A circular shaft having diameters D and d and a groove of radius r (see Fig. 3.17, with...

A circular shaft having diameters D and d and a groove of radius r (see Fig. 3.17, with M = 0 and P = 0) is made of steel with the allowable shear stress t_all. Find the maximum torque T that can be transmitted by the shaft. Given: D = 40 mm, d = 16 mm, r = 8 mm, and tall = 250 MPa.