Comparative fatigue tests on light alloy lugs with normal and with expanded holes

摘要

Programme fatigue tests and constant-amplitude tests were carried out on lugs (K. = 3.5) from 2024 and 7075 material. Normal lugs and lugs with 3 % expanded holes were tested. Variables studied were:remachining of the expanded hole, mean stress and type of alloy. Considerations on residual stresses, applied stresses, stress gradients and crack growth are given to explain the trends observed.