6. A hollow aluminum shaft and a solid steel shaft are rigidly connected at each end.  This compound shaft is then loaded as shown.  Determine the maximum shearing stress in each material and the angle of twist of the free end.  Assume elastic behavior.
Galuminum = 4x106 psi Gsteel = 12x106 psi

t_torsion = Tc/J

f = TL/GJ

key

T = T1 + T2 f1 = f2
T = T1 + T2 f1 + f2 = 0