Design of thermoset composites for high-speed additive manufacturing of lightweight sound absorbing micro-scaffolds

Non‐Planar Multiprocess Additive Manufacturing of Multifunctional Composites

“…Thus, the abradable thermosetting 0GM12FS formulation was developed by adding up to 12 wt% hydrophobic fumed silica (FS) (CAB‐O‐SIL TS‐720, Cabot, USA) to the neat resins (i.e., no GM content) of the commercial material, which was inspired by the previous work. [ 38 ] The 0GM12FS formulation was then prepared by mixing part A and B individually with 12 wt% of FS using the speed mixer at 2750 rpm and 30 s for three cycles. Both filled parts were then mixed together at the weight ratio of 94:100 (part A:part B) using the speed mixer at 2750 rpm for 30 s for one cycle only.…”

“…Viscosity measurements for $$\dot{\gamma }$$ > 10 0 s −1 were excluded from the fit due to material instabilities occurring in the rheometer. [ 38 ] The material's process‐related apparent viscosity η app at high shear rate was measured using capillary rheology method at room temperature for process‐related apparent shear rate $${\dot{\gamma }}_w$$ > 10 3 s −1 . [ 48,62 ] Results for η and η app were fitted using a power law model η = K $$\dot{\gamma }$$ n −1 .…”

“…[33][34][35][36] Our previous work demonstrated that small-scale DIW (i.e., few cm) of a thermosetting composite has potential for producing fine abradable microscaffolds featuring sound absorption functionalities in the frequency range of 500 to 6000 Hz. [37,38] Microscaffolds are a type of micro-scale, 3D periodic filaments stacking structure (e.g., with layer orientation at 0-90°). However, scaling these particular multifunctional composite microscaffolds into actual aircraft components is a challenging task because of the usually slow printing speed and the long printing time associated with such a complex non-planar, high-resolution structure, and the need to print the actual coating on a non-planar structural aircraft component.…”