Paper Title:
The Use of Diffraction to Study Fatigue Crack Tip Mechanics
  Abstract

Simple experimental tests of fatigue life are often insufficient to characterise fatigue behaviour. Fatigue crack growth in polycrystalline metals is governed by a number of interacting mechanical effects at the crack tip, such as the deformation inside a plastic zone and contact between the crack faces over part of the loading cycle. Typically, results tend to be interpreted in terms of an empirical fatigue law such as the Paris equation, which in itself fails to generalise to different load ratios or multiaxial load cases. While extensions to this equation have been used, these are mostly empirical and do little to enhance understanding of the fatigue growth mechanisms. Recently, the use of diffraction to characterise crack tip stress effects has become increasingly popular. In this paper, we consider the opportunities and the difficulties associated with making such measurements by neutron and synchrotron diffraction. In particular we examine grain size effects, plane stress/plane strain issues, optimisation of the gauge geometry, measurement of the plastic zone and crack closure effects.

  Info
Periodical
Edited by
Y. Akiniwa, K. Akita and H. Suzuki
Pages
216-221
DOI
10.4028/www.scientific.net/MSF.652.216
Citation
J. F. Kelleher, P. Lopez-Crespo, F. Yusof, P. J. Withers, "The Use of Diffraction to Study Fatigue Crack Tip Mechanics", Materials Science Forum, Vol. 652, pp. 216-221, 2010
Online since
May 2010
Export
Price
$32.00
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: R.H.C. Wong, Y.S.H. Guo, K.T. Chau, Wei Shen Zhu, Shu Cai Li
Abstract:This paper presents the crack growth mechanism from a 3-D surface flaw on gabbro specimens using strain measurement and acoustic emission...
2357
Authors: Stanislav Seitl, Pavel Hutař, Zdeněk Knésl
Abstract:The formulations of fatigue crack growth prediction are still mostly based on phenomenological models. A commonly used formula in the field...
557
Authors: Zhi Ping Yin, Jiong Zhang, Jin Guo, Qi Qing Huang
Abstract:The finite element software ANSYS was employed to create a finite element model of the cracked wing beam integrated structure, and the stress...
101
Authors: M.R.M. Aliha, Mahdi Rezaei
Abstract:Crack growth path was investigated experimentally, numerically and theoretically using two test specimens subjected to pure mode II loading....
159
Authors: Yu E Ma, Bao Qi Liu, Zhen Qiang Zhao
Chapter 2: Material Science and Engineering
Abstract:Al-Li alloy 2198-T8 was used in the fuselage application. Integral fuselage panels were joined by double friction stir welds. Fatigue tests...
651