Majid Reza Ayatollahi - Professor, Mechanical Engineering Department, Iran University of Science and Technology
Morteza Nejati - M.Sc. Student, Mechanical Engineering Department, Iran University of Science and Technology

Sharp notches, especially the 90° notches, are often found in many engineering structures. The ability to predict the initiation of brittle fracture is of fundamental importance for a reliable performance of engineering structures containing sharp notches. The concept of linear elastic fracture mechanics (LEFM) is widely used to study the influence of sharp notches on the structural performance. The notch stress intensity factors (NSIFs) characterize the singular stress field around the notch tip. Recent studies show that the non-singular higher order terms have significant effects on fracture behaviour. On the other hand, the boundary collocation (BC) method has been widely used in the past to determine the coefficients of crack tip asymptotic field, but not for the notch tip asymptotic field. In this paper the method of BC is employed to calculate thecoefficients of asymptotic field of a strip plate with single or double edge notches under uniaxial tension. The NSIFs as well as the coefficients of the higher order terms then can be calculated in pure mode I and mixed mode I/II loading conditions. A convergence study has been conducted to examine the effects of the number of terms in Williams expansion on the results. The accuracy of results is validated by comparing with the very few results available in the literature, or the results obtained by the finite element method.

sharp notch, notch tip asymptotic field,boundary collocation method, notch stress intensityfactor (NSIF), coefficients of higher order terms