The curing of a polymer composite is an exothermic process during which the material undergoes thermal expansion and chemical shrinkage due to the phase transformation. The study of curing process is crucial as it alters the material properties and produces residual stresses causing warping in components. These residual stresses are generally predicted by modelling the polymer composite as a viscoelastic material throughout the curing process [1]. Most of the existing studies do not account for the evolution of mechanical properties during curing as the polymer undergoes phase change from liquid to solid state [1]. Heinrich et al. developed a constitutive relationship for curing by modelling the uncured polymer as an ideal fluid and the cured polymer as an elastic solid [2]. The objective of present work is to improve the stress predictions by modelling the cured polymer as a viscoelastic material and uncured polymer as an ideal fluid. The model will also account for the evolution of thermo-physical properties during curing. An in-house coupled 3-D nonlinear finite element framework is developed to capture the thermo-chemical-mechanical response. The thermo-chemical module captures the evolution of temperature and degree of cure, which act as an input to the mechanical module which captures the evolution of residual stresses during curing. The proposed model’s predictions are also compared with the existing models and available experimental data. The current investigation is useful to optimize the process of fabrication of polymer composites, minimizing component rejections. REFERENCES [1] Yuan Z., Wang Y., Yang G., Tang A., Yang Z., Li S., Li Y., Song D., Evolution of curing residual stresses in composite using multi-scale method. Composites Part B: Engineering, Vol. 155, pp. 49-61, 2018. [2] Heinrich C., Aldridge M., Wineman A.S., Kieffer J., Waas A.M., Shahwan K.W., Generation of heat and stress during the cure of polymers used in fiber composites. International Journal of Engineering Science, Vol. 53, pp. 85-111, 2012.