Effect of heterogeneity on thermal warping of l-PBFed GF/PEEK composites

Glass fiber (GF) reinforced poly-ether-ether-ketone (PEEK) composites produced via laser powder bed fusion (l-PBF) have become a promising material option in the field of spacecraft structure manufacturing. However, the thermal warping of l-PBFed GF/PEEK composites is found to be a challenging issue in engineering practice. In the present study, the effect of heterogeneity on thermal warping deformation of l-PBFed GF/PEEK composites is investigated for space applications. Thin-wall strip specimens with fixed ends are subjected to thermal loading to simulate the constraints experienced by external plates in outer space. The thermal warping of l-PBFed GF/PEEK composites fabricated along different directions and with varying fiber contents are compared, revealing that increased fiber content and improved fiber alignment could mitigate the issue of thermal warping. Further, a computational tool integrating the constitutive relations of the constituents with micro-scale finite element analysis (FEA) models is developed for thermal warping simulation. The thermal constitutive relations of the constituents are assessed, with temperature-dependent stress-strain curves measured for l-PBFed PEEK. The thermal mechanical behavior of l-PBFed PEEK is characterized using the Tschogel’s yield criterion, a non-associated flow rule, and a Kriging surrogate model. The FEA models of l-PBFed GF/PEEK composites are established using a micro-scale reconstruction algorithm. The effect of heterogeneity on the thermal warping of l-PBFed GF/PEEK composites is elaborated using the computational tool, providing critical insights into the structure-property relationships of l-PBFed GF/PEEK composites.