Investigation of process induced warpage for pultrusion of a rectangular hollow profile

A novel thermo-chemical–mechanical analysis of the pultrusion process is presented. A process simulation is performed for an industrially pultruded rectangular hollow profile containing both unidirectional (UD) roving and continuous filament mat (CFM) layers. The reinforcements are impregnated with a commercial polyester resin mixture (Atlac 382). The reactivity of the resin is obtained from gel tests performed by the pultruder. The cure kinetics parameters are estimated from a fitting procedure against the measured temperature. The cure hardening instantaneous linear elastic (CHILE) model is adopted for the evolution of the resin elastic modulus using the temperature-dependent elastic response provided by the resin supplier. The numerical model predictions for the warpage trend at the end of the process are found to agree well with the warpage observed in the real pultruded products. In addition, the calculated warpage magnitude is found to be in the measured range of warpage magnitude for the manufactured part.