Research On Characteristic Of The Forced Response Of Shrouded Blades

The failure of blade causes by vibration in general. The shrouded blades are useful to reduce the response. It is very important to research the mechanism of the vibration absorption by dry friction between shrouded blades.In this thesis, the theory of dry friction is researched .The methods and the models are also studied. The validity of methods is verified by experiment. Some parameters affecting the vibration response are analyzed.(1) One-dimensional model is studied. The vibration response of the three-shrouded-blades is calculated. In the model, the normal pressure is supposed to be constant, and the vibration is taken place only in one direction. Therefore the 1-D model is simple. The result is satisfactory for a certain one-dimensional problem. The vibration response of the three-shrouded-blades is analyzed. The result shows that the vibration response decreases firstly, and then increases along with the normal pressure.(2) Two-dimensional model and three-dimensional model are researched. A numerical method based on three-dimensional model is set up. The validity of 3-D model is verified by experiment of reference. In the three-dimensional model, the normal pressure is considered as variable, and the vibrations are taken place in three directions. As a result, the effects for more parameters on vibration response can be evaluated in the 3-D model.(3) The vibration response of the three-shrouded-blades is calculated by the 3-D model. As the following parameters change, such as normal pressure, load and its phase, shroud angle etc., the different conditions of friction contact are given. The rules of the vibration response are calculated respectively. The result shows that a better range of normal pressure exists. The better normal pressure makes the response decreased effectively. As shroud angle increases, the better normal pressure decreases, together with less load and bigger load phase.