Concurrent optimisation of structural topology and fibre paths for 3D printing of continuous fibre composites based on chain primitive projection

This study proposes a novel topology optimisation method based on the Geometry Projection Topology Optimisation method (GPTO) with the consideration of manufacturing constraints for the 3D printing of continuous fibre reinforced polymer composite structures. The proposed method uses connecting bars in chains to represent the continuous fibre filaments in the composite structure, as opposed to the use of separate bars as primitives. Thus, the method is termed as Chain Projection Topology Optimisation (CPTO), in which the chain-like primitives are equivalent to clusters of real printing paths. The 3D printing paths can be acquired by splitting the primitives evenly, which simplified the printing path design procedure to a great extent. In addition, manufacturing constraints can be easily imposed on the primitives, making it superior to density-based topology optimisation methods. An MBB beam, a cantilever beam, and a bridge case are optimised to demonstrate the CPTO’s efficiency. It was found that the designs by CPTO possess comparable mechanical properties when compared to those by the Solid Orthotropic Material Penalization (SOMP) method while guaranteeing the composite structures are suitable for 3D printing and contain less microscopic defects in the printed fibre filaments.