航空发动机叶片掉角故障疲劳机理试验方法研究

Fatigue Mechanism Experiment Method of Blade Fracture Failure in Aero-engine

针对航空发动机叶片掉角故障,提出了一种采用叶片模拟试件进行高阶弯扭复合共振开展疲劳机理试验研究的方法。通过有限元模态分析,优化设计了一种方形平板叶片模拟试件,开展了高阶弯扭复合共振疲劳试验研究,验证了试件模拟叶片掉角故障的可行性。结果表明:模拟试件在"双扭弯曲复合"振型下进行共振试验可模拟引起掉角故障的高阶弯扭复合振型。在开展共振疲劳试验时,发现试件存在复杂的非线性振动特性,该特性对进行共振疲劳试验有重要影响。制定的疲劳裂纹判定方法可准确有效获得共振疲劳试验数据。

Aiming at the blade fracture failure of the aero-engine, a testing methodology for researching the fatigue mechanism is proposed, in which the square plate specimen is designed by FEM (finite element modal) analysis, as the simulation of the blade, is driven into the high order composite bending-torsional mode by base excitation. The results show that the high order composite bending-torsional mode which causes the blade fracture failure can be effectively simulated by the composite double-torsional and bending mode of the specimen in the resonant test. At the resonant fatigue test, complex nonlinearity is appeared in the vibration of the specimen, which significantly affects the progress of the experiment. The data of the resonant fatigue experiment results can be accurately determined by the crack criterion developed for the specimen, which confirms that it's feasible to simulate the blade fracture failure with the specimen.