Assessment of the crack development in the turbine blade with a change in radial acceleration

The study is devoted to the assessment of the development of an existing crack in the working blade of a gas turbine by the finite element method. A transverse crack in the root section of the working blade was modeled, the crack mouth passed perpendicular to the median line of the blade cross section. By the method of half division, the crack length was increased to half the median length of the cross section. It was necessary to evaluate the change in the stress state in the blade at different values of the relative crack length, as well as with a change in centripetal acceleration. The least squares method was used to obtain the dependencies of the studied parameters. The study is of great practical importance in order to predict the growth of existing cracks in the operating mode of the blade. According to the results obtained, with an increase in the relative crack length, the stress state increases non-linearly. With increasing centripetal acceleration, the stress state increases linearly. The blades with the longest crack length reach the limit values corresponding to the yield strength and ultimate strength of the material faster at low accelerations. Since the study required the calculation of the stress-strain state at different values of centrifugal force and different relative crack lengths, the results of the study can be widely used in the development of systems and technologies for detecting damage in the working blades of gas turbines, which will improve the safety of their operation in aviation and marine engineering.