The Ideal Materi al Endless and readily available source of supply Cheap to refine and produce Energy efficient Strong, stiff, and dimensionally stable at all temperatures Lightweight Corrosion resistant No harmful effects on the environment or people Biodegradable Secondary uses Is this a Composite? Golf Balls + Marbles + Water Is this a Composite? Golf Balls + Marbles + Ice Is this a composite? A. Wood fibers Water B. Wood fibers Ice C. Paper fibers (TP) Ice D. Cotton fibers Ice Composite Formal Definition A complex material, such as wood or fiberglass, in which two or more distinct, structurally complementary substances, especially metals, ceramics, glasses, and polymers, combine to produce structural or functional properties not present in any individual component. COMPOSITES reinforcing phase- fibers, sheets, or particles, and is embedded in the other material called the matrix phase. The reinforcing material and the matrix material may be metal, ceramic, glass, or polymer. Particulate Al 2 O 3 in Cu, SiC in Al, Gravel in Concrete Fiber Carbon fiber/Epoxy, Easter grass/cement Golf club, Wind turbine blade Honeycomb Carbon fiber sheet over hex Al Laminar Nano CuNb, Multilayer paper w glue Mixed Glass fiber sheet over Resin impregnated paper hexcell with elastomer interlayer Rebar in concrete Types of Composite Fiber Carbon fiber/Epoxy, Easter grass/cement Golf club, Wind turbine blade Cotton fiber in super glue Fiber strengthened composites can be 1, 2, or 3 dimensional Types of Composite Cotton Fiber in Super Glue Lay out a sheet of waxed paper Stretch a cotton string across the paper, hold taut Second person applies super glue to soak the string, stopping short of fingers Allow to cure ~ one minute Carefully pull waxed paper from string Cement Puck A.Neat portland cement, 100g with 50g water (1/2 cup cement, cup water) B.Mixture as above plus Easter grass C.Cast each in styrofoam bowls D.After several days, determine fracture characteristics Blast Resistance with Fiber-Reinforced Composites Cross section of extruded decking material. It is made up of 2/3 wood fiber and 1/3 plastic Bowed pole stores energy Hockey Stick Fiber reinforced golf club vs metal Honeycomb Carbon fiber sheet over hex Al Glass fiber sheet over impregnated paper Tape over paper hexagonal cells Types of Composite Ticket Stock Hexagonal Cell Ticket stock comes precut to an exact width. No cutting required. Take 6 lengths of 10 tickets each. Fold each ten ticket length at the perforations to form compact stacks: Compress: Fold each stack in half: Compress: Ticket Stock Composite Take one folded and compressed stack of ten tickets: Pull partway open: Ticket Stock Composite Add another: Join each contacting surface Repeat to make three joined units Join the three units: Then stretch a little. Apply tape to close the cells: Test by gently bending Test to failure between books with a weight on top Observe failure mode Laminar Nano CuNb Multilayer paper w glue Formica: paper + phenolic & melamine resins Plywood Auto windshield: glass/polymer/glass Foam beams with glue and paper or with tape Types of Composite Aluminum Board: The board is made of (2) 6005-T6 extruded aluminum beams that are epoxied along the centerline and press bonded Fiberglass Diving Boards Made of molded fiberglass and a laminated Douglas Fir wood core. Additional fiberglass reinforces tip, butt and fulcrum area. Composite Tension /Compression Polystyrene Foam Tape top side Tape bottom side Tape both sides Tape both sides, flaw one side Tape H Deflection L W Note length L is the portion beyond the support, NOT the total beam Deflection Weight Applied Young's Modulus, PSI E= 4x Load x L x L x L Def x W x H x H x H L = Length of the unsupported portion of the beam W= Width of the beam H= Height (thickness) of the beam D= Deflection Load in pounds, dimensions in inches In conventional US units the load in pounds equals the force, dimensions are in inches, E has the units of pounds per square inch. For Steel: E ~ 30,000,000 PSI The SI unit of modulus of elasticity (E )is the pascall (Pa or N/m or m 1 kgs 2 ).l The force of a Newton, 1 kgm /s 2 is that of a smallish apple at sea level. Typical Values: Polymer, Nylon 2 to 4 GPa FCC: Copper 117 GPa, Aluminum 69 GPa BCC: Steel 200 GPa, Tungsten 400 Gpa Carbon fiber reinforced plastic (70/30 fibre/matrix, unidirectional, along grain), 181 GPa Diamond 1220 GPa Weight Applied, kg Deflection, m 4 x mass x 9.81 x Length 3 Def x Width x Thickness 3 Mass in kilograms Acceleration g in m/s 2 Length, Deflection, Width, and Thickness in meters Modulus in Pascals, (kg m/s 2 )/m 2 Modulus = 1 m One Newton / meter 2 = One Pascal Summary at 0.10 kg Specific MassBeam Modulus appliedLengthDeflectionWidthThicknessModulus, Pa MassVolumeDensity{(kg m/s 2 )/m 2 } / kgmmmm(kg m/s 2 )/m 2 kgm3m3 kg/m 3 (kg/m 3 ) No Tape E E E+05 One side up E E E+05 two side E E E+06 Nylon3.00E E+032.6E+06 Steel2.00E+117.9E+032.5E+07 Diamond1.22E E E+08 4 x mass x 9.81 x Length 3 Def x Width x Thickness 3 Modulus = Camp Beams Wood Laminar Composite Defect Cracks(defects) in wood Randomization Of Defect Constructed from two pieces of Oriented Strand Board with a high density Polyurethane foam core. (Rigid, or cross-linked, polyurethane foams, likely with small closed cells) Mixed Glass fiber sheet over Resin impregnated paper hexcell w elastomer interlayer Brake pads Cement, Aggregate, Sand, & Rebar Types of Composite Re Bar in Concrete Fiber Carbon fiber in Epoxy Cotton fiber in epoxy Particulate Al 2 O 3 in Cu, WC w CoNi, SiC in Al, Gravel in Concrete Honeycomb Carbon fiber sheet over hex Al Laminar Nano CuNb, Multilayer paper w glue Mixed Glass fiber sheet over Resin impregnated paper hexcell w elastomer interlayer Brake pads Cement, Aggregate, Sand, & Rebar Types of Composite Composites illustrate the endless variety of engineered materials Extra Concrete is Made of. Portland Cement (Calcium, Silicon, Aluminum and Iron) + Water + Rocks, Sand, Gravel, Stone Cement Pucks Procedure 1. With a partner, get 2 Styrofoam bowls and label with names 2. Measure out cup cement and cup water 3. Mix and pour into the Styrofoam bowl 4. Add Easter grass to one bowl and mix in 5. Allow the cement to harden overnight 6 Parts Experiment Students make concrete, cast in lubricated rectangular drawer organizer(knife tray) Gravel Sand Cement Students choose proportions, distributing their six equal volumes among rock, sand and cement. Water to choice Components of Concrete Portland cement (clay and limestone whose origin is ground stone from Isle of Portland in Dorset. England.) 6 Parts Experiment (Second Year Camp) Concrete beams are tested in bending to failure(fracture) Beams are supported at each end with bricks and loaded in the center with more bricks to failure. An extension is to modify the concrete,( perhaps sticky rice?) Try adding wire scaled to size representing rebar Try adding Easter grass Examine, describe fracture surface: A. By eye B. With a magnifying glass C. With a low power microscope 6 Parts Experiment Students make concrete, cast in lubricated rectangular drawer organizer(knife tray) Gravel Sand Cement Students choose proportions, distributing their six equal volumes among rock, sand and cement. Water to choice The Ideal Material 1. Endless and readily available source of supply 2. Cheap to refine and produce 3. Energy efficient 4. Strong, stiff, and dimensionally stable at all temperatures 5. Lightweight 6. Corrosion resistant in use 7. No harmful effects on the environment or people 8. Biodegradable after use 9. Secondary uses For a simple beam, supported at one end, Deflection = = FL 3 /3EI = FL 3 /3E WH 3 /12 = 4 FL 3 / E WH 3 Moment of inertia, I = W H 3 / 12 for a rectangular cross section To obtain force F in the above equation, mass should be multiplied by the gravitational constant g (9.81 ms -2 ) The force of a Newton, 1 kgm /s 2 is that of a smallish apple. 1 Pa = 1 Nm -2 = kgms -2 m -2 Deflection = 4 mass 9.81 L 3 / E WH 3 [=] kg m s -2 m 3 / m 1 kgs 2 m m 3 = m Alternatively E = 4 mass 9.81 L 3 /Def WH 3 [=] m 1 kgs 2 [=] kgms -2 /m 2 Time for glue, 6 strips of paper A Bottom layer Place second strip over glued first strip Add stripes of glue to the surface of B, place a strip C on top and glue as A. Repeat alternating glue positions for 6 strips then add a cover strip. After drying, open as a honeycomb. This method is analogous to the actual manufacture of honeycomb for composites. It is sometimes difficult to open the honeycomb. The method using ticket stock is an adaptation for classrooms, yielding a more uniform hexagonal honeycomb. B B Al/Polyethylene Laminar Composite