Thermal and Mechanical Stress Analysis

Mechanical stress analysis, treated earlier in this chapter, does not suffice for analysis of laminates that have been cured at temperatures different from the design operating temperature. In such cases, thermal stresses arise and must be accounted for. The concepts of mechanical stress analysis will be reiterated in this section along with the necessary modifications for thermal stress analysis. 

The three-dimensional thermoelastic anisotropic strain-stress relations are 

In both Equations (4.100) and (4.101), the six Oj are the coefficients of thermal deformation (expansion or contraction and distortion, I.e., shear), and AT is the temperature difference. In Equation (4.101), the terms CjjCXjAT are the thermal stresses if the total strain is zero. 

For plane stress on an orthotropic lamina in principal material coordinates. 

Note that the coefficients of thermal expansion affect only extensional strains, not the shearing strain. 

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