Composite MaterialsComposite Materials

Bill PedersenBill Pedersen

Components of Polymer CompositesComponents of Polymer CompositesPolymer ResinPolymer Resin Usually a thermosetUsually a thermoset

EpoxyEpoxy

PolyesterPolyester

VinylesterVinylester Thermoplastics - Thermoplastics -

AerospaceAerospace

Reinforcing fiberReinforcing fiber FiberglassFiberglass

E, S, C (E most common)E, S, C (E most common) Graphite (Carbon)Graphite (Carbon) Aramid (Kevlar)Aramid (Kevlar) Spectra (PE)Spectra (PE)

Open MoldingOpen Molding

Female Mold of partFemale Mold of part Made of FRP (Fiberglass Made of FRP (Fiberglass

Reinforced Polymer)Reinforced Polymer) Has steel supportsHas steel supports Gel coated and waxedGel coated and waxed

To make part:To make part: Gel coat moldGel coat mold Spray on chop fibers, resin Spray on chop fibers, resin

and catalystand catalyst Roll out airRoll out air Add stiffeners or layers as Add stiffeners or layers as

desireddesired

Vacuum BaggingVacuum Bagging

Greatly reduced VOC Greatly reduced VOC (Volatile Organic (Volatile Organic Content) (Reduced Content) (Reduced emissions)emissions)

Cover reinforcement Cover reinforcement with cheap plastic with cheap plastic covercover

Suck resin into the Suck resin into the part to fill the voidpart to fill the void

Making a KayakMaking a Kayak

Open vs. Closed MoldingOpen vs. Closed Molding

Open MoldingOpen Molding As shown previouslyAs shown previously Only one sided moldOnly one sided mold Limited temperature Limited temperature

controlcontrol Lower capital cost for Lower capital cost for

moldsmolds

Closed molding – or Closed molding – or compression moldingcompression molding Two sided mold – part Two sided mold – part

is sandwiched is sandwiched between two mold between two mold halveshalves

Pressure appliedPressure applied Improved material Improved material

properties (fewer properties (fewer voids)voids)

Higher Capital costHigher Capital cost

Closed Closed MoldingMolding

Can be done using Pre-Can be done using Pre-preg or wet layuppreg or wet layup

Process:Process: Resin impregnated fibers Resin impregnated fibers

cut to proper geometrycut to proper geometry Heated Die sets close on Heated Die sets close on

partpart Part is cured at Part is cured at

temperaturetemperature Die opens and part is Die opens and part is

ejected from moldejected from mold

FilamentFilament Winding Winding

Control the orientation Control the orientation of the fiber using a of the fiber using a relative motion of relative motion of rotation and linear rotation and linear motionmotion

Example Products:Example Products: Pressure VesselsPressure Vessels Fishing PolesFishing Poles Light PolesLight Poles AntennasAntennas

PultrusionPultrusionFibers or cloth are Fibers or cloth are pulled through a resin pulled through a resin bathbath

Heated in a die with a Heated in a die with a shaped profileshaped profile

Cured to shapeCured to shape

Cut to lengthCut to length

Metal Matrix CompositesMetal Matrix Composites

Completely different field. The book has Completely different field. The book has them in the same chapter, but they are them in the same chapter, but they are very different.very different.

Combination of metal matrix, with ceramic Combination of metal matrix, with ceramic reinforcement.reinforcement.

Examples:Examples: Titanium with SiC fiber reinforcementTitanium with SiC fiber reinforcement Mg with SiC discontinuous reinforcementMg with SiC discontinuous reinforcement