Micro-Mechanics and Damping Capabilities of Turbine Blade Underplatform Dampers

This thesis focuses on underplatform damper kinematics and damping capabilities, a subject for which no through study can be found yet in literature. A test rig apt to investigate the relationship between the blade platform displacements and the contact forces is used . The aim is to experimentally estimate the effect of damper geometry and dynamics in order to validate available damper models. The first part of the work presents the available theory on contact mechanics, as a necessary preamble to its subsequent application in the study of contact models, both analytical and numerical. This preliminary chapter will also include a state of the art resume on the available damper models. The second part of the thesis will present an overview of above-mentioned test rig, which was developed in the previous years by the AERMEC (from Politecnico di Torino) group; particular relevance shall be given to the recently-adopted modifications and improvements. Lastly a measurement protocol will be established and later applied to a series of measurements on two different damper geometries. The results of the measurements will be compared with the available numerical model, adapted to the test rig setting and damper models.