690 likes | 893 Views
Order-Tuned Vibration Absorbers for Systems with Cyclic Symmetry. with Applications to Turbomachinery. MOTIVATION & BACKGROUND. Motivation. Bladed Disk Assemblies. Motivation. Engine Order Excitation. Motivation. Resonance Structure / Conditions for Resonance. Motivation.
E N D
Order-Tuned Vibration Absorbers for Systems with Cyclic Symmetry with Applications to Turbomachinery
Motivation Bladed Disk Assemblies
Motivation Engine Order Excitation
Motivation Resonance Structure / Conditions for Resonance
Motivation Order-Tuned Absorbers
Motivation Vibration Reduction via Order-Tuned Absorbers
Motivation Vibration Reduction via Order-Tuned Absorbers Sleeves Tuned Dampers Chamber & End Caps
Motivation Vibration Reduction via Order-Tuned Absorbers
Motivation Vibration Reduction via Order-Tuned Absorbers
Motivation Goals of this Work • Quantify/understand underlying linear resonance structure; • Design absorbers to eliminate/reduce blade vibrations; and • Generalize to include effects of nonlinearity. • How does Campbell diagram representation change when order-tuned absorbers are present? • Exploit underlying linear resonance structure for linear absorber design. • Can nonlinearity be exploited to further improve the linear design?
Outline • Motivation and Background Frequency- and Order-Tuned Absorbers Cyclic Systems Theory of Circulants / Mathematical Preliminaries Engine Order Excitation • The Linear Analysis Model / Formulation Modal Analysis / Forced Response Linear Resonance Structure / Absorber Tuning Effects of Damping • The Nonlinear Analysis Mathematical Model / Path Selection Formulation: Scaling / Averaging Traveling Wave Forced Response / Stability Nonlinear Absorber Tuning • Conclusions Recommendations for Absorber Design Summary of Contributions Directions for Future Work
Background Engine Order Excitation
Background Engine Order Excitation
Background Engine Order Excitation
Background Engine Order Excitation
Background Engine Order Excitation
Mathematical Model and THE LINEAR ANALYSIS Model / Formulation Modal Analysis / Forced Response Linear Resonance Structure / Absorber Tuning Effects of Damping Summary
Mathematical Model Bladed Disk Assembly with Absorbers
Mathematical Model Linearized System Model
Modal Analysis Block Decoupling the EOM
Modal Analysis Steady-State Modal Response
Modal Analysis Steady-State Modal Response
Special Cases1 • Blades Locked, Absorbers Free • Gives Linear Absorber Tuning Order • Blades Free, Absorbers Locked • A Benchmark to evaluate absorber performance • Single Isolated Sector, Blade/Absorber Free • Demonstrates the essential features of the full coupled system
Special Cases1 ( ) Blades Locked, Absorbers Free
Special Cases2 ( ) Blades Free, Absorbers Locked
Special Cases2 ( ) Blades Free, Absorbers Locked
Special Cases3 ( ) Single Isolated Sector, Blade/Absorber Free
Special Cases3 ( ) Single Isolated Sector, Blade/Absorber Free
Special Cases3 ( ) Single Isolated Sector, Blade/Absorber Free
Special Cases3 ( ) Single Isolated Sector, Blade/Absorber Free
Special Cases3 ( ) Single Isolated Sector, Blade/Absorber Free
Special Cases3 ( ) Single Isolated Sector, Blade/Absorber Free
Linear Resonance Structure N = 10 Sectors, Blades/Absorbers Free
Linear Resonance Structure The Effects of Detuning: No-Resonance Gap
Linear Forced Response Absorbers Free
Linear Forced Response Absorbers Free
Linear Absorber Design Summary
Linear Absorber Design Summary • Absorbers are effective • No-resonance zone* • Ideal tuning (Complete reduction of blade motions**) • Slight undertuning (Good reduction of blade motions and no resonances over full range of rotor speeds) * Persists in the presence of sufficiently small damping ** No absorber damping, independent of blade damping
Linear Absorber Design Summary • Absorbers are effective • No-resonance zone* • Ideal tuning (Complete reduction of blade motions**) • Slight undertuning (Good reduction of blade motions and no resonances over full range of rotor speeds) Recommendation * Persists in the presence of sufficiently small damping ** No absorber damping, independent of blade damping
THE NONLINEAR ANALYSIS Mathematical Model / Path Selection Formulation: Scaling / Averaging TW Forced Response / Stability NL Absorber Tuning Summary
Mathematical Model Nonlinear Sector
Mathematical Model Absorber Path
Formulation Scaled Sector Models
Formulation Linear Resonance Structure of the Scaled System
Formulation Linear Resonance Structure of the Scaled System
Formulation Averaged Sector Models
Formulation Averaged Sector Models