Models for heat transfer in thermoplastic composites made by automated fiber placement using hot gas torch

This paper presents a 2D transient heat transfer model, which has been developed using finite difference method for composites made by AFP process with a hot gas torch. The model includes non-linear distributions for the hot gas/air temperature and convection coefficients in the vicinity of composite, which are essential to increase the accuracy of the model. It is necessary not to just obtain the accurate maximum temperature of composite, but more importantly, the thermal gradients in the composite laminate. These thermal gradients have strong influence on the development of residual stresses and deformation in thermoplastic laminates made by AFP. In addition, the temperature dependencies of the material properties and inter-layer thermal contact resistance have been taken into account. Comparison of the experimental and theoretical results indicates how the accuracy of model increases by considering the above mentioned aspects.