Thin Film Active Materials

Transcription

1 Thin Film Active Materials Greg P. Carman An expert is a man who has made all the mistakes which can be made in a very narrow field Edward Tellar

2 Active Materials - Definition - Coupling thermal θ electric E ε D p m ρc/θ α σ i H B b µ d S s T E mechanical Curie in 1880 Shape Memory Chang & Read 1932 magnetic M Magnetostrictive Joule 1842 Multiferroism termed by Schmid, Ferroelectrics 1994

3 Classic Active Material Systems PZT Terfenol-D NiTi mw DSC NiMnGA-J4.tad DSC-Heating NiMnGA-J4.tad DSC-Cooling x10 0C 44.35x10 0C Heat x10 0mJ 6.06x10 0J/g x10 C Heat x10 0mJ 56.70x10 0C -8.27x10 0J/g File Name: NiMnGA-J4.tad Detector: DSC Acquisition Date 02/03/11 Acquisition Time 16:58:22 Sample Name: NiMnGA Sample Weight: [mg] Annotation: Temp [C] Piezo Strain 0.2% stress (MPa) 20 Specific Power (W/kg) , ,000 NiTi thin film 1990 Magn 0.1% ,000 Shape memory 4% THIN FILM <10 MICRONS Exchange coupling interaction Large resonant frequencies Increased surface to volume ratio

4 Macroscopic Applications (1980 s) Boeing Actuator stack Flap Blade ACTIVE FLAP ROTOR Boeing Straub et al s Whirl Tower Test

5 Building/Designing Sensors/Multiscale Magnetostrictive Shape Memory Multi-field Multiscale P M SMA microns Coupling Structural Dynamics Micro (resonant structure) Boeing Layered Coupling (Exchange coupling interaction) Mechanics of substructure Structural Integration sensing (Health, power, guidance)

6 New Thin Film Magnetometers Input magnetic energy Output electrical energy H Terfenol-D Composite α E (V/cmOe) Terfenol-D Composite PZT-5H 2.8 max α 48% E 39% % 22% 16% 2.0 V Thin film Exchange coupling interaction Large resonant frequencies Inexpensive Ceramic/Polymer H Bias (ka/m) Inventory Tracking

7 Energy Harvesting (mechanical-thermal) Structural Dynamic recharger Mechanics of Phase Transformation micro Boeing Coupled Structure (convert to electrical) Solar or Vibration energy to Electrical Power Solar Panel Thermoelectric Generator Drawbacks Low Efficiency Low Power Density (on volumetric or mass basis)

8 Energy Harvesting Waste Heat Strain (ppm) // Strain Cooling Heating GdSiGe FSMA T+ T ~ 8 o C Hysteresis Temperature ( o C) H, T Phase Transformation Thin Film (khz frequency) T cold Thermostrictive T cold Thermostrictive µm T hot T hot

9 Biological Replacement Components Diseased Heart Valves Mechanical or bioprosthetic artificial valves Requires invasive open heart surgery to implant Tissue valves only last 5-15 years Mechanical valves require anticoagulants to prevent blood clots NiTi Replacement valve Percutaneously placed outpatient Diseased Heart valve Blood clot on mechanical valve NiTi thin film

10 Test Results Thin Film Heart Valve Gage Pressure (psi) G age Pressure (psi) Before Valve Edwards Tissue Valve After Valve Before Valve Time (sec) Butterfly Valve After Valve L/min Flow Rates Theoretical Ball Valve Butterfly =SV*HR Valve 1.3 Edwards Tissue Valve 0.07 No Valve Time (sec) Animal Testing

11 Actuators Future Miniaturization Miniaturization Micron/millimeter scale Power density metric Thin film active materials Multi-assembly Actuator Requirements Force F Displacement d Response f Size -m Specific Power= F*d*f/m Thin Film Active Materials 10, ,000 Watts/kg PZT Terfenol-- SMA Conventional Motors specific power decreases with size 100 Watts/kg

12 Beginning - Active Material Motors Actuator Specific Power Density (W/kg) Electromagnetic Motor fist size SMA Pump * Piezohydraulic Pump * Burleigh Linear Motor * Ultrasonic Motor * UCLA Mad Device Inchworm ~ (1000) 160 (1000) 20 (100) 140 (700) 140 ~.05 Kinetic ceramics Burleigh Conventional motors Win in the large scale (bigger than a fist) Future lies in smaller (milli-micro-nano) scale systems MACRO Active MICRO-NANO Thin Films

13 Thin Film NiTi Motor 100Hz 125 kw/kg film Need Compact actuation missile guidance

14 Small Motors Required Artificial Pancreas Current technologies Future 1mm NiTi Pump Actuator

15 Summary Thin film active materials (e.g. NiTi, piezoelectric..) relatively new area of study Opportunities (multiscale & multifield) exist to design entirely new systems Actuation systems offers enormous opportunities in the small scale (microns), revolutionary concepts Multitude of biological, commercial, and defense applications exist for the area FABRICATION EVALUATION

16 Notable Quotes No other kind of thought except intuition is more accurate than scientific knowledge. Aristotle Most of the things worth doing in the world have been declared impossible before they were done. Louis Brandeis