Title:	Análise do crescimento à fadiga, interação e coalescência de múltiplas trincas com o método dos elementos de contorno dual
Other Titles:	Analysis of fatigue growth, interaction and linkup of multiple cracks with dual boundary element method
Authors:	Santana, Elvis Pereira de
Orientador(es)::	Portela, Artur Antonio de Almeida
Assunto::	Fadiga Indústria de construção civil Método dos momentos Trincas (Engenharia)
Issue Date:	25-Feb-2016
Data de defesa::	7-Dec-2015
Citation:	SANTANA, Elvis Pereira de. Análise do crescimento à fadiga, interação e coalescência de múltiplas trincas com o método dos elementos de contorno dual. 2015. xvi, 72 f., il. Dissertação (Mestrado em Estruturas e Construção Civil)—Universidade de Brasília, Brasília, 2015.
Abstract:	Multiple-site and widespread fatigue damage have been an issue to the aircraft and civil construction industry for a long period. Structural components develop cracks at several locations which grow with crack paths that are difficult to predict. When two cracks approach one to another, their stress fields influence each other leading to an enhancing or shielding effect which depends on the position and orientation of the cracks. Since there are no generalized analytical methods for predicting crack stress fields, simulation of multiple-crack growth, and the linkup between them, are important and challenging tasks of an research area that is still evolving. This work describes a two dimensional application of the dual boundary element method (DBEM) to the analysis of mixed-mode multiple-crack growth in linear elastic fracture mechanics, under fatigue loading. The crack-growth process is simulated with an incremental multiple-crack extension analysis based on the maximum principal stress criterion. For each increment of the analysis, in which crack extensions are modeled with new boundary elements, the DBEM is applied to perform a single-region stress analysis of the cracked structure and the J-integral is used to compute the stress intensity factors. The incremental analysis is based on a prediction-correction technique that defines, in each increment of the analysis, the direction and the extension of the multiple cracks, thus taking into account the discreteness of the analysis and ensuring that the requirement of the path uniqueness be satisfied. Based on the ligament yield criterion which assumes that when the plastic zones of two adjacent cracks touch each other, the ligament between them fails and the cracks coalesce, plates with multiple-site damage can be analyzed. The fatigue life and residual strength of the structure are introduced as a post-processing procedure on the results of the multiple-crack growth. Results of this incremental analysis are presented for several geometries with multiple-site damage, demonstrating the accuracy and efficiency of the strategies adopted in the analysis.
metadata.dc.description.unidade:	Faculdade de Tecnologia (FT) Departamento de Engenharia Civil e Ambiental (FT ENC)
Description:	Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2015.
metadata.dc.description.ppg:	Programa de Pós-Graduação em Estruturas e Construção Civil
Licença::	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
DOI:	http://dx.doi.org/10.26512/2015.12.D.19568
Appears in Collections:	Teses, dissertações e produtos pós-doutorado

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