Publication detail

Propagation of Long Fatigue Cracks under Remote Modes II and III in Ferritic-pearlitic Steel

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

Original Title

Propagation of Long Fatigue Cracks under Remote Modes II and III in Ferritic-pearlitic Steel

English Title

Propagation of Long Fatigue Cracks under Remote Modes II and III in Ferritic-pearlitic Steel

Type

journal article in Web of Science

Language

en

Original Abstract

The aim of this research was to determine the 3D crack path and the related growth micromechanism in specimens made of the ferritic-pearlitic steel loaded in modes II and III. Crack closure effects were minimized at the beginning of the experiments by a special technique of generation of precracks in order to measure effective values of fatigue thresholds. Dependences of the crack growth rate on the stress intensity factor range were plotted for the near-threshold region. The effective mode III threshold KIIIeff,th = 4.4 MPam^1/2 was found to be higher than that for mode II (KIIeff,th = 2.9 MPam^1/2, the theory predicts 3.1 MPam^1/2) which is in agreement with the results for other metallic materials and available theoretical models. Fractographical observations in three dimensions revealed that the remote mode II cracks deflected towards the opening mode I by the mean angle ~ 50°, which is signicantly different from the low-angle deflections (coplanar growth) previously observed in the ARMCO iron. The simple linear elastic fracture mechanics based criterion for growth of a mode I branch at the crack front loaded in mode II was fulfilled.

English abstract

The aim of this research was to determine the 3D crack path and the related growth micromechanism in specimens made of the ferritic-pearlitic steel loaded in modes II and III. Crack closure effects were minimized at the beginning of the experiments by a special technique of generation of precracks in order to measure effective values of fatigue thresholds. Dependences of the crack growth rate on the stress intensity factor range were plotted for the near-threshold region. The effective mode III threshold KIIIeff,th = 4.4 MPam^1/2 was found to be higher than that for mode II (KIIeff,th = 2.9 MPam^1/2, the theory predicts 3.1 MPam^1/2) which is in agreement with the results for other metallic materials and available theoretical models. Fractographical observations in three dimensions revealed that the remote mode II cracks deflected towards the opening mode I by the mean angle ~ 50°, which is signicantly different from the low-angle deflections (coplanar growth) previously observed in the ARMCO iron. The simple linear elastic fracture mechanics based criterion for growth of a mode I branch at the crack front loaded in mode II was fulfilled.

Keywords

mode II and mode III cracks, ferritic-pearlitic steel, micromechanism, mode I branching

RIV year

2015

Released

01.10.2015

Publisher

Polish Academy of Sciences

ISBN

0587-4246

Periodical

ACTA PHYSICA POLONICA A

Year of study

128

Number

4

State

PL

Pages from

611

Pages to

614

Pages count

4

Documents

BibTex


@article{BUT122986,
  author="Tomáš {Vojtek} and Jaroslav {Pokluda} and Anton {Hohenwarter} and Reinhard {Pippan}",
  title="Propagation of Long Fatigue Cracks under Remote Modes II and III in Ferritic-pearlitic Steel",
  annote="The aim of this research was to determine the 3D crack path and the related growth micromechanism in specimens made of the ferritic-pearlitic steel loaded in modes II and III. Crack closure effects were minimized at the beginning of the experiments by a special technique of generation of precracks in order to measure effective values of fatigue thresholds. Dependences of the crack growth rate on the stress intensity factor range were plotted for the near-threshold region. The effective mode III threshold KIIIeff,th = 4.4 MPam^1/2 was found to be higher than that for mode II (KIIeff,th = 2.9 MPam^1/2, the theory predicts 3.1 MPam^1/2) which is in agreement with the results for other metallic materials and available theoretical models. Fractographical observations in three dimensions revealed that the remote mode II cracks deflected towards the opening mode I by the mean angle ~ 50°, which is signicantly different from the low-angle deflections (coplanar growth) previously observed in the ARMCO iron. The simple linear elastic fracture mechanics based criterion for growth of a mode I branch at the crack front loaded in mode II was fulfilled.",
  address="Polish Academy of Sciences",
  chapter="122986",
  institution="Polish Academy of Sciences",
  number="4",
  volume="128",
  year="2015",
  month="october",
  pages="611--614",
  publisher="Polish Academy of Sciences",
  type="journal article in Web of Science"
}