The experimental-numerical analyses of the failure mechanisms of S355JR steel

https://doi.org/10.1016/j.tafmec.2020.102666Get rights and content
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Highlights

  • Critical stress level depends on plastic strain and Lode parameter.

  • Numerical and experimental analysis of ductile and cleavage mechanism was performed.

  • Three materials, five specimen shapes and three different temperatures were tested.

  • Failure mechanisms can be predicted with mechanical field parameters.

  • Absence brittle fracture can be explained by the evolution of the mechanical field.

Abstract

The results of experimental and numerical analyses concerning the failure mechanisms of S355JR steel are presented. Tests were performed on S355JR steel after three heat treatments at three different temperatures with five specimen geometries that were designed to provide different values of the stress triaxiality and Lode parameter as well as different critical strains and stresses at the onset of final failure. Depending on the test temperature and specimen geometry, cleavage or ductile fracture were observed; the latter occurred either by the void nucleation–growth–coalescence process or by the shear mechanism. The locations where the observed mechanism started were localized, and mechanical fields were computed in these domains. The critical effective plastic strains were determined as functions of the stress triaxiality and Lode parameter in the case of ductile fracture, and the critical opening stresses were determined as functions of the Lode parameter and effective plastic strains in the case of cleavage fracture.

Keywords

Ductile fracture
Cleavage fracture
Critical effective plastic strain
Stress triaxiality
Lode angle

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