Determination of static strength and fracture of aged aircraft structure using non-destructive quasi-static indentation test

Due to the impossibility of performing destructive tests, the need for new and Non-Destructive Tests (NDT) in this area is strongly felt. In the present study, using the non-destructive method of Automated Ball Indentation (ABI) test method, some mechanical properties of 4340 annealed steel and 7075 raw aluminum and prepared from aged aircraft are determined. To perform calculations related to ABI method, the explicit relations routine was coded in FORTRAN and verified. Then samples of uniaxial tensile test of 4340 annealed steel and 7075 raw aluminum and prepared from aged aircraft are prepared and their stress-strain curves are obtained. Also, ABI tests are performed on 4340 annealed steel samples and 7075 raw aluminum and prepared from aged aircraft and the results of the two methods were compared. The comparison of results showed that the calculated error of yield strength and ultimate strength was less than 9 and 14%, respectively. With increasing force, this value in some areas reached less than 0.7%.