Talking @ PASI (Pan-American Advanced Studies Institute) Workshop 2012 - CMS4E, Pontificia Universidad Católica de Chile, January 9-20, 2012, Santiago - Chile
Ultracold atoms in superlattices as quantum simulators for a spin ordering mo...
Piezoaeroelastic Energy Harvesting
1. PIEZOAEROELASTIC
ENERGY HARVESTING
Vagner Candido de Sousa – vagner@sc.usp.br
Aeronautical Engineering Department
Sao Carlos Engineering School
University of Sao Paulo – Brazil
PASI Workshop 2012
Computational Material Science for Energy Generation and Conversion
January 9 – 20, Santiago, Chile
2. Outline
• Vibration-based energy harvesting
• E.H. from aeroelastic vibrations
• Piezoelectrically coupled airfoil typical section
• Case Studies
– Linear model (interaction power - aeroelastic response)
– Nonlinear model (broadband generation)
• Conclusions
3. Vibration-based energy harvesting
• Motivation
– Vibrations are available in the environment
– Additional (long-term) power source
– Reduced power requirement of small devices
• Flow-induced energy harvesting
– Aeroelastic vibrations
– Potential application: UAV
• Piezoelectric transduction (direct effect)
4. Airfoil section for energy harvesting
2-DOF (Erturk et al., 2010) 3-DOF (Tang and Dowell, 2010)
• DOFs: plunge (h), pitch (α) and control surface rotation (β)
5. Piezoaeroelastic equations of motion
I ( I b(c a ) S ) S h d k M
( I b(c a ) S ) I S h d k M
S S (m me )h d h h k h h v p L
l
vp
C vp
eq
p h 0
Rl
6. State-space representation
I 0 0 0 x 0 I 0 0 x
0 0 K
M 0 x
B D Θs x
0
0 I 0 x a E1 E2 F 0 x a
eq
0
0 0
C p v p 0 Θe 0 1 / Rl v p
0 I 0 0
M 1K
M 1B
M 1D
M 1Θ s
A
E1 E2 F 0
0 1 / C Θ
eq
p e 0 1 / C p (1 / Rl )
eq
x Ai x a i
10. The “linear problem”
• U∞ < ULF: damped oscillation
• U ∞ > ULF: growing amplitudes of oscillation
• U ∞ = ULF: the ideal scenario for energy harvesting
– U ∞ = ULF is a very particular situation
• Nonlinear model
– Opportunity for persistent power generation
11. Nonlinear model
• Structural nonlinearities can induce subcritical LCOs
• The linear torsional spring is replaced by a bilinear spring
I ( I b(c a ) S ) S h d k f fp ( ) M
k fp fp
f fp ( ) 0 fp fp
k fp
fp
2-DOF with bilinear spring
3-DOF with bilinear spring
Sousa et al., 2011, Smart Mat. Struc.
3-DOF: Power with airspeed (70% ~ 98% ULF)
12. Summary and conclusions
• Piezoaeroelastically coupled typical section for
energy harvesting
• Harvests energy from linear and nonlinear
aeroelastic vibrations
• Nonlinear aeroelastic phenomena can provide
persistent power generation in a wide range of
airflow velocities
13. Thank you! Questions?
• The author gratefully acknowledge
– PASI 2012 CMS4E organizing committee
– CNPq