1. The problem statement, all variables and given/known data derive the equilibrium state of the stress at a point in a circular pressurized vessel, membrane equation, in terms of σ_a and σ_b and internal pressure b. Figure is picture of a thin walled pressurized elliptical vessel (like a sphere vessel except with horizontal diameter(a) not equal to vertical diameter (b)). 2. Relevant equations For a sphere, the equilibrium stress is denoted as pr/2t, with r being the radius and t being the thickness. 3. The attempt at a solution There are plenty of solutions available for the stress involving a spherical vessel, and for a cylindrical vessel, but I haven't seen anything for the elliptical one. Any help will be appreciated!!