Resonance frequency prediction approach of lattice structure fabricated by selective laser melting

Abstract

Lightweight structures composed of a closed shell and internal lattice infill are highly desirable in satellites on account of their superior specific stiffness and buckling strength, which are brought about by the sandwich effect. These lattice structures can be fabricated by various additive manufacturing techniques, such as selective laser melting (SLM). However, the sub-millimeter-scale shell thickness and lattice strut diameter of the fabricated structure often deviate from the designed dimensions and lead to noteworthy discrepancies between the resonance frequencies of the fabricated structure and those of the initial design model. In this work, a bracket structure for a satellite is designed via topology optimization-based lattice infill approach and fabricated using SLM. A resonance frequency prediction approach based on X-ray micro-computed tomography and the stiffness equivalence is then proposed. Vibration tests are conducted to obtain the resonance frequencies of the fabricated structure. The prediction errors of resonance frequencies for the first three modes are less than 1%, whereas that of the traditional approach based on finite element analysis is as large as 14%.