Вплив параметрів ребер жорсткості на вібраційні характеристки 3D друкованих стільникових балок з PLA-пластику

Additive manufacturing has provided a universal tool that enables the fabrication of three-dimensional objects of any complexity with minimal material consumption. Fused Filament Fabrication (FFF)-based 3D printing holds a dominant position in prototype and small-batch production of components. At the design stage, depending on the anticipated operating conditions, ensuring dynamic stability and strength under resonant vibrational excitation is crucial. A theoretical method for determining the frequency and modal spectrum of a component and an experimental verification of the obtained results have been developed for this purpose. This study investigates the vibration characteristics of honeycomb-structured PLA beams with dimensions (mm) 192.63×29.7×5.0 and an internal rib pitch of 5.0 mm, which were produced via 3D printing. The shell and rib thicknesses were set to be equal. The frequencies and mode shapes of five beam samples with 0.8 mm thick shell were experimentally determined using real-time electronic speckle pattern interferometry. The boundary conditions of the beam were free. The numerical vibration characteristics obtained by the finite element method were experimentally validated. The root-mean-square error of the calculated frequency values ranged from 0.6% for bending modes to 2.7% for torsional modes. Theoretically, the influence of shell and rib thicknesses in the range of 0.8 mm to 2.0mm on the vibrational behavior of the beam was studied. Reducing the rib (shell) thickness increases the natural frequencies of the honeycomb-structured beam. This dependence is more significant for torsional frequencies than for bending frequencies. Compared to a solid beam of the same external dimensions and material, the bending frequencies of the honeycomb beam increased by 5%–15%, while the torsional frequencies increase by 1.3 to 1.8 times, depending on rib thickness.