An experimental (digital photoelastic experiments) and numeric study of the stress field in the vicinity of two interacting cracks: stress intensity factors, T-stresses and coefficients of higher order terms

Abstract

The multi-parameter description of the stress field in the neighbourhood of the crack tips of two interacting crack based on the photoelastic study and finite element analyses is given. Digital photoelasticity method is used for obtaining the isochromatic and isoclinic patterns in the plate with two collinear horizontal and two inclined cracks in anisotropic linear elastic material. Stress intensity factors, T-stresses and coefficients of the higher order terms in the multi-parameter Williams series expansion are experimentally determined. The finite element analysis for the cracked plates with the same configurations has been performed. Stress intensity factors, T-stress and coefficients of nine-term asymptotic expansion for the stress field are numerically obtained and are compared with the experimental results. The comparison shows good agreement of experimental and numerical estimations of these fracture mechanics parameters. Very good agreement is shown to exist between the digital photoelasticity method and finite element results confirming the effectiveness of the photoelasticity technique in obtaining the coefficients of higher order terms of the Williams series expansion from the experimental stress field around the crack tip.