The effect of first nonsingular stress term of elastic stress field on fracture toughness around bi-material notch tip is studies in this paper. First, a modified maximum tangential stress criterion (MMTS) is proposed for determination of the fracture toughness at the tip of the interface notches. The proposed criterion takes into account the effect of first nonsingular stress term as well as the singular stress terms. Then, the effect of I-stress on determination of the fracture toughness is studied analytically. Finally, the proposed criterion is applied on a finite element (FE) simulated laboratory specimen. A very good correlation was observed between the FE results and theoretical predictions.

A land-based gas turbine may operate at the different environment including corrosive and dusty environments. These conditions can cause early damages in the “cold” parts as well as in the “hot” parts of the gas turbine. In this research, fatigue life of a compressor blade is predicted with and without damages. Damage is considered as a notch at the blade and is classified as three types of short, medium and long notches. These are numerically simulated in the compressor blade and fatigue crack initiation life is calculated. Stress analysis is carried out using finite element analysis followed by fatigue life calculations. Furthermore, the influence of blade tip displacement on life of the undamaged and damaged blade is investigated. Moreover, the effect of damage & apos; s size and location on blade’s life is reported. This procedure can be tuned with corrosion damages observed during the minor inspection where the gas turbines are operating in the unusual environments.