Randomized CFRTP tape piece laminates in structural automotive applications

Sammanfattning: The automotive industry is facing big challenges in meeting the future environmental demands. To be able to meet these demands reduced vehicle weight is an important part. A thorough investigation was made to better get an idea of which demands the automotive industry makes in the question of lightweight materials and how far they have come in the matter. This thesis work has been performed on behalf of Oxeon AB to investigate the future for carbon fiber thermoplastics in big scale production of structural details in the automotive industry. And also to see how the material can be improved and make implementation easier by changing the materials good properties in one direction to equal and good properties in two dimensions. This is made by randomly spreading small and thin tape pieces made from carbon fiber reinforced thermoplastics to form an "organo sheet". The idea is that Oxeon AB shall make these "organo sheets" and then forward them to the automotive industry for pressing to final parts by adding heat and pressure. The most important part for this thesis work was to develop a method to spread out the pieces of carbon fiber reinforced thermoplastic tape to get a material with good two dimensional properties. Different methods to achieve this were carried out and the results were then compared with simulations for randomized tape pieces. The randomized tape pieces were then consolidated in a belt press to form an "organo sheet" and then plate pressed to form a material that simulated the end product, this to enable further evaluation of the mechanical properties. The results of both tests and simulations show that the randomization doesn’t solve the problem entirely because there will remain a slight difference between the two dimensions. The results of mechanical tests that were carried out shows that the plate pressed material have good prospects but enhancements are to be needed.