Fretting fatigue of Ti-6Al-4V under flat-on-flat contact

A fretting fatigue test system has been developed to simulate the fretting fatigue damage that occurs in turbine engine blade attachments. The test system employs a flat-on-flat contact with blending radii, which reproduces the nominal levels of normal and internal shear stresses present in dovetails. These stress states are achieved through the application of the normal loads required to grip a fatigue specimen coupled with the cyclic axial loads used to generate fatigue data. Successful fretting tests have been conducted as evidenced by the characteristic fretting damage and failure locations observed in test specimens. In addition, variations in test parameters produced notable trends in stresses required for constant lives of 10(7) cycles for design. Fractography is used to determine crack initiation sites and to evaluate the extent of fretting damage. (C) 1999 Elsevier Science Ltd. All rights reserved.