고체역학 (Beer) — Transformations of Stress and Strain: Problem 7.114

7.114 The steel pressure tank shown has a 30-in. inner diameter and a 0.375-in. wall thickness. Knowing that the butt-welded seams form an angle $\beta = 50^\circ$ with the longitudinal axis of the tank and that the gage pressure in the tank is 200 psi, determine (a) the normal stress perpendicular to the weld, (b) the shearing stress parallel to the weld.