Reconstruction of fan blade dynamic loading prior to its fracture

To maintain the functionality of fan blades, it is important to know distribution dynamic stresses in blade, their amplitude and vibration frequency. Understanding loading pattern will allow us determine under what conditions engine was operated, identify prevent emergencies that could lead blade fracture. The purpose this work understand cause fracture occurred during ground start. Due fractographic analysis fragments revealed due initiation fatigue cracks blades. place crack parameters growth were established, spectral carried out. establish reason necessary state blades destruction. sections second stage stable growth, which striations are formed, determined using method. Using spacing Paris's law, stress intensity range determined. Modeling propagation out define state. ability factor at each step its comparison with research data made possible. simulation showed manifold increase occurs possible obtain expected value amplitude. Additional modal a resonant form caused nature propagation. demonstrated approach established