Order-Tuned and Impact Absorbers for Rotating Flexible Structures

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Order-Tuned and Impact Absorbersfor Rotating
Flexible Structures
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Background
Self-tuning Impact Damper
Turbine Blade
Sleeves
Tuned Dampers
Chamber End Caps
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Relevant Previous Work

• Order-Tuned Vibration Absorbers
• Den Hartog, Denman, Shaw et al., Borowski, Duffy,
  
• Impact Absorbers
• Caughey, Masri, Shaw, Brown North, Duffy,
• Vibration Characteristics of Bladed Disk
  Assemblies
• Many,

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Order-Tuned Vibration Absorbers
Idealized Model
IMPACTS
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Mathematical Model
Model Features
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Mathematical Model
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Mathematical Model
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Linear Isolated Absorber Response
y
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Free Linear Response
Frequencies versus Rotor Speed
Absorber Frequency
Engine Order
Natural Frequency
Blade Frequency
Natural Frequency
Resonance Zone
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Linear Response
Engine Order
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Linear Response
The Effects of Detuning
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Linear Response
The Effects of Detuning
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Linear Frequency Response
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Impact Response Single Sector
Ideal Collision Model
y
y
x
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Impact Response
Typical Steady-State Response Absorber (y) and
Blade (x) Phase Planes
Impacts
x Blade
y Absorber
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Impact Response Single Sector
Impact Force Threshold vs. Rotor Speed
f
Impacting
Non-Impacting
s
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Impact Response
Impact Force Threshold vs. Rotor Speed
f
Impacting
Non-Impacting
s
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Periodic Impact Response
Analytical Results vs. Rotor Speed
W/O Absorber
Blade Displacement
s
W/ Absorber
Unstable
Absorber Velocity At Impact
Stable
s
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Impact Response
Blade Displacement and Absorber Velocity vs.
Rotor Speed
Blade Displacement
xMAX
s
Grazing Chaos
Absorber Velocity At Impact
Simple
s
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Impact Response
Sample Response Transitions
Simple
Near-grazing
Chaos
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Impact Response
Interesting Chaos Observed
Blade Time Response
Chaotic Envelope
Blade Poincare Map
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Impact Response
Absorber Parameter Design Charts xMAX vs. force
amplitude
Increase m
Decrease e
Vary
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Summary

• Non-impacting Response
• Absorbers effective
• No-resonance zone
• Impacting Response
• Absorbers reduce resonance
• Chaos near resonance, but still effective
• Absorber parameters e, m, tuning
• Acknowledgment Funded by NSF CMS-0408866

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Directions for Future Work

• Non-impacting Response
• Effects of Damping
• Effects of Imperfections
• Parameter Studies
• Multi-mode sector models
• Impacting Response
• Parameter Studies
• Multi-sector analysis
• Multi-mode sector models
• Experiments