Caracterização dinâmica dos módulos de elasticidade e de cisalhamento do bambu

Abstract

In recent years, the usege of bamboo has been growing in various engineering applications. For projects with this kind of application being conducted with precision and reliability is essential to know the dynamic behavior of the material. For this, it is essential the knowledge of the bamboo’s properties. This work proposes a methodology for the dynamic characterization of the bamboo, in which dynamic bending and torsion tests were carried out to determine the Young and shear modulus of bamboo. The bending tests were made with beams in a cantilever condition with bamboo samples tested in different lengths. Using the experimental natural frequencies of the beams and the Euler-Bernoulli equations, together with the concept of equivalent stiffness, were determined the values Young modulus of each sample. The shear modulus was determined in a similar way, but the torsion tests were done with a disc attached to the end of the samples. To compare the characterized properties, a four-floors portico was used, and its first natural frequencies were measured. Through numerical analysis by the finite elements method, analyzes were carried out in some lengths of samples under bending conditions and also the behavior of the portico. Using the characterized properties, there was a convergence of the values found in the natural frequencies of the samples and some divergences in the natural frequencies of the portico.