On effects of perforated domains on parameter-dependent free vibration

Free vibration characteristics of thin perforated shells revolution vary depending not only on the dimensionless thickness shell but also perforation structure. All holes are assumed to be free, that is, without any kinematical constraints. For a given configuration there exists critical value below which homogenisation fails, since modes do have corresponding counterparts in non-perforated reference shell. regular g×g-perforation pattern, is reached when lowest mode has an angular wave number g?2. This observation supported both by geometric arguments and numerical experiments. The experiments been computed 2D with high-order finite element method supporting Pitkäranta’s mathematical model.