Advanced MaterialsAdvanced Materials

Human Powered Aircraft Human Powered Aircraft GroupGroup

Advanced MaterialsAdvanced Materials

Advanced materials Advanced materials are used in aircraft are used in aircraft design to:design to:

-Reduce weight-Reduce weight

-Improve strength-Improve strength

-Design morphing -Design morphing wingswings

-Create self-healing -Create self-healing structuresstructures

Examples of Advanced Examples of Advanced MaterialsMaterials

• Memory PolymersMemory Polymers

• CompositesComposites

• BiocompositesBiocomposites

• ThermoplasticsThermoplastics

• AlloysAlloys

Memory Polymers: Veriflex and Memory Polymers: Veriflex and VeritexVeritex

• Veriflex is a shape memory polymer resin Veriflex is a shape memory polymer resin which modifies its shape in response to which modifies its shape in response to temperature changes. temperature changes.

• Veritex is a dynamic composite that utilizes Veritex is a dynamic composite that utilizes Veriflex resin as its matrix. When heated, Veriflex resin as its matrix. When heated, Veritex is pliable and maintains shape as it Veritex is pliable and maintains shape as it cools, regaining structural stiffness. Once cools, regaining structural stiffness. Once reheated it returns to its original shape and reheated it returns to its original shape and can be remolded without degrading.can be remolded without degrading.

• Future polymers may respond to light, electric Future polymers may respond to light, electric fields and magnetic fields.fields and magnetic fields.

CompositesComposites

• Composites are a combination of two Composites are a combination of two or more organic or inorganic or more organic or inorganic components one of which serves as a components one of which serves as a matrix holding the materials together matrix holding the materials together and then other of which serves as and then other of which serves as reinforcement in the form of fibersreinforcement in the form of fibers

• Composites are lightweight and strong Composites are lightweight and strong but they are complex to manufacture, but they are complex to manufacture, expensive and hard to inspect for flawsexpensive and hard to inspect for flaws

ThermoplasticsThermoplastics

• Thermoplastics are a new type of Thermoplastics are a new type of materials that is replacing materials that is replacing thermosets such as epoxy, thermosets such as epoxy, bismaleimide, or polyimide, as the bismaleimide, or polyimide, as the matrix for compositesmatrix for composites

• Thermoplastics are easier to produce Thermoplastics are easier to produce and are much more durable and and are much more durable and tougher than thermosetstougher than thermosets

BiocompositesBiocomposites

• Biocomposites combine plant fibers with resins to Biocomposites combine plant fibers with resins to create natural based composite materials. create natural based composite materials.

• High tensile plant fibers including, kenaf, industrial High tensile plant fibers including, kenaf, industrial hemp, and flax, can be combined with traditional hemp, and flax, can be combined with traditional resins to create an alternative to traditionally steel resins to create an alternative to traditionally steel or fiberglass applications.or fiberglass applications.

• Some advantages over traditional composites: Some advantages over traditional composites: – Reduced weight Reduced weight – Increased flexibility Increased flexibility – Greater moldability Greater moldability – Less expensive Less expensive – Sound insulation Sound insulation – Renewable resource Renewable resource – Self-healing propertiesSelf-healing properties

AlloysAlloys

• Benefits of Alloys:Benefits of Alloys:– Decreased weightDecreased weight– DurableDurable– Easy to manufacture and repairEasy to manufacture and repair

Application to Morphing Application to Morphing WingsWings• Stronger, shape memory and self-healing Stronger, shape memory and self-healing

polymers are applicable to the design of polymers are applicable to the design of morphing wingsmorphing wings– Lockheed’s 14ft remote-control aircraft makes use Lockheed’s 14ft remote-control aircraft makes use

of Veriflex and Veritex polymers to change shape of Veriflex and Veritex polymers to change shape and ensure a streamline profile as the wings morph. and ensure a streamline profile as the wings morph.

– Nextgen Aeronautics tested a wing that's structure Nextgen Aeronautics tested a wing that's structure of aluminum lattices expanded and compressed of aluminum lattices expanded and compressed consequently stretching and shrinking the wings consequently stretching and shrinking the wings silicone-rubber skin and causing the wing tips to silicone-rubber skin and causing the wing tips to move forward and back, and changing the wing move forward and back, and changing the wing span and chord.span and chord.

Future development of Personal Air Future development of Personal Air Vehicles (PAV), calls for safer, easy Vehicles (PAV), calls for safer, easy to fly planes.to fly planes.– Self-healing (often biocomposite) Self-healing (often biocomposite)

materials can be utilized to reduce materials can be utilized to reduce maintenance. maintenance.

– An Aeronautic Vehicle Integrated Health An Aeronautic Vehicle Integrated Health Management System is looking into self-Management System is looking into self-healing materials that will fill cracks in healing materials that will fill cracks in the structure by breaking capsules and the structure by breaking capsules and releasing adhesive.releasing adhesive.

Aeronautical Integrated Vehicle Aeronautical Integrated Vehicle Health Monitoring System Health Monitoring System (IVHM)(IVHM)• Detection of damaging eventsDetection of damaging events

• Characterization of the damageCharacterization of the damage

• Prioritization of the seriousness of the Prioritization of the seriousness of the damagedamage

• Identification of the cause of the Identification of the cause of the damagedamage

• Formulation of the responseFormulation of the response

• Execution of the responseExecution of the response

• Intelligent sensing systemIntelligent sensing system– Detects and measures quantities and Detects and measures quantities and

uses this information to make forward uses this information to make forward looking decisionslooking decisions

– Uses thousands and perhaps millions of Uses thousands and perhaps millions of different sensors used to measure different sensors used to measure different quantities (stress, strain, different quantities (stress, strain, temperature, acoustics, etc…)temperature, acoustics, etc…)

What is IVHM?What is IVHM?

How Does IVHM work?How Does IVHM work?

• Separates structures (skin, ribs, Separates structures (skin, ribs, components, etc...) into a series of components, etc...) into a series of cellscells

• Each cell is equipped with a group of Each cell is equipped with a group of sensorssensors

• The sensors communicate with The sensors communicate with neighboring cells as well as a central neighboring cells as well as a central computer.computer.

Types of SensorsTypes of Sensors

• Fiber OpticFiber Optic

• PiezoelectricPiezoelectric

• Infrared imagingInfrared imaging

Fiber Optic SensorsFiber Optic Sensors

• Can measure strain, temperature and pressureCan measure strain, temperature and pressure

• Specifically they can measure bond line integrity, Specifically they can measure bond line integrity, acoustic emissions, and corrosionacoustic emissions, and corrosion

• Uses Bragg grating to measure changes in light Uses Bragg grating to measure changes in light signalsignal– A change in stress moves the Bragg grating producing a A change in stress moves the Bragg grating producing a

shift in the reflected wavelengthshift in the reflected wavelength

• Fiber Optics are brittle so they must be embedded Fiber Optics are brittle so they must be embedded into materials, this is very expensive and into materials, this is very expensive and complicates manufacturing and repair practices.complicates manufacturing and repair practices.

Piezoelectric MaterialsPiezoelectric Materials

• Convert mechanical input into an electrical signal Convert mechanical input into an electrical signal (sensor) or convert and electrical pulse into a (sensor) or convert and electrical pulse into a mechanical action (actuator)mechanical action (actuator)

• Can detect energies caused by impact events or Can detect energies caused by impact events or defect generation (cracks, delamination)defect generation (cracks, delamination)

• Arrays of sensors allow a pinpoint determination of Arrays of sensors allow a pinpoint determination of the damage locationthe damage location

• Sensors have been able to detect cracks 0.005 Sensors have been able to detect cracks 0.005 inches in length of six inchesinches in length of six inches

• Will be embedded or surface mounted. Less Will be embedded or surface mounted. Less expensive optionexpensive option

Infrared ImagingInfrared Imaging

• Detects heat signatures in Detects heat signatures in order to detect leaks, order to detect leaks, cracks, debonding, cracks, debonding, corrosion, poor electrical corrosion, poor electrical wiring and contacts, and to wiring and contacts, and to assess overall thermal assess overall thermal profiles of components.profiles of components.

• Most often used to detect Most often used to detect defects or damage in the defects or damage in the propulsion system.propulsion system.

• Widely used, inexpensiveWidely used, inexpensive

Joint Strike FighterJoint Strike Fighter

• Airframe StructuresAirframe Structures

• EngineEngine

• ElectronicsElectronics

• Mission SystemsMission Systems

• ComponentsComponents– HydraulicsHydraulics– Drive ShaftsDrive Shafts– Fuel systemFuel system– Electrical systemElectrical system

Summary of IVHMSummary of IVHM

• Rapidly growing field dependant on the Rapidly growing field dependant on the improvement and development of sensing improvement and development of sensing technologies.technologies.

• It will enable less reliance on statistical based It will enable less reliance on statistical based scheduled maintenance and moves towards a scheduled maintenance and moves towards a condition based maintenance which will greatly condition based maintenance which will greatly reduce ownership costsreduce ownership costs

ReferencesReferences

• http://showcase.netins.net/web/creativecomposites/Biocomposites.htmlhttp://showcase.netins.net/web/creativecomposites/Biocomposites.html, , Creative Composites, Ltd., 19 September 2006Creative Composites, Ltd., 19 September 2006

• http://www.crgrp.net/veriflex.htm, CRG Industries, LLC., 19 September http://www.crgrp.net/veriflex.htm, CRG Industries, LLC., 19 September 20062006

• ““Flying off the Drawing Board”, Jeff Wise, Popular Mechanics, volume 183 Flying off the Drawing Board”, Jeff Wise, Popular Mechanics, volume 183 no. 7, July 2006no. 7, July 2006

• http://www.crgindustries.com/veritex.htm, CRG Industries, LLC, 19 http://www.crgindustries.com/veritex.htm, CRG Industries, LLC, 19 September 2006September 2006

• http://www.centennialofflight.gov/essay/Evolution_of_Technology/http://www.centennialofflight.gov/essay/Evolution_of_Technology/composites/Tech40.htm, U.S. Centennial of Flight Commission, 23 composites/Tech40.htm, U.S. Centennial of Flight Commission, 23 September 2006September 2006

• http://ammtiac.alionscience.com/pdf/2004MaterialEASE27.pdf#search=http://ammtiac.alionscience.com/pdf/2004MaterialEASE27.pdf#search=%22Vehicle%20Integrated%20Health%20Monitoring%20System%22, The %22Vehicle%20Integrated%20Health%20Monitoring%20System%22, The AMPTIAC Quarterly, Volume 8, Number 3, “Sensors and Sensing AMPTIAC Quarterly, Volume 8, Number 3, “Sensors and Sensing Technologies for Integrated Vehicle Health Monitoring Systems”Technologies for Integrated Vehicle Health Monitoring Systems”