scholarly journals Dynamic Stability Analysis of Periodically Time-Varying Rotor System with a Transverse Crack

Engineering ◽  
2011 ◽  
Vol 03 (07) ◽  
pp. 719-725 ◽  
Author(s):  
Costin D. Untaroiu ◽  
Alexandrina Untaroiu ◽  
Mihail Boiangiu
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Transverse Crack ◽  
Rotor System ◽  
Time Varying

Approach for Stability Analysis of a Cracked Rotor With Time-Varying Stiffness

2013 ◽  
Author(s):  
Mohammad A. Al-Shudeifat
Keyword(s):  
Finite Element ◽  
Stability Analysis ◽  
Dynamic Stability ◽  
Coefficient Matrix ◽  
Rotor System ◽  
Time Varying ◽  
Cracked Rotor ◽  
Parametrically Excited ◽  
Time Periodic ◽  
Cracked Rotor System

An approach for dynamic stability analysis of a cracked rotor system with transverse crack is addressed here. The time-varying area moments of inertia of the cracked section are employed in formulating the time-periodic finite element stiffness matrix which yields a linear time-periodic system. The harmonic balance method (HB) is used in solving the finite element (FE) equations of motion for studying the dynamic stability of the system. The sign of the determinant of the scaled coefficient matrix resulting from applying the HB solution to the cracked rotor system is found to be a reliable approach for identifying the major unstable regions of the system in the parameter plane obtained by plotting the shaft speeds of rotation vs. the crack depths. Specifically, the negative values of the determinant of this scaled coefficient matrix identify the unstable regions of the cracked system. This approach is applied here to the parametrically excited Mathieu’s equation, two degree-of-freedom gyroscopic system, and then to the FE model of the cracked rotor system. The results of applying this approach are verified using the Floquet’s theory. Compared with the theory, the sign of the determinant of the scaled coefficient matrix is found here to be an efficient tool for identifying the unstable regions of linear parametrically excited systems, especially the large scale dynamic systems where this approach requires considerably less computational time than the Floquet’s theory.

Stability Analysis on a Crack Rotor System in the Special Speeds

2013 ◽  
Vol 675 ◽  
pp. 116-120 ◽  
Author(s):  
Feng Lan Wang
Keyword(s):  
Experimental Study ◽  
Stability Analysis ◽  
Theoretical Analysis ◽  
Stability Problem ◽  
Critical Speed ◽  
Transverse Crack ◽  
Crack Depth ◽  
Rotor System ◽  
Single Disk ◽  
The Stability

In this paper, the single disk rotor system with a transverse open and close crack has been taken as an example; the stability problem on the system in the special speeds has been discussed by theoretical analysis and experimental study. First, the conditions, positions and areas of the stable vibrations and the unstable vibrations on a rotor system with a transverse crack have been studied quantitatively theoretically. Not only the conclusions of other authors are verified，but also that the unstable vibrations are found in the regions near the rotational speed at 2/5and 2/7 of the critical speed in the large crack and the small damping case. Then the influence of some factors such as the crack depth parameters and the damping on stability of the system is qualitatively discussed.

Sign in / Sign up

Export Citation Format

Share Document