若单元体的主应力 sigma_(1) > sigma_(2) > sigma_(3) > 0，则其内最大切应力为()。 A. tau_(max) = (sigma_(1))/(2) B. tau_(max) = (sigma_(1) - sigma_(3))/(2) C. tau_(max) = (sigma_(2) - sigma_(3))/(2) D. tau_(max) = (sigma_(1) - sigma_(2))/(2)

$$ 若单元体的主应力 $\sigma_{1}\ \ > \sigma_{2}\ \ > \sigma_{3}\ \ > 0$，则其内最大切应力为()。 $$

• A. $$ $\tau_{max}\ \ = \frac{\sigma_{1}}{2}$ $$
• B. $$ $\tau_{max}\ \ = \frac{\sigma_{1}\ \ - \sigma_{3}}{2}$ $$
• C. $$ $\tau_{max}\ \ = \frac{\sigma_{2}\ \ - \sigma_{3}}{2}$ $$
• D. $$ $\tau_{max}\ \ = \frac{\sigma_{1}\ \ - \sigma_{2}}{2}$ $$