Principles of Composite Mechanics

Basics

• A composite material is a combination of two or more materials. They complement each other to create a better material. The combination can usually be seen macroscopically, as the eye can distinguish the combined materials easily. The basic mechanics governing this combination is that materials should bond together flawlessly in relatively large chunks, without the need for microscopic alterations.

Components

• There are two basic components of a composite material: reinforcement and matrix. The reinforcement material can be particles, flakes, fillers or fibers, while a matrix can be metal, ceramic or polymer. The matrix holds the composite materials together, while the reinforcement adds better mechanical properties to the composite material. One basic example of a composite material is poured concrete. It combines cement, stone, water and sand to create a stronger material.

Mechanics of Composite Materials

• There are several principles and reasons why composite materials are created: economical, less weight, better strength and stiffness, exceptional surface properties, better thermal properties and more efficient electrical properties. There is no specific composite material in existence today that can satisfy all these desired outputs, but typical composite materials today usually include at least one of these advantages. Composite mechanics plays a major role in determining material quality and whether it will have better and more efficient properties than their "uncombined" components.

Fabrication

• Fabricating composite materials typically involves a molding process. First, the reinforcement material is laid down in a mold and the matrix (in a semi-liquid or liquid form) is poured or sprayed onto the reinforcement material. The reinforcement material, for example, fiber, can either be randomly arranged or in a continuous and ordered formation. The combined materials are then heated to solidify the matrix. Some advanced composite materials also get covered with a polymer for added strength and durability; however, this process can be costly and is only used in select applications, such as making an aircraft's body panels.