Julio Cesar Molina

Analysis of the Stresses in Corrugated Sheets under Bending

This paper presents three different numerical models for the evaluation of the stresses in corrugated sheets under bending. Regarding the numerical simulations different approaches can be considered, i.e., a elastic linear analysis or a physical nonlinear analysis, that considers criteria to fail for the sheet material. Moreover, the construction of the finite element mesh can be used shell elements or solid elements. The choice of each finite element must be made from the consideration of their representativity before behavior to be simulated. Thus, the numerical modelling in this manuscript was performed from the three-dimensional models using the SAP2000Nonlinear software, version 7.42, which has as base the finite elements method (FEM). It was considered shell elements in the build the mesh of finite elements and an analysis of type elastic linear in this case. Five mm thick sheets were evaluated considering three different longitudinal dimensions (spans), i.e., 1100 mm, 1530 mm and 1830 mm. The applied load to the models was 2500 N/m and it was verified that the spans of support of sheets have a significant influence on the results of stresses. The sheets with larger spans present larger stresses for the same applied load. The most intense values of tension occur in the troughs (low waves) of the sheets, on the lower surface, while the most intense values of compression occur in the crests (high waves), on the upper surface of the sheet. The flanks, which are the parts among the troughs and crests of the sheets, are submitted to low levels of stresses. The numeric results of the stresses showed a good agreement with the results obtained from other researchers 3 and these results can be used to predict the behavior of corrugated sheets under bending.

Natural Fiber-Reinforced Polymer for Structural Application

The glued laminated lumber (glulam) beams technique is an efficient process for making sustainable use of wood. Fiber-reinforced polymers (FRPs) associated with glulam provide significant gains in terms of strength and stiffness, as well as modify the rupture mode of these structural elements. Certain natural fibers display sufficient mechanical properties to reinforce the polymer used in the glulam technique. This chapter presents a theoretical analysis considering the behavior of stressed lumber and fibers in glulam beam of Pinus sp. and Eucalyptus sp. with and without natural fiber-reinforced polymer (NFRP), and a numerical analysis evaluating the stresses and displacements in glulam beams using the finite element method. Curaua, bamboo, and jute fibers were used for reinforcement. NFRP introduced in the tensioned section of glulam beams guaranteed a gain of strength and stiffness in function of the thickness percentage of NFRP used. In terms of maximum stresses and vertical displacement, theoretical and numerical analyses provided analogous results.

Verificação da eficiência do modelo de Mohler na resposta do comportamento de vigas mistas de madeira e concreto

Neste trabalho de pesquisa avaliou-se o comportamento estrutural do sistema misto madeira e concreto para tabuleiros de pontes com enfase nos conectores metalicos de cisalhamento. Os ensaios experimentais foram realizados em corpos de prova mistos e em vigas mistas de madeira e concreto com sistema de conexao metalica, disposto em X, a partir da utilizacao de parafusos do tipo CS100900. Todos os corpos de prova e vigas foram submetidos a solicitacoes estaticas com carregamentos aplicados ate a ruptura, considerando-se os diversos materiais envolvidos na ligacao mista para a obtencao da resistencia e rigidez do sistema de conexao. Os resultados experimentais de rigidez das vigas foram comparados com os resultados analiticos fornecidos pelo modelo de Mohler, tendo apresentado boa concordância para carregamentos de servico. A partir dos resultados experimentais obtidos constatou-se que os danos mais significativos ocorreram nas regioes dos conectores.