| Aviation engine compressor blade is one of the key components of engine, will be affected by the interaction of a variety of load in the service process. High-cycle fatigue is one of the most important failure modes of blade because of the substantial increase in stress level of modern aviation engine compressor blade. When the blade fatigue cracks appear in the service process, maintenance personnel cannot determine the residual life of the blade and arrange the maintenance period of time to ensure that the blade can be replaced before the fracture failure.The three-dimensional point cloud data of blade can be obtained by the3D scanner in the study. The3D solid model can be modeled by UG based on the initial treatment by using reverse engineering software Geomagic Studio. The finite element model is established via pre-processing software Hypermesh. Finally, the stress distribution of blade can be obtained with the method of static’s analysis in the MSC.Patran&MSC.Nastran software. The fatigue life and crack growth analysis of blade also can be obtained by MSC.Fatigue software which is the professional software of fatigue.On the view of the blade with crack defects, the finite element analysis of the blade was carried out firstly. On this basis, the relationship between fatigue life and the stress concentration and the mean stress of the blade is discussed. The fatigue life of blade can be estimated by the S-N curve of materials, the Miner linear fatigue cumulative damage theory and Goodman mean stress correction method. At the same time, the different mean stress correction will have different impact on the fatigue life of the blade.This thesis discusses the calculation method of the stress intensity factors, the stress intensity factors of the blade crack tip can be calculated by three-dimensional finite element method and1/4-point distance-extrapolation method.This thesis researched the calculation method of crack propagation life of the blade according to crack growth analysis based on the liner elastic fracture mechanics, and crack growth analysis can be realized by MSC.Fatigue software. The relational curve between the length of crack and cycle index and the relationship between crack growth rate and the length of crack can be obtained in the results. The crack propagation life will be different with the different initial crack size. It shows that the initial crack size is very important to the crack growth analysis. |
PDF Full Text Request