Submitted by Natalie Mendes (nataliermendes@gmail.com) on 2015-07-29T00:55:23Z No. of bitstreams: 1 Disserta??o Thiago Pacheco.pdf: 4385957 bytes, checksum: bbeb8d3248bb5fe4a1563d8d8c81ffb1 (MD5) / Made available in DSpace on 2015-07-29T00:55:23Z (GMT). No. of bitstreams: 1 Disserta??o Thiago Pacheco.pdf: 4385957 bytes, checksum: bbeb8d3248bb5fe4a1563d8d8c81ffb1 (MD5) Previous issue date: 2014-11-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Concrete is a very versatile material widely used by the construction industry. However, the adequate application of your nonlinear behavior, by numerical methods is still a major challenge in structural engineering. In this workwas evaluated three methods of distributed crackingbased Fracture Mechanics: fixed rotational and multidirectional. , To this the flexural behavior of beam was simulated numerically by the commercial software DIANA ?, and compared with experimental results reported in the literature. For the beams that failed by bending, the numerical simulation for all three models shown agreement with experimental results with ability to predict the equilibrium path, the maximum load and deformation failure. However, to analysis of beams that failed by shear, the fixed crack model did not capture properly the rupture load and the rotational model presented numerical instability after the start of diagonal cracking. Moreover, the multidirectional model describes the complete load-displacement behavior and adequately predicts the appearance of diagonal cracks as well as the latest load and deformation. / O concreto ? um material muito vers?til e de larga utiliza??o pela ind?stria da constru??o civil. A avalia??o do seu comportamento n?o linear f?sico, por?m, ainda ? um dos grandes desafios da engenharia estrutural. Como forma de contribuir com esse ramo, esta disserta??o tem como pretens?o avaliar tr?s m?todos da Mec?nica da Fratura de fissura??o distribu?da: fixo, rotacional e multidirecional Para isso foram simuladas numericamente, atrav?s do software comercial DIANA?, ensaios de flex?o de vigas, registrados na literatura,com ruptura por flex?o e por cisalhamento. Para as vigas com falha por flex?o, todos os tr?s modelos apresentam bons resultados com capacidade para prever o caminho de equil?brio, a carga m?xima e a deforma??o de falha para o estado limite ?ltimo. Todavia, para as vigas com falha por cisalhamento, o modelo fixo de fissura??o n?o captou a ruptura corretamente e para o modelo rotacional de fissura??o foi verificada grande instabilidade num?rica ao determinar o caminho de equil?brio, ap?s o surgimento da fissura diagonal. J? o modelo multidirecional descreve com precis?o o caminho de equil?brio e capta o surgimento da fissura diagonal bem como, a carga e deforma??o ?ltimas.