| Abstract: | The limit pressure of a cylindrical shell with a two-dimensional array of penetrating nozzles and associated defects covering the whole shell has been calculated and compared with the limit pressure of the plain cylindrical shell. A lower-bound method was used. The conventional ligament efficiency method of calculating the limit pressure is too conservative. It is necessary to claim some strength from the nozzles. Hence a more elaborate method has been used here. If there are axial cracks in the main vessel tangential to some nozzles, the limit pressure is reduced to a value which is between the ligament efficiency and the value for a single crack in a plain cylinder. The actual reduction has been calculated for a range of crack lengths for a typical geometry. |
