Research on the Random Sonic Fatigue Life Estimation of a Combustor Liner Structure

As to the sonic fatigue problem of aero-engine combustor liner structure, by applying the coupled boundary element and finite element method, the Power Spectrum Density (PSD) of the vibrational stress response of an combustor liner structure to random acoustic loadings is calculated. And the critical stress concentration areas of the structure are determined according to the Von Mises stress distribution. On the basis of this, based on Miner fatigue damage cumulative theory, the probability density function of the Von Mises stress peak process are fitted at first, then by applying the rainflow counting (RFC) cycles method and so called the method of probability density function of Von Mises stress respectively, the sonic fatigue life of an aero-engine combustor liner structure is estimated. The results show that the two methods are both effective for calculating the random sonic fatigue of the structure, and comparing with the RFC method, the estimated results of sonic fatigue of the combustor liner structure by using the method of probability density function of Von Mises stress are more conservative to some extend. The work represented in this paper is of a reference value both to the fatigue faults analysis and the anti-sonic fatigue structure design of a combustor liner.