Publication detail

Propagation of Long Fatigue Cracks under Remote Mode II, III and II+III in Metals

VOJTEK, T. POKLUDA, J. HOHENWARTER, A. PIPPAN, R.

Original Title

Propagation of Long Fatigue Cracks under Remote Mode II, III and II+III in Metals

English Title

Propagation of Long Fatigue Cracks under Remote Mode II, III and II+III in Metals

Type

abstract

Language

en

Original Abstract

The aim of this research was to elucidate the crack growth micromechanism of modes II, III and mixed mode II+III in metallic materials. Experiments were performed on ferritic and austenitic steels and titanium (BCC, FCC and HCP metals) using CTS specimen loading for pure mode II, torsion device for pure mode III and special device for all modes II, III and the mixed mode II+III. The notches were precracked and thermally treated in a way that minimized crack closure effects. Crack growth rate dependences on stress intensity factor ranges were acquired and the threshold values for each loading mode and material were determined. Mode III thresholds were higher than those of mode II for different steels, which is in accordance with available micromechanism models. Similarly, mode II had higher contribution to mixed-mode II+III crack propagation. Fracture morphologies were studied using stereophotogrammetry in SEM and statistical evaluation of angles of crack-wake asperities. Significant differences between crack paths in ferritic and austenitic steel were found. Models based on different crystal lattices of investigated materials and the discrete dislocation theory were proposed to explain this phenomenon.

English abstract

The aim of this research was to elucidate the crack growth micromechanism of modes II, III and mixed mode II+III in metallic materials. Experiments were performed on ferritic and austenitic steels and titanium (BCC, FCC and HCP metals) using CTS specimen loading for pure mode II, torsion device for pure mode III and special device for all modes II, III and the mixed mode II+III. The notches were precracked and thermally treated in a way that minimized crack closure effects. Crack growth rate dependences on stress intensity factor ranges were acquired and the threshold values for each loading mode and material were determined. Mode III thresholds were higher than those of mode II for different steels, which is in accordance with available micromechanism models. Similarly, mode II had higher contribution to mixed-mode II+III crack propagation. Fracture morphologies were studied using stereophotogrammetry in SEM and statistical evaluation of angles of crack-wake asperities. Significant differences between crack paths in ferritic and austenitic steel were found. Models based on different crystal lattices of investigated materials and the discrete dislocation theory were proposed to explain this phenomenon.

Keywords

modes II and III, micromechanism, stereophotogrammetry, discrete dislocation theory, metals

Released

01.06.2013

Location

Beijing

ISBN

978-988-12-2652-5

Book

13th International Conference on Fracture (ICF13)

Pages from

86

Pages to

86

Pages count

1

Documents

BibTex


@misc{BUT103635,
  author="Tomáš {Vojtek} and Jaroslav {Pokluda} and Anton {Hohenwarter} and Reinhard {Pippan}",
  title="Propagation of Long Fatigue Cracks under Remote Mode II, III and II+III in Metals",
  annote="The aim of this research was to elucidate the crack growth micromechanism of modes II, III and mixed mode II+III in metallic materials. Experiments were performed on ferritic and austenitic steels and titanium (BCC, FCC and HCP metals) using CTS specimen loading for pure mode II, torsion device for pure mode III and special device for all modes II, III and the mixed mode II+III. The notches were precracked and thermally treated in a way that minimized crack closure effects.

Crack growth rate dependences on stress intensity factor ranges were acquired and the threshold values for each loading mode and material were determined. Mode III thresholds were higher than those of mode II for different steels, which is in accordance with available micromechanism models. Similarly, mode II had higher contribution to mixed-mode II+III crack propagation.

Fracture morphologies were studied using stereophotogrammetry in SEM and statistical evaluation of angles of crack-wake asperities. Significant differences between crack paths in ferritic and austenitic steel were found. Models based on different crystal lattices of investigated materials and the discrete dislocation theory were proposed to explain this phenomenon.",
  booktitle="13th International Conference on Fracture (ICF13)",
  chapter="103635",
  howpublished="print",
  year="2013",
  month="june",
  pages="86--86",
  type="abstract"
}