BEHAVIOR OF EARLY CRACK GROWTH AT THE VICINITY OF OBLIQUE NOTCHES UNDER BIAXIAL LOADINGS

a Mechanical Design Department, Mataria, Helwan University, Cairo, Egypt.

b Materials Engineering Dept., Faculty of Eng., Zagazig University, Zagazig, Egypt

c Mechanical Engineering Dept., Higher Technological Institute, Tenth of Ramadan, Egypt

The stress intensity factor is a traditional topic in mechanics and there have been many solutions

for many different cases. The crack problem which is emanating from elliptical oblique notch has

been studied previously under uniaxial load. Further, the study of SIF of short crack emanating

from notch under biaxial loading has not been considered in the literature. A plane stress elastictwo

dimensional finite element model was adopted to estimate mode I stress intensity factor

(SIF), stress concentration factor, (SCF), crack tip opening displacement (CTOD) and site of

crack initiation for biaxially loaded plate containing central elliptical oblique notch. Biaxial

loadings of different patterns, i.e. tension-tension or tension-compression were studied. Notches

studied. The effect of biaxial ratio, λb (the ratio of the two involved axial normal stresses) (λb= -1to 1) and notch angles (

surface of the notches was analyzed to detect the point of maximum equivalent stress and

subsequently locating the site of crack initiation.

The highest equivalent stress on the surface of inclined notch was found at the point that has the

largest horizontal coordinate (= horizontal projection), i.e. site of crack initiation. The SCF

increased with increasing the biaxial ratio. In the case of tension-tension biaxial loading, the

mode I SIF decreased with increasing the biaxial ratio.