Attached Crown Semal System Vibration Localization Studies

Bladed disk with shrouds is a general kind of bladed disks in steam turbine, gas turbine and aero engine, which was used with the advantages of excellent efficiency of vibration reduction, easy to assemble, and low demand for manufacturing. As a result, bladed disk with shrouds is the development tendency of bladed disks. However, studies on bladed disk with shrouds are not comprehensive until now. Therefore, the vibration localization of bladed disk with shrouds was analyzed based on theoretical models of bladed disk with shrouds.Firstly, the natural frequencies and modal shapes belonging separately to bladed disk with shrouds and bladed disk with free standing blades were compared based on finite element model, and it is proved that vibration characteristics of the two kinds of bladed disks are different, especially the way the vibration energy transfers is different. Because the vibration localization of mistuned bladed disk with shrouds was difficult to detect, it was imagined to apply the strain modes to vibration localization, and the vibration localization factors based on strain modes and displacement modes were compared with the condition that the bladed disk is mistuning.Secondly, based on a continuous parameter of bladed disk with different coupling modes, the vibration response characteristics of bladed disk with shrouds and bladed disk with free standing blades were compared, the non linear vibration features of bladed disk with shrouds were analyzed. What’s more, the effects of friction factors and exciting frequencies on vibration characteristics were analyzed.Finally, combined with engineering practice, another kind of mistuning, force mistuning was introduced, which has not been studied yet. The mechanism of force mistuning and the effect of force mistuning on the vibration characteristics of periodic structures was analyzed. Besides, the force mistuning was brought into bladed disk with shrouds and the effect of force mistuning on the vibration localization was analyzed.The conclusion could not only complete the research contents of mistuned periodic structures, but also develop the basic theory of vibration localization of bladed disk, which can provide theoretical support for the design, manufacturing and assembly of steam turbine, gas turbine and aero engine.