Numerical Simulation of the Natural Frequencies Dependence of Turbine Blade Vibrations on Single-Crystal Anisotropy

The subject of study of this article is one of the key tasks that appear in the development and operation of advanced aircraft gas turbine engines, namely the problem of ensuring the dynamic strength of their parts. Dynamic strength directly impacts the reliability and service life of the engine since most defects are caused by dynamic stresses from jump-like loads that increase significantly under resonance conditions. The turbine blades are one of the most highly loaded engine parts. At the design stage, it is necessary to evaluate and prevent the possibility of resonant vibrations of these blades throughout the entire range of operation of the aircraft gas turbine engine. To regulate the frequency characteristics of the blades to prevent dangerous resonant mode shapes of vibrations that arise from different harmonics of the exciting force, it is necessary to carry out a complex of various technological or structural changes. One of the most progressive and used methods for manufacturing turbine blades is single-crystal casting, which produces monocrystals with anisotropic properties. In this study, the authors developed a method for determining the elastic characteristics of a single crystal when the crystallographic system of directions is rotated. With the help of finite-element analysis, the dependence of its natural frequencies and mode shapes on elastic constants of a single crystal was investigated on the example of a typical blade model. Calculations were carried out using the ANSYS software package and the Maple computing complex.