RESONANCE CHARACTERISTICS OF TURBINE-BLADES WITH COMPOUND PERIODIC STRUCTURE

This paper describes the resonant response of the compound periodic st ructure, which includes both grouped and one-ringed blade structures i n a turbine wheel to form a circumferential periodicity with a packet as a unit. The resonant condition is derived by calculating the energy supplied from engine order excitation to a natural mode composed of p lural nodal diameter modes. Then, the resonant stresses are calculated by equating the supplied energy and the energy dissipated by damping. As an example the resonant response and stresses are determined for a simple blade model assuming a fixed mode firstly, and then a travelin g mode around the circumference.