Análise numérica e experimental de uma viga sujeita a cargas dinâmicas

Abstract

The purpouse of this work is to perform a study involving the finite element method and image processing in a beam subjected to dynamic loads. The beam was set at one end and free at the other, where an impulsive force was initially applied at its free end in order to determine its natural frequencies. After, from the same boundary conditions, a point mass was applied at the free end of the beam to evaluate its dynamic behavior. The properties of the stainless steel structure, such as modulus of elasticity and Poisson's coefficient were determined according to AISI (American Iron and Steel Institute). The linear finite element methodology was applied using the Euler-Bernoulli beam element model in commercial ANSYS® software, where the beam was discretized in 22 nodes, 21 elements, and each node had two degrees of freedom, translation and rotation. In the experimental analysis, a non-contact sensor camera was used, along with an algorithm previously implemented, for image processing, whose main idea is to read the video, frame by frame, after the binarization of the image, the conversion of the coordinates of the image matrix, that are in pixels, in measurement scales, in the case in millimeters and finally to apply the Fast Fourier Transform (FFT) to evaluate the dynamic behavior of the structure. In discretization of the system, each element of the beam has two degrees of freedom (displacement and rotation) in each node, where the displacement field is defined by the vertical displacement of the axis.