Efficient Computation Method for Total Fatigue Life of Aircraft Structural Components

The primary focus of this study is the development of efficient calculation methods and application software for the fatigue strength analysis of aircraft structural elements. This primarily indicates the long life of aircraft structure elements exposed to the spectrum of cyclical loads. Therefore, the total fatigue life can be divided into two parts: the first until the appearance of the initial damage, and the second after the appearance of the initial damage, that is, crack propagation. The conventional approach uses small-cycle fatigue characteristics to estimate the life until the appearance of an initial crack and dynamic characteristics to analyze crack propagation. In order to avoid very expensive and time-consuming tests, the Strain Energy Density (SED) method was used here, which uses the same low-cycle characteristics for both appearance and crack propagation. The Finite Element Method (FEM) was used to assess the life of complex constructions, such as aircraft, for the analysis of the stress state. By combining the SED method with FEM for stress state analysis, a reliable and efficient method for estimating the total life of aircraft structural elements is obtained. The results show that the predicted results agree well with the test data.