Component-wise vibration analysis of stiffened plates accounting for stiffener modes

This work has the aims to assess and compare the behavior of different finite element models in a free-vibration analysis of reinforced structures. The effects of the aspect ratio and cross-sectional shape of the stringers have been analyzed using both classical and refined FE. One- and two-dimensional classical finite element models, as well as refined one-dimensional elements, derived using the Carrera Unified Formulation, have been considered in an analysis of reinforced structures. The accuracy and efficiency of these models have been investigated. A three-dimensional model has been used as a reference solution. Three different modeling approaches have been considered in the present work. Two approaches are based on classical models provided by commercial tools: the first uses two-dimensional elements for both a plate and stringers, while the second uses two-dimensional elements to simulate the plate and the beam elements for the stringers. The third approach uses a refined one-dimensional model, based on the Carrera Unified Formulation. This refined one-dimensional model considers a variable kinematic displacement field over the beam cross section. In the present work, Lagrange polynomials are used to describe the cross-sectional displacement field. The use of a component-wise modeling approach allows the stiffeners to be modeled as independent entities. The component-wise approach was first assessed and convergence was then evaluated. The performances of these models in the analysis of reinforced structure were then compared with those from classical models. The use of refined one-dimensional models allows stiffener modes to be investigated. The results show that this approach is comparable to a full three-dimensional solution. The use of classical one- and two-dimensional models does not allow the local deformation of reinforcements to be taken into account. Therefore, these models cannot be considered accurate when the aim of the analysis is to investigate the local mode.