Experimental Determination of Stress Intensity Factor Distributions in Engineering Problems

Following a brief introduction of the concept of stress intensity factor from fracture mechanics and the frozen stress method from photoelasticity, an algorithm is developed from fracture mechanics equations and the stress-optic law for converting stress fringe measurements into a form useful for determining the stress intensity factor. This algorithm covers all three local modes of deformation and is used to analyse frozen stress slices along the border of cracks to obtain distributions for stress intensity factors K₁, K₂ and K₃. The use of the method is illustrated by three examples from practical engineering problems and results are compared with the literature where possible.