Dynamic stress prediction method for rubbing blades

• Main Authors: Qian Zhao, Ziliang Liu, Yonghui He, Hongliang Yao, Bangchun Wen
• Format: Article
• Language: English
• Published: JVE International 2016-02-01
• Series: Journal of Vibroengineering
• Subjects: blade; rubbing; dynamic stress analysis; incremental harmonic balance method; finite element method
• Online Access: https://www.jvejournals.com/article/16087

The common technique frequently employed in dynamic stress analysis of vibration systems is time-consuming and difficult to solve when dealing with the dynamic systems with nonlinear contacts, such as turbine blades subjected to rubbing faults. To address this deficiency, an approach combining the incremental harmonic balance (IHB) method with the finite element method (FEM) was proposed for predicting the dynamic stress of rubbing blades. First, the finite element model of a warp three-dimensional (3D) entity blade was developed, and its dynamic equation was established by considering the effect of centrifugal force under high speed revolution. Then, as the rubbing fault is highly nonlinear and strong coupling, the IHB method was applied to solve the periodic solutions of the system, and the deformation of each node was obtained. Third, taking the deformation response obtained as initial displacement constraints and imposing it on relevant points, the dynamic stresses were then obtained by using the static analysis in ANSYS. Since employing the IHB method, the transient nonlinear finite element analysis was transformed into the static analysis in the present method, so it significantly raised the solution efficiency. To show the effectiveness of the method, dynamic stress prediction and parameter analysis of a rubbing blade were studied as an example.