Experimental Research on Damping Characteristics for Vibration-impact Process of Steam Turbine Blades with Integral Shroud

Integral shroud is an advanced technique used to improve reliability of steam turbine blades.In this paper,a series of experiments are well performed on the platform of contracting and impacting of blades tips,and damping characteristics of vibration-impact process of steam turbine blades with integral shroud are studied.The dynamic strain data under different clearances,different loads and different rotating speeds are surveyed through which the log decrement at each condition is obtained,and the effects of vibration damping are obtained by comparing the log decrement.The results of experimental study show that the vibro-impact structure is a good vibration damper.The dynamic stress of the blade with integral shroud is insensitive to loads when the clearance between adjacent integral shrouds is small,and the asymmetry gap has better damping effect than symmetry one.