MODELING COMPOSITE PRESSURE VESSELS MANUFACTURED BY AUTOMATED FIBER PLACEMENT FOR LH2 AIRCRAFT

Kurzfassung

Composite pressure vessels manufactured by Automated Fiber Placement (AFP) are a promising solution for upcoming hydrogen airplanes. Significant weight reduction over metal tanks and high flexibility in fiber placement compared to filament winding are just a few advantages. In regards to modeling, AFP Tanks are complex. For Finite Element (FE) Modeling several AFP characteristics have to be considered. AFP courses can be designed highly flexible: each layer can vary differently from the geodesic path and utilize user-defined start and end locations. Another aspect is called tow cutting creating triangular shaped gap patterns on the doubly curved dome shape of the vessel. For assessing different composite layups and dome shapes an effective way of structural modeling is required. Thus, this work presents a method to generate FE Models of thin-walled composite pressure vessels manufactured by AFP. In the method the tank structure is divided into sections. Homogenization methods dependent on the gap pattern are used to calculate material properties for each section. The method can consider different course trajectories, such as geodesic path, constant angle or user-defined path to determine local fiber angles. A convergence study is carried out as well as sensitivity studies on influential parameters of the method. The work concludes with a simulated tank test as an example. Consequently, a validation case is planned to further assess the method's accuracy and applicability. The results will be used to calibrate and validate the approach.