Evaluating the linear normalization technique for deriving J-resistance curves

Authors

  • J. R. TARPANI,

    1. Materials, Aeronautical and Automotive Engineering Department, Engineering School of São Carlos, University of São Paulo, 13566-590, Brazil
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  • A. A. COLAFEMEA,

    1. Materials, Aeronautical and Automotive Engineering Department, Engineering School of São Carlos, University of São Paulo, 13566-590, Brazil
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  • W. W. BOSE FILHO,

    1. Materials, Aeronautical and Automotive Engineering Department, Engineering School of São Carlos, University of São Paulo, 13566-590, Brazil
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  • D. SPINELLI

    1. Materials, Aeronautical and Automotive Engineering Department, Engineering School of São Carlos, University of São Paulo, 13566-590, Brazil
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J. R. Tarpani. E-mail: jrpan@sc.usp.br

ABSTRACT

In this paper, results from the linear normalization (LN) technique of Reese and Schwalbe for deriving J-crack resistance (JR) curves have been compared, related to J–Δa (J-integral–ductile crack growth) data points, to those obtained from traditional elastic compliance technique. Research results regarding a nuclear grade steel exhibiting a wide range of elastic–plastic fracture resistance agree quite well for both techniques until a certain level of toughness of the material. Below this critical level, LN produces inconsistent results for the sub-sized compact tension specimens (0.4T C[T]). The evidence suggests that the loss of applicability of the LN technique can be determined on the basis of the η plastic factor (ηpl) for the best linear correlation achieved for ΔPN–Δa (normalised load gradient–ductile crack growth) data.

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