Análise numérica de cilindros de compósitos com ângulo de fibra variável

Abstract

The demand for lighter and stronger structures is increasing more and more, highly targeted in projects in which the mass factor is critical. In the meantime, the use of composite materials stands out; although it is a highly challenging area of research due to the complex effects on structures, they meet the characteristic design demands with quality. One of the best known effects is the potential of mechanical strength when the load is aligned to the fiber of the composite laminate. Aiming to explore the maximum of this potential, the variable angle tubes (VATs) appear, being structures designed for the filament to present an angular variation along its length, to align the fiber with the applied load. The present work aims to develop a numerical model of cylindrical tubes made of composite material submitted to axial compression, in order to preliminarily explore the effects of variable fiber angle and thickness. This is done by reproducing the results of models already studied by Wang et al. (2020). The development is carried out through numerical study based on the application of the finite element method for extracting eigenvalues to predict critical loads and buckling modes of seven different models - one constant angle model; a model with four sections and constant angle, a model with eight sections and constant angle; a linear variable angle and constant thickness model, a linear variable angle and variable thickness model, a polynomial variable angle and constant thickness model, and a polynomial variable angle and variable thickness model.Additionally, a comparative evaluation of critical loads and buckling modes was conducted, emphasizing the models with linear and second-order variations in the fiber angle, along with variable thickness. These models demonstrated a significant improvement of 20% in the critical buckling load. Finally, enhancements are proposed for the analyzed models.