To increase the design torques of a structural steel torsion member (Figure P6.66a), a sle...

To increase the design torques of a structural steel torsion member (Figure P6.66a), a sleeve of the same material is welded to it (Figure P6.66b). Determine the ratio of the fully plastic torques of the modified member and the original member.

FIGURE P6.66a

FIGURE P6.66b