A thin circular cylindrical shell subjected to internal pressure p is simultaneously compressed by an axial load P = 72 kN. The cylinder has
diameter d = 100 mm and wall thickness t = 4 mm. Calculate the maximum allowable internal pressure pmax based upon an allowable shear stress in the wall of the shell of 60 MPa. What is the change in wall thickness at this pressure? (E = 205 GPa, ν = 0.25)