Cure history dependence of residual deformation in a thermosetting laminate

The cure history dependent residual deformation in a thermosetting composite laminate was investigated using bi-lamina strip sample with [0/904] stacking-sequence. The samples were subjected to cure cycles with different heating profiles. Significant dependence of the residual strip deflection was found to relate to (i) the interaction of thermal expansion and cure shrinkage of resin and (ii) dependence of resin modulus development on cure strain rate. The lamina constitutive model was proposed to include cure induced shrinkage and composite hardening during cure. The model was calibrated following the single and multiple ramps cure cycles and applied to a number of two hold stage cure cycles with constant maximum temperature. The heating ramp of the cure cycle was varied allowing decreasing the residual deformation at ambient conditions after cure. The presented methodology can be applied for designing the cure cycle to reduce the amount of residual deformation in composite materials from manufacturing.