Effect of the length of basalt fibers on the shear mechanical properties of the core structure of biomimetic fully integrated honeycomb plates

To promote the application of basalt fibers, this study investigated the effect of different fiber lengths (L_f) of short basalt fibers on the shear mechanical properties of biomimetic fully integrated honeycomb plates, which were manufactured with a short basalt fiber-reinforced epoxy resin polymer composite, using a double shear experiment. The results showed that the fully integrated honeycomb plate with an L_f of 6 mm had the best mechanical properties, and the shear modulus of the fully integrated honeycomb plate with an L_f of 9 mm was close to that of the former. However, the shear strength and energy dissipation capacity of the 9 mm-fiber specimen were worse than those of the 6 mm-fiber specimen, and its energy dissipation capacity was even less than that of the fully integrated honeycomb plate with an L_f of 3 mm. The intrinsic mechanism underlying this effect is that the thicknesses of the laminates and honeycomb walls of the fully integrated honeycomb plate are smaller than the lengths of the short fibers, and the corresponding structure is complicated. However, for short basalt fiber-reinforced epoxy resin polymers, the larger the L_f is, the faster the growth rate of the shear elastic modulus, which, to some extent, eliminates the adverse effects of the longer L_f. Therefore, the shear modulus of the fully integrated honeycomb plate with an L_f of 9 mm was close to that of the fully integrated honeycomb plate with an L_f of 6 mm. This research provides a useful reference for promoting the engineering applications of basalt fibers and fully integrated honeycomb plates.