Consolidated derivation of fracture mechanics parameters and fatigue theoretical evolution models: basic review

Presence of cracks lead to structural steels failure below critical yield strength. The primary aim of the present article is to simplify and consolidate mathematical derivation of stress concentration, fracture stress, stress intensity factor, crack tip opening displacement and J-integral parameters from the first principle as well as application to fatigue. The review explains the mathematical derivation of fracture mechanics parameters from the theoretical concept, including alternatives to fatigue life prediction with strain-based approach method. The stress concentration around a notch can only be performed if the radius of the notch is far greater than zero and the stress field at sharp crack shows singularity when the crack tip radius is equal to zero. Furthermore, blunted crack tip violates stress singularity, while the crack tip opening displacement and J-integral parameters show the solution of a crack extending beyond zero crack tip radius, thus are used to characterize material stress fields with blunted crack tip. The review highlights benefit of characterizing fatigue crack growth with J-integral and crack tip opening displacement parameters over stress intensity factor. This paper would benefit majorly engineers and specialists in nuclear, aviation, oil and gas industries.