Concept Study on Optimized Auxiliary Material Designs and Application Techniques for Vacuum Bagging of Full-Scale CFRP Rocket Boosters

Abstract

Rising production rates in CFRP aerospace manufacturing cause a growing need for effectivity, reproducibility and enhanced quality standards. State of the art vacuum bagging for vacuum infusion technologies still involves a high amount of manual process steps. More efficient production technologies could increase the economic attractiveness of vacuum infusion processes for large aerospace structures. In the context of a research project, the German Aerospace Center (DLR), Augsburg and MT Aerospace GmbH, Augsburg develop design methods and application concepts for vacuum bagging on a full-scale CFRP rocket booster case. With a diameter of 3.4 m manual application of auxiliary materials is challenging in terms of deposition accuracy, reproducibility and reachability. Facing these challenges, a design method has been developed to generate near net-shape auxiliary materials with reduced wrinkling. As joining technology for auxiliary material packages, continuous ultrasonic welding has been selected and validated based on the suitability for vacuum infusion and out-of-autoclave curing. Manual application tests were conducted on a full-scale booster case demonstrator. The results show, that a developable shape design of the packages for the doubly curved dome sections allows best results with regards to wrinkle minimization and the complexity of the handling procedure.