Thermoelastic Behavior of PEEK Thermoplastic Composite during Cooling from Forming Temperatures

In the forming of advanced thermoplastic composite structures, the stresses generated during cooling have a profound effect on the distortion and strength of the formed parts. In this paper, the thermoplastic behavior of a PEEK matrix thermoplastic composite during cooling was investigated. A procedure for determining temperature-dependent thermal expansion coefficients using off-axis composite specimens was introduced. A simple thermoplastic constitutive model was used to calculate thermal stresses during cooling. Based on this model, an explanation of a strong scissoring effect on the thermal expansion behavior of symmetric [± ⁴⁵ ] _ns laminates and a calculation of warping in a non-symmetric laminate were presented