Abstract: Cracks are inevitable during the service of aeroengine hot-end components. The accurate prediction of crack behaviour is of great significance for service safety and life management, thus there is a great demand for research on the behaviour of three-dimensional cracks on hot end components. Focusing on the structure of the aero-engine hot-end components, the three-dimensional crack theories under complex geometry and stress conditions are systematically summarized from numerical application, and the key technologies employed in numerical analysis are studied. By solving the stress intensity factor components of mixed-mode cracks and selecting the appropriate crack growth path criterion, the complicated three-dimensional crack behaviour is simulated. The type of element around crack tip affect the accuracy of the calculation, and the accuracy of the three-dimensional crack parameter solution is ensured by controlling the feature size of the singular element. In order to obtain the evolution of the crack front curve in the simulation, the "point-by-point" node increment method is used as an updating strategy to reconstruct the new crack front. At the same time, the use of a three-layer element ring structure around crack tip ensures a stable remesh. By comparing the analytical method of surface cracks and numerical results, the accuracy of the method to solve the crack driving force parameters is verified. Finally, using the high pressure turbine blade as an example, the law of crack propagation at different positions of the turbine blade is obtained by numerical simulation.

Key words: 3D crack, aeroengine hot-end components, characteristic size of singularity element, crack front remodeling, mixed-mode crack, node increment method, numerical approach