Sürekli elyaf takviyeli termoplastik kompozitlerin sonlu elemanlar analizi

In recent years, polymer matrix composites have been preferred much more than traditional materials, such as metal, especially in the aerospace industry. The interest in thermoplastic composites is increasing day-by-day due to certain advantages, such as a very short process time when compared to thermoset composites, and the production of more durable integral part due to its weldability and recyclability. One of the most important thermoplastic composite part production methods is thermoforming. Although it has several advantages, such as a low cycle time and the easier production of complex parts, it is not yet widely used in the aerospace industry, where part accuracy is at the highest level. The aim of the study was to develop a method for manufacturing defect-free thermoplastic composite parts by means of the thermoforming. First, optimum process parameters were determined by finite element analysis performed via Ls-Dyna. Some of the mechanical properties of the fabric material were obtained through characterization tests in order to obtain more realistic results. At the same time, the first trial composite part with thermocouples was formed with the intent of standardizing the processing times for the experimental studies. Despite the determination that there were no shape distortions, it was observed that the surface quality was quite bad. In order to eliminate these defects, different spring configurations were developed and blank composite plate structures were designed. Thermoform analysis was then performed using the optimum parameters for all of the different configurations. The part with the U-beam structure was thermoformed in accordance with the analysis. It was seen that the experiments made for the validation were in very good agreement with the analysis. Comparisons were made of the fiber orientations and deformations. The effect of the homogeneous tool temperature, blank plate geometry, and gripper configurations on the manufacturing defects was evaluated. Experimental results showed that the homogeneous tool temperature is of great importance in thermoforming. Finally, it was concluded that none of the material models were sufficient to take into account all of the deformation mechanisms and deformations that occurred during and after the process.