Lightweight 3D carbon fibre reinforced composite lattice structures of high thermal-dimensional stability

In this study we develop and investigate a novel lightweight 3D composite lattice structure of high thermal -dimension stability, i.e., with zero coefficient of thermal expansion (CTE). First, a base planar composite lat-tice, comprised of a continuous carbon fibre reinforced polyamide (CCF/PA) central cross-lattice and four short carbon fibre reinforced polyamide (SCF/PA) outer strips for good thermal-dimensional stability, was additively manufactured in a rotated cross-ply sequence, i.e., at alternative 45 degrees/135 degrees. Experiments were performed to validate an effective numerical model where effective thermo-elastic properties were applied; the results proved the effective numerical model's accuracy and efficiency. Second, a novel 3D composite lattice structure was developed and calculated, exhibiting a negative effective CTE at-0.18 x 10-6/degrees C, based on the planar com-posite lattices. Then, parametric analysis was performed to investigate the effects of geometric parameters on the effective CTE and density. Finally, lightweight optimisation was conducted with a constraint of effective CTE as zero. The results show that the optimal 3D composite lattice structure can achieve an effective density of 0.0266 g/cm3 and an effective CTE of 0.0173 x 10-6/degrees C, which are 15.3 % and 90.39 %, respectively, improved over the initial 3D composite lattice. The outcomes proved the effectiveness of the design in achieving a novel lightweight 3D composite lattice structure of high thermal-dimensional stability.

Automated summary

In this study, a novel lightweight 3D composite lattice structure with zero coefficient of thermal expansion (CTE) was developed and investigated. A base planar composite lattice was first manufactured using continuous carbon fiber reinforced polyamide (CCF/PA) and short carbon fiber reinforced polyamide (SCF/PA) strips. A numerical model was validated and used to calculate a 3D composite lattice structure with a negative effective CTE of -0.18 x 10-6/degrees C. Parametric analysis and optimization were performed to improve the density and CTE of the lattice structure. The results showed significant improvements in both parameters, demonstrating the effectiveness of the design in achieving high thermal-dimensional stability.