Engineering model for Galfenol

Application of Iron-Gallium Alloy- Energy Harvester and SensorsJin-Hyeong YooUniversity of Maryland, College Park, MD 20742

Seminar topic 11ContentsIron-Gallium Alloy A New Magnetostrictive MaterialEnergy HarvesterSensor ApplicationsPossible Applications for Soldier SystemEnergy Harvester: Solar Cell

DrawbacksHigh costNeeds large amount of spaceHeavy weight - portabilityIt needs sun lightEfficienciesCrystalline silicon devices: 29% Max.GaAs multi-junction devices: 42.3 %K. Sangani, Eng. Technol., vol. 2 2007

Thermoelectric Generator

This is a conceptual illustration of typical applications in representative environments where natural temperature differences exist. (Pacific Northwest National Lab.)Average electric power of up to hundreds of milliwattsApplication tailoring achieved simply by varying number of thermocouples, deposition parameters, and substrate dimensions Projected life longer than equivalent batteries Provides power for the lifetime of the application Adaptable to wide range of ambient conditions

Small temperature differences for miniature size scalePoor thermodynamic efficiencyAmbient RF

IssuesPower levelDistance from sourceMantiply et al. Pervasive Comput., vol. 4, 2005Piezoelectric - VibratoryGranstrom, et al. Smart Materials and Structures. 16 (2007)

Energy Harvesting Running Shoes Shoulder Strap Energy Harvesting Nathan S. Shenck, et al. IEEE Micro, Vol. 21, No. 3 (2001)

Macro-Fiber Compositeswww.smart-material.comElectromagnetic

nPowerPEG.comSize: 9" tall, Top & Bottom Cylinders: 1'" diameter, Center Cylinder: 1.5" diameterWeight: 12 oz. (340 gram)Energy Storage Capacity: 1000mAh lithium Polymer batteryVoltage: 5V DC, 500mA output rangeWatts: 2.5 Watts

Faraday FlashlightsAmazon.comPower Shirt (GIT)

Image courtesy Zhong Lin Wang and Xudong Wang, GIT

Regents professor Zhong Lin Wang holds a prototype microfiber nanogenerator composed of two fibers that rub together to produce a small electrical current. Many pairs of these fibers could be woven into a garment to produce a "power shirt. (2008)

What is Magnetostriction?A change in dimensions exhibited by ferromagnetic materials when subjected to a magnetic field. (Random House Dictionary)Documented by James Joule in 1842Curie temperature quite high (~750C for Fe81-Ga19) Effect will not de-pole Domain ordering returns without the need for poling after exceeding Curie temperature.101-D Linearized EqnsActuation modeled by the direct effect:

Sensing modeled by the inverse effect:

where H=nI11DC or AC Magnetic Fieldll + D lMagnetostrictive Actuation

The Direct Effect: The change in the dimensions of a ferromagnetic body caused by a change in its state of magnetization.H=nIThe Inverse Effect: The change in the magnetic state of a ferromagnetic body caused by a change in its state of stress.Magnetostrictive Sensing

DC Magnetic Fieldl DBH0=110 OeABAB

Comparison of active materials

Smaller magnetizing coil Smaller size Higher power density Ability to withstand shock loads Bending structure14

The Inverse Effect: The change in the magnetic state of a ferromagnetic body caused by a change in its state of stress.Magnetostrictive Electric Harvesting

15Galfenol as Energy HarvesterGalfenol has high permeability and high saturation magnetization We expect high energy output!

High SaturationMagnetization~1.6 TeslaHigh Magnetic Efficiency~2500 Gauss/ppmStrain16Galfenol Energy HarvesterPickup CoilOn a vibration stage

Pickup coils

Galfenol beamAl beamMagnetConceptual diagram

17Pickup Coil21.5Aluminum(t=0.05)Galfenol (t=0.03)

Mode Shape at 223HzGalfenol Harvester PropertySymbolValueModulus of beamBeam dimensionLumped massDamping CoefficientEL x b x tM+meffz69 GPa1.5x0.25x0.085 in310.34 g0.0087Mechanical Response of Beam18Piezomagnetic Constitutive Equation

Piezomagnetic Coupling CoefficientSensor Coil Response

n= 1000 turns, A =b x t Magnetic Efficiency of Galfenol19

Strain range

H~50 Oe

Numerical Simulation20

Output Volts: Measured and Predicted21

Vibration CommandShaker ControllerFFT analyzerShakerResistance BoxAccelerometerOutput Power Test Setup22

Galfenol-Al beamRVOutput volt and current at given resistance load (n=1000)R = 1, 10, 36, 50, 100, 1000, inf Wa = 1.0, 2.0, 3.0, 4.0 gOutput Power Test Results23

Sensor CoilVibration Harvester

Mmeff

Pin

Max. Output and Efficiency24Applications for soldier system

Manpack Antennas (Hascall-Denke)

One early change by the US Army was to put multi-functional, low power, lightweight electronics on the wrist as shown in the picture and later work extensively employs energy harvesting.Micro Gyro Sensor Development26Permanent MagnetActuator prong(t)VDxFe79Ga21 StripsyGMR Magnetic sensorSensing prongOriginal DesignModified Design Gyro Sensor ConfigurationModified thickness of prongs and sensor coil measurementPermanent MagnetActuator prong(t)VDxySensing prongVS27Tuning Fork Gyro Sensor

z(t)VDVSxGalfenol Stripsy(a) Drive mode(b) Sensing modeGMR sensor Basic Principle Excite one tuning fork leg to induce sympathetic vibration of second legCoriolis force will induce orthogonal deflection Permeability will be changed by deflection of the Galfenol stripCoriolis Force

Maximize Dx to maximize F(t)DxGyro Sensor Structure

GMR Sensor

AdapterSensor AssemblyGMR Sensor HolderMagnetGMR sensor AssemblyDriving Coil GMR sensor (NVE AA002-02) 15 Oe max. 0.9828Oe/VJH Yoo, U Marschner and AB Flatau, Proceedings of SPIE, 5764-14, 2005.This slide shows a proto type of the Gyro sensor, so at this time its somewhat bulky, but eventually we will make small scale gyro.This design is for just concept verification.

Permanent MagnetActuator prong(t)VDxySensing prongVS

Sensor Coil Output Spectrum0Hz5Hz20HzVibration Mode Test30

1 Hz moment input0.2 Hz moment inputIt has high sensitivity at low frequency!31

Applications for Soldier System

Garmin Foretrex Lightweight Wrist Mounted GPS NavigationIndoor GPS compensation

Hand Shaking Compensation

Alloy 79 high permeable material as a flux return path.20 g of sprung mass, 0.3 Tesla permanent magnet3 Galfenol cylinders were tested (1/8, 1/16, and 1/32 wall thickness, long)

SensorcoilBaseGalfenol CylindersShaft &washersSprungMassWide Band Accelerometer

Hallsensor33Non-Contact Torque Measurement using GalfenolSingle Crystal-Like Galfenol Patch placed on the surface of Aluminum Shaft at 45 with bias magnetHall effect voltage vs. strain measured from strain gage at 45 on shaftBias MagnetHall SensorGalfenol PatchD. Douglas, SM Na, JH Yoo and AB Flatau, SPIE Smart Structures and Materials, 2010Rotational Test SetupRotational Test1/8 HP 30 rpm geared driving motor 220 inch-lbs torque1/10 HP brake motor 1.8 inch-lbs torque

Patch bonded to shaftBrakeMotorCommercialTorqueSensorHallSensorDrivingMotorD. Douglas, SM Na, JH Yoo and AB Flatau, SPIE Smart Structures and Materials, 2010Rotational Test ResultsBias magnet mounted with hall sensorRotationHall Sensor

Galfenol Patch corner 1Bias MagnetGalfenol patch corner 1 passing under hall sensorcorner 2Galfenol patch corner 2 passing under hall sensorSummary: Advantage of Galfenol SensorShock tolerable structural sensorNo energy input needed with sensor coil (Green)Easy to designHigh sensitivity @ high frequencyHarsh condition applicationPZTPMNTerfenol-DGalfenol

Maximum strain ()~1035

~2000

~1000

~400

Young modulus (GPa)70

20

25 - 35

55

Magnetic permeability ((r)-

-

3-10

300

Robustness

Robust

Brittle

Brittle

Machinable, not brittle