Influência do comportamento dinâmico em juntas do tipo "k" em estruturas reticuladas planas

Abstract

This thesis presents the study of plane frame structures, also called trusses. The great demand of construction, and projects increasingly bold motivated this research. Three models lattices were performed in order to compare the static problems concerning dynamic problem and check the influence of the joints efforts K type of truss. The joints of the truss were used to analyze the plasticized region and the stress (Von-Mises). The calculation routine for obtaining the results were implemented in Matlab software for the static problem and the results were compared with the FEM-Reticulado2D Matlab software and commercial software where the differences were less than one percent. In the dynamic damper problem was added, being closest to an actual structure. For this case we used the Rayleigh damping, which is found by means of the natural frequency and the method used for time integration method is the Newmark. The natural frequency was also obtained by formulations implemented in Matlab. The plasticity of the region and the tension (von Mises-) nodes were obtained with the help of Ansys software. Considering the results, it can be concluded that the dynamic problem by taking into account the influence of forces of inertia resulting in increased efforts in relation to the static problem. It was found that the more slender for the structure, the lower the natural frequency of the same, so one must be careful that slender structures will not absorb energy from external actions like wind and entering the resonance effect. The plasticity and the stress (Von-Mises) depend on the intensity of the forces and the geometrical and physical properties of the used profile.