prelims
AMT 630 Aircraft Materials Construction and Repair II (Composite/ Non-metallic)
Page 1: Course Overview
Focus on non-metallic materials used in aircraft construction and repair.
Page 2: Non-Metallic Materials
Various types of plastics are utilized in aircraft construction.
Types include transparent plastic, reinforced plastic, composite, and carbon fiber materials.
Page 3: Plastic Applications
Plastics serve multiple functions in modern aircraft.
Structural components made from thermosetting plastics reinforced with fiberglass.
Decorative trim made from thermoplastic materials.
Page 4: Transparent Plastic
Used in canopies, windshields, and other transparent enclosures.
Page 5: Reinforced Plastic
Applications include radomes, wingtips, stabilizer tips, antenna covers, and flight controls.
High strength-to-weight ratio.
Resistant to mildew and rot.
Page 7: Composite Materials
Definition: Combination of two or more different materials to create a superior material.
Formula: Composite = Matrix + Filler.
Page 11: Fiber Glass
Lightweight and environmentally friendly material used in aircraft manufacturing.
Commonly used for various industrial and individual goods.
Page 14: Composite and Carbon Fiber Materials
High-performance aircraft require a high strength-to-weight ratio.
Fabrication of composite materials meets these requirements.
Page 16: Advantages of Composites
Higher performance for a given weight leads to fuel savings.
Easier to achieve smooth aerodynamic profiles for drag reduction.
Excellent resistance to corrosion.
Page 17: Disadvantages of Composites
More brittle than wrought metals, making them more susceptible to damage.
Repair introduces new challenges.
Higher production costs.
Page 18: Laminated Structures
Composites consist of a combination of materials that act together without dissolving or merging completely.
Page 20: Isotropic vs. Anisotropic Materials
Isotropic materials have uniform properties in all directions (e.g., aluminum, titanium).
Anisotropic materials, like unidirectional composites, have properties that depend on fiber orientation.
Page 22: Role of the Matrix
The matrix supports and bonds fibers in composite materials.
Transfers loads to fibers and provides environmental resistance.
Page 23: Strength Characteristics
Structural properties depend on the stacking sequence of plies.
Example: A symmetric eight-ply laminate can have 24 different stacking sequences.
Page 24: Fiber Orientation
Strength and stiffness depend on ply orientation.
Proper selection is crucial for efficient structural design.
Page 27: Quasi-Isotropic Material Layup
A balanced approach to ply orientation for improved performance.
Page 28: Unidirectional (Tape)
Standard in aerospace; high strength in fiber direction, low strength across fibers.
Page 30: Bidirectional (Fabric)
Offers flexibility for complex shapes; tightly woven fabrics are preferred for weight savings.
Page 32: Nonwoven (Knitted or Stitched)
Provides mechanical advantages similar to unidirectional tapes; fibers held in place by stitching.
Page 35: Fiberglass
Used for secondary structures like fairings and rotor blades.
Types include E-glass (electrical applications) and S-glass (higher strength).
Page 37: Kevlar
DuPont's aramid fibers; lightweight and strong.
High impact resistance but weak in compression and hygroscopic.
Page 39: Carbon/Graphite Fibers
Distinction between carbon (disordered) and graphite (ordered) fibers.
Carbon fibers are strong and stiff, used in structural applications.
Page 42: Boron Fibers
High tensile and compressive strength; used for repairing aluminum aircraft skins.
Page 43: Ceramic Fibers
Used in high-temperature applications like turbine blades.
Page 44: Lightning Protection Fibers
Carbon fibers are highly resistive; aluminum dissipates lightning strikes effectively.
Page 46: Matrix Materials
Resins affect processing and properties of composites.
Page 47: Thermosetting Resins
Widely used, easily formed, and cure into insoluble solids.
Page 48: Polyester Resins
Inexpensive and fast processing; used for low-cost applications.
Page 49: Epoxy
Commonly used with high-performance reinforcements; cured with a hardener.
Page 50: Vinyl Ester Resin
Combines features of polyester and epoxy; stronger and more resistant.
Page 51: Phenolic Resin
Used for interior components due to low smoke and flammability.
Page 52: Thermoplastic Resins
Can be softened and hardened repeatedly; processing speed is a key advantage.
Page 53: Semicrystalline Thermoplastics
Flame-resistant and tough with good mechanical properties.
Page 55: Polyether Ether Ketone (PEEK)
High-temperature thermoplastic with excellent thermal and combustion characteristics.
Page 56-58: Curing Stages of Resins
A Stage: Components mixed, no chemical reaction.
B Stage: Reaction started, material tacky; stored in freezer to prevent further curing.
C Stage: Fully cured; some resins cure at room temperature, others