Numerical analysis of the temperature profile during the laser-assisted automated fiber placement of CFRP tapes with thermoplastic matrix

In this study, a thermodynamic model of a laser-assisted automated thermoplastic fiber placement process is developed and validated. The main focus is on modeling the heat transfer into the composite with a laser heat source, the thermal properties of the tape, and the resulting heat distribution in the part, the mold, and the compaction roller. A new integrated analytical method is presented to calculate the energy input of the laser based on the geometric boundary conditions, including first-order reflection and laser shadow. The carbon fiber/polyethersulphone tape is modeled by combining literature properties of carbon fiber and matrix as well as based on experimental data of the tape itself. Also a thermal contact resistance between the tape layers is modeled based on a literature model and own experimental measurements. The created model is discretized and implemented in a 2-D finite difference code. With the help of this simulation, the temperature distribution is calculated during layup. The influence of a possible thermal contact resistance between the composite layers is investigated. Furthermore, an experiment with a thermoplastic fiber placement machine from Advanced Fibre Placement Technology GmbH (AFPT) was conducted in order to evaluate the simulation. The simulation and the experiment show a good agreement and prove that thermal contact resistance between the layers is negligible for the investigation process.