Título: | CONSISTENT APPLICATION OF THE BOUNDARY ELEMENT METHOD TO FRACTURE MECHANICS PROBLEMS | ||||||||||||
Autor: |
OSMAR ALEXANDRE DO AMARAL NETO |
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Colaborador(es): |
NEY AUGUSTO DUMONT - Orientador |
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Catalogação: | 01/OUT/2024 | Língua(s): | PORTUGUESE - BRAZIL |
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Tipo: | TEXT | Subtipo: | THESIS | ||||||||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=68234&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=68234&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.68234 | ||||||||||||
Resumo: | |||||||||||||
As hitherto proposed in the technical literature, the boundary element
modelling of cracks is best carried out resorting to a hypersingular fundamental solution – in the frame of the so-called dual formulation –, since with the
singular fundamental solution alone the ensuing topological issues would not
be adequately tackled. A more natural approach might rely on the direct representation of the crack tip singularity, as already proposed in the frame of
the hybrid boundary element method – with implementation of generalized
Westergaard stress functions. On the other hand, recent mathematical assessments indicate that the conventional boundary element formulation – based on
Kelvin’s fundamental solution – is in fact able to precisely represent high stress
gradients and deal with extremely convoluted topologies provided only that the
numerical integrations be properly resolved. We propose in this work that independently of configuration a cracked structure be geometrically represented
as it would appear in laboratory experiments, with crack openings in the range
of micrometers. (The nanometer range is actually mathematically feasible in
the present formulation but not realistic in terms of continuum mechanics.)
Owing to the newly developed numerical integration scheme, machine precision evaluation of all quantities may be achieved and stress results consistently
evaluated at interior points arbitrarily close to crack tips. Importantly, no artificial topological issues are introduced, linear algebra conditioning is well kept
under control and arbitrarily high convergence of results is always attainable.
The present developments apply to two-dimensional problems. Some numerical
illustrations show that highly accurate results are obtained for cracks represented with just a few quadratic, generally curved, boundary elements – and a
few Gauss-Legendre integration points per element – and that the numerical
evaluation of the J-integral turns out to be straightforward (although not computationally cheap) and actually the most reliable means of obtaining stress
intensity factors.
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