The Present State of "Solid" under-Platform Damper Mechanics at AERMEC - POLITO

The numerical simulation of friction-damped blades in turbomachinery applications requires knowledge of contact parameters to be introduced in contact models. The equilibrium and kinematics of dampers are dominated by phenomena occurring at the two interfaces between the damper and the corresponding blade platforms. A precise knowledge of parameter values is vital to ensure trustworthy predictions of blades vibration frequency and of the available amount of amplitude damping. Test rigs developed at the AERMEC lab. during the last decade are presented, and reasons for their improvements are explained. These test rigs have the primary purpose to allow direct observations of contact forces and displacements, and the ensuing estimate of contact parameters. The reliability of the measurements and of their processing is demonstrated through a worked out example. (paper)