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Stress intensity factors for notched round bars using FEM

Publication . Fonseca, E.M.M.; Melo, F.J.M.Q. de; Valente, R.A.F.

This study proposes alternative methods to estimate the stress intensity factors (SIF) of notched round components having an axial hole and subjected to an axial force or a bending moment. The method is based on analytical equations proposed by (Harris 1997) and on alternative formulation using finite element method (FEM). The objective of this work is a contribution in fracture mechanics applied to tubular systems with typical defects generated in service or a consequence of the fabrication method. Computational effort is saved with this element in the evaluation of the stress field across the section carrying the defect. Numerical examples are presented to illustrate the proposed method referring to tubular structures with different end constraints and containing a circumferential notch. The comparisons with the elastic finite element showed satisfactory results and good agreement with others references.

2006Conference object

Open access

Determination of stress intensity factors along cracked surfaces in piping elbows structures

Publication . Fonseca, E.M.M.; Melo, F.J.M.Q. de; Valente, R.A.F.

Pipe elbows play an essential role in pipework systems, once such structure elements are part of the plant process fluid conduction practically in all chemical or energy production industries. High safety standards in design are inherent to these projects due to complex mechanical or thermal loading. When these accessories carry defects, project engineers should assess their integrity in duty. This paper present a contribution in fracture mechanics applied to piping systems. Stress intensity factors are determined along cracked surfaces in piping elbows subjected to bending moment using a developed finite curved pipe element. This element is based in high order polynomial for rigid beam displacement and Fourier series modelling the transverse section warping or ovalization. Computational effort is saved with this element in the evaluation of the stresses or strains. Numerical tests are performed for different pipe elbows with thick or thin flanges, containing a circumferential crack. This study is compared with analyses reported by other authors.

2006Conference object

Open access

Modelo de deformação numérico e experimental em secções tubulares

Publication . Fonseca, E.M.M.; Barreira, Luísa; Melo, F.J.M.Q. de; Valente, R.A.F.

Neste artigo apresenta-se um modelo numérico e experimental para a análise de secções tubulares quando submetidas a carregamentos transversais. O objectivo consiste na avaliação da integridade estrutural destes elementos função da sua resistência à deflexão através do seu comportamento para além do domínio elástico. O modelo numérico baseia-se na utilização de elementos sólidos com características de não linearidade geométrica e material utilizando o programa Ansys. O modelo experimental resulta de ensaios efectuados em componentes com as mesmas características para a comparação de resultados.

2007Conference object

Open access