ABSTRACT
The dimensions of most materials change as the temperature is changed. Thermal expansion is defined as the change of dimensions of a body or material as a result of a temperature change. Such a property is very important in the application of composite materials in structures that undergo temperature changes, such as engine parts and space structures. The material property constant describing this phenomenon is the coefficient of thermal expansion (CTE), indicated by the symbol α and defined as
α =
∆ε ∆T
(13.1)
where Δ ε is the increment of strain measured for an unconstrained material subject to a temperature change ΔT. Thus, the in-plane thermal deformations of an orthotropic composite lamina are, from Equation (13.1),
T α =
∆ε ∆
(13.2a)
T α =
∆ε ∆
(13.2b)
where 1∆ε and 2∆ε are the thermally induced strains in the principal material directions over the temperature interval ΔT.
