)

(This paper)

C

U

P

\( \sigma_{\text{ITS}} = \frac{{2P_{\hbox{max} } }}{\pi Dt}C_{f}^{\text{CUP}} \)

\( C_{f}^{\text{CUP}} = \left[ {1 - \left( {\frac{b}{R}} \right)^{2} } \right]^{{\frac{3}{2}}} = \cos^{3} \alpha ;\sin \alpha = \frac{b}{R} \)

(Tang 1994)

\( C_{f}^{\text{CUP}} = \frac{{4\sin \alpha \left( {\sin^{2} \alpha - 3} \right)^{2} }}{{3\left( {8\sin^{3} \alpha + 24\sin \alpha - 3\sin 2\alpha - 6\alpha } \right)}};\alpha \ge 10^{ \circ } \)

(This paper)

F

U

P

\( \sigma_{\text{ITS}} = \frac{{2P_{\hbox{max} } }}{\pi Dt}C_{f}^{\text{FUP}} \)

\( C_{f}^{\text{FUP}} = \frac{{\left( {2A^{2} + A + B} \right)^{2} }}{{8\left( {A + B} \right)B}};A = \cos \alpha ;B = \frac{\sin \alpha }{\alpha } \)

(Wang et al. 2004)

\( C_{f}^{\text{FUP}} = \frac{{ - \cos^{2} \alpha \sin \alpha }}{{\left( {\sin \alpha \cos \alpha - 2\alpha } \right)}};\alpha \ge 25^{ \circ } \)

(Huang et al. 2014)