Lightweight, High Performance Composites – What is a Composite Material?

Question: What is a composite?

Answer: One could write endlessly about this topic, but I’ve provided some basic information and a few FAQs to get you started.

Composite:

“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. One constituent is called the reinforcing phase and the one in which it is embedded is called the matrix. The reinforcing phase material may be in the form of fibers, particles or flakes. The matrix phase materials are generally continuous." Kaw, Autar K. Mechanics of Composite Materials.Boca Raton, FL: Taylor & Francis, 2006. Print. Page 2.

In other words

Composite = Matrix + Reinforcement

If you want an analogy, imagine an ice cube with numerous toothpicks embedded inside. The ice is the matrix and the toothpicks are the reinforcement.

Below I have noted some common types of reinforcement and matrix.

Reinforcement Phase 

Types of Reinforcement	Relevant Materials	Image Examples
Particulate	Aluminum, Silicon Carbide	Microscopic view of Particulate Reinforcement Source RVE of a Particulate Reinforced Composite RVE of Another Particulate Reinforced Composite
Flake	Glass, Mica, Aluimnum, Silver	Chopped Carbon Fiber Source Mica Flakes Source
Fibers	Glass, Graphite/Carbon, Aramid/Kevlar	Long Continuous Fibers in a Carbon Mat Source Short Chopped Fibers Source Microscopic View of Glass Fiber Polymer Matrix Composite Laminate Source Microscopic View of Short Chopped Fiber Polymer Composite Source

 

Matrix Phase

Types of Matrix Phases	Composite Classification	Relevant Materials
Polymer	Polymer Matrix Composites (PMCs)	Epoxies, phenolics, acrylic, urethane, and polyamides
Metal	Metal Matrix Composites (MMCs)	Aluminum, magnesium, titanium, cobalt
Ceramic, including Carbon	Ceramic Matrix Composites (CMCs)	Carbon, Silicon Carbide, Alumina, Mullite

Carbon Fiber Polymer Matrix Composite Source

Glass Fiber Polymer Matrix Composite Source

 

How would you analyze, through simulation, particulate, nano, or short fiber composites? These are a bit more challenging to analyze since the material is best defined as anisotropic. You can use an FEA program such as Marc or MSC Nastran, but you would need to supply your FEA with anisotropic material data provided by Digimat.

Short Fiber Polymer Matrix Composite
Short Fiber Polymer Matrix Composite

 

Micromechanical Analysis
The last two questions were regarding macromechanical analysis. Now, given the need to perform micromechanical analysis, how would you analyze composites through simulation? You can use Digimat to determine the constituitive behaviors of composites all before the first physical test.

Microscopic View of Glass Fiber Polymer Matrix Composite Laminate Source

MicroscopicRepresentative Volume Element Ready to Be Analyzed

Do you have a question? Email me at .