Multiscale design of coated structures with periodic uniform infill for vibration suppression
Bin Niu, Eddie Wadbro
Abstract
In this paper, a novel design strategy to minimize the dynamic compliance of a vibrating infill structure with a solid outer coating and a periodic uniform infill lattice is presented. The vibration of the linearly elastic infill structure is excited by time-harmonic external mechanical loading. The design optimization of the infill lattice is performed simultaneously with the topology optimization of the macroscale structure, which also includes the coating. Multiscale topological designs of infill structures are presented in numerical examples for different excitation frequencies, different limits on static compliance, different damping properties, and different boundary conditions. The results are obtained by the finite element method and gradient-based optimization using analytical sensitivity analysis, which is derived and presented in the fully discrete setting. The influences of excitation frequencies, static constraints, damping properties, coating thicknesses, and boundary conditions on the optimized macrostructures and microstructures are discussed in the numerical examples. In general, the optimized microstructures reflect the shape characteristics of the macrostructure configuration, where Kagome-like microstructures have been obtained in some examples. Moreover, in the optimized results the microstructures include more but finer structural members for the design optimized for low excitation frequencies.