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ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
ME 582 Advanced Materials Science
Chapter 1 Introduction to Composite Materials
Dr. Jan GouComposite Materials Research Laboratory
Department of Mechanical EngineeringUniversity of South Alabama, Mobile, AL 36688
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Definition of Composite Materials
A composite is a structural material that consists of two or more combined constituents that are combined at a macroscopic level and are not soluble in each other
Reinforcing phase: fibers, particles, or flakes
Matrix phase: polymers, metals, ceramics
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Fiber-Reinforced Composites
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Fiber-Reinforced Composites (Cont’d)
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Characteristics of Composite Materials
High specific strength and modulus, as well as high fatigue strength and fatigue damage tolerance
Anisotropic
Designable or tailorable materials for both microstructure and properties
Production of both material and structure or component in a single operation - manufacturing flexible, net-shape, complex geometry
Corrosion resistance and durable
Other unique functional properties - damping, low CTE (coefficient of thermal expansion)
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Specific Modulus
ρ/1
4
2
EPLM =
Lightest beam for specified deflection under a specified load is one with the highest modulus
Axial Deflection
EAPL
=μ
Mass
ALM ρ=
ρ/E
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Specific Modulus
Critical Load
2
2
LEIPcr
π=
Second Moment of Area
64
4dI π=
Mass of Rod
ρππρ
/12
4 2/1
22
EPLLdM cr==
Lightest beam for specific stiffness is one with the highest value of ρ/2/1E
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Specific Modulus
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Specific Modulus
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Disadvantages of Composites
High cost of fabrication of composites
Mechanical characterization of a composite structure is more complex than a metal structure
Repair of composites is not a simple process compared to that for metals
Composites do not have a high combination of strength and fracture toughness compared to metals
Composites do not necessarily give higher performance in all the properties used for material selection: strength, toughness, formability, joinability, corrosion resistance, and affordability
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Fracture Toughness of Composites
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Material Selection Parameters
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Factors vs Mechanical Performance
Fiber Factors
Length
Orientation
Shape
Materials
Matrix Factors
Fiber-Matrix Interface
Chemical bonding
Natural roughness
CTE of matrix
Reaction bonding
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Corrosion11%
Aircraft -1%
Construction20%
Consumer7%
Electrical10%
Marine11%
Appliance -5%
Other- 3%Transport
32%
2000 U.S. Composites Shipments
Source: CFA (June 2000)Est. 3.9 Billion Lbs of Shipments in 2000
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Types of Composites
Particulate composites
Flake composites
Fiber composites
Nanocomposites
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Polymer Matrix Composites
Polymer matrix composites
Polymer: epoxy, polyester, urethane
Fiber: graphite, aramids, boron
Drawbacks of PMCs
Low operating temperature
High coefficients of thermal
High moisture expansion
Low elastic properties
Mechanical properties of PMCs
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Mechanical Properties of PMCs
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Mechanical Properties of Fibers
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Manufacturing of Glass Fibers
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Manufacturing of Carbon Fibers
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Role of Matrices in Composites
• Transfer stresses between the fibers
• Provide a barrier against an adverse environment
• Protect the surface of the fibers from mechanical abrasion
• Determine inter-laminar shear shear strength
• Determine damage tolerance of composites
• Determine in-plane shear strength
• Determine the processibility of composites
• Determine heat resistance of composites
Model of unidirectional composite
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Common Matrices in PMCs
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Thermoplastics and Thermoset
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Sheet Molding Compounds (SMC)
• Matrix: polyester resin, vinyl ester resin
• Used for compression molding process
• SMC - R: randomly oriented discontinuous fibers
• SMC – CR: containing a layer of unidirectional continuous fibers
• XMC: containing continuous fibers arranged in an X pattern
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Manufacturing of SMC
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Prepreg Manufacturing
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Bag Molding Process/Autoclave Process
prepreg (B-stage resin)
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Filament Winding Process
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Analysis of Laminated Composites
ME 582 Advanced Materials Science • Department of Mechanical Engineering Dr. Jan Gou
Hybrid Laminates
Interply hybrid laminates
Intraply hybrid laminates
Interply-intraply laminates
Resin hybrid laminates