Two-dimensional and transient thermal model of the continuous tape laying process

Abstract

The purpose of this study is to simulate the two-dimensional, transient and continuous heat transfer during the thermoset Automated Tape Laying (ATL) process. The heat transfer analysis is coupled with a cure kinetics model of the thermoset prepreg tapes used for the process. Unlike most studies, the process is modelled in a Lagrangian framework and is based on the realistic boundary conditions of the ATL such as the stepwise laying down of the tapes. The model results provide information about the temperature values at any time and any location inside the thermoset composite tapes. The temperature simulation results of the model were compared with experiments. Three layers of unidirectional prepreg tapes were laid down on an aluminium mould by the TU Delft ATL machine. The experimental results were obtained from thermocouples and pyrometers placed at various locations in the lay-up and on the robotic head, respectively. The comparison between the numerical and experimental results generated three main findings. First, the pyrometer values and the thermocouple values provide insight into how important is the contact between the mould and the first layer. Secondly, the temperature fading out which was witnessed by the thermocouple measurements and could not entirely be captured by the model provided information about the influence of the heat transfer coefficients on the model predictions. Thirdly, the peak temperature magnitudes of the numerical predictions appeared to generally compare well with the experimental results. Overall, the code can be used for different parameter values such as different line speed, heated length and power of the heat source and, can predict the temperature distribution inside the composite.