Forming Simulation of Thick AFP Laminates and Comparison with Live CT Imaging

Automated fiber placement (AFP) process can be used to manufacture laminates by laying up unidirectional slit tapes along a desired path and placing multiple layers on top of each other. Usually, the slit tapes are placed direct onto the tooling to attain the final part geometry. Alternatively, the laminate can be built up on a planar substrate and can be subsequently formed into the final shape. This kind of processing allows manufacturing highly curved parts, which may not be possible with the direct placement. In the present work a forming simulation of thick AFP laminates is developed to predict the tapes’ orientations and delamination as well as transverse tape spread-ups and separations during the forming process. The simulation model is built up through the material characterization experiments. Validation is performed comparing the results of the simulation vs. the experimental forming on two generic geometries. An optical inspection is made on the external layers of the laminates. In a second step, live computer tomography (CT) scans are used to inspect the tapes within an AFP laminate during forming of an L- and a Z-flange. Tapes re-orientation, gaps and tapes widening are observed experimentally and compared to the simulation results. The simulation is capable to predict the tows orientation and provides indicators concerning the tows spread-up and separation.