Calculation of the Forced Response of a Turbine Bladed Disk with Strip Dampers

Blades in turbines can be mounted in contact with adjacent blades at their platforms through small metal masses called strip dampers. During the blades vibration, the friction generated at the contact surface by the dampers dissipates energy and consequently it reduces the vibration amplitude. The dynamic behavior of the blades, the shift of their frequency due to the strips and the damping introduced by friction, should be calculated at design stage in order to optimize the design of the system. This leads to a nonlinear calculation of the blade dynamic response, which cannot be performed by the commercial finite element codes. In the AERMEC lab., in Polytechnic of Turin, different numerical tools were already developed in Matlab to calculate the nonlinear forced response of blades with friction interfaces. The requirement is to extend one of these tools, already working with blades with underplatform rigid dampers between them, to the calculation of the forced response in the case of blades with strip flexible dampers.