In-plane elastic properties of the Euplectella aspergillum inspired lattice structures: Analytic modelling, finite element modelling and experimental validation

This study develops new analytical models for the two Euplectella aspergillum inspired 2D lattice structures. The analytical models for normal modulus and Poisson's ratio are derived using Castigliano's second theorem, where plate-like elements were considered Euler beams, subjected to stretching and bending deformations. The derived equations show the dependence of elastic properties on design and base material properties. The in-plane elastic properties are also simulated using finite element modelling (FEM). Furthermore, the theoretical parametric analysis is also carried out to investigate the effect of design variables on the elastic constants. Lastly, the modeled lattice structures are fabricated using the fused filament fabrication (FFF) process and used to validate the analytical and finite element results experimentally. The developed analytical models show good agreement with FEM and experimental results for effective modulus and Poisson's ratio. The bio-inspired structures showed a wide range of elastic properties and suggested their applications in energy absorption and lightweight structure designs.