Analysis of lattice structure with pre-mode configuration

This study introduces a design methodology for architected lattice structures utilizing pre-mode shape configurations inspired from buckling modes. Two families of hexagonal and parallelogram unit cells are developed with pre-mode-oriented struts that deviate from classical straight-beam configurations. These pre-mode geometries are parametrically controlled through curvature amplitude without altering node positions, enabling fine-tuning of mechanical behavior. A robust nonlinear beam theory is developed incorporating a 3D deformation field and hyperelastic constitutive model based on the Generalized Mooney-Rivlin formulation, capturing large strain effects in thermoplastic polyurethane (TPU) lattices fabricated via FDM. Micro- and macro-mechanical finite element models are formulated to investigate the effects of geometrical modes on stiffness, Poisson's ratio, and energy absorption. Experimental and numerical analyses reveal that mode-shaped configurations significantly influence both anisotropy and deformation mechanisms. Pre-mode geometrical parameters induce directional dependency and localized deformation, enabling tailored mechanical responses such as auxeticity and controlled collapse patterns. Validation through uniaxial tensile and compressive tests confirms excellent agreement with numerical predictions, demonstrating that pre-mode designs provide a powerful framework for engineering energy-absorbing and stiffness-tailored lattices in advanced manufacturing applications.