محدودیت فشار و معیار طراحی مخازن تحت فشار با استوانه با نازل

Limit pressures and corresponding maximum local membrane Stress Concentration Factors (SCF) are assessed for two orthogonally intersecting thin-walled cylindrical shells subjected to internal pressure. The limit pressures of 81 models with parameters ρ=d/D≤0.8, D/T≥10, d/t≥10, and d/D≤t/T≤2 are calculated using inelastic analyses by the 3D finite element method (3D FEM) in which the material is elastic-perfectly plastic. The plastic collapse pressures obtained by 3D FEM are in good agreement with test results presented by previous authors. The local membrane SCF at the intersections of two cylindrical shells subjected to the limit pressure load is calculated by elastic thin shell theoretical solutions presented by Xue and Hwang. The local membrane SCF decreases significantly as t/T increases, and decreases little as decreases when D/T is fixed. The local membrane SCF increases significantly as D/T increases, and varies little as increases when t/T is constant. The local membrane stress criterion km≤2.2 for reinforcement design of openings in a cylindrical pressure vessel subjected to internal pressure can be accepted generally except for a few cases of large thickness ratio t/T, and small opening ratio ρ.