Structural and Aeroelastic Evaluations of Wings with Lattice-Based Mechanical Metamaterials

Abstract

Mechanical metamaterials are artificially manufactured materials with properties, which cannot be obtained from natural materials, consisting of deliberately designed microscopic internal structures. Those conceptual artificial materials are ready to fabricate with the advent of the additive manufacturing technology. Recently, a class of metamaterials has been actively studied due to its potentials for performance improvements and extensions of structural capabilities. Mechanical metamaterials can exhibit exotic material characteristics or macroscopic behaviors attributed to their micro/mesoscale internal structural designs such as truss or porous in μm/mm order in addition to material properties constructing the structural components. In this paper, structural and aeroelastic characteristics of wings integrated with lattice-based mechanical metamaterials are studied. In order to efficiently model such wings, a computational homogenization method for lattice-based mechanical metamaterials capturing characteristics of a representative unit cell is implemented. By assuming periodic distributions of the mechanical metamaterials in the wing structure, a unit cell of the periodically distributed structure is modelled as representative finite elements. The equivalent stiffness properties of the unit cell are calculated based on a computational homogenization procedure. The obtained equivalent stiffness properties are used to perform a multi-scale structural and aeroelastic simulations of a wing with the lattice-based mechanical metamaterials by modelling the mechanical metamaterials as equivalent solid substructures. In the current study, simple rectangular thin wings integrated with the lattice-based substructures are designed, and the structural/aeroelastic performance of the wings are also explored using the multiscale analysis method to demonstrate the feasibility and potentials of such wings.