Composites part 1 - a Flashcards
What is a composite?
Two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct within the finished structure.Overall properties of the composites are superior to those of the individual components. Design goal: obtain a more desirable combination of properties (principle of combined action). E.g. low density and high strength.
Why are metals and ceramics/polymers not good enough sometimes?
Metals have excellent strength and toughness combinations but they are quite dense and many corrode in use. Ceramics and polymers are lighter and more corrosion-resistant, but often lack toughness
Examples of composites in nature?
Wood, bamboo, bones, muscles, tissue
What are the different materials in concrete?
Cement, stones and steel armaments
What are bricks and pottery reinforced with?
Plant fibers and straw
Definition of an engineering composite?
multi-phase (2 or more) material that is artificially engineered
What are the two phase types in a composite?
(1) Matrix - is continuous filler material
(2) Dispersed (particulate/fiber) - is discontinuous and surrounded by matrix
What is the purpose of the matrix phase?
Transfer stress to dispersed phase (protect dispersed phase from environment)
What are the different materials groupings in terms of matrix materials?
MMC - metal matrix composite
CMC - ceramic matrix composite
PMC - polymer matrix composite
What are the different classifications of composites?
- Particle reinforced
- Fiber-reinforced
- Structural
What are the different types of particle reinforced composites?
- Large particle
- Nanoscale dispersion
What are the different types of fiber-reinforced composites?
- Continuous (long-aligned)
- Discontinuous (short) –> aligned or random orientation
What are the different types of structural composites?
- Laminates
- Sandwich plates
What are laminates?
Stacked and bonded fiber-reinforced sheets
What is a benefit of laminates?
Balanced in-plane stiffness
