Abstract
Impellers and blades are the key components of turbomachines, and fatigue is the main failure mode of impellers and blades. The status and progress of fatigue research on impellers and blades were systematically introduced through reviewing fatigue failures, numerical simulations of fatigue, and fatigue tests of impellers and blades in several typical turbomachines. High cycle fatigue caused by vibration was the main failure mechanism, and fatigue cracks usually initiated from the location of stress concentration. The resonance caused by the aerodynamic load was the main cause of fatigue failure of impellers and blades in a steady operating condition. The coupling of the meshless method and the finite element method and the combined fatigue test of actual impellers and blades are the developmental direction and research focus of the future.
1. Introduction
Turbomachines play an important role in heavy industry, and have been widely used as the core driving force in aviation, energy, oil refining, petrochemical, coal chemical, natural gas transportation, metallurgy, and other important areas. The failures of impellers and blades (I&B) which are the key components of turbomachines not only cause significant economic losses to enterprises and society, but also threaten people's lives. In addition, there are many fundamental scientific problems about the failures of I&B. Therefore, research on failures, especially on fatigue, which is the main failure mode of I&B, provides references for the design, manufacture, application, inspection, monitoring, and remanufacturing of I&B. Moreover, the study of the fatigue of I&B is beneficial to guarantee the safe operation of turbomachines and gives supports to intense research on relevant fundamental scientific problems.
5. Conclusions
It can be concluded that:
(1) High cycle fatigue caused by vibration is the main failure mechanism of I&B. Fatigue failures of I&B are induced by the structure, material defect, processing techniques, corrosion, erosion, FOD, and other causes. Fatigue cracks usually initiate from the location of stress concentration. Fatigue failures of I&B can be prevented from aspects of design, material, manufacture, assembly, operation, and overhaul.
