ISBN 978-3-8439-5112-8

978-3-8439-5112-8, Reihe Ingenieurwissenschaften

Ralf Knott
Compaction Characteristics of Thermoset Automated Fiber Placement

219 Seiten, Dissertation Technische Universität München (2022), Softcover, A5

Zusammenfassung / Abstract

Automated Fiber Placement (AFP) is a well-established process in aerospace manufacturing with advantages regarding deposition accuracy and flexibility, reproducibility and potential lay-up rate compared to manual lay-up.

Process parameters are typically optimized regarding deposition quality and deposition rate - not taking into account ancillary processes like vacuum debulking, despite its influence on the overall process efficiency. Compaction is a key parameter of prepreg lay-up realizing laminate consolidation during deposition, additional vacuum debulking steps and during curing. The application of vacuum debulking is often based on trial and error, unquantified experience or manufacturing specifications for manual lay-up.

Automated lay-up offers the potential to improve compaction during deposition, allowing a reduction of additional debulking efforts.

In this thesis, the compaction characteristics of Thermoset Automated Fiber Placement (TS-AFP) and vacuum debulking are analyzed on laboratory and industrial full-scale. The influence of parameter variations on compaction behavior, mechanical performance and process efficiency is assessed.

On laboratory scale, the dominance of the process parameters temperature and pressure was identified. On full-scale, the influence of the AFP process on the deposition quality was proven. An optimized AFP process parameter set was developed and evaluated. Compaction during AFP processing was increased, while the need for separate vacuum debulking steps was eliminated. It was shown, that the optimized AFP process parameter set leads to equal or better mechanical performance compared to the benchmark including vacuum debulking steps. Process efficiency analyses showed that the proposed approach is economically competitive or superior to the benchmark for typical AFP use cases. The proposed optimization allows exploiting more of the potential of automated lay-up and opens new possibilities towards reduced curing efforts.