Effects of tool‐embedded dielectric sensors on heat transfer phenomena during composite cure

Abstract The present study examines the effects that placement of tool‐mounted dielectric sensors in the composite cure assembly has on the local thermal and degree‐of‐cure fields. A nonlinear heat transfer model, incorporating appropriate thermoset cure and thermal property submodels, is used to simulate the cure of carbon and glass composites of various thicknesses. The model is validated against experimental data obtained during the cure of composite samples in a resin‐transfer molding tool. The results of the simulations show that embedding a sensor can have a significant effect on the thermal field, because of the thermal conductivity mismatch between the metal tool and the sensor substrate material. In the heating‐up stage of the cure profile, sensors embedded in the heated tool side intensify thermal gradients, which causes a corresponding lag in the progress of the reaction in the area adjacent to the sensor. Exothermic effects are also intensified by the sensor presence, especially in the case of thick composite curing. These results suggest that control strategies based on the utilization of embedded sensors should take these effects into account. POLYM. COMPOS., 28:139–152, 2007. © 2007 Society of Plastics Engineers.