Comparative study on the effect of cure parameters on residual deformation for thermoset composite laminates

Abstract

Process-induced deformation in composite laminates usually occurs during the curing process and is strongly dependent on the cure parameters. To study the influence of the cure parameters on the warpage deformation, an experimental study was carried out with different heating rates and first dwell times. The full-field process-induced deformation was captured by contactless 3 D scanning system to validate the numerical method. Second, a multi-scale thermo-viscoelastic modeling technique was employed to predict the process-induced deformation. The results showed a good agreement between the simulation and experimental deformation, which demonstrates the effectiveness of the numerical model. The influence of six different cure parameters of the vacuum bagging process on the warping deformation and residual stress were considered in the numerical study. Knee points were found on the curves depicting the influence of cure parameters on the maximum residual deformation. Within the manufacturer’s specified range, a slower heating rate of 1.5°C/min reduced the process-induced deformation by 7%, while the other parameters affected the process-induced deformation by less than 1.4%. Meanwhile, the residual stress was also reduced with a slower heating rate. Consequently, a lower heating rate is suggested to reduce both the process-induced deformation and the residual stress for thin parts or the zero-bleeding process.