ABSTRACT

Most materials change their dimensions 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

(10.1)

where

∆ε

is the increment of strain measured for an unconstrained material subject to a temperature change,

T. For an orthotropic composite lamina under plane deformation, Equation (10.1) becomes

(10.2a)

(10.2b)

where

∆ε

and

∆ε

are the thermally induced strains in the principal material directions.