Strength of intersections in composite sandwich vessels under external pressure

Abstract

The behaviour of double skinned composite sandwich shells under external pressure has been investigated extensively by Montague and his collaborators. The characteristic of the composite shell is that it can be designed on the basis of strength calculations. This characteristic behaviour points towards the use of limit analysis for estimating the cylindrical shell and nozzle-to-vessel intersection performance. Approximate limit pressures obtained for the shell and intersection are shown to give close bounds to experimental results. A parametric study for steel nozzle-to-composite vessel intersections of a given vessel indicates that the limit pressure is roughly a linear function of the relative nozzle-to-vessel strength. For small nozzles (d/D ≤ 0.15), reinforcement by nozzle thickening may be adequate.