Overcoming aspect ratio detrimental effect of solid FE on free vibration by CUF 1D formulation

Solid finite elements, although widely used in structural mechanics, have significant limitations: aspect-ratio sensitivity, mesh dependency, and the need for highly refined discretizations. These issues lead to locking phenomena, poor convergence, and severe challenges in analyzing thin, slender, and laminated composite structures. To overcome these challenges, this work employs higher-order one-dimensional (1D) beam elements with three-dimensional (3D) capabilities, developed within the Carrera Unified Formulation (CUF). Instead of relying on full 3D elasticity formulations, it is shown that comparable accuracy can be achieved through refined 1D structural theories. These refined beam models are derived from 3D elasticity and can reproduce the solid’s response while dramatically reducing computational effort. The proposed formulation eliminates mesh sensitivity and delivers accurate, efficient analyses of isotropic and composite compact or thin-walled structures. The free vibration results demonstrate the clear computational and methodological benefits of CUF-based beam models, establishing them as a necessary and convenient alternative to traditional solid elements.