Long-fiber reinforced thermoplastic composite lattice structures: Fabrication and compressive properties

Recyclable lightweight materials with advanced processing techniques are essential for the sustainable development of future transportation. Thermoplastic composites lattice structures were developed to meet this demand. An additive manufacturing method is presented here to fabricate such lattice structures by reversible assembly of several long-fiber reinforced thermoplastic composite parts (LFTCPs) which were economically processed by injection molding. The resulting thermoplastic lattice structures (density of 30 kg·m⁻³) assembled with different sequences and connections are structurally evaluated and compared. Out-of-plane compression tests revealed that their mechanical properties were more sensitive to the presence of the connections rather than their assembly sequence, although their structural failure mode was always brake of inclined struts followed by fracture of the horizontal struts. Potential solutions to the problem of internal stresses, induced during assembly, are also explored by designing novel LFTCPs. The novel fabrication route for thermoplastic lattice structures will improve the prospects for their industrial application.