고체역학 (Beer) — Transformations of Stress and Strain: Problem 7.99

7.99 A spherical gas container having an outer diameter of 15 ft and a wall thickness of 0.90 in. is made of steel for which \( E = 29 \times 10^6 \) psi and \( \nu = 0.29 \). Knowing that the gage pressure in the container is increased from zero to 250 psi, determine (a) the maximum normal stress in the container, (b) the corresponding increase in the diameter of the container.