Abstract: Total transient stress, which is the sum of residual, mechanical and thermal stresses, is calculated. Transient stresses are estimated using compressor discharge temperature and pressure, the rotational speed of the component and the elapsed time from the beginning of a transient. By using a general stress calculation, the total stress at the end of transients at each location in the rotary part being measured can be calculated. Maximum and minimum stress peaks are recorded for the transients and stress intensity factors for each location are calculated. Crack propogation is then calculated based on the stress intensity factors and the remaining life of the machine can then be calculated using new assumed crack length and design cycle of the machine.