An internally pressurized steel tube sees axial (x) and tangential (y) stresses on the outer surface of 30 ksi and 45 ksi, respectively. It is also torsionally loaded with a shear stress of 18 ksi.
a) Calculate the maximum principal stress on the outer surface of the steel tube.
b) Determine the maximum shear stress on the outer surface.
c) Find the von Mises stress on the outer surface of the tube.