Design of a New Test Rig to Evaluate Under-Platform Damper Performance

Abstract

This work presents the development of a test rig capable of measuring the forces transferred between the blade platforms through the under-platform damper. This test rig is composed of two distinct parts each one representing a platform. The static part contains the load cells, which measure the forces in two perpendicular directions; the moving part controlled using two piezoelectric actuators reproduces any in-plane relative displacement between two adjacent platforms. In this scheme, the damper is placed between these two platforms and loaded by dead weights that reproduce the effects of centrifugal force. The hysteresis cycle, of the damper system, is obtained using the measured forces and the imposed displacement. In addition, two laser beams can be used to measure the damper displacement and its tilt angle, which allows validating dynamic models of the damper. Moreover, the test rig is designed to allow heating the specimens up to temperatures which are normally found in real operation. Finally, the test rig provides necessary variables to study the damper performance and to evaluate some contact models used to simulate under-platform dampers.

On the relevance of a microslip contact model for under-platform dampers

“…A complete description of the test rig components, calibration procedures and the error estimation techniques can be found in [23,26,24]. Table 2 lists all the measured and derived quantities together with their level of uncertainty.…”

“…These authors have, in the past few years, devoted time and effort to the development of tools for the experimental-numerical characterization of underplatform dampers: a test rig capable of measuring the damper working parameters [23,24]; error estimates of measured and derived forces and displacements [24][25][26]; estimation of friction and stiffness parameters at the contact from experimental data [24][25][26][27][28]; development of a numerical routine representing the damper between the platforms [24][25][26][27][28] solved either in the time or in the frequency domain.…”

Estimation accuracy vs. engineering significance of contact parameters for solid dampers

“…The need for the safe determination of contact parameters led to AERMEC's Test Rigs. Some focus on single contacts under constant normal loads and high temperatures (Lavella et al, 2011;Botto et al, 2012;Lavella, 2016), while the Damper Test Rig, built in 2008 (Gola et al, 2010) aims at estimating contact parameters of UPDs under more realistic working conditions in terms of variable normal load and complex interface kinematics. Since then, the test rig has been used to investigate the behaviour of several dampers in terms of kinematics and force transmission characteristics (Gola and Liu, 2014).…”

A novel test rig to investigate under-platform damper dynamics

“…These test rigs are not capable of analyzing the dynamics of the damper in depth, nor its kinematics in terms of damper/under-platform relative displacement. On the other side several test rigs [17,18,19,20,21,22,23] This rig was built in 2008 [24] and was a first step towards a deep investigation of dampers kinematics. In this rig, piezoelectric actuators, feedback controlled, move the under-platforms with a given rule.…”