Prediction of the Resonant Fatigue Residual Life of Stiffened Panel by Measuring Frequency

Stiffened panels are apt to fatigue failure in the resonance. In this process, the dynamic characteristics will change with crack propagation. The solo crack propagation life of the typical stiffened panel is studied on the basis of synthetic research of testing and calculation in this paper. Some models with different length of crack are built to simulate the route of crack propagation, then the relation between the crack length, normal modes, stress intensity factors and residual life of the stiffened panel structure can be obtained by dynamic simulation. The resonant fatigue residual life can be predicted by measuring the mode frequency of the structure after these relations are known. An example of the typical stiffened panel structure made of LY12CZ is studied by testing and calculation in the paper. The results prove that the method can be used to monitor structural dynamic damage and predict residual life.