Crack path under fretting wear/fatigue
José Alexander Araújo, Universtiy of Brasília, Brazil
Sabrina Vantadori, University of Parma, Italy
Keywords: crack path, fretting wear, fretting fatigue, fretting crack orientation
Many engineering assemblies of great practical interest, such as riveted or bolted connections, dovetail joints of turbine blade/disc fixings, and overhead conductors/suspension clamps are subjected either to fretting fatigue or fretting wear. The term fretting denotes a minute movement between two solid surfaces in contact and the surface degradation, which occurs due to this motion, is called fretting damage. Mechanical parts under fretting due to vibration experience a rapid variation of the magnitude and relative contribution of the stress components away from the surface. Further, multiaxial non-proportional stress histories are present and some loss of material is involved. These features of the fretting problem pose a substantial difficulty for the modeling of the early cracking orientation in the vicinity of the contact surface. Two important mechanical problems may arise from this phenomenon: (i) fretting wear, which may lead to the loosening of joints demanding the replacement of parts and (ii) fretting fatigue, that may occur if one or both components of the assembly carry a bulk fatigue load (evidences have shown that the conjoint action of fretting and fatigue may produce strength reduction factors varying from 2 up to 10). For both cases, a further understanding of the crack path formation, mainly at its early stages, is of utmost importance to try to capture the relevant mechanical/tribological quantities that govern the problem. This thematic symposium aims to join worldwide scientists and engineers from the academic and industrial sectors to present new data, modeling and numerical work on crack path studies under fretting conditions of mechanical assemblies.