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Performance of some simple ductile fracture criteria in small punch testing

conference paper

en

Small punch testing is a well-established testing technology in situations where only tiny fragments of material are at disposal. In addition to the identification of the basic characteristics of the material, the ductility is an important output of such testing. Many existing ductile fracture models could be used for such identification, but the simplicity of the model is, in addition to its reliability, an important feature. The reason is that a limited number of experiments with the same type of specimen prevents the reliable identification of sophisticated ductile fracture models with many material parameters. That is why the work is focused on simple one-parameter criteria such as Rice and Tracey dependent on stress triaxiality, or Cockroft–Latham–Oh related to maximum principal stress, normalized by the equivalent stress. These are calibrated first by notched cylindrical specimens loaded in tension only and second by a set of broader variety of experiments under different stress states. The results of both the ductile fracture models and identification strategies with respective material constants are then applied to the numerical simulation of the small punch testing with element erosion to see their predictability of crack formation and propagation.

sdaf

Small punch testing is a well-established testing technology in situations where only tiny fragments of material are at disposal. In addition to the identification of the basic characteristics of the material, the ductility is an important output of such testing. Many existing ductile fracture models could be used for such identification, but the simplicity of the model is, in addition to its reliability, an important feature. The reason is that a limited number of experiments with the same type of specimen prevents the reliable identification of sophisticated ductile fracture models with many material parameters. That is why the work is focused on simple one-parameter criteria such as Rice and Tracey dependent on stress triaxiality, or Cockroft–Latham–Oh related to maximum principal stress, normalized by the equivalent stress. These are calibrated first by notched cylindrical specimens loaded in tension only and second by a set of broader variety of experiments under different stress states. The results of both the ductile fracture models and identification strategies with respective material constants are then applied to the numerical simulation of the small punch testing with element erosion to see their predictability of crack formation and propagation.

Tvárné porušování

Ductile fracture

07.07.2025

1742-6588

COMAT-2024

3035

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