Chapter 4 L10 Flashcards
What is a composite material?
- It is a combination of at least 2 materials with different mechanical and chemical properties
Name some natural composites
Wood, muscles, bones
What elements make up a Composite ?
A Matrix material (base material) and a Reinforcement material
How can the reinforcment material in a composite be distributed?
- Layer composites
- Particle composites
- Fiber composites
- Inflitrated composites
“Notes”
What are the main mechanical benefits of using composites?
- Low density and leightweight
- Adjustment of mechanical properties
Describe reinforcing fibres
- Function: Increasing strenght & stiffness of the composite
- Typical materials: Carbon, Glass, Aramid
- Use: Single or multive fibers inside a material
Advantages and disadvantages of carbon fibres
+ : High strength / Low density
- : High costs
Advantages and disadvantages of glass fibres
+ : Good chemical resistance
- : High thermal expansion
Advantages and disadvantages of aramid fibres
+ : High tensile strenght
- : Low compressive strength
Describe the matrix of a composite
- Function: It gives the shape of the composite, protects and transfers the loads to the fibers
- Typical materials: Polymers
Advantages and disadvantages of thermosets
+ : Performance at high temperatures
- : Melting after curing not possible
Advantages and disadvantages of elastomers
+ : High creep resistance
- : Difficult recycling
Advantages and disadvantages of thermoplastics
+ : Melteable after curing
- : Sensitive to creep
What assumptions are made during mechanical modelling of a composite material?
- Constant cross sectional areas
- Imperfections are negelcted
What is a mutliscale approach?
It considers both small scales and big scales (molecular levels and complete structure level)
What is Elastic homogenization used for?
It is a way to predict the stiffness of a composite based on the E of the martix and reinforcement
What are RVE, ROM, FVF?
“Notes”
What is a laminate?
Strucutre made of different layers. Each layer may have different arrangement of fibers
Name some assumptions for laminate theory
Small displacements and quasi-homogeneous layers
What are typical failure modes of composite materials?
Fiber, Matrix or Interface dominated failure
Name some composite manufacturing technologies
Prepreg, AFP or Pultrusion
What are typical industrial applications for composites
Automovile and Aerospace sectors
