![](https://cos-cdn.shuashuati.com/pipixue-web/2020-1231-2005-12/ti_inject-812ce.png)
A hollow circular shaft with the ratio of the inner diameter to the outer diameter of α=d/D has torsion deformation due to the torques exerted at the two ends. Make the value of α be 0, 0.5, 0.6, and 0.8, respectively, and the cross-sectional area be unchanged, determine the shaft with will obtain the highest bearing capacity.