JULIO RICARDO BARRETO CRUZ
13 resultados
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Capítulo IPEN-doc 06721 A simplified transformation approach to obtain structural calibration functions1998 - CRUZ, J.R.B.; LANDES, J.D.Artigo IPEN-doc 12368 Methodology to obtain semi-elliptical cracks in a nuclear reactor pressure vessel model2007 - VIDA GOMES, P.T.; BARRETO CRUZ, J.R.; MATTAR NETO, MIGUEL; MARTINS, G.A.S.Artigo IPEN-doc 11046 Influence of the materials mechanical properties on the structural integrity assessment of cracked piping of PWR nuclear reactors primary systems2005 - MATTAR NETO, M.; CRUZ, J.R.B.; JONG, R.P.The structural integrity assessment methods of cracked components manufactured with ductile materials request the evaluation of parameters of the Elastic-Plastic Fracture Mechanics (EPFM) and of the Limit Load Analysis (LL). Since the use of numerical methods to apply the concepts of EPFM and LL may be costly and time demanding, the existence of the so-called simplified methods for cracked piping evaluation is still considered of great relevance. The following simplified methods for evaluation of the ductile behavior of piping systems are available in the literature and were considered in this work: J-T Method (J Integral versus the Tearing Modulus T), R6 Method and DPFAD Method (Deformation Plasticity Failure Assessment Diagram). The methods were applied for the computation of instability loads of some piping systems, with through-wall circumferential cracks, subjected to bending moments, made with high toughness steels. Changes in the values of the materials properties were considered. The estimated instability loads were compared with experimental results obtained in the literature. From those comparisons, some conclusions and comments could be made, being the main focus of the work the aspects related to the characterization of the materials properties to the appropriate application of the methods to cracked piping of pressurized water nuclear reactor (PWR) primary systems, in evaluations of the LBB (Leak-Before-Break) concept. As the methods are strongly dependent on the properties, some recommendations must be followed. These properties are basically expressed by means of the stressstrain curves and fracture resistance curves (JR curves).Artigo IPEN-doc 11048 3-D constraint effects on fracture mechanics specimens2005 - RABELLO, E.G.; MATTAR NETO, M.; CRUZ, J.R.B.; GOMES, P.T.V.The constraint is accepted as a measure of the triaxiality level at the crack-tip. Specimens with different a/W ratios present variation on the stress field ahead of the crack-tip. A stress relaxation can occur depending on the a/W values which is known as loss of constraint and has strong influence on the structural steels fracture toughness. Different approaches have been proposed to quantify constraint and to describe the effects of constraint variations on engineering fracture toughness characterized by J-integral, or equivalently the crack-tip opening displacement, CTOD. This paper presents the results of a numerical investigation, in which single-edge cracked bars in three point bend SE(B) and compact tension C(T) specimens, with different relative crack lengths, were systematically studied via detailed three-dimensional finite element analyses. A new parameter is then proposed to quantify crack-tip constraint.Artigo IPEN-doc 10706 Numerical study of 3-D constraint effects in SE(B) specimens2004 - RABELLO, E.G.; CRUZ, J.R.B.; MATTAR NETO, M.; MIRANDA, C.A.J.Artigo IPEN-doc 08700 Determinacao da carga de colapso de tubulacoes contendo trincas circunferenciais2002 - JONG, R.P.; MATTAR NETO, M.; CRUZ, J.R.B.Artigo IPEN-doc 11200 Routines for the assessment of cracked piping of PWR nuclear reactors primary systems2005 - MATTAR NETO, M.; CRUZ, J.R.B.; JONG, R.P.Artigo IPEN-doc 05506 Aplicacao da mecanica da fratura a analise de tubulacoes nucleares1994 - CRUZ, J.R.B.; AQUINO, C.T.E.Artigo IPEN-doc 06669 Integridade de tubos de geradores de vapor de reatores PWR: Criterios de tamponamento para PWSCC na regiao de transicao proximo ao espelho1999 - MATTAR NETO, M.; CRUZ, J.R.B.Artigo IPEN-doc 06329 A common format approach for applying ductile fracture mechanics1997 - LANDES, J.D.; CRUZ, J.R.B.