图示简支梁两端由铰链约束,已知铰链轴的许用切应力为[τ],梁中间受集中力F作用,则铰链轴的合理直径d是( )。
A <img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23411996_0_1.png"> B
<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23411996_0_2.png"> C
<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23411996_0_3.png"> D
<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23411996_0_4.png">