A Composite Material is made by combining two or more materials to give a unique combination of properties. More specifically, fiber-reinforced composite materials have two or more phases with substantially different physical and or mechanical properties, so that the final composite material has different properties than its constituent phases/materials.
The reinforcing fiber or fabric provides strength and stiffness to the composite, whereas the matrix - or resin - gives rigidity, continuity and environmental resistance. Reinforcing fibers are found in different forms, from long continuous fibers to woven fabric to short chopped fibers and mat. Each configuration results in different properties. Mechanical properties strongly depend on the way the fibers are distributed and aligned in the composite. Hence, design of composite structures allows tailoring the material and its properties according to the load conditions, characterizing fiber directions along the maximum designed stress. Long continuous fibers in the direction of the load result in a composite with properties far exceeding the matrix resin itself.
The advantages of composite materials are significant for NG application as they offer several advantages over traditional engineering materials:
It is possible to design fiber directions according to the required loads, improving structural efficiency.
Their specific strength is typically in the range of 3 to 5 times higher than that of steel and aluminum alloys, resulting in lighter designs.
Composites allow the possibility of in-service monitoring or online process monitoring with the help of embedded sensors.
The fatigue strength is much higher for composite materials especially for carbon/epoxy composites.
Composites offer superior corrosion resistance.
Composites get stronger with colder temperatures.
Composites offer increased design flexibility, with a wide choice of fiber, matrix materials and manufacturing techniques.