Manufacturing and quality characterisation of pre-preg fibre-placed composite lattice structures

Abstract

Composite lattice structures (CLS) offer high performance and demonstrate significant mass savings in space structure applications. Local modifications of regular lattice designs have the potential to further improve the lattice performance. This research explored the micro-structural quality features of CLSs manufactured with pre-preg fibre-placement, and how quality is impacted by lattice modifications.
Modifications to a regular lattice for a representative case of an attachment point load are identified using a topology optimisation tool. Three lattice modifications techniques were identified: rib width variations, rib angle variations and additional ribs. A sample lattice with modifications was manufactured and evaluated by C-scan, CT techniques and micro-sections. An explanation of quality features in CLS is described and quantified using a presented characterisation model based on node transition waviness.
Using the presented explanation, a quantitative quality model was developed to relate lattice design geometry to manufactured quality for this process. The model was used to design and manufacture a second panel with improved implementation of lattice modifications. The quality model was improved and shown to explain more than 75% of all observed quality variation in the two panels with a linear regression. Future work and limitations the of the quality model are discussed.