Dynamic response of a clamped/ring-stiffened circular cylindrical shell under non-axisymmetric loading

In order to investigate the structural integrity of light water reactors in case of a blowdown accident the reactor core barrel is modeled as a linear-elastic thin walled circular cylindrical shell, clamped at the upper end and ring-stiffened at the lower end. A computer code CYLDY2 has been developed for analysis of the dynamic response of sych shells. In this paper the mathematical model on which the code CYLDY2 is based is described in some detail. The transient shell deformations are represented by sets of orthogonal modal functions and the appropriate amplitudes are determined by variational principles. Test calculations confirm that the spatial resolution provided by CYLDY2 is satisfactory even for peak types of loadings having a peak width smaller than 1/10 of the cylinder length and that the computer time is by one or two orders of magnitude smaller than the computer time required for application of well known finite element codes. (Auth.)