CRACK INITIATION AND GROWTH-BEHAVIOR OF AL 2024-T4 UNDER FRETTING FATIGUE

A fretting fatigue experiment is conducted with Al 2024-T4 pad and spe cimen. A pad has a rectangular foot for simulating punch pressure on t he contact surface of the specimen. Fretting fatigue cracks are monito red and analysed by image processing. The crack initiation sites and o bliquities are examined. The behaviour of the crack growth rate is als o shown. An analysis is carried out along the mid plane of specimen to deal with a plane strain condition. The elastic solution of square pu nch is utilized to estimate the crack initiation site with assuming th e elastic-perfectly plastic behaviour of material. The predictions are in good agreement with the experimental data. The surface traction fi elds are suggested,from which stress intensity factors are evaluated. Copyright (C) 1997 Elsevier Science Limited.