Fatigue behaviour of mechanically fastened aluminium joints tested in spectrum loading

The objective of the present work was to investigate the fatigue behaviour of single overlap mechanically fastened aluminium joints tested in FALSTAFF spectrum. In order to induce varying degrees of fatigue damage, three joints were loaded with different number of spectrum blocks. Strain gauges were used to measure strain distribution between bolt rows and to determine the degree of secondary bending at certain points. Two instrumented bolts were employed to measure their axial and shear response during loading. The load transfer between the bolt rows was calculated using the measured strain distributions. The achieved results were then compared with the ones obtained from measurements done on the instrumented bolts. The overall test results indicated that the friction wear between the joint parts significantly affected the fatigue behaviour of the inspected joints.