Título:	Obtenção do fator de intensidade de tensão utilizando varias formulações com o método dos elementos de contorno
Autor(es):	Medeiros, Jaqueline Moreira de Souza De
Orientador(es):	Bezerra, Luciano Mendes
Assunto:	Engenharia de estruturas Elasticidade Método dos elementos de contorno
Data de publicação:	2-Abr-2020
Data de defesa:	10-Ago-2000
Referência:	MEDEIROS, Jaqueline Moreira de Souza De. Obtenção do fator de intensidade de tensão utilizando várias formulações com o método dos elementos de contorno. Brasília , 2000. xiv, 100 f., il. Dissertação (Mestrado em Estruturas e Construção Civil)—Universidade de Brasília, Brasília, 2000.
Abstract:	Fracture Mechanics emerged as a need to explain some accidents that took place in Structures working with stress levels below the allowable stress values adopted in the projects. Some of these accidents, with stresses below the critical values, were due to defects, flaws or cracks present in the structure material. Sometimes those defects were inherent to the own production process of the material. When analyzing the integrity of a structure, it is an important task to anticipate how critical an existing defect can be. One of the objectives of Fracture Mechanics is the determination of the load capacity in a structure carrying a crack, or the knowledge of the maximum dimension that an existing crack may achieve without taking the structure to a collapse. One of the most important parameter of the Linear Elastic Fracture Mechanics is the Stress Intensity Factor "K" that describes the magnitude of the stress field in the vicinity of a crack tip. The critical value of "K" is an intrinsic characteristic of the material and is linked to the material toughness to propagate fracture. In practice the determination of "K" is very important because it allows foreseeing if a structure is in the onset of collapse. There are several techniques to determine "K"; among these techniques we can mention some experimental and numerical approaches. Based on such approaches, several handbooks are also available offering simplifíed formulations for a quick and simplifíed evaluation of "K". However, for some geometric confíguration of cracks encountered in practice one cannot find simplifíed formulations on the handbooks for the determination of "K". In such cases, "K" can only be evaluated by experimental or numerical techniques. In spite of some advantages over numerical techniques, the experimental approaches are usually more expensive and also more time consuming. Therefore, numerical techniques, when suffíciently tested, can easily and quickly be used for the precise determination of "K" for any geometrical confíguration of a crack. This work is presented with the objective of providing a reliable formulation for the numerical determination of "K". Here the Boundary Element Method (BEM) is employed as a numerical tool for the determination of the Stress Intensity Factor "K". We use several numerical techniques, such as, displacement extrapolation, potential energy dissipation and J-Integral with sensitivity. In this work, it is shown that the BEM is an accessible numerical tool and that, despite its mathematical complexity, can be used in an economical way, because it demands less time in the data preparation and less computational effort as the BEM decrease by one the dimensionality of the problem. At the end of this work the effectiveness of the proposed formulations is tested, compared and discussed making use of some classical crack confíguration which precise Solutions for "K" are well known.
Unidade Acadêmica:	Faculdade de Tecnologia (FT) Departamento de Engenharia Civil e Ambiental (FT ENC)
Informações adicionais:	Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil, 2000.
Programa de pós-graduação:	Programa de Pós-Graduação em Estruturas e Construção Civil
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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