Transcript Angle Amplification

Carbon Nanotube (CNT) Aerogel
Muscles
Yi Rao
May 4th, 2008
Yi Rao, UC Berkeley
1
By Ray H. Baughman, UT Dallas
Natural Muscle
CNT Aerogel
Density (kg/m3)
1037
1.5
Strain (%)
20-40
220
50
3.7×104
0.1-0.35
3.2
40
30
Ambient
80-1900
106k
140k
Strain Rate (%/s)
Stress (MPa)
Work per Cycle (J/Kg)
Operating temp. (K)
Cycle Life *
Yi Rao, UC Berkeley
2
Preparation of CNT Aerogel Sheet Actuator
MWNT forest were synthesized by catalytic CVD
CNT Aerogel Sheet is drawn from straight sidewalls of MWNT
Speed: 2m/s Outer diameter: 12nm with 9 walls
Yi Rao, UC Berkeley
3
Measurement of Actuation
Apply voltage to positively charge to CNT sheet
The CNT sheet is expanded by change repulsion
Changes is recorded by optical diffraction
Yi Rao, UC Berkeley
4
Actuation in width and thickness direction
Voltage, L/W ratio and temperature dependence
Sheets num
Yi Rao, UC Berkeley
5
Operating at resonance with low voltage
Q is 455, the strain can be 30% with Vrms=10V
Yi Rao, UC Berkeley
6
Actuation in the length direction (Strength)
Stress on length direction and work capacity
Different applied voltage
to width expansion
Yi Rao, UC Berkeley
7
Conclusion and Drawback

The CNT Aerogel muscle shows some amazing
properties compared with human muscle




Strain, Strain Rate, Stress
Density
Temperature tolerance
But there are still some concerns




The material volume is not large and dense enough for real use
The property of CNT sheet becomes worse when add more layers
The apply voltage on low frequency is too large
Very high cost ($100/g)
Yi Rao, UC Berkeley
8
Complementary: Aerogel



Aerogel is a solid-state material with the lowest known density
Aerogel is gel in which the liquid component of the gel has been
replaced with gas.
Aerogel is thermal insulator
Yi Rao, UC Berkeley
9