INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
artículos
Título:
Estimation of notch sensitivity and size effect on fatigue resistance
Autor/es:
CHAPETTI, M D; A.O. GUERERO FARRO
Revista:
procedia Engineering
Editorial:
Elsevier
Referencias:
Año: 2013 vol. 66 p. 323 - 333
ISSN:
1877-7058
Resumen:
This paper addresses the problem of high cycle fatigue resistance
associated to notches and the role of short crack propagation in the fatigue
notch sensitivity quantified by the notch factor kf. An integrated fracture mechanics approach is
proposed to estimate the fatigue notch sensitivity, by including the effect of
both blunt and sharp notches.
Whether fatigue strength at a given life is controlled by crack
initiation (very blunt notches, kf
= kt), by microstructuraly
short cracks (blunt notches, kf
< kt), or by
mechanically short crack propagation (sharp notches, kf << kt),
depends on the stress concentration kt,
the notch length D and the material threshold to crack initiation DseR, to short crack propagation DKth and to long crack propagation DKthR.
The approach includes the prediction of the fatigue crack propagation
threshold for short cracks, previously developed to analyze the short crack
behavior in metallic materials with or without blunt notches, and is integrated
adding the influence of sharp notches and accounting for the controlling
parameters. It estimates the fatigue resistance of the component by comparing
the threshold for fatigue crack propagation as a function of crack length, DKth, with the applied DK for the given configuration. Estimations for results reported in
published bibliography are presented.
The proposed fracture mechanics approach allows accounting for the
effects of notch acuity, notch size and intrinsic material fatigue properties
on fatigue notch sensitivity. It opens the door to a new simple method for
predicting fatigue notch sensitivity and fatigue strength of components with
geometric concentrators by using parameters that can be easily measured or
estimated, without the necessity of any fitting parameter.