Cracking analysis of an aero-engine combustor

Failure analysis on an aero-engine combustor is carried out for the cranking failure of combustor liner during its service period. Crack macroscopic observation and microscopic observation are performed. Fluid-structure coupling simulation of aero-engine combustor under typical working conditions is carried out to obtain the temperature distribution of combustor using a CFD commercial code, ANSYS FLUENT. Based on the results of fluid-structure coupling simulation, nonlinear statics analysis of the aero-engine combustor liner is carried out using a commercial code, MSC/NASTRAN. The visual inspection results show that obvious fatigue characteristics are found at fractures, and fatigue is responsible for observed cracks. The simulation results show that the maximum plastic strain of the combustor is located at the edge of the mixing holes near the two cracks. The maximum plastic strain is 0.4476%, 0.4154% respectively. During aero-engine's service period, the start and stop of engine would cause cyclic loading of plastic strain, which give rise to fatigue damage and fatigue damage leads to cracking of combustor.