Coefficient of thermal expansion

The coefficient of thermal expansion (CTE) is very directionally dependent with the CTE in the fibre direction being far smaller than that of the resin. Carbon fibres can have a negative CTE. CTE can be measured directly using thermomechanical analysis (TMA). Other methods such as laser interferometry or dilatometry are perhaps more commonly used. The CTE is measured on a unidirectional composite parallel and transverse to the fibre direction to obtain the relative CTE. Using laminate theory it is possible to determine the overall CTE of a multidirectional laminate.