In order to determine fracture parameters of the body and fracture conditions, stress and strain fields in the crack zone should be precisely calculated, especially near the crack tip. These goals can be achieved by performing experiments which are very complicated and expensive. More efficient numerical finite element and boundary element methods yielding the reliable data faster than experiments are usually used for practical calculations. A great number of classical analytical, experimental and numerical investigations are restricted to solving two-dimensional problems by making different assumptions. The results may be uncertain when three-dimensional state is simplified to two-dimensional one. Therefore, it is very important to study the effect of this simplification, in other words, to investigate the influence of three-dimensionality. The dissertation research belongs to the area of numerical fracture mechanics.

In order to determine fracture parameters of the body and fracture conditions, stress and strain fields in the crack zone should be precisely calculated, especially near the crack tip. These goals can be achieved by performing experiments which are very complicated and expensive. More efficient numerical finite element and boundary element methods yielding the reliable data faster than experiments are usually used for practical calculations. A great number of classical analytical, experimental and numerical investigations are restricted to solving two-dimensional problems by making different assumptions. The results may be uncertain when three-dimensional state is simplified to two-dimensional one. Therefore, it is very important to study the effect of this simplification, in other words, to investigate the influence of three-dimensionality. The dissertation research belongs to the area of numerical fracture mechanics.

Made available in DSpace on 2016-12-08T17:19:18Z (GMT). No. of bitstreams: 1 Daniel Kohls .pdf: 57388 bytes, checksum: 061e1c40382138d4efd671ca1d144b1a (MD5) Previous issue date: 2003-04-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O presente trabalho teve Poe objetivo projetar, construir e validar um equipamento de baixo custo para pré-nucleação de trinca em CDP entalhado. Teve também por meta mostrar os resultados obtidos nos ensaios de resistência a fratura em metais na determinação do fator de intensidade de tensão critico Kic efetivados em corpos de prova metálicos do tipo SENB, os quais foram pré-trincados no dispositivo de pré nucleação de CDP construído em laboratórios.