Fatigue Life Prediction of the High Lock Bolts in Aircraft Connection Structure

For high lock bolt in aircraft connection structure, a new method is proposed to approximate real experiment values with high accuracy to predict the fatigue life. In the method, the computation algorithms of the nominal stress method and the Goodman correction method are introduced. To calculate the stress amplitude under different life and fit the fatigue S-N curve of the test piece, different stress concentration coefficients are calculated and the life of two typical bolt structure is estimated using the theory of Miner damage. With the application of the principle of damage equivalence to the results, the life values under multiple load are converted into those in single load. Then, the calculation results are compared with the real fatigue test results, which shows that the fatigue life of the bolt structure obtained by the numerical calculation has high precision. Therefore, fatigue life of the high lock bolts can be predicted through the proposed methods to provide guidance for the structure design.