Fracture Failure Analysis on Engine Turbine Blade

An engine of an aircraft suddenly stopped working,the damage of all the low-pressure turbine blades and the fracture from roots of all the high-pressure turbine blades were found after checking up. The first broken blade was confirmed after fracture macro analysis on all the low-pressure and high-pressure turbine blades,and the character of the blade fracture was fatigue fracture. By fracture micro analysis on the first broken blade,fatigue characteristic and development process of the crack were researched. The cause of the blade fracture was due mainly to the fact that the larger total gaps of up-marginal and under-marginal lead to abnormal vibration of the blade,so centrifugal stress with vibration stress made the blade break in the work process.