COMPOSITE MATERIALS د. ناظم مجبل فالح مواد هندسية 1-8

1. الجامعة المستنصرية كلية الهندسة قسم الهندسة الميكانيكية مواد هندسية مرحلة 3 COMPOSITE MATERIALSد. ناظم مجبل فالحمواد هندسية 1-8

2. MECH 473 ~ LECTURE 15: COMPOSITES MATRIX MATERIALS

3. MECH 473 ~ LECTURE 15: COMPOSITES -There are two basic categories of polymer matrices: -Thermoplastics -Thermoset plastics -Roughly 95% of the composite market uses thermosetting plastics -Thermoseting plastics are polymerized in two ways: -By adding a catalyst to the resin causing the resin to ‘cure’, basically one must measure and mix two parts of the resin and apply it before the resin cures -By heating the resin to it’s cure temperature POLYMER MATRIX MATERIAL

4. MECH 473 ~ LECTURE 15: COMPOSITES Common thermosetting plastics: -Phenolics: good electrical properties, often used in circuit board applications -Epoxies: low solvent emission (fumes) upon curing, low shrink rate upon polymerization which produces a relatively residual stress-free bond with the reinforcement, it is the matrix material that produces the highest strength and stiffness, often used in aerospace applications -Polyester: most commonly used resin, slightly weaker than epoxy but about half the price, produces emission when curing, used in everything from boats to RVs to piping to Corvette bodies POLYMER MATRIX MATERIAL

5. MECH 473 ~ LECTURE 15: COMPOSITES Common Metal Matrices: -Metal martices include aluminum, magnesium, copper, nickel, and intermetallic compound alloys -MMCs are better at higher temperatures than PMCs although production is much more difficult and expensive -MMCs can have applications such as fan blades in engines, clutch and brake linings, engine cylinder liners, etc. METAL MATRIX MATERIAL

6. MECH 473 ~ LECTURE 15: COMPOSITES MANUFACTURING WITH POLYMER MATRIX MATERIALS

7. MECH 473 ~ LECTURE 15: COMPOSITES -The method of manufacturing composites is very important to the design and outcome of the product -With traditional materials one starts out with a blank piece of material ie: rod, ingot, sheet, etc and works it to produce the desired part. -However, this is not the case with polymer-matrix composites. -With these composites the material and the component are being produced at the same time, therefore we aim for the product to be a net or near net shape with little to no post processing MANUFACTURING OF POLYMER-MATRIX COMPOSITES

8. MECH 473 ~ LECTURE 15: COMPOSITES Hand Lay-Up/Spray-Up -Oldest and most commonly used manufacturing method -Usually used to produce polyester or epoxy resin parts such as boat hulls, tanks and vessels, pick-up truck canopies -The method is quite simple, the resin and reinforcement is placed against the surface of an open (one sided) mold and allowed to cure or in the case of spray-up the resin/reinforcement is sprayed onto the mold with a spray gun MANUFACTURING OF POLYMER-MATRIX COMPOSITES -Often a gel coat is applied to the mold prior to produce a better surface quality and protect the composite from the elements -A gel coat is a resin usually 0.4 to 0.7 mm thick, commonly seen on the outer surface of smaller boats

9. MECH 473 ~ LECTURE 15: COMPOSITES Hand Lay-Up/Spray-Up -The pros of this process include: low initial start up cost, easy to change mold/design, on-site production possible (ie portable process) -The cons include: labor intensive, the quality of parts depends on operator’s skill and therefore inconsistent, only one good side to the part MANUFACTURING OF POLYMER-MATRIX COMPOSITES