dowling 4th ed. 6.24: a thin-walled tube with closed ends has an inside radius of 80 mm and a wall thickness of 6mm. it is subjected to an internal pressure of 20 mpa, a torque of 60 kn-m and an axial compressive force of 200 kn. a. draw the stress state on a representative element. b. determine the maximum normal stress. c. determine the maximum shear stress.