Abstract—Geometric discontinuities cause a large variation of stress and produce a significant increase in stress. The stress at any discontinuity is higher than the normal stress in the machine element. This high stress is known as stress concentration. There are many investigators who have studied the stress distribution around the notches, groove, and other irregularities of various machine components. The present research work analyses the effects of thermal and fatigue load on a steam turbine blade under the operating conditions. Stresses due to thermal and dynamic loads of High Pressure Steam Turbine blade of 210 MW power stations are analyzed in two stages. In first stage a three dimensional model of turbine blade was prepared in Pro-E. This model was imported in ANSYS-11 for Finite Element Analysis. A source code is developed for calculating the nominal stress at each section of HPT blade. Maximum stress is obtained using Finite Element Analysis (FEA) at the corresponding section. Thermal and Fatigue Stress Concentration Factors at each section are calculated. It is observed that the SCF due to the combined effect of thermal and dynamic loads at the temperatures beyond 540 °C is exceeding the safe limits.

Index Terms—Stress concentration factor, FEM, Steam turbine blade

Cite: Sandip G Ghugal, Rajendra K Pohane and Sandeep M Pimpalgaonkar, "Determination of Stress Concentration Factor in Steam Turbine Blade by Finite Element Method," International Journal of Mechanical Engineering and Robotics Research, Vol.2 No.3, pp. 55-60, July 2013.