Three Dimensional Investigation of Mode I Stress Intensity Factor Variations in Crack Front Using Finite Element Method

Overall failure may occur in many engineering structures due to the initiation and growth of cracks. Stress intensity factors are extensively used to investigate crack growth in Linear Elastic Fracture Mechanics (LEFM). In many cracked specimens, the stress singularity varies through the thickness and therefore, investigation of stress intensity factor variation in crack front and determination of its maximum value becomes important. In this study, mode I stress intensity factor (KI) variation in different sections of crack front is investigated using finite element method for three typical fracture test specimens. Then, these variations were compared with the result of two-dimensional analytical values. The results show that the stress intensity factor variations are independent with the thickness for all the specimens. Marked discrepancies are shown between the maximum values of stress intensity factors in crack front and those of obtained from two-dimensional analysis.