Author(s): Yan Zhang; Fang Liu
Linked Author(s): Fang Liu
Keywords: Hydraulic structure; Modal order determine; Singular entropy; Powerhouse with bulb tubular unit
Abstract: The modal parameter identification is a core issue in the health monitoring and damage diagnosis of hydraulic structures. For the roof overflow hydropower station with a bulb tubular unit under ambient excitation, a complex ‘unit-powerhouse-dam’ coupling vibration system will increase the difficulties of the powerhouse modal parameter identification. In this study, based on the modal order determine difficulties and the noise jamming caused by ambient excitation, along with false modes identification and eliminating problems, we propose an improved eigensystem realization algorithm (ERA) method. The results show that the errors of the improved ERA in the first four orders were less than 10% , while that of stochastic subspace identification (SSI) were already over 10% in the second order. Therefore, the improved ERA method can be a more appropriate method to identify the structural modal parameters precisely for this powerhouse layout.
Year: 2013