Increasing the accuracy of estimates of numerical prediction of fatigue life of highly zones aircraft structures using the modified fatigue curves
Domestic and foreign companies in the calculation of resource widely used correction factors that take into account structural and technological features of a real aircraft structure. The results of the fatigue life according to traditional methods based on the use of correction factors do not correspond to the results of the fatigue life at bench trials. Studies have been conducted to improve the traditional method of calculating the resource using the modified fatigue curves. Depending on the theoretical stress concentration factor, the thickness of the sample, the test temperature, manufacturing techniques and so forth were obtained modified fatigue curves for different designs. Calculation of fatigue life using the modified fatigue curves carried out according to traditional methods, but to account for the structural and technological factors was the correction of fatigue curves based on relationships obtained in the analysis of changes in the regression coefficients. The proposed technique is checked when calculating the fatigue life of structural elements of the military, civilian and light aircraft. In carrying out the numerical analysis were developed finite-element models that reflect the design features of structural elements. Calculated loading was carried out in accordance with the Program conducted the experiment. Correctness of numerical studies confirmed the results of bench tests of structural elements of aircraft. Calculation durability using modified fatigue curves increases the accuracy of more than 2 times.