Spherical Tanks Angular Distortion Calculation

As a kind of welded defect, angular distortion produces large stress concentration and strain concentration to destroy pressure vessels under inner pressure. Now there are some different studies of spherical tanks. But they all have shortages. So it is important to make precise calculation and further study. In this paper, a summary of anterior studies is made and change regulations of every parameter are compared, and the prototypes----Shitian formula and Panzhao formula are analyzed. Common angular distortion differential equation is got in theoretical way. Finite element calculations are made about four types of angular distortion---- convex shape of circumferential type, concave shape of circumferential type, convex shape of protuberant type and concave shape of protuberant type. And change regulations of stress coefficient of every type of angular distortion are got about diameter, wall thickness, highness of angular distortion, and pressure. Stress distribution of angular distortion zone is got. Additional bending stress coefficient Ke and stress coefficient Kt formulas of every angular distortion shape are established. At last, conversion of angular distortion's highness by big templet and that by 1000mm?templet is got.