TY - JOUR
TI - Study on vibration characteristics of damping blade with snubber and shroud based on fractal theory
AU - Zhao Wei
AU - Li Liang-Liang
AU - Zhang Di
JN - Thermal Science
PY - 2016
VL - 20
IS - 13
SP - 887
EP - 894
PT - Article
AB - Snubber and shroud have been widely adopted in steam turbine last stage  blades to decrease the vibration stress. The contact surfaces between snubber  and shroud own obviously fractal geometry characteristics. Based on fractal  geometry theory and finite element nonlinear vibration theory, the fractal  friction model that describes friction damping contact could be accurately  established. In this paper, the contact fractal elements are set up and the  nonlinear vibration response characteristics of a long steam turbine last  stage blade with snubber and shroud are calculated. The results show that,  with the increase of shroud normal force, the resonant amplitude of the blade  experiences a decreasing period followed by an increasing period while the  modal damping ratio increases first and then decreases when there is only  shroud contact. The regulations are similar when there are both shroud and  snubber contacts. The resonant frequency increases until the normal contact  forces increase to some degree.